ROAD AGGREGATESROAD AGGREGATES

ROAD AGGREGATESROAD AGGREGATES

bull Man has used sand and stone for foundations for thousands of years Significant refinement of the production and use of aggregate occurred during the Roman Empire which used aggregate to build its vast network of roads and aqueducts

Aggregates forms the major part of Aggregates forms the major part of pavement structurepavement structure

bull All bituminous and concrete surfacing are principally composed of aggregatesthey play an important role in the behavior of the pavement surfacing

bull Woodrsquos definitionWoodrsquos definition - Aggregate is an aggregation of sandgravelstoneslag or any other materialin combination with some cementing material attains higher engineering properties and form highway materials like WBMBM etc

bull Road aggregate or simply ldquoaggregate is a broad category of coarse particulate material used in construction including sand gravel crushed stone slag recycled concrete and geosynthetic aggregates

bull Aggregates are a component of composite materials such as concrete and asphalt concrete the aggregate serves as reinforcement to add strength to the overall composite material

bull Aggregates are widely used in drainage

applications such as foundation drains retaining wall drains and road side edge drains Aggregates are also used as base material under foundations roads

ClassificationClassification

bull 1) Origin - Natural aggregates - Igneous rocks grain size gt 2mm - coarse

bull 2 to 02mm - medium

bull lt 02mm - fine

bull Composition Acidic gt 66 of silica

bull Intermediate 55 to 66 silica

bull Basic lt 55 silica

Sedimentary rocks - classified as per predominating material

bull Calcareous Siliceous ArgillaceousCalcareous Siliceous Argillaceousbull Chalklimestone sandstone clayshell etc bull dolomite Flintchertbull Metamorphic rocksbull Artificial aggregate - by product of industrial

processes ex Blast furnace slagbull 2) Strength - Hard aggregate - granitebasaltbull Soft aggregate - cankermoorum

etc

bull 3) Shape of aggregate CubicalRoundAngularFlaky amp Elongated

bull 4) Grading bull Open graded -when some particular type and size is

usedbull Dense graded - different size and shape of aggregates

are usedbull Skip graded - if a particular size is missingbull Uniformly graded - if all the particles are of same sizebull 5) Size bull C A - gt 236 mm F A - passing 236 mm

retained on 75 micronbull Filler - passing 75 micron

bull

Desirable properties of aggregatesDesirable properties of aggregatesbull 1) Resistance to crushing 1) Resistance to crushing

bull 2) Resistance to abrasion2) Resistance to abrasion

bull 3) Resistance to impact3) Resistance to impact

bull 4) Good shape4) Good shape

bull 5) Water absorption5) Water absorption

bull 6) Resistance to weathering6) Resistance to weathering

bull 7) Good adhesion7) Good adhesion

bull 8) Surface texture8) Surface texture

bull 9) Porosity9) Porosity

bull 10) Surface chemistry10) Surface chemistry

bull Aggregate Characterization

bull 1048710 Aggregate Physical Properties

bull 1048710 Maximum Aggregate Size

bull 1048710 Gradation

bull 1048710 Other Aggregate Properties

bull 1048710 Toughness and Abrasion Resistance

bull 1048710 Specific Gravity

bull 1048710 Particle Shape and Surface Texture

bull 1048710 Durability and Soundness

bull 1048710 Cleanliness and Deleterious Materials

bull IS2386-1963 Methods of test for aggregates

bull Part 1 Particle size and shape

bull Part 2 Estimation of deleterious materials and organic impurities

bull Part 3 Specific gravity density voids absorption and bulking

bull Part 4 Mechanical properties

bull Part 5 Soundness

Aggregate Gradation IS2386-1963 Part IThe gradation and size test (Figure 1) is used to determine aggregate particle size distribution Size distribution is perhaps the single most important aggregate quality associated with the control of HMA mixtures Aggregate gradation and size affect HMA volumetric properties as well as mixture permeability and workability

bull In a gradation and size analysis a sample of dry aggregate of known weight is separated through a series of sieves with progressively smaller openings

bull Once separated the weight of particles retained on

each sieve is measured and compared to the total sample weight

bull Particle size distribution is then expressed as a percent retained by weight on each sieve size

bull The particle size distribution or gradation of the constituent aggregate is one of the most influential characteristics in determining how an aggregate mixture will perform as a pavement material

bull Aggregate gradation influences almost every important property including stiffness stability durability permeability workability fatigue resistance skid resistance and resistance to moisture damage (Roberts et al 1996)

bull Gradation is often expressed in graphical form Typically gradation graphs use concepts of maximum density gradation and its expression in equation form to plot a special graph referred to as the FHWA (Federal Highway Administration) 045 power graph

bull Maximum Density Gradation bull Theoretically there exists a particular gradation

that for a given maximum aggregate size will produce the maximum density

bull This gradation would involve a particle arrangement where successively smaller particles are packed within the voids between larger particles

bull If done ideally this would result in a minimum void space between particles and produce a maximum density

bull Practically an aggregate gradation of

maximum density is not desired because a certain amount of void space is required to provide adequate volume for the asphalt binder to occupy

Fuller and Thompsons Equation (Interactive Equation)

bull Regardless of its practical use a maximum density gradation provides a convenient reference In 1907 Fuller and Thompson developed a widely used equation to describe a maximum density gradation for a given maximum aggregate size

Where P = percent finer than an aggregate size

d = aggregate size being considered D = maximum aggregate size

n = parameter which adjusts curve for fineness or coarseness (for maximum

particle density n asymp 05 according to Fuller and Thompson)

The 045 Power Maximum Density Graph bull In the early 1960s the FHWA introduced the

standard gradation graph used in the HMA industry today

bull This graph uses Fuller and Thompsons equation with n = 045 and is convenient for determining the maximum density line and adjusting gradation (Roberts et al 1996)

bull This graph is slightly different than other gradation graphs because it uses the sieve size raised to the nth power (usually 045) as the x-axis units Thus a plot of Fuller and Thompsons maximum density equation with n = 045 appears as a straight diagonal line

bull This straight line goes from zero to the maximum aggregate size for the gradation being considered There is some debate as to whether this line should end at maximum aggregate size or nominal maximum aggregate size or somewhere in between however the most commonly accepted practice is to end it at the maximum aggregate size

To illustrate how the maximum density curves was determined Table shows the associated calculations for a

maximum aggregate size of 190 mm

Calculations for a 045 Power Gradation Curve Using 190-mm (075-inch) Maximum Aggregate Size

Desired Gradation

bull Gradation has a profound effect on material performancebull What is the best gradation

bull The answer to which will vary depending upon the material (HMA or PCC) its desired characteristics loading environmental material structural and mix property inputs

bull The best gradation is one that produces the maximum

density bull A particle arrangement where smaller particles are packed

between the larger particles which reduces the void space between particles

bull This creates more particle-to-particle contact which would increase stability and reduce water infiltration

Desired Gradation

bull Some minimum amount of void space is necessary to

bull Provide adequate volume for the binder (asphalt binder or portland cement) to occupy

bull Promote rapid drainage and resistance to frost

action for base and subbase courses

bull Therefore although it may not be the best aggregate gradation a maximum density gradation does provide a common reference

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

ROAD AGGREGATESROAD AGGREGATES

bull Man has used sand and stone for foundations for thousands of years Significant refinement of the production and use of aggregate occurred during the Roman Empire which used aggregate to build its vast network of roads and aqueducts

Aggregates forms the major part of Aggregates forms the major part of pavement structurepavement structure

bull All bituminous and concrete surfacing are principally composed of aggregatesthey play an important role in the behavior of the pavement surfacing

bull Woodrsquos definitionWoodrsquos definition - Aggregate is an aggregation of sandgravelstoneslag or any other materialin combination with some cementing material attains higher engineering properties and form highway materials like WBMBM etc

bull Road aggregate or simply ldquoaggregate is a broad category of coarse particulate material used in construction including sand gravel crushed stone slag recycled concrete and geosynthetic aggregates

bull Aggregates are a component of composite materials such as concrete and asphalt concrete the aggregate serves as reinforcement to add strength to the overall composite material

bull Aggregates are widely used in drainage

applications such as foundation drains retaining wall drains and road side edge drains Aggregates are also used as base material under foundations roads

ClassificationClassification

bull 1) Origin - Natural aggregates - Igneous rocks grain size gt 2mm - coarse

bull 2 to 02mm - medium

bull lt 02mm - fine

bull Composition Acidic gt 66 of silica

bull Intermediate 55 to 66 silica

bull Basic lt 55 silica

Sedimentary rocks - classified as per predominating material

bull Calcareous Siliceous ArgillaceousCalcareous Siliceous Argillaceousbull Chalklimestone sandstone clayshell etc bull dolomite Flintchertbull Metamorphic rocksbull Artificial aggregate - by product of industrial

processes ex Blast furnace slagbull 2) Strength - Hard aggregate - granitebasaltbull Soft aggregate - cankermoorum

etc

bull 3) Shape of aggregate CubicalRoundAngularFlaky amp Elongated

bull 4) Grading bull Open graded -when some particular type and size is

usedbull Dense graded - different size and shape of aggregates

are usedbull Skip graded - if a particular size is missingbull Uniformly graded - if all the particles are of same sizebull 5) Size bull C A - gt 236 mm F A - passing 236 mm

retained on 75 micronbull Filler - passing 75 micron

bull

Desirable properties of aggregatesDesirable properties of aggregatesbull 1) Resistance to crushing 1) Resistance to crushing

bull 2) Resistance to abrasion2) Resistance to abrasion

bull 3) Resistance to impact3) Resistance to impact

bull 4) Good shape4) Good shape

bull 5) Water absorption5) Water absorption

bull 6) Resistance to weathering6) Resistance to weathering

bull 7) Good adhesion7) Good adhesion

bull 8) Surface texture8) Surface texture

bull 9) Porosity9) Porosity

bull 10) Surface chemistry10) Surface chemistry

bull Aggregate Characterization

bull 1048710 Aggregate Physical Properties

bull 1048710 Maximum Aggregate Size

bull 1048710 Gradation

bull 1048710 Other Aggregate Properties

bull 1048710 Toughness and Abrasion Resistance

bull 1048710 Specific Gravity

bull 1048710 Particle Shape and Surface Texture

bull 1048710 Durability and Soundness

bull 1048710 Cleanliness and Deleterious Materials

bull IS2386-1963 Methods of test for aggregates

bull Part 1 Particle size and shape

bull Part 2 Estimation of deleterious materials and organic impurities

bull Part 3 Specific gravity density voids absorption and bulking

bull Part 4 Mechanical properties

bull Part 5 Soundness

Aggregate Gradation IS2386-1963 Part IThe gradation and size test (Figure 1) is used to determine aggregate particle size distribution Size distribution is perhaps the single most important aggregate quality associated with the control of HMA mixtures Aggregate gradation and size affect HMA volumetric properties as well as mixture permeability and workability

bull In a gradation and size analysis a sample of dry aggregate of known weight is separated through a series of sieves with progressively smaller openings

bull Once separated the weight of particles retained on

each sieve is measured and compared to the total sample weight

bull Particle size distribution is then expressed as a percent retained by weight on each sieve size

bull The particle size distribution or gradation of the constituent aggregate is one of the most influential characteristics in determining how an aggregate mixture will perform as a pavement material

bull Aggregate gradation influences almost every important property including stiffness stability durability permeability workability fatigue resistance skid resistance and resistance to moisture damage (Roberts et al 1996)

bull Gradation is often expressed in graphical form Typically gradation graphs use concepts of maximum density gradation and its expression in equation form to plot a special graph referred to as the FHWA (Federal Highway Administration) 045 power graph

bull Maximum Density Gradation bull Theoretically there exists a particular gradation

that for a given maximum aggregate size will produce the maximum density

bull This gradation would involve a particle arrangement where successively smaller particles are packed within the voids between larger particles

bull If done ideally this would result in a minimum void space between particles and produce a maximum density

bull Practically an aggregate gradation of

maximum density is not desired because a certain amount of void space is required to provide adequate volume for the asphalt binder to occupy

Fuller and Thompsons Equation (Interactive Equation)

bull Regardless of its practical use a maximum density gradation provides a convenient reference In 1907 Fuller and Thompson developed a widely used equation to describe a maximum density gradation for a given maximum aggregate size

Where P = percent finer than an aggregate size

d = aggregate size being considered D = maximum aggregate size

n = parameter which adjusts curve for fineness or coarseness (for maximum

particle density n asymp 05 according to Fuller and Thompson)

The 045 Power Maximum Density Graph bull In the early 1960s the FHWA introduced the

standard gradation graph used in the HMA industry today

bull This graph uses Fuller and Thompsons equation with n = 045 and is convenient for determining the maximum density line and adjusting gradation (Roberts et al 1996)

bull This graph is slightly different than other gradation graphs because it uses the sieve size raised to the nth power (usually 045) as the x-axis units Thus a plot of Fuller and Thompsons maximum density equation with n = 045 appears as a straight diagonal line

bull This straight line goes from zero to the maximum aggregate size for the gradation being considered There is some debate as to whether this line should end at maximum aggregate size or nominal maximum aggregate size or somewhere in between however the most commonly accepted practice is to end it at the maximum aggregate size

To illustrate how the maximum density curves was determined Table shows the associated calculations for a

maximum aggregate size of 190 mm

Calculations for a 045 Power Gradation Curve Using 190-mm (075-inch) Maximum Aggregate Size

Desired Gradation

bull Gradation has a profound effect on material performancebull What is the best gradation

bull The answer to which will vary depending upon the material (HMA or PCC) its desired characteristics loading environmental material structural and mix property inputs

bull The best gradation is one that produces the maximum

density bull A particle arrangement where smaller particles are packed

between the larger particles which reduces the void space between particles

bull This creates more particle-to-particle contact which would increase stability and reduce water infiltration

Desired Gradation

bull Some minimum amount of void space is necessary to

bull Provide adequate volume for the binder (asphalt binder or portland cement) to occupy

bull Promote rapid drainage and resistance to frost

action for base and subbase courses

bull Therefore although it may not be the best aggregate gradation a maximum density gradation does provide a common reference

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Man has used sand and stone for foundations for thousands of years Significant refinement of the production and use of aggregate occurred during the Roman Empire which used aggregate to build its vast network of roads and aqueducts

Aggregates forms the major part of Aggregates forms the major part of pavement structurepavement structure

bull All bituminous and concrete surfacing are principally composed of aggregatesthey play an important role in the behavior of the pavement surfacing

bull Woodrsquos definitionWoodrsquos definition - Aggregate is an aggregation of sandgravelstoneslag or any other materialin combination with some cementing material attains higher engineering properties and form highway materials like WBMBM etc

bull Road aggregate or simply ldquoaggregate is a broad category of coarse particulate material used in construction including sand gravel crushed stone slag recycled concrete and geosynthetic aggregates

bull Aggregates are a component of composite materials such as concrete and asphalt concrete the aggregate serves as reinforcement to add strength to the overall composite material

bull Aggregates are widely used in drainage

applications such as foundation drains retaining wall drains and road side edge drains Aggregates are also used as base material under foundations roads

