irc_109-1997 wet mix macadam

7/28/2019 Irc_109-1997 Wet Mix Macadam

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LRC ~IO9~19~7

GUIDELINES

FOR

WET MIX MACADAM


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IRC: 109-1997

GUIDELINESFOR

WET MIX MACADAM


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IRC: 109-1997

Published in April, 1997

(ThsRigh~iq~Publicwioi~a~sdTrai~vIatuz~iareRe.,eri~ed)


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IRC:109-1997

MEMBERS OF THE HIGHWAYS SPECEflCATIONS AND

STANDARDS COMMITTEE(As on 313.96)

1. AD. Narain DO (RD), MinistryofSurface Transport(Convener) (Roads Wing), New Ddhi

2. SC. Shunts Chief Engineer (R) Sids/R, Ministry of(Member-Secretary) Surface Transport (Roads Wing), New Delhi

3. CC. Garg Engineerin-Chief, Municipal Corporationof Delhi, Town flaB, Delhi-1IOX)6

4. Dr. MR Dhir Director, CSIR (RetcL),A-1/133,SafdarjangEnclave, New Delhi-I 10029

5. RN.Malik Chief Engineer (Mechj, Ministry ofSurfaceTransport (Roads Wing), NEWDELHI

6. (IS. Tawarrnalani AddI. Director General (Ski),CPWD,Ninnan Bhawan, New Delhi-I 1(X)l1

7. Dr. AK. Gupta Professor & Coordinator, Centre of TransportEngg., University ofRooricee, Roorkee

S. ii.?. Jamdar Secretary to the Govt. of Gujarat,R & BDept. Block No.14, Sachivalays Compler.,Gandhinagar-382010

9. MB. Jayawant Synthetic Asphalts, 103, Pooja Mahu l Road,themhur,Bombay-400074

10 . KS.Narayanan Chief Engineer (CCC), Mb. Environment&Forests (Reid), 13-23, Central Govt. Qtrs.,


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IRC: 109-1997

IS. The Director General,

lb. D r. S. Raghava Chari,

17 . Vinod Kumar

18. Ri Rao

19 Prof CV. R ats

20 Prof CC. Su amiisaihan

21 B. Megu

22. M.K. Saxena

23. Prof. DV. Singh

24. The Director

25. A. Sen

National Council forCement & BuildingMateiials, P21, South Eatn. IT, Ring Road,

New Delhi-Il 0049Transport Engg . Section, Depu. ofCivilEngg., Regional l3ngg. College, Warangal

Director & Ilead (Civil Engg.), Bureau ofindian Standards, Manak Rhawan, 9,

Bahadurshah Jafar Marg, New Delhi-Il 0002

Dy . Director & Head, Geotechnical Engg.l)ivision, Central Road Research Institute,DelhiMathura Road, New Delhi-Il ((020

Prof. ofCivil Engg., I.T.T., Ilau~iKhas,New Delhi-I 10016

Radii, 50, Thiruvankadam Street,R.A, Puram, Madras-600028

Chief Engineer (Zone-I), Arunachal Pradesh,PWD, ltanagar-79 1111

Director, National Institute for Trainingof

Highway Engineers, 174, Jo r Bagh,New Delhi-IIIXXI3

Director, Central Road Research lnstittiie,Delhi-Mathura Road, P.(XCRRI,Okhla,New Delhi-Il 0020

Highway Research Station, Guindy,Madraa~600025

Chief Engineer (Civil), indian RoadsConsiniction Corpn. Ltd., 6,Core, 6th lloor,Scope Complex, l,odhi Road, New Delhi


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IRC: 109-1997

3 2. Maj. Gen. ( 1 Chari

3 3 , Prof. N. Rangarusihan

3 4. RN. Siivastava

5 AK. Mishra

36. U.S. i3hatia

37. R.K. lain

38. President,Indian Roads Congress

39 Ron. Treasurer,

Indian Roads Congress

40. Seeretars,Indian Roads Congress

D.G.W., 13-in-Chiefs Branch, Anny }lqrs.,Kashmir House, I)IIQP0, New Delhi- 110011

