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CONTENTS

College Certificate ii

Abstract iii

Acknowledgement iv

Table of Contents 01

List of Figures 03

1. Introduction 05

1.1. Types of Pavements 05

1.2. Design of Flexible Pavements 07

1.3. Traffic and Loading 07

1.3.1. Fixed traffic 08

1.3.2. Fixed vehicle 08

1.3.3. Variable traffic and vehicle 08

2. Material used 09

2.1. Cement 09

2.1.1. Properties of cement 09

2.1.2. Harmful constituents of cement 09

2.2. Aggregate 10

2.3. Sand 11

2.4. Bitumen 11

3. Construction methodology 14

3.1 Construction of bituminous roads 14

3.2 Types of bituminous construction 14

3.3 Methods of construction 15

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3.3.1. Bituminous Construction procedures 15

3.3.2. Construction Procedure for Bituminous Concrete 16

3.4. Specifications of materials 16

4. Highway Pavement Failure 18

4.1. Introduction 18

4.2. Failures 19

4.3. Causes of Premature Failures 19

4.4. Common Flexible Pavement Failure/ Distresses. 20

4.5. Types of Distresses/Failures and Definitions. 20

5. Highway Maintenance 33

5.1. Definition / Objectives 33

5.2. Surface treatment of highways 38

5.3. Mowing 39

5.4. Drainage Systems 40

5.5. Traffic Control Devices 40

6. Conclusion 42

7. References 43

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LIST OF FIGURES

Figure 1 : Pavement Layers 06

Figure 2 : Aggregates 10

Figure 3 : Bitumen 12

Figure 4 : Asphalt Surfacing 15

Figure 5 : Wheel load on pavement 18

Figure 6 : Load Distribution 19

Figure 7 : Longitudinal Cracking 21

Figure 8 : Fatigue Cracking 21

Figure 9 : Transverse Cracking 22

Figure10: Reflection Cracking 22

Figure11: Block Cracking 23

Figure12: Edge Cracking 23

Figure13: Rutting 24

Figure14: Corrugation 24

Figure15: Shoving 25

Figure16: Depression 25

Figure17: Overlay Bumps 26

Figure18: Delamination 26

Figure19: Pot Holes 27

Figure20: Patching 27

Figure21: Raveling 28

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Figure22: Stripping 28

Figure23: Polished Aggregate 29

Figure24: Pumping 29

Figure25: Segregation 30

Figure26: Checking 30

Figure27: Bleeding & Flushing 31

Figure28: Rock Loss 31

Figure29: Bleeding 32

Figure30: Maintenance Work 34

Figure31: Crack Sealing 35

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1.INTRODUCTION TO HIGHWAY

Roads are considered as the lifeline of any country. Some of the important roles roads in India’s

economy are:

1. Connection to villages.

2. Communication in hilly terrain.

3. Carriers of freight and passengers complementing the railways

4. Helps agricultural development

5. Administrative convenience, etc.

Engineers have been always with open mind to adopt any material available to them for its use

for the construction purposes. It is logical to see that the purpose of highway construction is to

provide a firm and even surface for the carriageway or the pavement which could stand the stress

caused due to number of load applications.

Types of Highway construction

Earth road and gravel roads.

Soil stabilized roads.

Water bound macadam (WBM) road.

Bituminous or black-top roads.

Cement concrete roads.

1.1 Types of Pavements:-

From the point of view of structural performance, pavements can be classified as:

Flexible

Rigid

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Semi-rigid

Composite

Fig.-1 Pavement Layers

Flexible pavements are so named because the total pavement structure defects, or exes, under

loading. A flexible pavement structure is typically composed of several layers of materials. Each

layer receives loads from the above layer, spreads them out, and passes on these loads to the next

layer below. Thus the stresses will be reduced, which are maximum at the top layer and

minimum on the top of sub grade. In order to take maximum advantage of this property, layers

are usually arranged in the order of descending load bearing capacity with the highest load

bearing capacity material (and most expensive) on the top and the lowest load bearing capacity

material (and least expensive) on the bottom.

A Rigid pavement derives its capacity to withstand loads from the flexural strength or beam

strength, permitting the slab to bridge over minor irregularities in the sub grade, sub-base or base

upon which it rests. A Semi-rigid pavement represents an intermediate state between the flexible

and the rigid pavement. It has much lower flexural strength compared to concrete slabs. A

Composite pavement is one which comprises of multiple, structurally significant layers of

different-sometimes heterogeneous-composition.