ClassificationClassification

bull 1) Origin - Natural aggregates - Igneous rocks grain size gt 2mm - coarse

bull 2 to 02mm - medium

bull lt 02mm - fine

bull Composition Acidic gt 66 of silica

bull Intermediate 55 to 66 silica

bull Basic lt 55 silica

Sedimentary rocks - classified as per predominating material

bull Calcareous Siliceous ArgillaceousCalcareous Siliceous Argillaceousbull Chalklimestone sandstone clayshell etc bull dolomite Flintchertbull Metamorphic rocksbull Artificial aggregate - by product of industrial

processes ex Blast furnace slagbull 2) Strength - Hard aggregate - granitebasaltbull Soft aggregate - cankermoorum

etc

bull 3) Shape of aggregate CubicalRoundAngularFlaky amp Elongated

bull 4) Grading bull Open graded -when some particular type and size is

usedbull Dense graded - different size and shape of aggregates

are usedbull Skip graded - if a particular size is missingbull Uniformly graded - if all the particles are of same sizebull 5) Size bull C A - gt 236 mm F A - passing 236 mm

retained on 75 micronbull Filler - passing 75 micron

bull

Desirable properties of aggregatesDesirable properties of aggregatesbull 1) Resistance to crushing 1) Resistance to crushing

bull 2) Resistance to abrasion2) Resistance to abrasion

bull 3) Resistance to impact3) Resistance to impact

bull 4) Good shape4) Good shape

bull 5) Water absorption5) Water absorption

bull 6) Resistance to weathering6) Resistance to weathering

bull 7) Good adhesion7) Good adhesion

bull 8) Surface texture8) Surface texture

bull 9) Porosity9) Porosity

bull 10) Surface chemistry10) Surface chemistry

bull Aggregate Characterization

bull 1048710 Aggregate Physical Properties

bull 1048710 Maximum Aggregate Size

bull 1048710 Gradation

bull 1048710 Other Aggregate Properties

bull 1048710 Toughness and Abrasion Resistance

bull 1048710 Specific Gravity

bull 1048710 Particle Shape and Surface Texture

bull 1048710 Durability and Soundness

bull 1048710 Cleanliness and Deleterious Materials

bull IS2386-1963 Methods of test for aggregates

bull Part 1 Particle size and shape

bull Part 2 Estimation of deleterious materials and organic impurities

bull Part 3 Specific gravity density voids absorption and bulking

bull Part 4 Mechanical properties

bull Part 5 Soundness

Aggregate Gradation IS2386-1963 Part IThe gradation and size test (Figure 1) is used to determine aggregate particle size distribution Size distribution is perhaps the single most important aggregate quality associated with the control of HMA mixtures Aggregate gradation and size affect HMA volumetric properties as well as mixture permeability and workability

bull In a gradation and size analysis a sample of dry aggregate of known weight is separated through a series of sieves with progressively smaller openings

bull Once separated the weight of particles retained on

each sieve is measured and compared to the total sample weight

bull Particle size distribution is then expressed as a percent retained by weight on each sieve size

bull The particle size distribution or gradation of the constituent aggregate is one of the most influential characteristics in determining how an aggregate mixture will perform as a pavement material

bull Aggregate gradation influences almost every important property including stiffness stability durability permeability workability fatigue resistance skid resistance and resistance to moisture damage (Roberts et al 1996)

bull Gradation is often expressed in graphical form Typically gradation graphs use concepts of maximum density gradation and its expression in equation form to plot a special graph referred to as the FHWA (Federal Highway Administration) 045 power graph

bull Maximum Density Gradation bull Theoretically there exists a particular gradation

that for a given maximum aggregate size will produce the maximum density

bull This gradation would involve a particle arrangement where successively smaller particles are packed within the voids between larger particles

bull If done ideally this would result in a minimum void space between particles and produce a maximum density

bull Practically an aggregate gradation of

maximum density is not desired because a certain amount of void space is required to provide adequate volume for the asphalt binder to occupy

Fuller and Thompsons Equation (Interactive Equation)

bull Regardless of its practical use a maximum density gradation provides a convenient reference In 1907 Fuller and Thompson developed a widely used equation to describe a maximum density gradation for a given maximum aggregate size

Where P = percent finer than an aggregate size

d = aggregate size being considered D = maximum aggregate size

n = parameter which adjusts curve for fineness or coarseness (for maximum

particle density n asymp 05 according to Fuller and Thompson)

The 045 Power Maximum Density Graph bull In the early 1960s the FHWA introduced the

standard gradation graph used in the HMA industry today

bull This graph uses Fuller and Thompsons equation with n = 045 and is convenient for determining the maximum density line and adjusting gradation (Roberts et al 1996)

bull This graph is slightly different than other gradation graphs because it uses the sieve size raised to the nth power (usually 045) as the x-axis units Thus a plot of Fuller and Thompsons maximum density equation with n = 045 appears as a straight diagonal line

bull This straight line goes from zero to the maximum aggregate size for the gradation being considered There is some debate as to whether this line should end at maximum aggregate size or nominal maximum aggregate size or somewhere in between however the most commonly accepted practice is to end it at the maximum aggregate size

To illustrate how the maximum density curves was determined Table shows the associated calculations for a

maximum aggregate size of 190 mm

Calculations for a 045 Power Gradation Curve Using 190-mm (075-inch) Maximum Aggregate Size

Desired Gradation

bull Gradation has a profound effect on material performancebull What is the best gradation

bull The answer to which will vary depending upon the material (HMA or PCC) its desired characteristics loading environmental material structural and mix property inputs

bull The best gradation is one that produces the maximum

density bull A particle arrangement where smaller particles are packed

between the larger particles which reduces the void space between particles

bull This creates more particle-to-particle contact which would increase stability and reduce water infiltration

Desired Gradation

bull Some minimum amount of void space is necessary to

bull Provide adequate volume for the binder (asphalt binder or portland cement) to occupy

bull Promote rapid drainage and resistance to frost

action for base and subbase courses

bull Therefore although it may not be the best aggregate gradation a maximum density gradation does provide a common reference

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Aggregates forms the major part of Aggregates forms the major part of pavement structurepavement structure

bull All bituminous and concrete surfacing are principally composed of aggregatesthey play an important role in the behavior of the pavement surfacing

bull Woodrsquos definitionWoodrsquos definition - Aggregate is an aggregation of sandgravelstoneslag or any other materialin combination with some cementing material attains higher engineering properties and form highway materials like WBMBM etc

bull Road aggregate or simply ldquoaggregate is a broad category of coarse particulate material used in construction including sand gravel crushed stone slag recycled concrete and geosynthetic aggregates

bull Aggregates are a component of composite materials such as concrete and asphalt concrete the aggregate serves as reinforcement to add strength to the overall composite material

bull Aggregates are widely used in drainage

applications such as foundation drains retaining wall drains and road side edge drains Aggregates are also used as base material under foundations roads

ClassificationClassification

bull 1) Origin - Natural aggregates - Igneous rocks grain size gt 2mm - coarse

bull 2 to 02mm - medium

bull lt 02mm - fine

bull Composition Acidic gt 66 of silica

bull Intermediate 55 to 66 silica

bull Basic lt 55 silica

Sedimentary rocks - classified as per predominating material

bull Calcareous Siliceous ArgillaceousCalcareous Siliceous Argillaceousbull Chalklimestone sandstone clayshell etc bull dolomite Flintchertbull Metamorphic rocksbull Artificial aggregate - by product of industrial

processes ex Blast furnace slagbull 2) Strength - Hard aggregate - granitebasaltbull Soft aggregate - cankermoorum

etc

bull 3) Shape of aggregate CubicalRoundAngularFlaky amp Elongated

bull 4) Grading bull Open graded -when some particular type and size is

usedbull Dense graded - different size and shape of aggregates

are usedbull Skip graded - if a particular size is missingbull Uniformly graded - if all the particles are of same sizebull 5) Size bull C A - gt 236 mm F A - passing 236 mm

retained on 75 micronbull Filler - passing 75 micron

bull

Desirable properties of aggregatesDesirable properties of aggregatesbull 1) Resistance to crushing 1) Resistance to crushing

bull 2) Resistance to abrasion2) Resistance to abrasion

bull 3) Resistance to impact3) Resistance to impact

bull 4) Good shape4) Good shape

bull 5) Water absorption5) Water absorption

bull 6) Resistance to weathering6) Resistance to weathering

bull 7) Good adhesion7) Good adhesion

bull 8) Surface texture8) Surface texture

bull 9) Porosity9) Porosity

bull 10) Surface chemistry10) Surface chemistry

bull Aggregate Characterization

bull 1048710 Aggregate Physical Properties

bull 1048710 Maximum Aggregate Size

bull 1048710 Gradation

bull 1048710 Other Aggregate Properties

bull 1048710 Toughness and Abrasion Resistance

bull 1048710 Specific Gravity

bull 1048710 Particle Shape and Surface Texture

bull 1048710 Durability and Soundness

bull 1048710 Cleanliness and Deleterious Materials

bull IS2386-1963 Methods of test for aggregates

bull Part 1 Particle size and shape

bull Part 2 Estimation of deleterious materials and organic impurities

bull Part 3 Specific gravity density voids absorption and bulking

bull Part 4 Mechanical properties

bull Part 5 Soundness

Aggregate Gradation IS2386-1963 Part IThe gradation and size test (Figure 1) is used to determine aggregate particle size distribution Size distribution is perhaps the single most important aggregate quality associated with the control of HMA mixtures Aggregate gradation and size affect HMA volumetric properties as well as mixture permeability and workability

bull In a gradation and size analysis a sample of dry aggregate of known weight is separated through a series of sieves with progressively smaller openings

bull Once separated the weight of particles retained on

each sieve is measured and compared to the total sample weight

bull Particle size distribution is then expressed as a percent retained by weight on each sieve size

bull The particle size distribution or gradation of the constituent aggregate is one of the most influential characteristics in determining how an aggregate mixture will perform as a pavement material

bull Aggregate gradation influences almost every important property including stiffness stability durability permeability workability fatigue resistance skid resistance and resistance to moisture damage (Roberts et al 1996)

bull Gradation is often expressed in graphical form Typically gradation graphs use concepts of maximum density gradation and its expression in equation form to plot a special graph referred to as the FHWA (Federal Highway Administration) 045 power graph

bull Maximum Density Gradation bull Theoretically there exists a particular gradation

that for a given maximum aggregate size will produce the maximum density

bull This gradation would involve a particle arrangement where successively smaller particles are packed within the voids between larger particles

bull If done ideally this would result in a minimum void space between particles and produce a maximum density

bull Practically an aggregate gradation of

maximum density is not desired because a certain amount of void space is required to provide adequate volume for the asphalt binder to occupy

Fuller and Thompsons Equation (Interactive Equation)

bull Regardless of its practical use a maximum density gradation provides a convenient reference In 1907 Fuller and Thompson developed a widely used equation to describe a maximum density gradation for a given maximum aggregate size

Where P = percent finer than an aggregate size

d = aggregate size being considered D = maximum aggregate size

n = parameter which adjusts curve for fineness or coarseness (for maximum

particle density n asymp 05 according to Fuller and Thompson)

The 045 Power Maximum Density Graph bull In the early 1960s the FHWA introduced the

standard gradation graph used in the HMA industry today

bull This graph uses Fuller and Thompsons equation with n = 045 and is convenient for determining the maximum density line and adjusting gradation (Roberts et al 1996)

bull This graph is slightly different than other gradation graphs because it uses the sieve size raised to the nth power (usually 045) as the x-axis units Thus a plot of Fuller and Thompsons maximum density equation with n = 045 appears as a straight diagonal line

bull This straight line goes from zero to the maximum aggregate size for the gradation being considered There is some debate as to whether this line should end at maximum aggregate size or nominal maximum aggregate size or somewhere in between however the most commonly accepted practice is to end it at the maximum aggregate size

To illustrate how the maximum density curves was determined Table shows the associated calculations for a

maximum aggregate size of 190 mm

Calculations for a 045 Power Gradation Curve Using 190-mm (075-inch) Maximum Aggregate Size

Desired Gradation

bull Gradation has a profound effect on material performancebull What is the best gradation

bull The answer to which will vary depending upon the material (HMA or PCC) its desired characteristics loading environmental material structural and mix property inputs

bull The best gradation is one that produces the maximum

density bull A particle arrangement where smaller particles are packed

between the larger particles which reduces the void space between particles

bull This creates more particle-to-particle contact which would increase stability and reduce water infiltration

Desired Gradation

bull Some minimum amount of void space is necessary to

bull Provide adequate volume for the binder (asphalt binder or portland cement) to occupy

bull Promote rapid drainage and resistance to frost

action for base and subbase courses

bull Therefore although it may not be the best aggregate gradation a maximum density gradation does provide a common reference

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Road aggregate or simply ldquoaggregate is a broad category of coarse particulate material used in construction including sand gravel crushed stone slag recycled concrete and geosynthetic aggregates

bull Aggregates are a component of composite materials such as concrete and asphalt concrete the aggregate serves as reinforcement to add strength to the overall composite material

bull Aggregates are widely used in drainage

applications such as foundation drains retaining wall drains and road side edge drains Aggregates are also used as base material under foundations roads