Prof. & head, Depu. of Transport Planning,School ofPlanning & Architecture, 4,Block-li, Indraprastha Estate, New Delhi

Chief Engineer, Dy. Director General/DSI)te. General horsIer Roads, Kashmir ilouse,

Dl IQ P0, New I)elhi-1 10011

Director (Technical), Oil CoordinationCommittee,2nd Floor, Core-8, Scope Complex,7, Instituiional Area, Lixlhi Road, New Delhi-l 10003

(Thief Corrstiltant, Engineers & Management

Assoeiaies,3/5, Kalkaji Extn., New Delhi

ProjectDirector, ADR Project, Kothi No.1,Ninnan Kunj, Secsor-16A, Faridahad

MS. Curare,Chief Engineer, Punjab PWI),

B&R Branch, Patiala

AD. Narain,Director General (Road Develox-rsent),Ministry of Surface Transport(RoadsWing), New i)elhi

S.C SharmaChief Engineer (R), Ministry ofSurface Transport (Roads Wing),New I)elhi

- Er -Officio

Er.-Off icio

- E r. -Officio

CORREcp(:WD INCMEMBE)iS


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!RC:109-1997

CONTENTS

PageNo.

1. Introduction 1

2. Description 2

3. Materials 2

4. Construction Operations 4

5. Opening to Traffic 7

6. Surface Finish and Quality Control of Work 8

7. Measurement for Payment 9

8, Construction Process 9

9. Equipment Needs 9

10. Production of Aggregates 9

11. Proportioning of Aggregates and Mixing 10

12. Transportation 11

13 Spreading and Laying 11


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IRC:109-1997

GUIDELINES FOR WET MIX MACADAM

1 . INTRODUCTiON

Conventional Water Botind Macadam (WBM) construction is generallytime consum ing and manual, with copious u s e of water, The other disadvantagein WBM is that the segregation of aggregate takes place in the mix and the workresults in non-uniformity in thc finished surface. Wet Mix Macadam (WMM~construction is an improvement upon the conventionalWBMand is intended to bea s a n alternative a n d more durable pavement layer. It consists of clean, crushed,g r a d e d a gg r e ga t e s premixed with other granular materials and waterand rolled toa d e n s e m a ss o n a prepared su r f a c e .

The draft document p r e pa re d by flexible Pavement Committee wasd i sc u ss e d by th e Highways Specifications and Standards Committee in its meetingheld o n 12t h May, 1994 and it was decided that another draft prepared byMechanisation Com m ittee o n Wet Mix Macadam should b e clubbed with this inlight of comments of members since both th e s e items pertained to wet m ixmacadam. Accordingly the above drafts were referredback to th e newly constitutedFlexible Pavement Committee consisting of the following personnel for in-depthstudy:

Prof. A-K. GuptaProf. 5.5. J a m

Members

ConvenorMernber-Secre:ar~

Prof. C.G. SwaminathanEngineer-in-ChiefBranchMaj. Gen. C,T. ChariChief Engineer (S&R) (MOST)

DGF3R (B.L Tikko)I.C.G odC.S. SanwatDr. LR. Kadiyali


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IRC: 109-1997

The above Committce in i ts meeting held o n 24th May, 1994 requestedDr,L.R, Kadiyali to finalize th e draft on WMM in light of th e comments madc inH.S.S. Comtnittee o n 12th May, 1994, Accordingly, th e draft h a s b e e n finalised

by Dr. L,R. Kadiyali and was approved by th e Flexible Pavement Committee in itsmeeting held o n 13 th February, 1996.