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1.2 Design of Flexible Pavements:-

In the design of flexible pavements, it has yet not been possible to have a rational design method

wherein design process and service behaviour of the pavement can be expressed or predicted

theoretically by mathematical laws.

Flexible pavement design methods are accordingly either empirical or semi-empirical. In these

methods, the knowledge and experience gained on the behaviour of the pavements in the past are

usefully utilized.

There are some various methods used to design of flexible pavement:

Group Index Method

California Bearing Ratio Method

California R Value or Stability meter method

Tri axial test method

McLeod method

Burmister method

The design method, the GI, CBR, Stability meter and McLeod methods are empirical methods.

The Tri axial test method is a theoretical method using empirical modifications as suggested by

Kansas State highway Department and therefore may be considered as a semi-empirical method.

Bur mister method is a theoretical approach using elastic two-layer theory.

1.3 Traffic and Loading:-

There are three different approaches for considering vehicular and traffic characteristics, which

affects pavement design.

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1.3.1 Fixed traffic:-

Thickness of pavement is governed by single load and number of load repetitions is not

considered. The heaviest wheel load anticipated is used for design purpose. This is an old

method and is rarely used today for pavement design.

1.3.2 Fixed vehicle:-

In the fixed vehicle procedure, the thickness is governed by the number of repetitions of a

Standard axle load. If the axle loads is not a standard one, then it must be converted to an

equivalent axle load by number of repetitions of given axle load and its equivalent axle load

factor.

1.3.3 Variable traffic and vehicle:-

In this approach, both traffic and vehicle are considered individually, so there is no need to

assign an equivalent factor for each axle load. The loads can be divided into a number of groups

and the stresses, strains, and deflections under each load group can be determined separately; and

used for design purposes. The traffic and loading factors to be considered include axle loads,

load repetitions, and tyre contact area.

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2.MATERIAL USED IN CONSTRUCTION

2.1 Cement:-

The natural cement is obtained by burning and crushing the stones containing clay, carbonate of

lime and some amount of carbonate of magnesia. The clay content in such stones is about 20 to

40 percent. The natural cement is brown in colour and its best variety is known as the Roman

Cement. The natural cement resembles very closely eminent hydraulic lime. It sets very quickly

after addition of water. It is not so strong as artificial cement and hence it has limited use in

practice. The artificial cement is obtained by burning at a very high temperature a mixture of

calcareous and argillaceous materials. The mixture of ingredients should be intimate and they

should be in correct proportion. The calcined product is known as clinker. A small quantity of

gypsum is added to the clinker and it is then pulverized into very fine powder which is known as

the cement.

2.1.1Properties of cement:-

Following are the important properties of good cement which primarily depend upon its

chemical composition, thoroughness of burning and fineness of grinding:

It gives strength to the masonry.

It is an excellent binding material.

It is easily workable.

It offers good resistance to the moisture.

It possesses a good plasticity.

It stiffens or hardness early.

2.1.2 Harmful constituents of cement:-

The presence of the following two oxides adversely affects the quality of cement:

Alkali oxides K2O and Na2O

Magnesium oxide MgO

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If the amount of alkali oxides exceeds 1 percent, it leads to the failure of concrete made from that

cement. Similarly, if the content of the magnesium oxide exceeds 5 %, it causes cracks after

mortar or concrete hardens. It is due to the fact that magnesium oxide, burned at a temperature of

about 1500°C, slakes very slowly, when mixed with water.

2.2 Aggregate:-

Construction aggregate, or simply "aggregate", is a broad category of coarse particulate material

used in construction, including sand, gravel, crushed stone, slag, recycled concrete and geo

synthetic aggregates. 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. Due to the relatively high hydraulic conductivity value as compared to most soils,

aggregates are widely used in drainage applications such as foundation and French drains, septic

drain fields, retaining wall drains, and road side edge drains. To put it another way, aggregates

are used as a stable foundation or road/rail base with predictable, uniform properties (e.g. to help

prevent differential settling under the road or building), or as a low-cost extender that binds with

more expensive cement or asphalt to form concrete.

