final report on road construction

7/27/2019 Final Report on Road Construction

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CHAPTER-1

INTRODUCTION

An ambitious road construction plan is underway in India, which primarily involves

bituminous pavements. At the present time, Ministry of Road Transport & Highways

(MORTH) Specification for Road and Bridge Works, 2001 Edition is used for construction

of all roads including national highways. Advances in bituminous construction

technologies are made in the world almost every year. This paper describes such advances

in terms of materials, mix design, special bituminous mixes, and recycling. There is a need

to incorporate these advances in MORTH specifications which are about 10 years old, to

keep abreast of latest technologies.

Road Classification:-

There are the following two types of road classification.

1. Non-urban road

2. Urban road

Non-urban Roads:-

Non-urban roads in the country are classified into six categories:

1. Expressways: -

The function of expressways is to cater for movement of heavy volumes

of motor traffic at high speeds. They connect major points of traffic generation and are

intended to serve trips of medium and long length between large residential areas,

industrial or commercial concentrations and the central business district. They are divided

highways with high standards of geometrics and full or partial control of access and

provided generally with grade separation at intersections. Parking, loading and unloading

of goods and passengers and pedestrian traffic are not permitted on these highways.

2. National Highways:-

These are main highways running through the length and breadth of the

country connection major ports, highways of neighbouring countries, State capitals, large

industrial and tourist centres etc.

Maharishi Ved Vyas Engineering College , JagadhriPage 1


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1 State Highways:- These are main arterial routes of a state linking district

headquarters and important cities within the state and connecting them with

National Highways of the neighbouring states.

2 Major District Roads:- These are important roads within a district serving areas

of production and markets, and connecting these with each other or with the main

highways.

3 Other District Roads:- These are roads serving rural areas of production and

providingthem with outlet to market centres, taluka/tehsil headquarters, block

development headquarters or other main roads.

4 Village Roads:- These are roads connecting villages or group of villages with

each other and to the nearest road of a higher category.

Urban Roads:-

Urban roads are classified into the following three categories:

1) Expressways:- The function of expressways is the same whether the traverse

through urban areas or non-urban areas.

2) Collector Streets:- The function of collector streets is to collect traffic from local

streets and feed it to the arterial and sub-arterial streets or vice versa. These may

be located in residential neighbourhoods, business areas and industrial areas.

Normally, full access is allowed on these streets from abutting properties. There

are few parking restrictions except during the peak hours.

3) Local Streets:- These are intended primarily to provide access to abutting

properly and normally do not carry large volumes of traffic. Majority of trips in

urban areas originate from or terminate on these streets. Local streets may be

residential, commercial or industrial, depending on the predominant use of the

adjoining land.They allow unrestricted parking and pedestrian movements.



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CHAPTER-2

BITUMINOUS MATERIALS

The term bituminous materials is generally used to denote substances in which bitumen

is present or from which it can be derived [Goetz and Wood, 1960]. Bitumen is defined asan amorphous, black or dark-colored, (solid, semi-solid, or viscous) cementitious

substance, composed principally of high molecular weight hydrocarbons, and soluble in

carbon disulfide. For civil engineering applications, bituminous materials include

primarily aphalts and tars. Asphalts may occur in nature (natural asphalts) or may be

obtained from petroleum processing (petroleum asphalts). Tars do not occur in nature and

are obtained as condensates in the processing of coal, petroleum, oil-shale, wood or other

organic materials. Pitch is formed when a tar is partially distilled so that the volatile

constituents have evaporated off from it. Bituminous mixtures are generally used to

denote the combinations of bituminous materials (as binders), aggregates and additives.

Types of Bituminous Materials Used in Pavement Construction

There are the following types of bituminous material

Asphalt cement:-

It is an asphalt which has been specially refined as to quality and consistency for direct

use in the construction of asphalt pavements. An asphalt cement has to be heated to an

appropriate high temperature in order to be fluid enough to be mixed and placed.

Cutback asphalt :-

Itis a liquid asphalt which is a blend of asphalt and petroleum solvents such as gasolineand kerosene ). A cutback asphalt can be mixed and placed with little or no application ofheat. After a cutback asphalt is applied and exposed to the atmosphere, the solvent will

gradually evaporate, leaving the asphalt cement to perform its function as a binder.

Emulsified asphalt (or asphalt emulsion):-

It is an emulsion of asphalt cement and water that contains a small amount of

emulsifying agent. In a normal emulsified asphalt, the asphalt cement is in the form of

minute globules in suspension in water.