The guidelines were discussed by lhe Highways Standards andSpecifications Committee in its meeting held on 19th March, 1996. It was decidedthat guidelines would have Iwo parts; Part I would deal with th e sp e c iIication of

Wet Mix Macadam and Part II v~otiklcover th e equipments for WMM, With thesemodifications, th e draft was approved. The guidelines approved by the ExecutiveCommittee in its meeting held on 17th April, 1996 wasconsidered by th e Councilin its meeting held on 24.5 .96 at Darjeeling. The guidelines were approvedby theCouncil subject to th e observations of th e members, which shottld b e consideredby th e Executive Committee before its publication. As decided by th e Executive

Committee in i t . s meeting held o n 4th September, 1996, th e comments of th emembers were duly examined by Shri A,P. Bahadur, in consultation with th eConvenor of Flexible Pavement Cotnmittee. The modified draft w as approved forpublication by th e Executive Committee in i ts meeting held o n 21.12.96.

PART I SPECIFICATIONS FOR WET MIX MACAI)AM

2. IWSCRWflOS

Wet Mix Macadam is a pavement layer wherein crushed gradedaggregates a n d granular material, like, g r a d e d c o u r s e s a n d a re mixed with water inmixing plant and rolled to a dense mass on a prepared surface, It h a s many

advantages over th e WBM construction. These include superior gradation ofaggregate, faster rate of construction, higher standard of densilication that can heachieved, less consumption of water and stricter standards of quality achievable.The specification can b e adopted for sub-base and base courses. The work may b edone in many layers. The thickness of a n individual layer shall not he less than 75


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IRC: 109-1997

if the water absorption value of the coarse aggregates is greatCr than 2 per

cent, soundness test shall b e carried out on th e material as per IS :2386 (Part V).

Table I. Physical Requirement olCoarse Aggregates for Wet-Mix

lest TestMethod Requirements

Lo s Angles -

Abrasion Value

IS:2386

(Part IV)

40 percent (Max)

orAggregate ImpactValue

IS:2386(Part tV or

IS:5640)

30 per cent (Max)

2. * (omhined Flakinessa n d Elongation

indices (Total

15:2386(Pan t)

30 per cent (Max)***

Aggregates m ay satisfy requirements ofeither of the two tests.*~ iodesenninethe combined proportion of flakyand elongated particles, theflaky stone

from a representative sample shoutd first he separated out. Flakiness index is weightof flaky stone metal dividesl hy weight ofstone sample. Only the elongated particlesbe separated out from the remaining (Non-flaky) stone metat. Elongation index is

weight of elongated partides divided by total non-flaky particles. The value offlakiness index and elongation index so found are added up.Requirement ol3Opereentcan berelaxed upto35percent (only) in e a se s whereWMM

is to he used a s sub base,

3.1.2. Grading requirements: The aggregates shall conform to the grading

given in Table 2.

Table 2. Grading Requirements orAggregates for Wet Mix Macadam

15 Sieve Deiugnauon Per cent by Weight Passing Sieve


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The nominal size of aggregate to b e used in a given c a s e would depend

on availability. While both the grading can b e used for b a s e / s u b - b a s e courses,course using Grading No.1 shall not b e laid over th e course using Grading No.2

The final gradation within the limits set forth in Table 2 shEll be wellgraded from c o a r s e to fine and shall not vary from the lower limit on one sieve tothe higher limit o n th e adjacent sieve or vice versa.

4. CONSTRUCflON OPERATIONS

4.1. Weather and Seasonal Limitations

The work of laying of wet m ix m a ca d a m shall not be done during rain.

4.2. Preparation of B a se

The surface of the sub-grade/sub-base/base to receive the WMM courseshall b e p r e pa re d to the specified lines and cross-fall (camber) and made free ofdust and otherextraneous matter. Any ruts or soft yielding placesshall b e correctedin a n approved manner and rolled until firm surface is obtained, if necessary bysprinkling water.

As far a s possible, laying of WMM course over a n existing thickbituminous layer may b e avoided since itwill c a u s e problems of internal drainageof the pavement at the interface of tw o co u r se s . . It is desirable to completelyexcavate the existing thin bituminous wearing c o u r s e where WMM is proposed tob e laid over it. However, where the intensity of rain is low (less th a n 1300 mm),and the interface drainage is efficient, WMM can b e bid over th e existing thinbituminous surfacing by cutting 50mm x 50mm furrow s atan angle of 45 d e g r e e sto the center line of the pavement at one meter intervals on the existing mad. Thedi ti d d th f f h ll b h th t th id d t b d


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IRO 109-1997

4.4. Preparation of Mix

WMM shall b e p r e pa re d in a n approved mixing plant of suitable capacityhaving provision for controlled addition of water and forced/positive mixingarrangement, like, pugmill or pan type mixer. For small quantity ofwet mix work,mixing may be done in ordinary concrete mixers. The Specifications andrequirements for equipment for WMM are discussed in Part H . The equipment

should conform to requirements detailed in Part II.