Fig.-2 Aggregates

The American Society for Testing and Materials publishes an exhaustive listing of specifications

for various construction aggregate products, which, by their individual design, are suitable for

specific construction purposes. These products include specific types of coarse and fine

aggregate designed for such uses as additives to asphalt and concrete mixes, as well as other

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construction uses. State transportation departments further refine aggregate material

specifications in order to tailor aggregate use to the needs and available supply in their particular

locations.

2.3 Sand:-

Sand is a naturally occurring granular material composed of finely

divided rock and mineral particles. The composition of sand is highly variable, depending on the

local rock sources and conditions, but the most common constituent of sand in inland continental

settings and non-tropical coastal settings is silica(silicon dioxide, or SiO2), usually in the form

of quartz.

As the term is used by geologists, sand particles range in diameter from 0.0625mm (or 1⁄16 mm,

or 62.5 μm) to 2 mm. An individual particle in this range size is termed a sand grain. The next

larger size class above sand is gravel, with particles ranging from 2 mm up to 64 mm

(see particle size for standards in use). The next smaller size class in geology is silt: particles

smaller than 0.0625 mm down to 0.004 mm in diameter. The size specification between sand and

gravel has remained constant for more than a century, but particle diameters as small as 0.02 mm

were considered sand under the Albert Atterberg standard in use during the early 20th century. A

1953 engineering standard published by the American Association of State Highway and

Transportation Officials set the minimum sand size at 0.074 mm. A 1938 specification of

the United States Department of Agriculture was 0.05 mm sand feels gritty when rubbed

between the fingers (silt, by comparison, feels like flour).

2.4 Bitumen:-

Bitumen is a black, oily, viscous material that is a naturally-occurring organic by product of

decomposed organic materials. Also known as asphalt or tar, bitumen was mixed with other

materials throughout prehistory and throughout the world for use as a sealant, adhesive, building

mortar, incense, and decorative application on pots, buildings, or human skin. The material was

also useful in waterproofing canoes and other water transport, and in the mummification process

toward the end of the New Kingdom of ancient Egypt. It is also flammable. And, thanks to recent

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scholarship, this gooey stuff is also identifiable to source.

Fig.-3 Bitumen

POINTS TO CONSIDER:-

The producer of bituminous mixtures, in purchasing a specified bitumen binder will expect that

binder to possess the properties he has specified.

The producer will expect the binder to be delivered at the time he has specified, not before,

holding tanks may not be empty and cleaned, and not after, he may have run out of that particular

binder and had to cease production causing "knock on" problems.

The producer will expect binders to be delivered at agreed temperatures that do not cause

handling or storage problems.

The producer should be able to store bitumen in the manner recommended by the supplier and in

accordance with various appropriate British Standards specifications.

The producer should incorporate the purchased binder into bituminous mixtures, regarding

amount, type and mixing temperature, as specified in a British Standard specification or

Published Document, as set down in the design of a proprietary material, or as an agreed

design/specification supplied by the Engineer.

The production plant will use a "recipe" to manufacture any bituminous mixture whether a

"specified" mixture or a proprietary material, even if the material is to be assessed on a

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performance basis. There is no other way to produce large amounts of a uniform material, you

need a "recipe" in the control room of the mixing plant to know what to mix together to obtain

the material you want.

The producer will have manufactured the material in accordance with the order placed at the

plant by the laying contractor or engineer in charge of the work.

The producer cannot be held responsible if the material ordered is not suitable for the situation in

which it is being used, he will produce and supply the material ordered.

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3.CONSTRUCTION METHOLOGY AND GENERAL

SPECIFICATIONS

3.1 Construction of Bituminous Roads:-

Bituminous pavements are in common use in India and abroad. Flexible pavements could be

strengthened in stages by constructing bituminous pavement layers one after another in a certain

period of time unlike the cement concrete pavement construction. The problem associated with

the construction of bituminous pavements is control of the proper viscosity of the bituminous-

aggregate mixtures during mixing and compaction operations. Bituminous constructions are also

adopted for base and binder courses of pavements on heavy-traffic roads.

3.2 Types of Bituminous Constructions:-

The followings construction techniques are in use:

Interface treatments like prime coat and tack coat

Surface dressing and seal coat

Ground or penetration type constructions.