ClassificationClassification

bull 1) Origin - Natural aggregates - Igneous rocks grain size gt 2mm - coarse

bull 2 to 02mm - medium

bull lt 02mm - fine

bull Composition Acidic gt 66 of silica

bull Intermediate 55 to 66 silica

bull Basic lt 55 silica

Sedimentary rocks - classified as per predominating material

bull Calcareous Siliceous ArgillaceousCalcareous Siliceous Argillaceousbull Chalklimestone sandstone clayshell etc bull dolomite Flintchertbull Metamorphic rocksbull Artificial aggregate - by product of industrial

processes ex Blast furnace slagbull 2) Strength - Hard aggregate - granitebasaltbull Soft aggregate - cankermoorum

etc

bull 3) Shape of aggregate CubicalRoundAngularFlaky amp Elongated

bull 4) Grading bull Open graded -when some particular type and size is

usedbull Dense graded - different size and shape of aggregates

are usedbull Skip graded - if a particular size is missingbull Uniformly graded - if all the particles are of same sizebull 5) Size bull C A - gt 236 mm F A - passing 236 mm

retained on 75 micronbull Filler - passing 75 micron

bull

Desirable properties of aggregatesDesirable properties of aggregatesbull 1) Resistance to crushing 1) Resistance to crushing

bull 2) Resistance to abrasion2) Resistance to abrasion

bull 3) Resistance to impact3) Resistance to impact

bull 4) Good shape4) Good shape

bull 5) Water absorption5) Water absorption

bull 6) Resistance to weathering6) Resistance to weathering

bull 7) Good adhesion7) Good adhesion

bull 8) Surface texture8) Surface texture

bull 9) Porosity9) Porosity

bull 10) Surface chemistry10) Surface chemistry

bull Aggregate Characterization

bull 1048710 Aggregate Physical Properties

bull 1048710 Maximum Aggregate Size

bull 1048710 Gradation

bull 1048710 Other Aggregate Properties

bull 1048710 Toughness and Abrasion Resistance

bull 1048710 Specific Gravity

bull 1048710 Particle Shape and Surface Texture

bull 1048710 Durability and Soundness

bull 1048710 Cleanliness and Deleterious Materials

bull IS2386-1963 Methods of test for aggregates

bull Part 1 Particle size and shape

bull Part 2 Estimation of deleterious materials and organic impurities

bull Part 3 Specific gravity density voids absorption and bulking

bull Part 4 Mechanical properties

bull Part 5 Soundness

Aggregate Gradation IS2386-1963 Part IThe gradation and size test (Figure 1) is used to determine aggregate particle size distribution Size distribution is perhaps the single most important aggregate quality associated with the control of HMA mixtures Aggregate gradation and size affect HMA volumetric properties as well as mixture permeability and workability

bull In a gradation and size analysis a sample of dry aggregate of known weight is separated through a series of sieves with progressively smaller openings

bull Once separated the weight of particles retained on

each sieve is measured and compared to the total sample weight

bull Particle size distribution is then expressed as a percent retained by weight on each sieve size

bull The particle size distribution or gradation of the constituent aggregate is one of the most influential characteristics in determining how an aggregate mixture will perform as a pavement material

bull Aggregate gradation influences almost every important property including stiffness stability durability permeability workability fatigue resistance skid resistance and resistance to moisture damage (Roberts et al 1996)

bull Gradation is often expressed in graphical form Typically gradation graphs use concepts of maximum density gradation and its expression in equation form to plot a special graph referred to as the FHWA (Federal Highway Administration) 045 power graph

bull Maximum Density Gradation bull Theoretically there exists a particular gradation

that for a given maximum aggregate size will produce the maximum density

bull This gradation would involve a particle arrangement where successively smaller particles are packed within the voids between larger particles

bull If done ideally this would result in a minimum void space between particles and produce a maximum density

bull Practically an aggregate gradation of

maximum density is not desired because a certain amount of void space is required to provide adequate volume for the asphalt binder to occupy

Fuller and Thompsons Equation (Interactive Equation)

bull Regardless of its practical use a maximum density gradation provides a convenient reference In 1907 Fuller and Thompson developed a widely used equation to describe a maximum density gradation for a given maximum aggregate size

Where P = percent finer than an aggregate size

d = aggregate size being considered D = maximum aggregate size

n = parameter which adjusts curve for fineness or coarseness (for maximum

particle density n asymp 05 according to Fuller and Thompson)

The 045 Power Maximum Density Graph bull In the early 1960s the FHWA introduced the

standard gradation graph used in the HMA industry today

bull This graph uses Fuller and Thompsons equation with n = 045 and is convenient for determining the maximum density line and adjusting gradation (Roberts et al 1996)

bull This graph is slightly different than other gradation graphs because it uses the sieve size raised to the nth power (usually 045) as the x-axis units Thus a plot of Fuller and Thompsons maximum density equation with n = 045 appears as a straight diagonal line

bull This straight line goes from zero to the maximum aggregate size for the gradation being considered There is some debate as to whether this line should end at maximum aggregate size or nominal maximum aggregate size or somewhere in between however the most commonly accepted practice is to end it at the maximum aggregate size

To illustrate how the maximum density curves was determined Table shows the associated calculations for a

maximum aggregate size of 190 mm

Calculations for a 045 Power Gradation Curve Using 190-mm (075-inch) Maximum Aggregate Size

Desired Gradation

bull Gradation has a profound effect on material performancebull What is the best gradation

bull The answer to which will vary depending upon the material (HMA or PCC) its desired characteristics loading environmental material structural and mix property inputs

bull The best gradation is one that produces the maximum

density bull A particle arrangement where smaller particles are packed

between the larger particles which reduces the void space between particles

bull This creates more particle-to-particle contact which would increase stability and reduce water infiltration

Desired Gradation

bull Some minimum amount of void space is necessary to

bull Provide adequate volume for the binder (asphalt binder or portland cement) to occupy

bull Promote rapid drainage and resistance to frost

action for base and subbase courses

bull Therefore although it may not be the best aggregate gradation a maximum density gradation does provide a common reference

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

ClassificationClassification

bull 1) Origin - Natural aggregates - Igneous rocks grain size gt 2mm - coarse

bull 2 to 02mm - medium

bull lt 02mm - fine

bull Composition Acidic gt 66 of silica

bull Intermediate 55 to 66 silica

bull Basic lt 55 silica

Sedimentary rocks - classified as per predominating material

bull Calcareous Siliceous ArgillaceousCalcareous Siliceous Argillaceousbull Chalklimestone sandstone clayshell etc bull dolomite Flintchertbull Metamorphic rocksbull Artificial aggregate - by product of industrial

processes ex Blast furnace slagbull 2) Strength - Hard aggregate - granitebasaltbull Soft aggregate - cankermoorum

etc

bull 3) Shape of aggregate CubicalRoundAngularFlaky amp Elongated

bull 4) Grading bull Open graded -when some particular type and size is

usedbull Dense graded - different size and shape of aggregates

are usedbull Skip graded - if a particular size is missingbull Uniformly graded - if all the particles are of same sizebull 5) Size bull C A - gt 236 mm F A - passing 236 mm

retained on 75 micronbull Filler - passing 75 micron

bull

Desirable properties of aggregatesDesirable properties of aggregatesbull 1) Resistance to crushing 1) Resistance to crushing

bull 2) Resistance to abrasion2) Resistance to abrasion

bull 3) Resistance to impact3) Resistance to impact

bull 4) Good shape4) Good shape

bull 5) Water absorption5) Water absorption

bull 6) Resistance to weathering6) Resistance to weathering

bull 7) Good adhesion7) Good adhesion

bull 8) Surface texture8) Surface texture

bull 9) Porosity9) Porosity

bull 10) Surface chemistry10) Surface chemistry

bull Aggregate Characterization

bull 1048710 Aggregate Physical Properties

bull 1048710 Maximum Aggregate Size

bull 1048710 Gradation

bull 1048710 Other Aggregate Properties

bull 1048710 Toughness and Abrasion Resistance

bull 1048710 Specific Gravity

bull 1048710 Particle Shape and Surface Texture

bull 1048710 Durability and Soundness

bull 1048710 Cleanliness and Deleterious Materials

bull IS2386-1963 Methods of test for aggregates

bull Part 1 Particle size and shape

bull Part 2 Estimation of deleterious materials and organic impurities

bull Part 3 Specific gravity density voids absorption and bulking

bull Part 4 Mechanical properties

bull Part 5 Soundness

Aggregate Gradation IS2386-1963 Part IThe gradation and size test (Figure 1) is used to determine aggregate particle size distribution Size distribution is perhaps the single most important aggregate quality associated with the control of HMA mixtures Aggregate gradation and size affect HMA volumetric properties as well as mixture permeability and workability

bull In a gradation and size analysis a sample of dry aggregate of known weight is separated through a series of sieves with progressively smaller openings

bull Once separated the weight of particles retained on

each sieve is measured and compared to the total sample weight

bull Particle size distribution is then expressed as a percent retained by weight on each sieve size

bull The particle size distribution or gradation of the constituent aggregate is one of the most influential characteristics in determining how an aggregate mixture will perform as a pavement material

bull Aggregate gradation influences almost every important property including stiffness stability durability permeability workability fatigue resistance skid resistance and resistance to moisture damage (Roberts et al 1996)

bull Gradation is often expressed in graphical form Typically gradation graphs use concepts of maximum density gradation and its expression in equation form to plot a special graph referred to as the FHWA (Federal Highway Administration) 045 power graph

bull Maximum Density Gradation bull Theoretically there exists a particular gradation

that for a given maximum aggregate size will produce the maximum density

bull This gradation would involve a particle arrangement where successively smaller particles are packed within the voids between larger particles

bull If done ideally this would result in a minimum void space between particles and produce a maximum density

bull Practically an aggregate gradation of

maximum density is not desired because a certain amount of void space is required to provide adequate volume for the asphalt binder to occupy

Fuller and Thompsons Equation (Interactive Equation)

bull Regardless of its practical use a maximum density gradation provides a convenient reference In 1907 Fuller and Thompson developed a widely used equation to describe a maximum density gradation for a given maximum aggregate size

Where P = percent finer than an aggregate size

d = aggregate size being considered D = maximum aggregate size

n = parameter which adjusts curve for fineness or coarseness (for maximum

particle density n asymp 05 according to Fuller and Thompson)

The 045 Power Maximum Density Graph bull In the early 1960s the FHWA introduced the

standard gradation graph used in the HMA industry today

bull This graph uses Fuller and Thompsons equation with n = 045 and is convenient for determining the maximum density line and adjusting gradation (Roberts et al 1996)

bull This graph is slightly different than other gradation graphs because it uses the sieve size raised to the nth power (usually 045) as the x-axis units Thus a plot of Fuller and Thompsons maximum density equation with n = 045 appears as a straight diagonal line

bull This straight line goes from zero to the maximum aggregate size for the gradation being considered There is some debate as to whether this line should end at maximum aggregate size or nominal maximum aggregate size or somewhere in between however the most commonly accepted practice is to end it at the maximum aggregate size

To illustrate how the maximum density curves was determined Table shows the associated calculations for a

maximum aggregate size of 190 mm

Calculations for a 045 Power Gradation Curve Using 190-mm (075-inch) Maximum Aggregate Size

Desired Gradation

bull Gradation has a profound effect on material performancebull What is the best gradation

bull The answer to which will vary depending upon the material (HMA or PCC) its desired characteristics loading environmental material structural and mix property inputs

bull The best gradation is one that produces the maximum

density bull A particle arrangement where smaller particles are packed

between the larger particles which reduces the void space between particles

bull This creates more particle-to-particle contact which would increase stability and reduce water infiltration

Desired Gradation

bull Some minimum amount of void space is necessary to

bull Provide adequate volume for the binder (asphalt binder or portland cement) to occupy

bull Promote rapid drainage and resistance to frost

action for base and subbase courses

bull Therefore although it may not be the best aggregate gradation a maximum density gradation does provide a common reference

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Sedimentary rocks - classified as per predominating material

bull Calcareous Siliceous ArgillaceousCalcareous Siliceous Argillaceousbull Chalklimestone sandstone clayshell etc bull dolomite Flintchertbull Metamorphic rocksbull Artificial aggregate - by product of industrial

processes ex Blast furnace slagbull 2) Strength - Hard aggregate - granitebasaltbull Soft aggregate - cankermoorum

etc

bull 3) Shape of aggregate CubicalRoundAngularFlaky amp Elongated

bull 4) Grading bull Open graded -when some particular type and size is

usedbull Dense graded - different size and shape of aggregates

are usedbull Skip graded - if a particular size is missingbull Uniformly graded - if all the particles are of same sizebull 5) Size bull C A - gt 236 mm F A - passing 236 mm

retained on 75 micronbull Filler - passing 75 micron

bull

Desirable properties of aggregatesDesirable properties of aggregatesbull 1) Resistance to crushing 1) Resistance to crushing

bull 2) Resistance to abrasion2) Resistance to abrasion

bull 3) Resistance to impact3) Resistance to impact

bull 4) Good shape4) Good shape

bull 5) Water absorption5) Water absorption

bull 6) Resistance to weathering6) Resistance to weathering

bull 7) Good adhesion7) Good adhesion

bull 8) Surface texture8) Surface texture

bull 9) Porosity9) Porosity

bull 10) Surface chemistry10) Surface chemistry

bull Aggregate Characterization

bull 1048710 Aggregate Physical Properties

bull 1048710 Maximum Aggregate Size

bull 1048710 Gradation

bull 1048710 Other Aggregate Properties

bull 1048710 Toughness and Abrasion Resistance

bull 1048710 Specific Gravity

bull 1048710 Particle Shape and Surface Texture

bull 1048710 Durability and Soundness

bull 1048710 Cleanliness and Deleterious Materials

bull IS2386-1963 Methods of test for aggregates

bull Part 1 Particle size and shape

bull Part 2 Estimation of deleterious materials and organic impurities

bull Part 3 Specific gravity density voids absorption and bulking

bull Part 4 Mechanical properties

bull Part 5 Soundness

Aggregate Gradation IS2386-1963 Part IThe gradation and size test (Figure 1) is used to determine aggregate particle size distribution Size distribution is perhaps the single most important aggregate quality associated with the control of HMA mixtures Aggregate gradation and size affect HMA volumetric properties as well as mixture permeability and workability

bull In a gradation and size analysis a sample of dry aggregate of known weight is separated through a series of sieves with progressively smaller openings

bull Once separated the weight of particles retained on

each sieve is measured and compared to the total sample weight

bull Particle size distribution is then expressed as a percent retained by weight on each sieve size

bull The particle size distribution or gradation of the constituent aggregate is one of the most influential characteristics in determining how an aggregate mixture will perform as a pavement material

bull Aggregate gradation influences almost every important property including stiffness stability durability permeability workability fatigue resistance skid resistance and resistance to moisture damage (Roberts et al 1996)

bull Gradation is often expressed in graphical form Typically gradation graphs use concepts of maximum density gradation and its expression in equation form to plot a special graph referred to as the FHWA (Federal Highway Administration) 045 power graph

bull Maximum Density Gradation bull Theoretically there exists a particular gradation

that for a given maximum aggregate size will produce the maximum density

bull This gradation would involve a particle arrangement where successively smaller particles are packed within the voids between larger particles

bull If done ideally this would result in a minimum void space between particles and produce a maximum density

bull Practically an aggregate gradation of

maximum density is not desired because a certain amount of void space is required to provide adequate volume for the asphalt binder to occupy

Fuller and Thompsons Equation (Interactive Equation)

bull Regardless of its practical use a maximum density gradation provides a convenient reference In 1907 Fuller and Thompson developed a widely used equation to describe a maximum density gradation for a given maximum aggregate size

Where P = percent finer than an aggregate size

d = aggregate size being considered D = maximum aggregate size

n = parameter which adjusts curve for fineness or coarseness (for maximum

particle density n asymp 05 according to Fuller and Thompson)