Optimum moisture for mixing shall be determined, in accordance withIS :2720 (Part VIII), after replacing the aggregate fraction retained on 19mm sievewith material of 4.7 5 to 19mm s ize . However, the O M C and required number ofpa sse s to achieve the desired density may b e determined at s i t e duringproofmlling,

using th e rollerselected for compaction. While adding water, due allowance shouldb e made for evaporation l o s se s , However, at the time of compaction, water in thewet mix should not vary by more th a nI per cent.

4.5. Spreading of Mix

Immediately after mixing, th e mixed material sh all b e transported to s i t eand spread uniformly and evenly upon the prepared subgrade/sub-base/base inrequired quantities. Hauling of th e mix over a freshly completed stretch is notpermitted.

The mix may b e sp r e a d either by a paver finisher or motor grader or a

combination of both. However, th e u s e of paver finisher should b e preferred tomotor grader for spreading. For portions where mechanica) m e a n s cannot b e u s e d ,manual method of spreading c a n h e adopted. The equipment used for spreadingshall b e capable of spreading th e material uniformly all over the su r f a c e . Its bladeshall have hydraulic controls suitable for initial adjustments and maintaining th e


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IR(: 109.1997

material as may b e required, The layer thickness may b e checked by depth blocks

during construction, No segregation of coarse or fine particles shall b e allowed.The layer as spread shall b e of uniform gradation and shalt not have pockets of finematerials.

4.6. Compaction

After the mix h a s been laid to the required thickness, grade andcross-fall/camber, th e same shall b e t in iformly com pacted to th e full depth with asuitable roller, If th e thickness of th e single compactc.d layer does not exceed 1 (X )mm, a smooth wheel roller of 80 to 1(X ) kN weight may b e used. For compactingsingle laser of higher thickness uplo 200 mm, th e compaction sh a l l h e d o ne withth e help of vibratory roller of minimum 80.1(X) kN static weight or equivalent

capacity to achieve th e desired density. The speed ofrollershall notexceed 5km/hr.

In portiotis having ttnidireclional cross-fall/supcrnlevation, rolling shallcommence from th e lower edge and progress gradually towards th e tipper edge.Therealier roller should progress parallel to the center line of th e road, uniformlyoverlapping each preceding track by at least one-third width untilthe entire surface

h a s been rolled ttpto the centre line. The process of compaction is then to h erepealed from th e 01 her edge of th e pavement upto th e centre line, until th e entirepavement is compacted. Any displacement occurring as a result of reversing ofth e di rection of a roller or from any ot her catise shall he corrected,

Along fornts, kerhs. walls or other places not accessible to th e roller, th e

ttiix shall h e thoroughly compacted with mechanical tatnpers or a platecompactor.Skin patching of a n area without scarifying th e stirface 10 permit proper bondingof the added material shall nol h e permitted.

Rolling should not h e (lone when the subgrade is soft or yielding or when

1 0 9 1 9 9


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defective areas shall be made good to the full thickness of th e layers andrecorril)acted.

Longitudinal joints and e d g e s shall b e constructed true to th e delineatingline parallel to th e centre line of th e road, All longitudinal and transverse jointsshall b e cut vertical to th e full thickness of the previously laid mix before layingth e fresh mix.