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An emulsified asphalt can be mixed and applied without any application of heat. After an

asphalt emulsion is applied, sufficient time is required for the emulsion to break and the

water to evaporate to leave the asphalt cement to perform its function as a binder.

Conventional Tests on Asphalt Cements and Their Significance :-

In this section, the purpose and significance of the commonly-used tests on asphalt

cements are described. Readers may refer to the appropriate standard test methods for

detailed description of the test procedure

There are the following tests which are used for testing bituminous material

1. Penetration Test

2. Flash Point Test

3. Ductility Test

4. Viscosity Tests



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Penetration Test :-

The penetration test is one of the oldest and most commonly-used tests on asphalt

cements or residues from distillation of asphalt cutbacks or emulsions. It is an empirical

test which measures the consistency (hardness) of an asphalt at a specified test condition.In the standard test condition, a standard needle of a total load of 100 g is applied to the

surface of an asphalt sample at a temperature of 25 C for 5 seconds. The amount of

penetration of the needle at the end of 5 seconds is measured in units of 0.1 mm (or

penetration unit). A softer asphalt will have a higher penetration, while a harder asphalt

will have a lower penetration. Other test conditions which have been used include (1) 0

C, 200 g, 60 sec., and (2) 46 C, 50 g, 5 sec

Flash Point Test :-

The flash point test determines the temperature to which an asphalt can be safely heated

in the presence of an open flame. The test is performed by heating an asphalt sample in an

open cup at a specified rate and determining the temperature at which a small flame

passing over the surface of the cup will cause the vapors from the asphalt sample

temporarily to ignite or flash.

Ductility Test :-

The ductility test (ASTM D113) measures the distance a standard asphalt sample will

stretch without breaking under a standard testing condition (5 cm/min at 25 C). It is

generally considered that an asphalt with a very low ductility will have poor adhesive

properties and thus poor performance in service.

Viscosity Tests :-

The viscosity test measures the viscosity of an asphalt. Both the viscosity test and the

penetration test measure the consistency of an asphalt at some specified temperatures and

are used to designate grades of asphalts. The advantage of using the viscosity test as

compared with the penetration test is that the viscosity test measures a fundamental

physical property rather than an empirical value.

Viscosity is defined as the ratio between the applied shear stress and induced shear rate of

a fluid. The relationship between shear stress, shear rate and viscosity can be expressed

as: Shear Rate = Shear Stress / Viscosity



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AGGREGATE:-

Binder:-

The binder shall be an appropriate type of bituminous material complying with the

relevant Indian Standard (IS), as defined in the appropriate Clauses of these specifications

,or as otherwise specified here in. The choice of binder shall be stipulated in the Contract

or by the Engineer. Where penetration grades of bitumen are specified, they are referred

to by a single figure des ignation in accordance with IS:73. T hus bitumen grade

35 refers to bitumen in the penetration range 30 to 40.

Coarse Aggregates:-

The coarse aggregates shall consist of crushed rock, crushed gravel or other hardmaterial retained on the 2.36mm sieve. They shall be clean, hard, durable, of cubical

shape, free form dust and soft or friable matter, organic or other deleterious matter.

Where the Contractors selected source of aggregates have poor affinity for

bitumen, as a condition for the approval of that source, the bitumen shall be treated

with approved anti striping ag en t s . Where crushed gravel is proposed for use as

aggregate , not less than 90% by weight of the crushed material retained on the

4.75mm sieve shall have at least two fractured faces.

Fine Aggregates:-

Fine aggregates shall consist of crushed or naturally occurringmaterial, or a

combination of the two, passing 2.36mm sieve and retained on the 75micron sieve.They

shall be clean, hard, durable, dry and free from dust, and soft or friable matter, organic

or other deleterious matter.

PHYSICAL PROPERTIES OF AGGREGATES:-

The physical properties of aggregates are those that refer to the physicalstructure of the

particles that make up the aggregate.

ABSORPTION, POROSITY, AND PERMEABILITY

The internal pore characteristics are very important properties of aggregates. The size, the

number, and the continuity of the pores through an aggregate. Particle may affect the

strength of the aggregate, abrasion resistance, surface texture, specific gravity, bonding



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capabilities, and resistance to freezing and thawing action. Absorption relates to the

particle's ability to take in a liquid.

Porosity is a ratio of the volume of the pores to the total volume of the particle.

Permeability refers to the particle's ability to allow liquids to pass through. If the rock

pores are not connected, a rock may have high porosity and low permeability.