The 045 Power Maximum Density Graph bull In the early 1960s the FHWA introduced the

standard gradation graph used in the HMA industry today

bull This graph uses Fuller and Thompsons equation with n = 045 and is convenient for determining the maximum density line and adjusting gradation (Roberts et al 1996)

bull This graph is slightly different than other gradation graphs because it uses the sieve size raised to the nth power (usually 045) as the x-axis units Thus a plot of Fuller and Thompsons maximum density equation with n = 045 appears as a straight diagonal line

bull This straight line goes from zero to the maximum aggregate size for the gradation being considered There is some debate as to whether this line should end at maximum aggregate size or nominal maximum aggregate size or somewhere in between however the most commonly accepted practice is to end it at the maximum aggregate size

To illustrate how the maximum density curves was determined Table shows the associated calculations for a

maximum aggregate size of 190 mm

Calculations for a 045 Power Gradation Curve Using 190-mm (075-inch) Maximum Aggregate Size

Desired Gradation

bull Gradation has a profound effect on material performancebull What is the best gradation

bull The answer to which will vary depending upon the material (HMA or PCC) its desired characteristics loading environmental material structural and mix property inputs

bull The best gradation is one that produces the maximum

density bull A particle arrangement where smaller particles are packed

between the larger particles which reduces the void space between particles

bull This creates more particle-to-particle contact which would increase stability and reduce water infiltration

Desired Gradation

bull Some minimum amount of void space is necessary to

bull Provide adequate volume for the binder (asphalt binder or portland cement) to occupy

bull Promote rapid drainage and resistance to frost

action for base and subbase courses

bull Therefore although it may not be the best aggregate gradation a maximum density gradation does provide a common reference

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull 3) Shape of aggregate CubicalRoundAngularFlaky amp Elongated

bull 4) Grading bull Open graded -when some particular type and size is

usedbull Dense graded - different size and shape of aggregates

are usedbull Skip graded - if a particular size is missingbull Uniformly graded - if all the particles are of same sizebull 5) Size bull C A - gt 236 mm F A - passing 236 mm

retained on 75 micronbull Filler - passing 75 micron

bull

Desirable properties of aggregatesDesirable properties of aggregatesbull 1) Resistance to crushing 1) Resistance to crushing

bull 2) Resistance to abrasion2) Resistance to abrasion

bull 3) Resistance to impact3) Resistance to impact

bull 4) Good shape4) Good shape

bull 5) Water absorption5) Water absorption

bull 6) Resistance to weathering6) Resistance to weathering

bull 7) Good adhesion7) Good adhesion

bull 8) Surface texture8) Surface texture

bull 9) Porosity9) Porosity

bull 10) Surface chemistry10) Surface chemistry

bull Aggregate Characterization

bull 1048710 Aggregate Physical Properties

bull 1048710 Maximum Aggregate Size

bull 1048710 Gradation

bull 1048710 Other Aggregate Properties

bull 1048710 Toughness and Abrasion Resistance

bull 1048710 Specific Gravity

bull 1048710 Particle Shape and Surface Texture

bull 1048710 Durability and Soundness

bull 1048710 Cleanliness and Deleterious Materials

bull IS2386-1963 Methods of test for aggregates

bull Part 1 Particle size and shape

bull Part 2 Estimation of deleterious materials and organic impurities

bull Part 3 Specific gravity density voids absorption and bulking

bull Part 4 Mechanical properties

bull Part 5 Soundness

Aggregate Gradation IS2386-1963 Part IThe gradation and size test (Figure 1) is used to determine aggregate particle size distribution Size distribution is perhaps the single most important aggregate quality associated with the control of HMA mixtures Aggregate gradation and size affect HMA volumetric properties as well as mixture permeability and workability

bull In a gradation and size analysis a sample of dry aggregate of known weight is separated through a series of sieves with progressively smaller openings

bull Once separated the weight of particles retained on

each sieve is measured and compared to the total sample weight

bull Particle size distribution is then expressed as a percent retained by weight on each sieve size

bull The particle size distribution or gradation of the constituent aggregate is one of the most influential characteristics in determining how an aggregate mixture will perform as a pavement material

bull Aggregate gradation influences almost every important property including stiffness stability durability permeability workability fatigue resistance skid resistance and resistance to moisture damage (Roberts et al 1996)

bull Gradation is often expressed in graphical form Typically gradation graphs use concepts of maximum density gradation and its expression in equation form to plot a special graph referred to as the FHWA (Federal Highway Administration) 045 power graph

bull Maximum Density Gradation bull Theoretically there exists a particular gradation

that for a given maximum aggregate size will produce the maximum density

bull This gradation would involve a particle arrangement where successively smaller particles are packed within the voids between larger particles

bull If done ideally this would result in a minimum void space between particles and produce a maximum density

bull Practically an aggregate gradation of

maximum density is not desired because a certain amount of void space is required to provide adequate volume for the asphalt binder to occupy

Fuller and Thompsons Equation (Interactive Equation)

bull Regardless of its practical use a maximum density gradation provides a convenient reference In 1907 Fuller and Thompson developed a widely used equation to describe a maximum density gradation for a given maximum aggregate size

Where P = percent finer than an aggregate size

d = aggregate size being considered D = maximum aggregate size

n = parameter which adjusts curve for fineness or coarseness (for maximum

particle density n asymp 05 according to Fuller and Thompson)

The 045 Power Maximum Density Graph bull In the early 1960s the FHWA introduced the

standard gradation graph used in the HMA industry today

bull This graph uses Fuller and Thompsons equation with n = 045 and is convenient for determining the maximum density line and adjusting gradation (Roberts et al 1996)

bull This graph is slightly different than other gradation graphs because it uses the sieve size raised to the nth power (usually 045) as the x-axis units Thus a plot of Fuller and Thompsons maximum density equation with n = 045 appears as a straight diagonal line

bull This straight line goes from zero to the maximum aggregate size for the gradation being considered There is some debate as to whether this line should end at maximum aggregate size or nominal maximum aggregate size or somewhere in between however the most commonly accepted practice is to end it at the maximum aggregate size

To illustrate how the maximum density curves was determined Table shows the associated calculations for a

maximum aggregate size of 190 mm

Calculations for a 045 Power Gradation Curve Using 190-mm (075-inch) Maximum Aggregate Size

Desired Gradation

bull Gradation has a profound effect on material performancebull What is the best gradation

bull The answer to which will vary depending upon the material (HMA or PCC) its desired characteristics loading environmental material structural and mix property inputs

bull The best gradation is one that produces the maximum

density bull A particle arrangement where smaller particles are packed

between the larger particles which reduces the void space between particles

bull This creates more particle-to-particle contact which would increase stability and reduce water infiltration

Desired Gradation

bull Some minimum amount of void space is necessary to

bull Provide adequate volume for the binder (asphalt binder or portland cement) to occupy

bull Promote rapid drainage and resistance to frost

action for base and subbase courses

bull Therefore although it may not be the best aggregate gradation a maximum density gradation does provide a common reference

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Desirable properties of aggregatesDesirable properties of aggregatesbull 1) Resistance to crushing 1) Resistance to crushing

bull 2) Resistance to abrasion2) Resistance to abrasion

bull 3) Resistance to impact3) Resistance to impact

bull 4) Good shape4) Good shape

bull 5) Water absorption5) Water absorption

bull 6) Resistance to weathering6) Resistance to weathering

bull 7) Good adhesion7) Good adhesion

bull 8) Surface texture8) Surface texture

bull 9) Porosity9) Porosity

bull 10) Surface chemistry10) Surface chemistry

bull Aggregate Characterization

bull 1048710 Aggregate Physical Properties

bull 1048710 Maximum Aggregate Size

bull 1048710 Gradation

bull 1048710 Other Aggregate Properties

bull 1048710 Toughness and Abrasion Resistance

bull 1048710 Specific Gravity

bull 1048710 Particle Shape and Surface Texture

bull 1048710 Durability and Soundness

bull 1048710 Cleanliness and Deleterious Materials

bull IS2386-1963 Methods of test for aggregates

bull Part 1 Particle size and shape

bull Part 2 Estimation of deleterious materials and organic impurities

bull Part 3 Specific gravity density voids absorption and bulking

bull Part 4 Mechanical properties

bull Part 5 Soundness

Aggregate Gradation IS2386-1963 Part IThe gradation and size test (Figure 1) is used to determine aggregate particle size distribution Size distribution is perhaps the single most important aggregate quality associated with the control of HMA mixtures Aggregate gradation and size affect HMA volumetric properties as well as mixture permeability and workability

bull In a gradation and size analysis a sample of dry aggregate of known weight is separated through a series of sieves with progressively smaller openings

bull Once separated the weight of particles retained on

each sieve is measured and compared to the total sample weight

bull Particle size distribution is then expressed as a percent retained by weight on each sieve size

bull The particle size distribution or gradation of the constituent aggregate is one of the most influential characteristics in determining how an aggregate mixture will perform as a pavement material

bull Aggregate gradation influences almost every important property including stiffness stability durability permeability workability fatigue resistance skid resistance and resistance to moisture damage (Roberts et al 1996)

bull Gradation is often expressed in graphical form Typically gradation graphs use concepts of maximum density gradation and its expression in equation form to plot a special graph referred to as the FHWA (Federal Highway Administration) 045 power graph

bull Maximum Density Gradation bull Theoretically there exists a particular gradation

that for a given maximum aggregate size will produce the maximum density

bull This gradation would involve a particle arrangement where successively smaller particles are packed within the voids between larger particles

bull If done ideally this would result in a minimum void space between particles and produce a maximum density

bull Practically an aggregate gradation of

maximum density is not desired because a certain amount of void space is required to provide adequate volume for the asphalt binder to occupy

Fuller and Thompsons Equation (Interactive Equation)

bull Regardless of its practical use a maximum density gradation provides a convenient reference In 1907 Fuller and Thompson developed a widely used equation to describe a maximum density gradation for a given maximum aggregate size

Where P = percent finer than an aggregate size

d = aggregate size being considered D = maximum aggregate size

n = parameter which adjusts curve for fineness or coarseness (for maximum

particle density n asymp 05 according to Fuller and Thompson)

The 045 Power Maximum Density Graph bull In the early 1960s the FHWA introduced the

standard gradation graph used in the HMA industry today

bull This graph uses Fuller and Thompsons equation with n = 045 and is convenient for determining the maximum density line and adjusting gradation (Roberts et al 1996)

bull This graph is slightly different than other gradation graphs because it uses the sieve size raised to the nth power (usually 045) as the x-axis units Thus a plot of Fuller and Thompsons maximum density equation with n = 045 appears as a straight diagonal line

bull This straight line goes from zero to the maximum aggregate size for the gradation being considered There is some debate as to whether this line should end at maximum aggregate size or nominal maximum aggregate size or somewhere in between however the most commonly accepted practice is to end it at the maximum aggregate size

To illustrate how the maximum density curves was determined Table shows the associated calculations for a

maximum aggregate size of 190 mm

Calculations for a 045 Power Gradation Curve Using 190-mm (075-inch) Maximum Aggregate Size

Desired Gradation

bull Gradation has a profound effect on material performancebull What is the best gradation

bull The answer to which will vary depending upon the material (HMA or PCC) its desired characteristics loading environmental material structural and mix property inputs

bull The best gradation is one that produces the maximum

density bull A particle arrangement where smaller particles are packed

between the larger particles which reduces the void space between particles

bull This creates more particle-to-particle contact which would increase stability and reduce water infiltration

Desired Gradation

bull Some minimum amount of void space is necessary to

bull Provide adequate volume for the binder (asphalt binder or portland cement) to occupy

bull Promote rapid drainage and resistance to frost

action for base and subbase courses

bull Therefore although it may not be the best aggregate gradation a maximum density gradation does provide a common reference

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Aggregate Characterization

bull 1048710 Aggregate Physical Properties

bull 1048710 Maximum Aggregate Size

bull 1048710 Gradation

bull 1048710 Other Aggregate Properties

bull 1048710 Toughness and Abrasion Resistance

bull 1048710 Specific Gravity

bull 1048710 Particle Shape and Surface Texture

bull 1048710 Durability and Soundness

bull 1048710 Cleanliness and Deleterious Materials

bull IS2386-1963 Methods of test for aggregates

bull Part 1 Particle size and shape

bull Part 2 Estimation of deleterious materials and organic impurities

bull Part 3 Specific gravity density voids absorption and bulking

bull Part 4 Mechanical properties

bull Part 5 Soundness

Aggregate Gradation IS2386-1963 Part IThe gradation and size test (Figure 1) is used to determine aggregate particle size distribution Size distribution is perhaps the single most important aggregate quality associated with the control of HMA mixtures Aggregate gradation and size affect HMA volumetric properties as well as mixture permeability and workability

bull In a gradation and size analysis a sample of dry aggregate of known weight is separated through a series of sieves with progressively smaller openings

bull Once separated the weight of particles retained on

each sieve is measured and compared to the total sample weight

bull Particle size distribution is then expressed as a percent retained by weight on each sieve size

bull The particle size distribution or gradation of the constituent aggregate is one of the most influential characteristics in determining how an aggregate mixture will perform as a pavement material

bull Aggregate gradation influences almost every important property including stiffness stability durability permeability workability fatigue resistance skid resistance and resistance to moisture damage (Roberts et al 1996)

bull Gradation is often expressed in graphical form Typically gradation graphs use concepts of maximum density gradation and its expression in equation form to plot a special graph referred to as the FHWA (Federal Highway Administration) 045 power graph

bull Maximum Density Gradation bull Theoretically there exists a particular gradation

that for a given maximum aggregate size will produce the maximum density

bull This gradation would involve a particle arrangement where successively smaller particles are packed within the voids between larger particles

bull If done ideally this would result in a minimum void space between particles and produce a maximum density

bull Practically an aggregate gradation of

maximum density is not desired because a certain amount of void space is required to provide adequate volume for the asphalt binder to occupy

Fuller and Thompsons Equation (Interactive Equation)

bull Regardless of its practical use a maximum density gradation provides a convenient reference In 1907 Fuller and Thompson developed a widely used equation to describe a maximum density gradation for a given maximum aggregate size

Where P = percent finer than an aggregate size

d = aggregate size being considered D = maximum aggregate size

n = parameter which adjusts curve for fineness or coarseness (for maximum

particle density n asymp 05 according to Fuller and Thompson)

The 045 Power Maximum Density Graph bull In the early 1960s the FHWA introduced the

standard gradation graph used in the HMA industry today

bull This graph uses Fuller and Thompsons equation with n = 045 and is convenient for determining the maximum density line and adjusting gradation (Roberts et al 1996)

bull This graph is slightly different than other gradation graphs because it uses the sieve size raised to the nth power (usually 045) as the x-axis units Thus a plot of Fuller and Thompsons maximum density equation with n = 045 appears as a straight diagonal line

bull This straight line goes from zero to the maximum aggregate size for the gradation being considered There is some debate as to whether this line should end at maximum aggregate size or nominal maximum aggregate size or somewhere in between however the most commonly accepted practice is to end it at the maximum aggregate size