Penetration Macadam

Built-up Spray Grout

Premix which may be any one of the following:

Bituminous bound macadam

Carpet

Bituminous Concrete

Sheet Asphalt or Rolled Asphalt

Mastic Asphalt

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3.3 Methods of Construction:-

Premix types of Bituminous Constructions are generally carried out in the field using appropriate

plants. There are two types of Mixing Plant and Travelling Plant. The canter mixing plant

consists of units for batching different materials, separate heating units for mixed aggregates and

bitumen and a mixing unit of large capacity. The aggregates, filler and bitumen are transported to

the site of the mixing plant which is stationed at a suitable location and the bituminous mix is

again transported from the plant to the construction site. Generally there is very good control on

the quality of the mix obtained from the central mixing plant. The travelling Plant is a smaller

unit and can be shifted from time to time the road side as the bituminous construction progresses.

In hot mix constructions the heated aggregates are mixed with heated bitumen in a central or

travelling plant. In cold mix method, the aggregates at atmospheric temperature are mixed with

bituminous material of low viscosity in cold or after slight heating.

Fig.- 4 Asphalt Surfacing

3.3.1 Bituminous Construction procedures:-

In this Article, the material requirements, plant and equipment and construction process

Employed for the following types of bituminous constructions have been presented:

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Surface Dressing

Grouted or Penetration Macadam

Built-up Spray Grout

Bitumen Bound Macadam

Bitumen Carpet

3.3.2 Construction Procedure for Bituminous Concrete:-

The bituminous concrete is the highest quality of construction in the group of black top surfaces.

Being of high cost specifications, the bituminous mixes are properly designed to satisfy the

design requirements of the stability and durability. The mixture contains dense grading of coarse

aggregate, fine aggregate and mineral filler coated with bitumen binder. The mix is prepared in

hot-mix plant. The thickness of the bituminous concrete layer depends upon the traffic and

quality of base course. The mix is prepared in a hot-mix plant. The thickness of the bituminous

concrete layer depends upon the traffic and quality of base course.

3.4 Specifications of materials:-

(a) Binder: Bitumen of grade 30/40, 60/70, or 80/100 may be chosen depending upon the

climatic condition of the locality.

(b) Aggregate and filler: The coarse aggregate should fulfil the following requirements:

Aggregate impact value, maximum percent : 30

Los Angles abrasion value, max percent : 40

Flakiness Index, max percent : 25

Stripping at 40°C after 24 hours, max percent : 25

Soundness:

Loss with sodium sulphate in 5 cycles, max. Percent : 12

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Loss with magnesium sulphate in 5 cycles, max. Percent : 18

(c) Bituminous concrete mix:

Marshall Stability Test-number of blows to be applied on either side of specimen:50

Marshall Stability value, Minimum kg : 340

Marshall Flow value, 0.25 mm units : 8 to 16

Voids in mix, Percent : 3 to 5

Voids filled with bitumen, Percent : 75 to 85

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4.HIGHWAY PAVEMENT FAILURE

4.1 Introduction:-

A highway pavement is a structure consisting of superimposed layers of processed materials

above the natural soil sub-grade, whose primary function is to distribute the applied vehicle loads

to the sub-grade. The pavement structure should be able to provide a surface of acceptable riding

quality, adequate skid resistance, favorable light reacting characteristics, and low noise pollution.

The major Flexible pavement failures are fatigue cracking, rutting, and thermal cracking. The

fatigue cracking of flexible pavement is due to horizontal tensile strain at the bottom of the

asphaltic concrete. The failure criterion relates allowable number of load repetitions to tensile

strain and this relation can be determined in the laboratory fatigue test on asphaltic concrete

specimens. Rutting occurs only on flexible pavements as indicated by permanent deformation or

rut depth along wheel load path. Two design methods have been used to control rutting: one to

limit the vertical compressive strain on the top of sub-grade and other to limit rutting to a

tolerable amount (12 mm normally. Thermal cracking includes both low temperature cracking

and thermal fatigue cracking.

Fig.- 5 Wheel load on pavement

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Fig.- 6 Load Distribution

4.2 Failures may be:-

Failure in sub grade

Inadequate Stability

Excessive application of stresses

Plastic deformation

Failures in sub base or Base course

Inadequate stability

Loss of binding action

Loss of bearing course materials

Inadequate wearing course

4.3 Causes of premature failures:-

Rutting due to high variation in ambient temperature.