SURFACE TEXTURE:-

Surface texture is the pattern and the relative roughness or smoothness of the aggregate

particle. Surface texture plays a big role in developing the bond between an aggregate

particle and a cementing material. A rough surface texture gives the cementing material

something to grip, producing a stronger bond, and thus creating a stronger hot mix asphalt

or portland cement concrete. Surface texture also affects the workability of hot mix

asphalt, the asphalt requirements of hot mix asphalt, and the water requirements of

portland cement concrete.Some aggregates may initially have good surface texture, but

may polish smooth later under traffic. These aggregates are unacceptable for final

wearing surfaces. Limestone usually falls into this category. Dolomite does not, in

general, when the magnesium content exceeds a minimum quantity of the material.

STRENGTH AND ELASTICITY :-

Strength is a measure of the ability of an aggregate particle to stand up to pulling or

crushing forces. Elasticity measures the "stretch" in a particle. High strength and elasticity

are desirable in aggregate base and surface courses. These qualities minimize the rate of

disintegration and maximize the stability of the compacted material. The best results for

portland cement concrete may be obtained by compromising between high and low

strength, and elasticity. This permits volumetric changes to take place more uniformly

throughout the concrete.

DENSITY AND SPECIFIC GRAVITY

Density is the weight per unit of volume of a substance. Specific gravity is the ratio of the

density of the substance to the density of water.



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HARDNESS:-

The hardness of the minerals that make up the aggregate particles and the firmness with

which the individual grains are cemented or interlocked control the resistance of the

aggregate to abrasion and degradation. Soft aggregate particles are composed of minerals

with a low degree of hardness. Weak particles have poor cementation. Neither type is

acceptable.

PARTICLE SHAPE:-

The shape of the aggregate particles affects such things as:

1) The asphalt demands of hot mix asphalt

2) The workability and the strength of both portland cement concrete and asphalt

pavements.

The best aggregates to use for strength are crushed stone or crushed gravel.Crushed

aggregate have irregular, angular particles that tend to interlock when compacted or

consolidated. The crushed stone or crushed gravel aggregate make the asphalt or concrete

mix somewhat difficult to place. To improve the workability, many mixes contain both

angular and round particles. The coarse aggregate particles are usually crushed stone or



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crushed gravel, and the fine aggregate particles are usually natural sand. The Standard

Specifications detail the requirements for crushed materials for various uses.

Pavement composition:-

Sub-base :-

Sub-base materials comprise natural sand, gravel, laterite, brick metal, crushed stone or

combinations thereof meeting the prescribed grading and physical requirements. The sub-

base material should have a minimum CBR of 20 % and 30 % for traffic upto 2 msa and

traffic exceeding 2 msa respectively. Sub-base usually consist of granular or WBM and

the thickness should not be less than 150 mm for design traffic less than 10 msa and 200

mm for design traffic of 1:0 msa and above.

Base :-

The recommended designs are for unbounded granular bases which comprise

conventional water bound macadam (WBM) or wet mix macadam (WMM) or equivalent

conforming to MOST specifications. The materials should be of good quality with

minimum thickness of 225 mm for traffic up to 2 msa an 150 mm for traffic exceeding 2

msa.

Bituminous surfacing:-

The surfacing consists of a wearing course or a binder course plus wearing course. The

most commonly used wearing courses are surface dressing, open graded premix carpet,

mix seal surfacing, semi-dense bituminous concrete and bituminous concrete. For binder



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course, MOST specifies, it is desirable to use bituminous macadam (BM) for traffic upto

5 msa and dense bituminous macadam (DBM) for traffic more than 5 msa.

REQUIREMENT OF STONES FOR ROAD:-

Stones for Kerb and Channels :-

Kerb and channel stones are provided on roads having raised berms for foot path etc.

These shall be of selected hard stone, sound, durable free from laminations and other

structural defects. The length of each kerb and channel stone shall be not less than 49.5

cm except that 29.5 cm long stones shall be permitted for closures and for curves. The

other dimensions shall be 30 x 20 cm for kerb stones and 30 x 10 cm for channel stones,

unless specified otherwise. Kerb and channel stones shall be chisel dressed on exposed

surface and edges. The dimensions of the exposed faces of kerb and channel stones shall

be of sizes as specified with a tolerance of 10 mm in width and depth. In the case of kerb

stones a tolerance of 5 cm shall be allowed in the dimensions of unexposed back and

bottom faces and in the case of channel stones a tolerance of 10 mm shall be allowed in

thickness.