To illustrate how the maximum density curves was determined Table shows the associated calculations for a

maximum aggregate size of 190 mm

Calculations for a 045 Power Gradation Curve Using 190-mm (075-inch) Maximum Aggregate Size

Desired Gradation

bull Gradation has a profound effect on material performancebull What is the best gradation

bull The answer to which will vary depending upon the material (HMA or PCC) its desired characteristics loading environmental material structural and mix property inputs

bull The best gradation is one that produces the maximum

density bull A particle arrangement where smaller particles are packed

between the larger particles which reduces the void space between particles

bull This creates more particle-to-particle contact which would increase stability and reduce water infiltration

Desired Gradation

bull Some minimum amount of void space is necessary to

bull Provide adequate volume for the binder (asphalt binder or portland cement) to occupy

bull Promote rapid drainage and resistance to frost

action for base and subbase courses

bull Therefore although it may not be the best aggregate gradation a maximum density gradation does provide a common reference

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull IS2386-1963 Methods of test for aggregates

bull Part 1 Particle size and shape

bull Part 2 Estimation of deleterious materials and organic impurities

bull Part 3 Specific gravity density voids absorption and bulking

bull Part 4 Mechanical properties

bull Part 5 Soundness

Aggregate Gradation IS2386-1963 Part IThe gradation and size test (Figure 1) is used to determine aggregate particle size distribution Size distribution is perhaps the single most important aggregate quality associated with the control of HMA mixtures Aggregate gradation and size affect HMA volumetric properties as well as mixture permeability and workability

bull In a gradation and size analysis a sample of dry aggregate of known weight is separated through a series of sieves with progressively smaller openings

bull Once separated the weight of particles retained on

each sieve is measured and compared to the total sample weight

bull Particle size distribution is then expressed as a percent retained by weight on each sieve size

bull The particle size distribution or gradation of the constituent aggregate is one of the most influential characteristics in determining how an aggregate mixture will perform as a pavement material

bull Aggregate gradation influences almost every important property including stiffness stability durability permeability workability fatigue resistance skid resistance and resistance to moisture damage (Roberts et al 1996)

bull Gradation is often expressed in graphical form Typically gradation graphs use concepts of maximum density gradation and its expression in equation form to plot a special graph referred to as the FHWA (Federal Highway Administration) 045 power graph

bull Maximum Density Gradation bull Theoretically there exists a particular gradation

that for a given maximum aggregate size will produce the maximum density

bull This gradation would involve a particle arrangement where successively smaller particles are packed within the voids between larger particles

bull If done ideally this would result in a minimum void space between particles and produce a maximum density

bull Practically an aggregate gradation of

maximum density is not desired because a certain amount of void space is required to provide adequate volume for the asphalt binder to occupy

Fuller and Thompsons Equation (Interactive Equation)

bull Regardless of its practical use a maximum density gradation provides a convenient reference In 1907 Fuller and Thompson developed a widely used equation to describe a maximum density gradation for a given maximum aggregate size

Where P = percent finer than an aggregate size

d = aggregate size being considered D = maximum aggregate size

n = parameter which adjusts curve for fineness or coarseness (for maximum

particle density n asymp 05 according to Fuller and Thompson)

The 045 Power Maximum Density Graph bull In the early 1960s the FHWA introduced the

standard gradation graph used in the HMA industry today

bull This graph uses Fuller and Thompsons equation with n = 045 and is convenient for determining the maximum density line and adjusting gradation (Roberts et al 1996)

bull This graph is slightly different than other gradation graphs because it uses the sieve size raised to the nth power (usually 045) as the x-axis units Thus a plot of Fuller and Thompsons maximum density equation with n = 045 appears as a straight diagonal line

bull This straight line goes from zero to the maximum aggregate size for the gradation being considered There is some debate as to whether this line should end at maximum aggregate size or nominal maximum aggregate size or somewhere in between however the most commonly accepted practice is to end it at the maximum aggregate size

To illustrate how the maximum density curves was determined Table shows the associated calculations for a

maximum aggregate size of 190 mm

Calculations for a 045 Power Gradation Curve Using 190-mm (075-inch) Maximum Aggregate Size

Desired Gradation

bull Gradation has a profound effect on material performancebull What is the best gradation

bull The answer to which will vary depending upon the material (HMA or PCC) its desired characteristics loading environmental material structural and mix property inputs

bull The best gradation is one that produces the maximum

density bull A particle arrangement where smaller particles are packed

between the larger particles which reduces the void space between particles

bull This creates more particle-to-particle contact which would increase stability and reduce water infiltration

Desired Gradation

bull Some minimum amount of void space is necessary to

bull Provide adequate volume for the binder (asphalt binder or portland cement) to occupy

bull Promote rapid drainage and resistance to frost

action for base and subbase courses

bull Therefore although it may not be the best aggregate gradation a maximum density gradation does provide a common reference

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Aggregate Gradation IS2386-1963 Part IThe gradation and size test (Figure 1) is used to determine aggregate particle size distribution Size distribution is perhaps the single most important aggregate quality associated with the control of HMA mixtures Aggregate gradation and size affect HMA volumetric properties as well as mixture permeability and workability

bull In a gradation and size analysis a sample of dry aggregate of known weight is separated through a series of sieves with progressively smaller openings

bull Once separated the weight of particles retained on

each sieve is measured and compared to the total sample weight

bull Particle size distribution is then expressed as a percent retained by weight on each sieve size

bull The particle size distribution or gradation of the constituent aggregate is one of the most influential characteristics in determining how an aggregate mixture will perform as a pavement material

bull Aggregate gradation influences almost every important property including stiffness stability durability permeability workability fatigue resistance skid resistance and resistance to moisture damage (Roberts et al 1996)

bull Gradation is often expressed in graphical form Typically gradation graphs use concepts of maximum density gradation and its expression in equation form to plot a special graph referred to as the FHWA (Federal Highway Administration) 045 power graph

bull Maximum Density Gradation bull Theoretically there exists a particular gradation

that for a given maximum aggregate size will produce the maximum density

bull This gradation would involve a particle arrangement where successively smaller particles are packed within the voids between larger particles

bull If done ideally this would result in a minimum void space between particles and produce a maximum density

bull Practically an aggregate gradation of

maximum density is not desired because a certain amount of void space is required to provide adequate volume for the asphalt binder to occupy

Fuller and Thompsons Equation (Interactive Equation)

bull Regardless of its practical use a maximum density gradation provides a convenient reference In 1907 Fuller and Thompson developed a widely used equation to describe a maximum density gradation for a given maximum aggregate size

Where P = percent finer than an aggregate size

d = aggregate size being considered D = maximum aggregate size

n = parameter which adjusts curve for fineness or coarseness (for maximum

particle density n asymp 05 according to Fuller and Thompson)

The 045 Power Maximum Density Graph bull In the early 1960s the FHWA introduced the

standard gradation graph used in the HMA industry today

bull This graph uses Fuller and Thompsons equation with n = 045 and is convenient for determining the maximum density line and adjusting gradation (Roberts et al 1996)

bull This graph is slightly different than other gradation graphs because it uses the sieve size raised to the nth power (usually 045) as the x-axis units Thus a plot of Fuller and Thompsons maximum density equation with n = 045 appears as a straight diagonal line

bull This straight line goes from zero to the maximum aggregate size for the gradation being considered There is some debate as to whether this line should end at maximum aggregate size or nominal maximum aggregate size or somewhere in between however the most commonly accepted practice is to end it at the maximum aggregate size

To illustrate how the maximum density curves was determined Table shows the associated calculations for a

maximum aggregate size of 190 mm

Calculations for a 045 Power Gradation Curve Using 190-mm (075-inch) Maximum Aggregate Size

Desired Gradation

bull Gradation has a profound effect on material performancebull What is the best gradation

bull The answer to which will vary depending upon the material (HMA or PCC) its desired characteristics loading environmental material structural and mix property inputs

bull The best gradation is one that produces the maximum

density bull A particle arrangement where smaller particles are packed

between the larger particles which reduces the void space between particles

bull This creates more particle-to-particle contact which would increase stability and reduce water infiltration

Desired Gradation

bull Some minimum amount of void space is necessary to

bull Provide adequate volume for the binder (asphalt binder or portland cement) to occupy

bull Promote rapid drainage and resistance to frost

action for base and subbase courses

bull Therefore although it may not be the best aggregate gradation a maximum density gradation does provide a common reference

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull In a gradation and size analysis a sample of dry aggregate of known weight is separated through a series of sieves with progressively smaller openings

bull Once separated the weight of particles retained on

each sieve is measured and compared to the total sample weight

bull Particle size distribution is then expressed as a percent retained by weight on each sieve size

bull The particle size distribution or gradation of the constituent aggregate is one of the most influential characteristics in determining how an aggregate mixture will perform as a pavement material

bull Aggregate gradation influences almost every important property including stiffness stability durability permeability workability fatigue resistance skid resistance and resistance to moisture damage (Roberts et al 1996)

bull Gradation is often expressed in graphical form Typically gradation graphs use concepts of maximum density gradation and its expression in equation form to plot a special graph referred to as the FHWA (Federal Highway Administration) 045 power graph

bull Maximum Density Gradation bull Theoretically there exists a particular gradation

that for a given maximum aggregate size will produce the maximum density

bull This gradation would involve a particle arrangement where successively smaller particles are packed within the voids between larger particles

bull If done ideally this would result in a minimum void space between particles and produce a maximum density

bull Practically an aggregate gradation of

maximum density is not desired because a certain amount of void space is required to provide adequate volume for the asphalt binder to occupy

Fuller and Thompsons Equation (Interactive Equation)

bull Regardless of its practical use a maximum density gradation provides a convenient reference In 1907 Fuller and Thompson developed a widely used equation to describe a maximum density gradation for a given maximum aggregate size

Where P = percent finer than an aggregate size

d = aggregate size being considered D = maximum aggregate size

n = parameter which adjusts curve for fineness or coarseness (for maximum

particle density n asymp 05 according to Fuller and Thompson)

The 045 Power Maximum Density Graph bull In the early 1960s the FHWA introduced the

standard gradation graph used in the HMA industry today

bull This graph uses Fuller and Thompsons equation with n = 045 and is convenient for determining the maximum density line and adjusting gradation (Roberts et al 1996)

bull This graph is slightly different than other gradation graphs because it uses the sieve size raised to the nth power (usually 045) as the x-axis units Thus a plot of Fuller and Thompsons maximum density equation with n = 045 appears as a straight diagonal line

bull This straight line goes from zero to the maximum aggregate size for the gradation being considered There is some debate as to whether this line should end at maximum aggregate size or nominal maximum aggregate size or somewhere in between however the most commonly accepted practice is to end it at the maximum aggregate size

To illustrate how the maximum density curves was determined Table shows the associated calculations for a

maximum aggregate size of 190 mm

Calculations for a 045 Power Gradation Curve Using 190-mm (075-inch) Maximum Aggregate Size

Desired Gradation

bull Gradation has a profound effect on material performancebull What is the best gradation

bull The answer to which will vary depending upon the material (HMA or PCC) its desired characteristics loading environmental material structural and mix property inputs

bull The best gradation is one that produces the maximum

density bull A particle arrangement where smaller particles are packed

between the larger particles which reduces the void space between particles

bull This creates more particle-to-particle contact which would increase stability and reduce water infiltration

Desired Gradation

bull Some minimum amount of void space is necessary to

bull Provide adequate volume for the binder (asphalt binder or portland cement) to occupy

bull Promote rapid drainage and resistance to frost

action for base and subbase courses

bull Therefore although it may not be the best aggregate gradation a maximum density gradation does provide a common reference

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull The particle size distribution or gradation of the constituent aggregate is one of the most influential characteristics in determining how an aggregate mixture will perform as a pavement material

bull Aggregate gradation influences almost every important property including stiffness stability durability permeability workability fatigue resistance skid resistance and resistance to moisture damage (Roberts et al 1996)

bull Gradation is often expressed in graphical form Typically gradation graphs use concepts of maximum density gradation and its expression in equation form to plot a special graph referred to as the FHWA (Federal Highway Administration) 045 power graph

bull Maximum Density Gradation bull Theoretically there exists a particular gradation

that for a given maximum aggregate size will produce the maximum density

bull This gradation would involve a particle arrangement where successively smaller particles are packed within the voids between larger particles

bull If done ideally this would result in a minimum void space between particles and produce a maximum density

bull Practically an aggregate gradation of

maximum density is not desired because a certain amount of void space is required to provide adequate volume for the asphalt binder to occupy

Fuller and Thompsons Equation (Interactive Equation)

bull Regardless of its practical use a maximum density gradation provides a convenient reference In 1907 Fuller and Thompson developed a widely used equation to describe a maximum density gradation for a given maximum aggregate size

Where P = percent finer than an aggregate size

d = aggregate size being considered D = maximum aggregate size

n = parameter which adjusts curve for fineness or coarseness (for maximum

particle density n asymp 05 according to Fuller and Thompson)

The 045 Power Maximum Density Graph bull In the early 1960s the FHWA introduced the

standard gradation graph used in the HMA industry today

bull This graph uses Fuller and Thompsons equation with n = 045 and is convenient for determining the maximum density line and adjusting gradation (Roberts et al 1996)

bull This graph is slightly different than other gradation graphs because it uses the sieve size raised to the nth power (usually 045) as the x-axis units Thus a plot of Fuller and Thompsons maximum density equation with n = 045 appears as a straight diagonal line

bull This straight line goes from zero to the maximum aggregate size for the gradation being considered There is some debate as to whether this line should end at maximum aggregate size or nominal maximum aggregate size or somewhere in between however the most commonly accepted practice is to end it at the maximum aggregate size

To illustrate how the maximum density curves was determined Table shows the associated calculations for a

maximum aggregate size of 190 mm

Calculations for a 045 Power Gradation Curve Using 190-mm (075-inch) Maximum Aggregate Size

Desired Gradation

bull Gradation has a profound effect on material performancebull What is the best gradation

bull The answer to which will vary depending upon the material (HMA or PCC) its desired characteristics loading environmental material structural and mix property inputs

bull The best gradation is one that produces the maximum

density bull A particle arrangement where smaller particles are packed

between the larger particles which reduces the void space between particles

bull This creates more particle-to-particle contact which would increase stability and reduce water infiltration

Desired Gradation

bull Some minimum amount of void space is necessary to

bull Provide adequate volume for the binder (asphalt binder or portland cement) to occupy

bull Promote rapid drainage and resistance to frost

action for base and subbase courses

bull Therefore although it may not be the best aggregate gradation a maximum density gradation does provide a common reference