4.7. Important Considerations in Construction Process

While dtte care and attention is required on th e whole process of WMM

construction, th e following are important points needing more attention:-i) Sometimes heeause of moisture in the fines, these will not flow out from thebinof the

three-bin feeder to the belt, In such sttuauon, it wouldbe neeetsary to have a smatt

vibrator fitted on one ofthe side w aU s of the binto

intemsiteniiy shake it.

u) Cssntrot ott water in the mix is of utmost importance; hence there should not he anyvanation in the grading, particularly offines a s it witt effect themoisture content andunifonn m i sing. Similarly, excessive fitictuations in the nsoiteure content of the finesshould be avoided, tfnecessary, slight increase m ay he made in the moisture contentstoaccount for the moisture tots in transit s o the taying site.

itt) Excessive siltor clay in fines shoulst not h e permitted, a s besides spoiling the qualityofmix,it will cause cloggtng in pugmit and storage silo.

iv) lhe mixed maienal should he transported directty to site. Stockpiting of mixedmaterial should be discouraged a s excessive handling is the cause of segregation andmoisture loss, both of which are detrimental to the quality of the wet mix macadam.

4 There should he minimum joints in laying wet mix macadam. To ensure this, the dailyoutput should at least he 500 linear meters. The widthof laying also should be s oadjusted to avoid the necessity of laying narrow strips e.g. against kerbs.

1RC 109 1997


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1RC:109-1997

6. SURFACE FINISH AND QUALITY CONTROL OF WORK

6.1. The surface levels of a wet mix layer laid as a sub-base shall have a

tolerance of notmore than + I 0mm and -20mm from the designed longitudinal andcross profile. When laid as a base course with machines, the tolerance shall be+10mm and -10mm. For checking compliance with this, surface levels shall betaken on a grid of points placed 6.25 m longitudinally and 3.5m transversely. Forany 10 consecutive measurements taken longitudinally or transversely, not morethan one measurement shall he permitted toexceed the above tolerances, thus one

measurement being not in excess of5mm above the permitted tolerance.

6.2. The longitudinal profile shall also be checked by a 3 meter straight edgeat the middle of each traffic lane along a line parallel to the centre line ofthe road.The maximum allowable diFference between the road surfaceand underside of a 3meter straight edge shall be 8 mm.

The frequency of the Quality Control tests shall be as under:

I, Gradation One Test per 200 o f2 . Ptasticit~index One lest per 2( X ) m3 . Moisture Ccwitent prior to cx%npaction One test per 250m~4 . t)ensttv of compacted layer One test per 50(1m~

5 . Aggregate Impact Value or 1.os 5Angeles Abrasion Value One test per 500 m~

6, Ilakinecs and Etongat on Index One test per 500 m

6.3. For testing the compaction requirements, test locations shall be chosenonly through random sampling techniques.. Control shall nothe based on the resultofany one test but on the mean value of5-10 density determinations, The numberof tests in one set ofmeasurements shall be 6 (ifnon-destructive tests are carriedout, the number of tests shall he doubled) as long as it is felt that sufficientcontrolover the constituent materials forming the mix is being exercised. Ifconsiderablevariations i.e. 1 5~fand above are observed between individual density results, the


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IRC: 109-1997

affected area reshaped with added premix material or removedand replaced withfresh premix material and recompacted. The area treated in thismanner shall not

be less than 5 m longand 2 m wide. In no case shall depressions be filled up withunmixed and ungraded material or fines,

7. MEASUREMENT FOR PAYMENT

Wet mix macadam shall be measured as finished work in position in cubic

meters.

PART II: EQUIPMENT FOR WET MIX MACADAM

8. CONSTRUCTION PROCESS

The construction process of wet mix macadam involves the following

sub-activities:-1) Production ofaggregates in required sizes.ii) Proportioningofaggregates and mixing with water.

iii) Transportation ofntix,iv) Spreading and taving.

v) Compaction.

The whole process should be such that methods adopted and equipmentused meet the laid down requirements ofend result specifications inrespectofsizesand grading ofaggregates, optimum moisture content, proper mixing, laying inuniform thickness to the correct profile and reqtiired compaction.