Uncontrolled heavy axle loads.

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Limitation of pavement design procedures to meet local environmental conditions.

4.4 Common Flexible Pavement Failure/ Distresses:-

Cracking

Deformation

Deterioration

Mat problems

Problems associated with seal coats

Category Distress type 1. Cracking Longitudinal, Fatigue, Transverse, reflective, block, edge

2.Deformation Rutting, Corrugation, Shoving, depression, overlay bumps

3. Deterioration Delamination, Potholes, Patching, raveling, stripping, Polished

aggregate, Pumping

4.Mat Problems Segregation, Checking, Bleeding

5.Seal coats

Rock loss, Segregation, bleeding/fat spots, Delamination

4.5 Types of Distresses/Failures and Definitions:-

Longitudinal Cracking:

Cracks that are approximately parallel to pavement centre line and are not in the wheel path.

Longitudinal cracks are non-load associated cracks. Location within the lane (wheel path versus

non-wheel path) is significant. Longitudinal cracks in the wheel path are normally rated as

Alligator ‘A 'cracking.

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Fig.- 7 Longitudinal Cracking

Fatigue Cracking:

Cracks in asphalt layers that are caused by repeated traffic loadings. The cracks indicate fatigue

failure of the asphalt layer. When cracking is characterized by interconnected cracks, the

cracking pattern resembles that of an alligator’s skin or chicken wire. Therefore, it is also

referred to as alligator cracking.

Fig.- 8 Fatigue Cracking

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Transverse Cracking:

Cracks that are predominately perpendicular to pavement centerline and are not located over

Portland cement concrete joints. Thermal cracking is typically in this category.

Fig.- 9 Transverse Cracking

Reflection Cracking:

Cracks in HMA overlay surfaces that occur over joints in concrete or over cracks in HMA

pavements.

Fig.- 10 Reflection Cracking

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Block Cracking:

Pattern of cracks that divides the pavement into approximately rectangular pieces. Rectangular

blocks range in size from approximately 0.1 square yard to 12 square yards.

Fig. - 11 Block Cracking

Edge Cracking:

Crescent-shaped cracks or fairly continuous cracks that intersect the pavement edge and are

located within 2 feet of the pavement edge, adjacent to the unpaved shoulder. Includes

longitudinal cracks outside of the wheel path and within 2 feet of the pavement edge.

Fig.- 12 Edge Cracking

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Rutting:

Longitudinal surface depression that develops in the wheel paths of flexible pavement under

traffic. It may have associated transverse displacement.

Fig.- 13 Rutting

Corrugation:

Transverse undulations appear at regular intervals due to the unstable surface course caused by

stop-and-go traffic.

Fig.- 14 Corrugation

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Shoving:

A longitudinal displacement of a localized area of the pavement surface. It is generally caused by

braking or accelerating vehicles, and is usually located on hills or curves, or at intersections. It

also may have vertical displacement.

Fig.- 15 Shoving

Depression:

Small, localized surface settlement that can cause a rough, even hazardous ride to motorists.

Fig.- 16 Depression

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Overlay Bumps:

In newly overlaid pavements, bumps occur where cracks in old pavements were recently filed.

This problem is most prevalent on thin overlays.

Fig.- 17 Overlay Bumps

Delamination:

Loss of a large area of pavement surface. Usually there is a clear separation of the pavement

surface from the layer below. Slippage cracking may often occur as a result of poor bonding or

adhesion between layers.

Fig.- 18 Delamination

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Pot holes:

Bowl-shaped holes of various sizes in the pavement surface. Minimum plan dimension is 150

mm.

Fig.- 19 Pot Holes

Patching:

Portion of pavement surface, greater than 0.1 sq. meter, that has been removed and replaced or

additional material applied to the pavement after original construction.

Fig.- 20 Patching

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Raveling:

Wearing away of the pavement surface in high-quality hot mix asphalt concrete that may be

caused by the dislodging of aggregate particles and loss of asphalt binder.

Fig.- 21 Raveling

Stripping:

The loss of the adhesive bond between asphalt cement and aggregate, most often caused by the

presence of water in asphalt concrete, which may result in raveling, loss of stability, and load

carrying capacity of the HMA pavement or treated base.