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Gradation is often expressed in graphical form Typically gradation graphs use concepts of maximum density gradation and its expression in equation form to plot a special graph referred to as the FHWA (Federal Highway Administration) 045 power graph

bull Maximum Density Gradation bull Theoretically there exists a particular gradation

that for a given maximum aggregate size will produce the maximum density

bull This gradation would involve a particle arrangement where successively smaller particles are packed within the voids between larger particles

bull If done ideally this would result in a minimum void space between particles and produce a maximum density

bull Practically an aggregate gradation of

maximum density is not desired because a certain amount of void space is required to provide adequate volume for the asphalt binder to occupy

Fuller and Thompsons Equation (Interactive Equation)

bull Regardless of its practical use a maximum density gradation provides a convenient reference In 1907 Fuller and Thompson developed a widely used equation to describe a maximum density gradation for a given maximum aggregate size

Where P = percent finer than an aggregate size

d = aggregate size being considered D = maximum aggregate size

n = parameter which adjusts curve for fineness or coarseness (for maximum

particle density n asymp 05 according to Fuller and Thompson)

The 045 Power Maximum Density Graph bull In the early 1960s the FHWA introduced the

standard gradation graph used in the HMA industry today

bull This graph uses Fuller and Thompsons equation with n = 045 and is convenient for determining the maximum density line and adjusting gradation (Roberts et al 1996)

bull This graph is slightly different than other gradation graphs because it uses the sieve size raised to the nth power (usually 045) as the x-axis units Thus a plot of Fuller and Thompsons maximum density equation with n = 045 appears as a straight diagonal line

bull This straight line goes from zero to the maximum aggregate size for the gradation being considered There is some debate as to whether this line should end at maximum aggregate size or nominal maximum aggregate size or somewhere in between however the most commonly accepted practice is to end it at the maximum aggregate size

To illustrate how the maximum density curves was determined Table shows the associated calculations for a

maximum aggregate size of 190 mm

Calculations for a 045 Power Gradation Curve Using 190-mm (075-inch) Maximum Aggregate Size

Desired Gradation

bull Gradation has a profound effect on material performancebull What is the best gradation

bull The answer to which will vary depending upon the material (HMA or PCC) its desired characteristics loading environmental material structural and mix property inputs

bull The best gradation is one that produces the maximum

density bull A particle arrangement where smaller particles are packed

between the larger particles which reduces the void space between particles

bull This creates more particle-to-particle contact which would increase stability and reduce water infiltration

Desired Gradation

bull Some minimum amount of void space is necessary to

bull Provide adequate volume for the binder (asphalt binder or portland cement) to occupy

bull Promote rapid drainage and resistance to frost

action for base and subbase courses

bull Therefore although it may not be the best aggregate gradation a maximum density gradation does provide a common reference

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull If done ideally this would result in a minimum void space between particles and produce a maximum density

bull Practically an aggregate gradation of

maximum density is not desired because a certain amount of void space is required to provide adequate volume for the asphalt binder to occupy

Fuller and Thompsons Equation (Interactive Equation)

bull Regardless of its practical use a maximum density gradation provides a convenient reference In 1907 Fuller and Thompson developed a widely used equation to describe a maximum density gradation for a given maximum aggregate size

Where P = percent finer than an aggregate size

d = aggregate size being considered D = maximum aggregate size

n = parameter which adjusts curve for fineness or coarseness (for maximum

particle density n asymp 05 according to Fuller and Thompson)

The 045 Power Maximum Density Graph bull In the early 1960s the FHWA introduced the

standard gradation graph used in the HMA industry today

bull This graph uses Fuller and Thompsons equation with n = 045 and is convenient for determining the maximum density line and adjusting gradation (Roberts et al 1996)

bull This graph is slightly different than other gradation graphs because it uses the sieve size raised to the nth power (usually 045) as the x-axis units Thus a plot of Fuller and Thompsons maximum density equation with n = 045 appears as a straight diagonal line

bull This straight line goes from zero to the maximum aggregate size for the gradation being considered There is some debate as to whether this line should end at maximum aggregate size or nominal maximum aggregate size or somewhere in between however the most commonly accepted practice is to end it at the maximum aggregate size

To illustrate how the maximum density curves was determined Table shows the associated calculations for a

maximum aggregate size of 190 mm

Calculations for a 045 Power Gradation Curve Using 190-mm (075-inch) Maximum Aggregate Size

Desired Gradation

bull Gradation has a profound effect on material performancebull What is the best gradation

bull The answer to which will vary depending upon the material (HMA or PCC) its desired characteristics loading environmental material structural and mix property inputs

bull The best gradation is one that produces the maximum

density bull A particle arrangement where smaller particles are packed

between the larger particles which reduces the void space between particles

bull This creates more particle-to-particle contact which would increase stability and reduce water infiltration

Desired Gradation

bull Some minimum amount of void space is necessary to

bull Provide adequate volume for the binder (asphalt binder or portland cement) to occupy

bull Promote rapid drainage and resistance to frost

action for base and subbase courses

bull Therefore although it may not be the best aggregate gradation a maximum density gradation does provide a common reference

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Fuller and Thompsons Equation (Interactive Equation)

bull Regardless of its practical use a maximum density gradation provides a convenient reference In 1907 Fuller and Thompson developed a widely used equation to describe a maximum density gradation for a given maximum aggregate size

Where P = percent finer than an aggregate size

d = aggregate size being considered D = maximum aggregate size

n = parameter which adjusts curve for fineness or coarseness (for maximum

particle density n asymp 05 according to Fuller and Thompson)

The 045 Power Maximum Density Graph bull In the early 1960s the FHWA introduced the

standard gradation graph used in the HMA industry today

bull This graph uses Fuller and Thompsons equation with n = 045 and is convenient for determining the maximum density line and adjusting gradation (Roberts et al 1996)

bull This graph is slightly different than other gradation graphs because it uses the sieve size raised to the nth power (usually 045) as the x-axis units Thus a plot of Fuller and Thompsons maximum density equation with n = 045 appears as a straight diagonal line

bull This straight line goes from zero to the maximum aggregate size for the gradation being considered There is some debate as to whether this line should end at maximum aggregate size or nominal maximum aggregate size or somewhere in between however the most commonly accepted practice is to end it at the maximum aggregate size

To illustrate how the maximum density curves was determined Table shows the associated calculations for a

maximum aggregate size of 190 mm

Calculations for a 045 Power Gradation Curve Using 190-mm (075-inch) Maximum Aggregate Size

Desired Gradation

bull Gradation has a profound effect on material performancebull What is the best gradation

bull The answer to which will vary depending upon the material (HMA or PCC) its desired characteristics loading environmental material structural and mix property inputs

bull The best gradation is one that produces the maximum

density bull A particle arrangement where smaller particles are packed

between the larger particles which reduces the void space between particles

bull This creates more particle-to-particle contact which would increase stability and reduce water infiltration

Desired Gradation

bull Some minimum amount of void space is necessary to

bull Provide adequate volume for the binder (asphalt binder or portland cement) to occupy

bull Promote rapid drainage and resistance to frost

action for base and subbase courses

bull Therefore although it may not be the best aggregate gradation a maximum density gradation does provide a common reference

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

The 045 Power Maximum Density Graph bull In the early 1960s the FHWA introduced the

standard gradation graph used in the HMA industry today

bull This graph uses Fuller and Thompsons equation with n = 045 and is convenient for determining the maximum density line and adjusting gradation (Roberts et al 1996)

bull This graph is slightly different than other gradation graphs because it uses the sieve size raised to the nth power (usually 045) as the x-axis units Thus a plot of Fuller and Thompsons maximum density equation with n = 045 appears as a straight diagonal line

bull This straight line goes from zero to the maximum aggregate size for the gradation being considered There is some debate as to whether this line should end at maximum aggregate size or nominal maximum aggregate size or somewhere in between however the most commonly accepted practice is to end it at the maximum aggregate size

To illustrate how the maximum density curves was determined Table shows the associated calculations for a

maximum aggregate size of 190 mm

Calculations for a 045 Power Gradation Curve Using 190-mm (075-inch) Maximum Aggregate Size

Desired Gradation

bull Gradation has a profound effect on material performancebull What is the best gradation

bull The answer to which will vary depending upon the material (HMA or PCC) its desired characteristics loading environmental material structural and mix property inputs

bull The best gradation is one that produces the maximum

density bull A particle arrangement where smaller particles are packed

between the larger particles which reduces the void space between particles

bull This creates more particle-to-particle contact which would increase stability and reduce water infiltration

Desired Gradation

bull Some minimum amount of void space is necessary to

bull Provide adequate volume for the binder (asphalt binder or portland cement) to occupy

bull Promote rapid drainage and resistance to frost

action for base and subbase courses

bull Therefore although it may not be the best aggregate gradation a maximum density gradation does provide a common reference

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull This straight line goes from zero to the maximum aggregate size for the gradation being considered There is some debate as to whether this line should end at maximum aggregate size or nominal maximum aggregate size or somewhere in between however the most commonly accepted practice is to end it at the maximum aggregate size

To illustrate how the maximum density curves was determined Table shows the associated calculations for a

maximum aggregate size of 190 mm

Calculations for a 045 Power Gradation Curve Using 190-mm (075-inch) Maximum Aggregate Size

Desired Gradation

bull Gradation has a profound effect on material performancebull What is the best gradation

bull The answer to which will vary depending upon the material (HMA or PCC) its desired characteristics loading environmental material structural and mix property inputs

bull The best gradation is one that produces the maximum

density bull A particle arrangement where smaller particles are packed

between the larger particles which reduces the void space between particles

bull This creates more particle-to-particle contact which would increase stability and reduce water infiltration

Desired Gradation

bull Some minimum amount of void space is necessary to

bull Provide adequate volume for the binder (asphalt binder or portland cement) to occupy

bull Promote rapid drainage and resistance to frost

action for base and subbase courses

bull Therefore although it may not be the best aggregate gradation a maximum density gradation does provide a common reference

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

To illustrate how the maximum density curves was determined Table shows the associated calculations for a

maximum aggregate size of 190 mm

Calculations for a 045 Power Gradation Curve Using 190-mm (075-inch) Maximum Aggregate Size

Desired Gradation

bull Gradation has a profound effect on material performancebull What is the best gradation

bull The answer to which will vary depending upon the material (HMA or PCC) its desired characteristics loading environmental material structural and mix property inputs

bull The best gradation is one that produces the maximum

density bull A particle arrangement where smaller particles are packed

between the larger particles which reduces the void space between particles

bull This creates more particle-to-particle contact which would increase stability and reduce water infiltration

Desired Gradation

bull Some minimum amount of void space is necessary to

bull Provide adequate volume for the binder (asphalt binder or portland cement) to occupy

bull Promote rapid drainage and resistance to frost

action for base and subbase courses

bull Therefore although it may not be the best aggregate gradation a maximum density gradation does provide a common reference

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Desired Gradation

bull Gradation has a profound effect on material performancebull What is the best gradation

bull The answer to which will vary depending upon the material (HMA or PCC) its desired characteristics loading environmental material structural and mix property inputs

bull The best gradation is one that produces the maximum

density bull A particle arrangement where smaller particles are packed

between the larger particles which reduces the void space between particles

bull This creates more particle-to-particle contact which would increase stability and reduce water infiltration

Desired Gradation

bull Some minimum amount of void space is necessary to

bull Provide adequate volume for the binder (asphalt binder or portland cement) to occupy

bull Promote rapid drainage and resistance to frost

action for base and subbase courses

bull Therefore although it may not be the best aggregate gradation a maximum density gradation does provide a common reference

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Desired Gradation

bull Some minimum amount of void space is necessary to

bull Provide adequate volume for the binder (asphalt binder or portland cement) to occupy

bull Promote rapid drainage and resistance to frost

action for base and subbase courses

bull Therefore although it may not be the best aggregate gradation a maximum density gradation does provide a common reference

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Nominal Maximum and Maximum Size

bull Nominal maximum size - one size larger than the first sieve to retain more than 10 Maximum size - one size larger than nominal maximum size

bull ASTM STP 1147 demonstrates the importance of correctly defining the maximum size to ensure a valid maximum density line is drawn

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Fineness Modulus

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Aggregate Crushing Value IS 2386 (Part IV)

bull bull Metal measurebull Tamping rod

Below mentioned are its specifications

bull Three sizes 75mm dia for 18 to 14 Size aggregate 150mm dia for 38 to 34 Size aggregate 300mm dia for 1acirc to 2acirc size aggregate

The aggregate crushing value indicates the ability of an aggregate to resist crushing The lower the figure the stronger the aggregate ie the greater its ability to resist crushing

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Aggregate passing IS sieve 125 mm and retained on 10 mm sieve is generally used

bull Oven dried aggregates are filled in the measuring cylinder of 115cm dia amp 180cm height in 3 equal layers each layer being subjected to 25 tamps with a tamping rod of 16mm dia and 45 to 60mm long

bull The crushing test apparatus consist of a 15cm dia open ended heavy steel cylinderplunger and a base plate

bull Compression testing machine a load of 40 tonnes is applied in 10 mincrushed agg Sieved through 236 mm sieve

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Agg crushing value gt 35 weak for pavement

bull Agg crushing value lt 10 exceptionally strong

bull For majority of aggregates the impact value and crushing value are numerically similar

bull Rock group Crushing value Impact value

bull Basalt 14 15

bull Granite 20 19

bull Lime stone 24 23

bull Quartzite 16 21

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Aggregate Impact Value Aggregate Impact Value IS 2386 (Part IV) Toughness of an aggregate is its resistance to failure by impact

A base which helps in supporting the columns to form a rigid framework around the quick release trigger mechanism for ensuring the effective free fall of the hammer during test The hammer is offered with locking arrangement and the free fall can be easily adjusted through the 380+ 5mm cylindrical cup with the metal measure 75 mm dia x 50 mm high and tamping rod

Satisfactory resistance to crushing under roller during construction Adequate resistance to surface abrasion under traffic

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Impact valueImpact valuebull Due to traffic loads the road stones are subjected to the

pounding action or impact

bull IS sieves 125 mm10 mm amp 236 mm

bull Cylindrical steel cup of dia 102 cm amp depth 5 cm

bull Metal hammer of weight 135 to 14 kgHeight of fall 38 cm Cylindrical measure with internal dia 75 cm amp depth 5 cm

bull Metal tamping of 1 cm dia23 cm long

bull lt 10 exceptionally strong

bull 10 - 20 strong

bull 20 - 30 satisfactory gt 35 weak

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Elongation amp Flakiness Index IS 2386

bull When the length is more than 18 of the mean dimension then the aggregate particles are considered elongated

The aggregate particles are to be flaky if the thickness is less than the 06 of their mean dimension