9. EQUtPMENT NEEDS

The equipment requirement for WMM is simple. Mostof the equipmentneeded for other activities, like stone crushers, tippers, motor grader, paver and


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II. PROPORTIONING OF AGGREGATFS AND MIXING

11.1. Pmportioning and mixing can be done indifferent ways depending on thetotal methodology ofworkadopted.

11.2. Concrete Mixer

Forsmall quantitiesof WMM, concrete mixercan be used for production

ofmix and diffcrent fractions can be added by box measurement as in the case ofmanual feeding of mixer for producing concrete, In this method, the usual facilityof measuring water is a overhead tank which will not be very accurate. Further,because of limitations such as the size and capacity of mixer, manual feeding andnon-continuous production ofmix makes~,this method i s unsuitable for large scalework.

11.3. Batching and Mixing Plant

11,3.1. In order 1 0 obtain uniform WMM material using batch plant, only pantype mixing plant should be used,since it provides the force mixing ofthe differentconstituents ofthe in ix. The mixing time may have to be increasedformore uniform

dispersal of low water content in the mix. Blending of aggregates and mixing canbe achieved through storage bins and weigh hoppers.

11.3.2. Bin feeder & pugm ill

For continuousproduction ofmix in a pugmill in sufficient quantity, the

best way to feed the aggregates and control the grading is by means of a 3 or 4 binsfeeder with belt conveyor. It is similar to the bin feeder of a hot mix plant hutwithout variable speed motors and load sensor as the required grading can beachieved with the adjustment of gate openings itself. Such a unitconsisting of3or 4 bins feeder, belt conveyors, pugmill and water pump arrangementis the most


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IRC: 109-1997

v) lhe angle ofinclination of secondary conveyor should not be more than 1 9 degrees.

vi) The twin-shaft pugmiti should have replaceable inner linerplatea.

vii) The clearance between the tips ofthe paddles and linenshould he less than maximumstone size sothat the aggregates arepushed forward whilemixing. This typeofpaddlesshould bc adjustable so that clearance can he set according to maximum size ofaggregate.

The mixing of aggregates and water is done in a continuous twin-shaftpugmill or paddle mixer. Unlike a drum mixer where mixing is achieved by

rotation of the drum and flights inside it, there is forced action-mixing ina pugmillwhich is better for uniform coating offilm ofmoisture. As such the use ofDrumMix Plant is notsuitable for producing WMM. The controlled amount of water isadded in the pugmill by a spray bar with the help of a variable speed pump and aflow meter. This arrangement provides a precise control on the quantityofwaterwhich is very critical for the successofWMMconstruction. In this method, feeding

ofaggregates, addition of water and mixing are continuous operations. The mixcan be either directly discharged into the tipping truck or taken through a beltconveyor to a storage silo. lt is advantageous to have a storage silo, as it helps incontinuous production of mix even when no tipping truck is readily available forloading, Also loading oftipper through storage silo takes less time. Thus therewill be saving in the number of tipping trucks required.

12. TRANSPORTATION

Transportationofmix i s usually done by tipping trucks,

I n order t o avoid moisture loss i n tra n sit due to ev aporation, mix should

b e cov ered with T arp au lin .13. SPREADING AND LAYING

For this j ob, there are two c lear altern atives in the choice ofequipment.


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IRC: 109-1997

b) Better control of thicknessand profile ofthe layer.

c) Paver has the facilityofpreconipaettng the layer andhence th e surface finish isbetter,

d) Initial cost oftht mechanical

paver is low.

e) No wastage of wet mix macadamwhile laying as there is notide flow ofthe mix.

ii) Grader

a) Faster to work.

Advantage

h) Can work on slightly imper-

fect sub-grade.

c) Require less maintenance.

b) Wear &tear ofaugerand chain ar e frequent;as such maintenance

cost is htgh.

c) Maximum gap betweenaugerand side plateshould not he morethan 15cm, otherwisethe spaces will have

to he fill manually, whichin turn will not heproperly compactedleading to difficultyin maintaining the levels.

1)isadvantage

a) Lets accurate inprofile and surface finish

h) Wasteofmaterial is

high due to sideslippage ofthe mix.

c) Lack ofuniformity andproper levelling of layers.


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S

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irc_109-1997 wet mix macadam

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