Fig.- 22 Stripping

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Polished aggregate:

Surface binder worn away to expose coarse aggregate.

Fig.- 23 Polished Aggregate

Pumping:

Seeping or ejection of water and fines from beneath the pavement through cracks.

Fig.- 24 Pumping

Segregation: Separation of coarse aggregate from fine aggregate as a result of mishandling of

the mix at several points during mix production, hauling, and placing operations. Segregation

leads to non-uniform surface texture and non-uniform density.

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Fig.- 25 Segregation

Checking:

Short transverse cracks, usually 1 to 3 inches in length and 1 to 3 inches apart, which occur in the

surface of the HMA mat at some time during the compaction process. The cracks do not extend

completely through the depth of the course, but are only about ½inch deep.

Fig.- 26 Checking

Bleeding/Flushing:

Excess bituminous binder occurring on the pavement surface. May create a shiny, glass-like,

reflective surface that may be tacky to the touch. Usually found in the wheel paths.

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Fig.- 27 Bleeding & Flushing

Rock Loss: Wearing away of the pavement surface in seal coats.

Fig.- 28 Rock Loss

Bleeding/Fat Spots:

Excess binder occurring on the surface treated pavements. May create a shiny, glass-like,

reflective appearance. Fat spots are localized bleeding.

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Fig. 29 Bleeding

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5.HIGHWAY MAINTENANCE

5.1 Definition / Objectives:-

Preserving and keeping each type of roadway, roadside, structures as nearly as possible in its

original condition as constructed or as subsequently improved and the operation of highway

facilities and services to provide satisfactory and safe transportation, is called maintenance of

Highways.

The various maintenance functions includes:-

1. Surface maintenance

2. Roadside and drainage maintenance

3. Shoulder and approaches maintenance

4. Snow and ice control

5. Bridges maintenance

6. Traffic service

Highway maintenance is closely related to the quality of construction of original road.

Insufficient pavement or base thickness or improper construction of these elements soon

results in expensive patching or surface repair.

Shoulder care becomes a serious problem where narrow lanes force heavy vehicle to

travel with one set of wheels off the pavement.

Improperly designed drainage facilities, mean erosion or deposition of material and costly

cleaning operation or other corrective measures.

Sharp ditches and steep slopes require manual maintenance as compare to cheap

maintenance of flatter ditch and soil by machine.

In snowy country, improper location extremely low fills and narrow cuts leave no room

for snow storage, creating extremely difficult snow removal problems.

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Fig.- 30 Maintenance Work

5.1.1 Surface maintenance of Roads:-

Pavement maintenance and rehabilitation programs, restore riding quality and maintain the

structural integrity of the pavement over its full design life. Asphalt concrete pavements are

subjected to various types of pavement distress or Failure these include.

i. Alligator Cracking:

A series of interconnecting or interlaced cracks caused by fatigue of the asphalt concrete surface

under repeated traffic leading. [Cracking is due to foundation movement at subgrade]

ii. Block Cracking:

Cracks forming large interconnected polygon usually with sharp corners or angles. These cracks

are generated by hardening or shrinking e.g. asphalt or reflection cracking for underlying layers

such as cement treated base.

iii. Transverse Cracking:

Cracks approximately at right angle to the pavement center line. These may be caused by

hardness and shrinkage of asphalt or differential thermal stresses of asphalt concrete or may be

reflection cracking.

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iv. Longitudinal Cracking:

Cracks approximately parallel to the pavement centerline. These are caused by poorly

constructed construction joints and shrinkage of the asphalt concrete surface. Longitudinal cracks

may also be reflection cracks.

Fig.- 31 Crack Sealing

v. Raveling:

Wearing away the pavement surface caused by dislodging of aggregate particles and binders.

This is usually a result of insufficient asphalt binder in the mix or stripping of asphalt from

particles of aggregate.

vi. Drip Track Raveling:

Progressive disintegration of the surface between wheel paths caused by dripping of gasoline oil

from vehicle.

vii. Bleeding or Flushing (Fatting Up):

The exuding of bitumen on to the pavement surface causing reduction in skid resistance.