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull A revisit to aggregate shape parametersbull Animesh Das

bull Aggregates constitute major part of the pavement structure The engineering properties of the aggregates as well as its shape (ie form and angularity) and texture substantially affect the overall performance of the pavement (Kuo and Freeman 1998 Maerz 2004)

bull A number of researchers reported that form and surface texture of aggregates have significant effect on the mechanical property of the bituminous mixes for example shear resistance durability stiffness fatigue resistance rutting resistance workability bitumen demand etc (Herrin and Goetz 1954 Benson 1970 Ishai and Gelber 1982 Kalcheff and

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Aggregate Abrasion Value IS 2386 (Part IV) The Los Angeles (LA) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing degradation and disintegration in order to produce a high quality HMA

Aggregates must be tough and abrasion resistant to prevent crushing degradation anddisintegration when stockpiled fed through an asphalt plant placed with a paver compacted withrollers and subjected to traffic loadings

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Abrasive charge shall consist of a solid steel sphere having a mass between 390 and 445 g with a diameter of 465 plusmn 05 mm

GRADINGS FOR TEST SPECIMENSA B C D E F and G Total Mass = 5000 plusmn 10 gm for A B C and DTotal Mass = 10000 plusmn 20 gm for E F and G

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull For the LA abrasion test the portion of an aggregate sample retained on the 170 mm sieve is placed in a large rotating drum that contains a shelf plate attached to the outer wall

bull A specified number of steel spheres are then placed in the machine and the drum is rotated for 500 revolutions at a speed of 30 - 33 revolutions per minute (RPM)

bull The material is then extracted and separated into material passing and retained on the 170 mm sieve

bull The retained material is then weighed and compared to the original sample weight The difference in weight is reported as a percent of the original weight and called the percent loss

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Rock Type LA Abrasion value

General Values

Hard igneous rocks 10

Soft limestones and sandstones 60

Ranges for Specific Rocks

Basalt 10 - 17

Dolomite 18 ndash 30

Gneiss 33 ndash 57

Granite 27 - 49

Limestone 19 ndash 30

Quartzite 20 - 35

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Polished StoneValue (PSV)BS 812 Testing Aggregates Part 114

The PSV of an aggregate is a measure of the resistance of an aggregate to polishing The value is established by subjecting the aggregate to a standard polishing process and then testing the aggregate with the Portable Skid Resistance Tester to determine its PSV

The property that an aggregate possesses which gives it a good PSV is often referred to as its MICRO-TEXTURE

Aggregates that retain a significant microtexture after polishing are the aggregates that give good resistance to skiddingie have a high Polished Stone Value

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

The PSV is a value applicable to a particular aggregate and NOT the road surface however the use of high PSV aggregate in a bituminous mixture laid as a surface course will produce a road surface with a high Skid Resistance Value (SRV) subject to the road surface having sufficient texture (MACRO-TEXTURE)

Aggregate that has a PSV over 60 is regarded as a High Skid Resistant Aggregate but aggregate with a PSV over 65 is needed for particularly high stressed sites The higher the the PSV figure the greater resistance the aggregate has to polishing and the greater the ability the aggregate has to retain its inherent very fine surface texture ie MICRO-TEXTURE

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

BITUMEN ADHESION

bull ONE OF THE PRINCIPLE FUNCTION OF BITUMEN IS TO ACT AS AN ADHESIVE

bull NATURE OF AGGREGATES HAVE A CONSIDERABLE INFLUENCE ON BITUMEN ADHESION

bull HYDROPHILIC HYDROPHOBIC AGGREGATES

bull AGGREGATE WITH HIGH SILICON OXIDE CONTENT LIKE QUARTZGRANITE THAT IS ACIDIC AGGREGATES ARE MORE DIFFICULT TO COAT WITH BITUMEN THAN BASIC AGGREGATE LIKE BASALT

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Angularity number Angular particles possess well defined edges

and are commonly found in aggregates prepared by crushing of rocks

Angularity or absence of rounding of particles in aggregate is a property which is of importance because it affects ease of handling a mixture of aggregate and binder

The degree of packing of particles of single sized aggregates depends upon the shape and angularity of the aggregate

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Angularity of aggregate can be estimated from properties of voids in a sample of aggregate compacted in a particular manner

Rounded gravel particles possess lesser voids

(mostly 33 ie 67 solids by volume) as compared to the angular particles

Angularity number measures the percentage of voids in angular particles in excess of that in the rounded gravel particles

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Angularity number

bull = of solid volume in a vessel filled with aggregate in a standard manner - 67 (ie volume of solids of the rounded gravel)

bull The higher the angularity number the more angular the aggregate

bull The range of angularity number for practical aggregates is between 0 and 11

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Unit Weight(unit mass or bulk density)

The weight of the aggregate required to fill a container of a specified unit volume

bull Volume is occupied by both the aggregates and the voids between the aggregate particles

bull Depends on size distribution and shape of particles and how densely the aggregate is packed

bull Loose bulk density

bull Rodded or compact bulk density

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Specific Gravity (Relative density)Absolute the ratio of the weight of the solid to the weight of an

equal volume of water (both at a stated temperature)

bull refers to volume of the material excluding all pores

Apparent ratio of the weight of the aggregate (dried in an oven at 212- 230ordmF for 24 hours) to the weight of water occupying

a volume equal to that of the solid including the impermeable pores

bull volume of solid includes impermeable pores (but not capillary pores)

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Shrinkage of Aggregates

fine grained sandstones slate basalt trap rock clay-containing

Large Shrinkage =

Low Shrinkage = quartz limestone granite feldspar

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

UNIFORMITY COEFFICIENT (UC)

bull The ratio of (1) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 60 percent of the material (by weight) to pass through to (2) the diameter of a grain (particle) of a size that is barely too large to pass through a sieve that allows 10 percent of the material (by weight) to pass through The resulting ratio is a measure of the degree of uniformity in a granular material such as filter media

bull Test to determine relation of sieve size at which 60 of aggregate passes against the sieve size at which 10 passes The result is expressed as a number the higher the number the more blended the coarse and fine elements of the material

bull The measure of variation in particle sizes of filter and ion exchange

media The coefficient is defined as the ratio of the sieve size that will permit passage of 60 of the media by weight to the sieve size that will permit passage of 10 of the media material by weight

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Uniformity Coefficient Cu (measure of the particle size range)

bull Cu is also called Hazen Coefficient bull Cu = D60D10 bull Cu lt 5 ----- Very Uniform bull Cu = 5 ----- Medium Uniform bull Cu gt 5 ----- Nonuniform

Uniformity coefficient CuCu= D60D10where D60is the diameter for which 60 of the sample is finer than D60The ratio of two characteristic sizes are the uniformity coefficient Cu Apparently larger Cu means the size distribution is wider and vice versa Cu= 1 means uniform all grains are in the same size such as the case of dune sands On the other extreme is the glacial till for which its Cu can reach 30from Cu= D60D10 then D60= CuD10

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Granular subbases and bases

bull A subbase is layer of material between base and subgrade Sometimes a granular material under a rigid pavement is called a subbase

bull Subbase may consist of select materials such as natural gravels that are stable but that have characteristics which make them not completely suitable as base course They may also be of stabilized soil or merely select borrow

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull The purpose of a subbase is to permit the building of relatively thick pavements at low cost Thus the quality of subbase can vary within wide limits as long as the thickness design criteria are fulfilled

bull A base course is defined as a layer of granular material which lies immediately below the wearing surface of a pavement

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Purpose of base coursesbull Base and subbase courses under flexible pavements are

primarily to increase the load supporting capacity by distributing the load through a finite thickness of pavement this will reduce shear and consolidation deformation in the subgrade

bull Base courses are used under rigid pavements for bull 1) Prevention of pumpingbull 2) Protection against frost actionbull 3) Drainagebull 4) Prevention of volume change of subgradebull 5) Increased structural capacitybull 6) Expedition of construction

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull To prevent pumping a base course must be relatively well gradedmust be free from excessive fines and should be compacted to a relatively high density

bull To provide drainage the base may or may not be a well graded material but it should contain little or no fines

bull Base course designed for frost action should be non frost susceptible and free draining

bull Base course need not to be free draining to provide adequate structural capacity

bull Base course should be well graded and should resist deformation due to loading

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Properties of soil aggregate mixbull Density and stability depends upon particle

size distributionparticle shaperelative densityinternal friction and cohesion

bull An aggregate which contains little or no fines and is well graded gains its stability from grain to grain contact but usually has relatively low density but is pervious and non frost susceptibleThis material is very difficult to handle during construction because of its noncohesive nature

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull An aggregate which contains sufficient fines to fill all the voids will still gain its strength from grain contact but with increased resistance against deformationIts density is highits permeability is lowand it may be frost susceptibleThis material is moderately difficult to compact but is ideal from stability pointit will have relatively high shearing resistance

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull An aggregate which contains great amount of fines has no grain to grain contact and the aggregate merely floats in the soilIts density is lowit is practically imperviousand it is frost susceptibleIn addition the stability of this type of mixture is greatly affected by adverse water conditions The material is at times is quite easy to handle during construction and compacts quite readily

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Maximum CBR resulted when the quantity of fines was somewhat less than that indicated for maximum density

bull CBR of mixtures made up of angular particles are usually somewhat greater than those containing mostly rounded particles

bull Density as well as CBR increases as size of aggregate increased but optimum soil content decreased

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Permeability The permeability characteristics of soil aggregate mixtures are dependent upon

bull 1) Grain size distribution

bull 2) Type of coarse aggregate

bull 3) Type of binder

bull 4) Density

bull The coefficient of permeability is defined in the equation v = KIA

bull v = discharge velocitybull I = hydraulic gradient (loss in head per unit of length)bull K = coefficient of permeability 0001 to 10

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Effect of plasticity The liquid limit for base courses is 25 and the plasticity index is 6

bull Soundness Soundness is defined as the ability of aggregate to withstand abrasion crushingThis is important from the standpoint of generation of fines under the action of rollers and trafficSoft aggregate should not be used

bull Aggregate which breakdown excessively under freezing and thawing should not be used

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Behavior under load Laboratory testas well as field performancehave indicated that the behavior of base course - subgrade combinations under load is reflected by the stability of base course itself

bull Laboratory and field data indicate that a base course which contains quantity of fines slightly less than that required for maximum density will be stable

bull If a granular base course is used for drainage purpose or for protection against frost action it is essential that it remain open graded throughout the pavement lifeThis can be done by placing a thin blanket of sand or other fine granular material between the subgrade and base course

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

GRADING REQUIREMENTSbull The purpose of gradation specifications for base courses

and sub bases is to assure adequate stability under repeated loads

bull Proportioning materials of different specific gravities Any gradation specification is valid only so long as the fine fractions and the coarse aggregates have approximately the same specific gravity

bull Although the physical characteristics of the soil aggregate mixture are dependent upon relative volumes of the course to fine aggregate However it is not practical to attempt proportioning of materials on the basis of volume therefore specifications are always set up on the per cent by weight basis

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull If the coarse aggregate has a specific gravity considerably higher than that of the fine fraction gradation will result in mixtures which are too rich Conversely if the specific gravity of the fine fraction is higher than that of the coarse aggregate the quantity of fines will be low

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

CONSTRUCTIONbull Soil aggregate mixtures To ensure adequate

stability base and subbase materials must be compacted to a high density Moisture control is extremely important

bull Granular base course materials may be compacted in lifts ranging upto 6rdquo depending upon the type of compaction equipment If smooth wheeled compactors are used the lift should be controlled to about 4rdquoHowever if vibratory compactors are used lifts upto 8 or 10rdquo are permitted

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Field experience has indicated that compaction of base course materials to

densities in excess of the modified AASHO values is quite common when

vibrating compactors are used

bull Care should be exercised to insure uniform distribution of the base course materials

over the subgrade to prevent segregation

bull Make certain that the clay binder and aggregate are thoroughly mixed

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

MORTampH Section 400Sub-BasesBases (Non-Bituminous) and

Shouldersbull Materialsbull Natural sand crushed gravel crushed

stone or combination The material shall be free from organic or other deleterious constituents

bull Table 400-1 Four gradings for Granular Sub-Base

bull Gradings I and II -well graded granular sub-base Used at locations where drainage requirement are not predominant

bull Gradings III and IV - gap graded for drainage requirements For location experiencing heavy rainfall flooding etc

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Where GSB is to be provided in two layers grading III or IV for lower layer and grading I or II for upper layer Minimum thickness of lower layer not less than 200 mm

bull Physical requirements 10 percent fines value of 50kN or more (for sample in soaked condition) IS2386 (Part IV) 1963

bull The water absorption value of the coarse aggregate as per IS2386 (Part 3) If this value is greater than 2 percent the soundness test shall be carried out as per IS383

bull For Gradings II and IV materials the CBR shall be determined at the density and moisture content likely to be developed in the field

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Strength of Sub-Base

bull The material to be used in the sub-base satisfies the requirements of CBR and other physical requirements

bull The material passing 425 micron (0425 mm) sieve when tested according to IS2720 (Part 5) shall have liquid limit and plasticity index not more than 25 and 6 percent respectively

bull The material should be compacted to achieve at least 98 percent of the maximum dry density as per IS2720 (Part 8)

IS Sieve Percent by weight passing the IS sieve

Grading I

Grading II Grading III Grading IV

750 mm 100 - 100 -

530 mm 80-100 100 100 -

265 mm 55 ndash90 70-100 55-75 50-80

950 mm 35-65 50-80 -

475 mm 25 ndash 55 40-65 10- 15 15-35

236 mm 20- 40 30-50 - -

0425 mm 10-15 10-15 - -

0075 mm lt5 lt5 lt5 lt5

CBR Value (Minimum) 30 25 30 25

bullTable 400-1 Grading for Granular Sub-base Materials

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE

bull Laying and compacting sub-gradelower sub-base of soil treated with lime on prepared sub-grade Lime treatment is generally effective for soils which contain a relatively high percentage of clay and silty clay

bull Soil The soil used for stabilization shall be the local clayey soil having a plasticity index greater than 8

bull Lime Commercial dry lime slaked at site purity not less than 70 by weight of Quick-lime (CaO) IS1514 properly stored to avoid prolonged exposure to the atmosphere and consequent carbonation which would reduce its binding properties