Bleeding is generally caused by excessive amount of asphalt in the mix or low air void content. It

occurs in the mix in hot weather.

viii. Corrugations:

Due to instability of base or poor original riding surface (plastic movement of pavement)

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ix. Pot Holes:

When cracks become deep.

x. Ruts:

Depressions formed under the wheel due to heavy load, this causes consolidation, deformation or

plastic flow.

General surface maintenance:

For maintenance of gravel roads blading and occasional resurfacing is required.

For surface treatments of low type bituminous surface in maintenance of roads; Patching,

seal coating or possible loosening oiling, re mixing and relaying are involved.

For high type bituminous concrete and Portland cement concrete, the Removal and

replacement of failure areas and resurfacing are approximate treatment methods for

highway maintenance.

Use same material and methods for road surface maintenance as far as possible.

Highway Maintenance must be planned for rapid performance and to cause least possible

disruption or hazard to traffic.

5.1.2 Shoulders:-

Depend on the surface character of these areas:

SOD shoulders must be moved and occasionally bladed down to the level of the roadway

so that water is not trapped in the traveled way. Gross must be kept in good condition.

Shoulders protected by bituminous blankets or surface treatments same as for roadway

surface.

Gravel and earth shoulders that leaves a drop off at the pavement edges creates a serious

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accident hazard, hence, should be corrected by reconstruction, resurfacing or other

appropriate means.

Due to continuous wetting and drying of shoulder, edge joints result between lane and

shoulder which may cause settlement of pavement due to entrance of water in sub grade

soil. It can Repaired by filling the joint with sand and asphalt concrete.

5.1.3 Snow and ice control:-

Ice forming on the roadway reduces coefficient of friction between tires and surface, which

makes vehicle control almost impossible. In highway maintenance we can apply abrasive to

heavily traveled roadway and street. Suitable materials that can be used are clean and sharp sand,

cinders and washed stone screening.

5.1.4 Bridge maintenance:-

Bridges maintenance is a major part of highway maintenance. Bridges can be maintained in good

condition by following the below guidelines:-

Exposed steel work must be cleaned by sand blasting flame or other means followed

by repainting.

Deck joint may extrude or become filled with dirt so that cleaning and resealing is

necessary

.Out of control vehicle, causing damage to guard rail, must be Repaired and strengthened.

If bridge deck become rough resurfacing is required

Remedial measures to correct serious scour around and under piers and abutments.

5.1.5 Traffic services:-

Include stripping, sign repair and maintenance (particularly needed for repair after stormy

weather.

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5.2 Surface treatment of highways:-

Although the best type of surface course is pre-mix carpet for highway maintenance;

1. Intensity of traffic is not very high.

2. the pro-mix mixers are not easily available due to long transportation or technical

reasons.

3. when the cost is high.

The surface treatment methods are employed. The surface treatment may be single or multiple.

Single Surface Treatment:

Is wearing course in which the bituminous material is sprayed and the aggregate is placed

uniformly over the applied bitumen mineral. The thickness of such layer approximate the

nominal size of aggregate used.

Multiple Surface Treatment:

(Double or Triple) is a wearing surface in which a course aggregate is placed on bitumen coat

(prime coat) already applied, followed by spraying of bitumen and then by subsequent

application of finer aggregate over a second bitumen coat. Generally the minimum size of the

smallest aggregate is one of the aggregate used in the preceding application usually thickness of

single layer approximately maximum size of aggregate.

Function of surface treatment:

To provide long lasting economical surface for granular base road having light and

medium traffic volume.

To prevent entry of surface water into old pavement that has been weathered or cracked.

It improves the skid resistance of bitumen surface where the surface has polished under

traffic.

To provide temporary cover in case of delayed incomplete pavement.

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In Highway Maintenance, for good surface treatment it is necessary that:

Base course is well prepared to its profile and is made more free from pot holes and ruts.

Excellence of surface dressing depends upon the correct proportion of binder aggregate.

Before laying that first surface dressing coat, the base should be made free from all dust

loose soil etc.

In all bituminous construction it is necessary that the newly surface posses a bond with

the existing base at the interface. It is also necessary that the base is nearly impervious.

5.3 MOWING:-

Vegetation along the right-of-way will be mowed for the following reasons:

Eliminate obstructions to sight distance on curves.

Control weed and brush growth.

Reduce snow drifting on the roadway.