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Quantity of lime in stabilized mix bull Percentage by weight of the dry soil and depending

upon Cao content The mix design shall be done to arrive at the appropriate quantity of lime to be added

bull Water Potable water shall be preferredbull Lime-soil stabilisation shall not be done when the air

temperature in the shade is less than 10 Cbull The thickness of any layer to be stabilized shall be not

less than 100 mm when compacted The maximum thickness can be 200 mm

IS Sieve Minimum percent by weight

passing the IS Sieve

265 mm 100

56 mm 80

bullTable 400-2 Soil Pulverisation Requirements for Lime Stabilisation

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Moisture content for compaction shall not be less than the optimum moisture content corresponding to IS2720 (Part 8) nor more than 2 percent above it

bull Curing A minimum period of 7 days bull Strength The soil-lime mix shall be tested for its CBR Value unconfined

compressive strength (UCS) at 7 days

bull CEMENT TREATED SOIL SUB-BASEBASE

bull Laying and compacting a sub-basebase course of soil treated with cement on prepared subgradesub-base

bull Material to be stabilised soil including sand and gravel laterite kankar brick aggregate crushed rock or slag or any combination of these The material shall have a grading shown in Table 400-3(a) It shall have a uniformity coefficient not less than 5 capable of producing a well-closed surface finish

bull If the material passing 425 micron sieve is plastic it shall have a liquid limit not greater than 45 and a plasticity index not more than 20 IS2720 (Part 5) The physical requirements for the material to be treated with cement for use in a base course shall be same as for Grading I Granular Sub-base

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Cement Ordinary portland cement portland slag cement or portland puzzolana cement comply with the requirements of IS269 455 or 1489 respectively

bull Table 400-3 Grading Limits of Material for Stabilisation with Cement

IS sieve size Percentage by mass passing

Sub-BaseBase

Within the range

5300 mm 100

375 mm 95 ndash 100

190 mm 45 ndash 100

95 mm 35 ndash 100

475 mm 25 ndash 100

600 micron 8 ndash 65

300 micron 5 ndash 40

75 micron 0 ndash 10

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Lime If needed for pre-treatment of highly clayey soils

bull Quantity of cement in stabilised mix Percent by weight of the dry soil The mix design shall be done on the basis of 7 day UCS andor durability test under 12 cycles of wet-dry conditions The laboratory strength values shall be at least 15 times the minimum field UCS value

bull Water Clean and free from injurious substances potable water

bull Degree of pulverisation Same as that for lime treated surfaces

bull Moisture content for compaction Shall not be less than the OMC corresponding to IS2720 (Part 8) nor more than 2 per cent above it

bull Curing Suitably cured for 7 days

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

WATER BOUND MACADAM SUB-BASEBASE

bull Clean crushed aggregates mechanically interlocked by rolling and bonding together with screening binding material This specification is meant for repairs and minor works of widening nature and also at locations where it is not feasible to lay WMM

bull Materialsbull Coarse aggregates Crushed or broken stone crushed slag overburnt

(Jhama) brick aggregates or any other naturally occurring aggregates such as kankar and laterite

bull Materials other than crushed or broken stone and crushed slag shall be used in sub-base courses only If crushed gravel shingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-5 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried as per IS2386 (Part 5)

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Table 400-5 Physical Requirements of Coarse Aggregates for Water Bound Macadam for Sub-baseBase Courses

SNo Test Test

Method

Requirements

1 Los Angeles Abrasion value

IS2386 (Part-1V) 40 percent (Max)

2

Aggregate Impact value

IS 2386 (Part-4) or

IS5640

30 percent (Max)

3 Combined

Flakiness and

Elongation

Indices (Total)

IS2386 (Part-1) 40 percent (Max)

Aggregates which get softened in presence of water shall be tested for Impact value under wet conditions in accordance with IS5640 The requirement of flakiness index and elongation index shall be enforced only in the case of crushed broken stone and crushed slag

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Crushed or broken stone It shall be hard durable and free from excess flat elongated soft and disintegrated particles dirt and other deleterious material

bull Crushed slag It shall be made from air-cooled blast furnace slag It shall be of angular shape reasonably uniform in quality and density and generally free from thin elongated and soft pieces dirt or other deleterious materials The weight of crushed slag shall not be less than 112 kN per m3 and the percentage of glossy material shall not be more than 20 It should also comply with the following requirements

bull i) Chemical stability To comply with requirements ofbull appendix of BS1047bull ii) Sulphur content Maximum 2 percentbull iii) Water absorption Maximum 10 percent

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Overburnt (Jhama) brick aggregates Shall be made from overburnt bricks or brick bats and be free from dust and other objectionable and deleterious materials This shall be amount only for road stretch when traffic is low

bull Grading requirement of coarse aggregates As per Table 400-6 The use of Grading No1 shall be restricted to sub-base courses only

bull The compacted thickness for a layer shall be 75 mm

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Grading no

Size Range IS sieve designation by weight passing

1 63 mm to 45 mm 75 mm 100

63 mm 90 ndash 100

53 mm 25 ndash 75

45 mm 0 ndash 15

224 mm 0 ndash 5

2 53 mm to 224 mm 63 mm 100

53 mm 95 ndash 100

45 mm 65 ndash 90

224 mm 0 ndash 10

112 mm 0 ndash 5

bullTable 400-6 Grading Requirements of Coarse Aggregates

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Screenings Screenings to fill voids in the coarse aggregate shall generally consist of the same material as the coarse aggregate However where permitted predominantly non-plastic material such as moorum or gravel (other than rounded river borne material) may be used for this purpose provided liquid limit and plasticity index of such material are below 20 and 6 respectively and fraction passing 75 micron sieve does not exceed 10 percent

bull Screenings shall conform to the grading set forth in Table 400-7 The consolidated details of quantity of screenings required for various grades of stone aggregates are given in Table 400-8 The table also gives the quantities of materials (loose) required for 10 m2 for sub-basebase compacted thickness of 75 mm

bull The use of screenings shall be omitted in the case of soft aggregates such as brick metal kankar laterites etc as they are likely to get crushed to a certain extent under rollers

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Binding material It is to be used for water bound macadam as a filler material meant for preventing ravelling shall comprise of a suitable material approved by the Engineer having a Plasticity Index (PI) value of less than 6 as determined in accordance with IS2720 (Part-5)

bull The quantity of binding material where it is to be used will depend on the type of screenings

bull Generally the quantity required for 75 mm compacted thickness of water bound macadam will be 006ndash009 m3 per 10 m2

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Grading Classification

Size of Screenings

IS Sieve Designation

Per cent by weight

passing the sieve

A 132mm 132mm 100

112mm 95-100

56mm 15-35

180 micron 0-10

B 112mm 112mm 100

56mm 90-100

180 micron 15-35

Table 400-7 Grading For Screenings

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

CRUSHED CEMENT CONCRETE SUB-BASEBASE

bull This work shall consist of breaking and crushing the damaged cement concrete slabs and re-compacting the same as sub-basebase course in one or more layers Where specified it shall also include treating the surface of the top layer with a penetration coat of bitumen

bull Materialsbull Coarse aggregates broken cement concrete slabs crushed to a size

not exceeding 75 mm and as far as possible conforming to one of the gradings given in Table 400-7

bull Key aggregates Key aggregate for the penetration coat shall consist of

bull crushed stone crushed gravel shingle or other stones The aggregate shall be 112 mm size defined as 100 percent passing through 132 mm sieve and retained on 56 mm sieve and shall satisfy the physical requirements set forth in Table 500-3

bull Binder Binder for the penetration coat for the top layer shall be bitumen of a suitable grade as directed by the Engineer and satisfying the requirements of IS73 217 or 454 as applicable or any approved cutback or emulsion satisfying the requirements of IS8887

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

WET MIX MACADAM SUB-BASEBASEbull Laying and compacting clean crushed graded aggregate and granular

material premixed with water to a dense mass on a prepared sub-gradesubbase base or existing pavement

bull The thickness of a single compacted Wet Mix Macadam layer shall not be less than 75 mm When vibrating or other approved types of compacting equipment are used the compacted depth of a single layer of the sub-base course may be upto 200 mm

bull Materialsbull Aggregates

bull Physical requirements Coarse aggregates shall be crushed stone Ifbull crushed gravelshingle is used not less than 90 percent by weight of

the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the physical requirements set forth in Table 400-9 If the water absorption value of the coarse aggregate is greater than 2 percent the soundness test shall be carried out on the material delivered to site as per IS2386 (Part-5)

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Grading requirements The aggregates shall conform to the grading given in Table 400-10

SNo Test Test Method Requirements

1 Los Angeles Abrasion value IS2386 (Part-4) 40 percent (Max)

Aggregate Impact value IS2386 (Part-4) or IS5640

30 percent (Max)

2 Combined Flakiness and Elongation indices (Total)

IS2386 (Part-1) 40 percent (Max)

bullTable 400-9 Physical Requirements of Coarse Aggregates for Wet Mix Macadam for Sub- baseBase Courses

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Table 400-10 Grading Requirements of Aggregates for Wet Mix Macadam

IS Sieve Designation

Per cent by weight passing the IS Sieve

Grade 1 layer thickness ge 100mm

Grade 2lt100 mm

5300 mm 100 -

4500 mm 95 ndash 100 -

2650 mm _ 100

2240 mm 60 ndash 80 50-100

1120 mm 40 ndash 60 -

475 mm 25 ndash 40 35-55

236 mm 15 ndash 30 -

60000 micron 8 ndash 22 10-30

7500 micron 0 ndash -5 2-5

Material finer than 425 micron shall have Plasticity Index (PI) not exceeding 6

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

SHOULDERS ISLANDS AND MEDIANS

bull The work shall consist of constructing shoulder (hardpavedearthen with brick or stone block edging) on either side of the pavement median in the road dividing the carriageway into separate lanes and islands for canalizing the traffic at junctions

bull Materialsbull Shoulder on either side of the road may be of selected earthgranular

materialpaved conforming to the requirements of Clause 305401 and the median may be of selected earth conforming to the requirements of Clause 305

bull MedianTraffic islands shall be raised and kerbed at the perimeter and the enclosed area filled with earth and suitably covered with grass turfshrubs Paved shoulders shall consist of sub-base base and surfacing courses and materials for the same shall conform to relevant Specifications of the corresponding items Where paved or hard shoulders are not provided the pavement shall be provided with brickstone block edgings

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

CEMENT CONCRETE KERB AND KERB WITH CHANNEL

bull This work shall consist of constructing cement concrete kerbs and kerbs with channel in the central median andor along the footpaths or separators

bull Materials

bull Kerbs and kerb with channel shall be provided in cement concrete of Grade M 20 in accordance with Section 1700 of these Specifications

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

FOOTPATHS AND SEPARATORSbull Constructing footpaths andor separators including provision of all drainage

arrangementsbull Materialsbull The footpaths and separators shall be constructed with any of the following

typesbull a) Cast-in-situ cement concrete of Grade M 20 as per Section 1700 ofbull the Specificationsbull b) Precast cement concrete blockstiles of Grade M 20 as per Section 1700 of

the Specifications The minimum thickness of the cement concrete blocktile shall be 25 mm and minimum size shall be 300 mm x 300 mm

bull c) Natural stone slab cut and dressed from stone of good and sound quality uniform in texture The minimum thickness of the natural stone slab shall be 25 mm and minimum size shall be 300 mm x 300 mm

CRUSHER-RUN MACADAM BASE

This work shall consist of furnishing placing and compacting crushed stone aggregate sub-base and base courses constructed in accordance with the requirements set forth in these Specifications and in conformity with the lines grades thickness and cross-sections shown on the plans or as directed by the Engineer

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

bull Materialsbull Crushed rock if crushed

gravelshingle is used not less than 90 percent by weight of the gravelshingle pieces retained on 475 mm sieve shall have at least two fractured faces The aggregates shall conform to the grading and quality requirements given in Tables 400-11 and 400-12

Sieve Size Per cent passing by weight

53 mm max size

375 mm max size

63 mm 100 -

45 mm 87 ndash 100 100

224 mm 50 ndash 85 90 ndash 100

56 mm 25 ndash 45 35 ndash 55

710 mm 10 ndash 25 10 ndash 30

90 mm 2 ndash 5 2 ndash 5

Table 40011 Aggregate Grading Requirements

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89

Test Test Method Requirements

Los Angeles Abrasion value

Aggregate Impact value

IS2386 (Part-4)

IS2386 (Part-4) or IS5640

40 maximum

30 maximum

Combined Flakiness and Elongation Indices (Total)

IS2386 (Part-1) 40 maximum

Water absorption IS2386 (Part-3) 2 percent maximum

Liquid Limit of material passing 425 micron

IS2720 (Part-5) 25 maximum

Plasticity Index of material passing 425 micron

IS2720 (Part-5) 6 maximum

Table 40012 Physical Requirements of Coarse Aggregates for Crusher-run Macadam Base

If the water absorption is more than 2 percent soundness test shall be carried out as per IS2386 (Part-5) Combined Flakiness index and Elongation index

• ROAD AGGREGATES
• Slide 2
• Slide 3
• Aggregates forms the major part of pavement structure
• Slide 5
• Classification
• Sedimentary rocks - classified as per predominating material
• Desirable properties of aggregates
• Slide 10
• Slide 11
• Aggregate Gradation IS2386-1963 Part I
• Slide 13
• Slide 14
• Slide 15
• Slide 16
• Fuller and Thompsons Equation (Interactive Equation)
• The 045 Power Maximum Density Graph
• Slide 19
• Slide 20
• Slide 21
• To illustrate how the maximum density curves was determined Table shows the associated calculations for a maximum aggregate size of 190 mm
• Desired Gradation
• Slide 24
• Nominal Maximum and Maximum Size
• Fineness Modulus
• Aggregate Crushing Value IS 2386 (Part IV)
• Slide 28
• Slide 29
• Aggregate Impact Value IS 2386 (Part IV)
• Impact value
• Elongation amp Flakiness Index IS 2386
• Slide 33
• Aggregate Abrasion Value IS 2386 (Part IV)
• Slide 35
• Slide 36
• Slide 37
• Polished StoneValue (PSV) BS 812 Testing Aggregates Part 114
• Slide 39
• BITUMEN ADHESION
• Angularity number
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• UNIFORMITY COEFFICIENT (UC)
• Slide 48
• Granular subbases and bases
• Slide 50
• Purpose of base courses
• Slide 52
• Properties of soil aggregate mix
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• GRADING REQUIREMENTS
• Slide 61
• CONSTRUCTION
• Slide 63
• MORTampH Section 400 Sub-BasesBases (Non-Bituminous) and Shoulders
• Slide 65
• Strength of Sub-Base
• Slide 67
• LIME TREATED SOIL FOR IMPROVED SUB-GRADESUB-BASE
• Slide 69
• Slide 70
• Slide 71
• Slide 72
• WATER BOUND MACADAM SUB-BASEBASE
• Slide 74
• Slide 75
• Slide 76
• Slide 77
• Slide 78
• Slide 79
• Slide 80
• CRUSHED CEMENT CONCRETE SUB-BASEBASE
• WET MIX MACADAM SUB-BASEBASE
• Slide 83
• Slide 84
• SHOULDERS ISLANDS AND MEDIANS
• CEMENT CONCRETE KERB AND KERB WITH CHANNEL
• FOOTPATHS AND SEPARATORS
• Slide 88
• Slide 89