Provide for unobstructed drainage.

Reduce the fire hazard in some areas.

Improve road aesthetics.

Eliminate obstruction to signs.

Increase the visibility of large animals on the right-of-way.

All high traffic volume highways will receive one shoulder cut in the late spring and an

additional full right-of-way cut. All other provincial highways in Alberta will receive up to 2

shoulder cuts per year (as required) and a full right-of-way cut once every 3 years or as

warranted for brush control purposes. The first shoulder cut will be 4.5 metres in width and

should be completed during the early summer months. The second shoulder cut or full cut may

be warranted in the late fall, depending on re-growth. Where required, trimming around all

appurtenances located adjacent to the highway will be carried out during the second cut. In urban

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areas the mowing of boulevards and raised medians will be the responsibility of the municipality.

The department will discuss their area’s mowing plans and arrangements with local municipal

officials. Where possible, the department will try to coordinate their operations with that of the

municipalities.

5.4 DRAINAGE SYSTEMS:-

As flowing water can be one of the greatest natural destructive forces affecting a road, it is very

important that all structures and other features of the drainage system are well designed and

properly maintained. In order to maintain a roadway in optimum condition, water must be kept

from saturating the subgrade and also from eroding the roadway. Drainage systems include the

following components:

Ditches

Culverts

Ditch Blocks

Curbs/Gutters

Down Drains

Subsurface Drains

Bridges

Each spring, the department will update and prioritize the culvert maintenance program. This

program will describe any drainage system deficiencies and identify what corrective action needs

to be taken.

5.5 TRAFFIC CONTROL DEVICES:-

5.5.1 SIGNING

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Signs are used to inform motorists of traffic regulations, warn of changes in the roadway

characteristics or hazards, and to provide directional/distance information that is necessary to

motorists.

All highways should be checked on a regular basis to ensure that all signs are properly in place,

functional and conform to established standards. In addition to daytime inspections, night

inspections should be carried out regularly to ensure that signs are reflective and legible during

hours of darkness. Lighting which has been installed on overhead sign structures should be

inspected regularly to ensure that all fixtures are operational. Signs larger than 3m2 should be

placed on breakaway bases to minimize the potential for injury and vehicle damage if struck by

vehicles leaving the roadway. Shear bolts should be checked periodically for proper torque so

that the breakaway feature will function as intended.

5.5.2 TRAFFIC SIGNALS:-

The function of a traffic control signal is to safely assign the right-of-way between the

conflicting flows of traffic at an intersection. Standards related to the installations and operation

of traffic control signals can be found in the Manual of Uniform Traffic Control Devices for

Canada.

5.5.3 LIVESTOCK GUARDS:-

Livestock guards are used to prevent domestic and wild animals from entering the roadway.

Most livestock guards are installed on approaches to highways; however, there are a small

number located on the main highway. The department will maintain and inspect all livestock

guards located on the Provincial Highway System. The department shall inspect the guards to

ensure that the guard is carrying out its intended function of preventing domestic and wild

animals from entering roadway. Accumulated debris must be removed before it causes water

drainage problems or builds to a height that it renders the guard ineffective. Repairs to guard and

associated fencing are done as required.

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6.CONCLUSION

Engineers have been always with open mind to adopt any material available to them for its use

for the construction purposes. It is logical to see that the purpose of highway construction is to

provide a firm and even surface for the carriageway or the pavement which could stand the stress

caused due to number of load applications.

The various materials used in the construction of highway are Cement, Soil, Aggregates,&

Bitumen. Therefore, the materials should of good quality to ensure good quality of pavement

construction. There are various methods of construction of highway such as bituminous

construction or concrete construction. The major Flexible pavement failures are fatigue cracking,

rutting, and thermal cracking. The fatigue cracking of flexible pavement is due to horizontal

tensile strain at the bottom of the asphaltic concrete.

Preserving and keeping each type of roadway, roadside, structures as nearly as possible in its

original condition as constructed or as subsequently improved and the operation of highway

facilities and services to provide satisfactory and safe transportation, is called maintenance of

Highways. Highway Maintenance must be planned for rapid performance and to cause least

possible disruption or hazard to traffic.

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7.REFERENCES

1. www.Google.com

2. www.Youtube.com

3. www.wikipedia.com