Boundary Stone :-

The boundary stones shall be of either hard stone or sound and durable quality or precast

R.C.C. These shall be in blocks of size 15 15 90 cm unless directed otherwise by the

Engineer-in-Charge. A tolerance of 12.5 mm shall be permitted in the specified size. In

the case of boundary stones of hard stone, the upper 30 cm shall be chiesel dressed on all

the four sides and on the top. The R.C.C. boundary stones shall be cast in cement concrete

1 : 1 : 3 (1 cement : 1 coarse sand : 3 graded stone aggregate 20 mm nominal size),

reinforced with 10 mm diameter tor steel bars or as directed and finished smooth with

cement mortar 1 : 3 (1 cement : 3 fine sand ). The specifications for R.C.C. work shall

apply.

Kilometer stone :-

Ordinary kilometer stone for National Highways, State highways and Major District shall

be of the size 35 111 25 cm. One cm offset shall be provided around the stone slab in

10 cm height above the formation level to serve as the pedestal. The kilometer stones



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shall be fixed at right angle to the centre line of the carriage way. The kilometer stone

shall indicate the name and distance of the next (intermediate) important town only. On

the side of the kilometre stone facing the carriage way, the number of the kilometre stone

shall be inscribed (without the name of any place).

THE ELEMENTS OF DESIGN:-

Design speed :-

Traffic speeds are measured and quoted in kilometers per hour. The Highway Capacity

Manual(Transportation Research Board 1994) lists definitions of ten different speeds,

such as spot speed, time mean speed, space mean speed, overall travel speed, running

speed, etc. In this document, reference is principally to design speed and operating speed.

The design speed is a speed selected for the purposes of the design and correlation of

those features of a road (such as horizontal curvature, vertical curvature, sight distance

and super elevation) upon which the safe operation of vehicles depends.

SIGHT DISTANCE :-

Sight distance is a fundamental criterion in the design of any road or street. It is essential

for the driver to be able to perceive hazards on the road, with sufficient time in hand to

initiate any required action safely.

On a two-lane two-way road it is also necessary for him or her to be able to enter the

opposing lane safely while overtaking. In intersection design, the application of sight



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distance is slightly different from that applied in design for the rest of the road or street

system but safety is always the chief consideration.

Stopping sight distance (SSD) :-

Stopping distance involves the ability of the driver to bring the vehicle safely to astandstill and is thus based on speed, driver reaction time and skid resistance. The

distance covered during the drivers reaction period



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CHAPTER -3

PREPARATION AND SURFACE TREATMENT OF FORMATION

Preparation and surface treatment of the formation, that is top of the sub-grade, shall be

carried out only after completion of any specified sub-grade drainage and unless

otherwise agreed by the Engineer, immediately prior to laying the sub-base or the

road base where no sub-base is required. The sequence of operations shall be as follows:

1) All surfaces below carriageway, lay byes, footways and hard shoulders shall, after

reinstatement of any soft areas to the required Specifications be well cleaned and freed of

mud and slurry.

2) The surface shall be compacted by 4 passes of a smooth wheeled roller of 80 to 100 KNweight after spraying requisite amount of water, if required, before the commencement

of rolling.

3) The formation shall, where ever necessary, be regulated and trimmed to the

requirements with motor grader.

4) The trimmed formation shall be rolled by one pass of smooth wheeled roller of

80 to 100KNweight after spraying requisite amount of water, if required, before

the commencement of rolling.

SUB-GRADE :-

PREPARATION AND CONSOLIDATION:-

In sub-grade composed of clay, fine sand or other soils that may be forced up into the coarse

aggregate during rolling operation, an insulation layer of suitable thickness of granular

materials or over size brick aggregate not less than 10 cm thick shall be provided for

blanketting the sub-grade, which shall be paid for separately, unless otherwise specified.

In slushy soils or in areas that are water logged, special arrangements shall be made to

improve the sub-grade and the total pavement thickness shall be designed after testing the

properties of the subgrade soil. Necessary provision for the special treatment required shall be

made in the project and paid for separately.



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Preparation of Sub-Grade:-

The surface of the formation for a width of sub-base, which shall be 15 cm more on either

side of base course, shall first be cut to a depth equal to the combined depth of sub-base and

surface courses below the proposed finished level (due allowance being made forconsolidation). It shall then be cleaned of all foreign substances. Any ruts or soft yielding

patches that appear due to improper drainage conditions, traffic hauling or from any other

cause, shall be corrected and the sub-grade dressed off parallel to the finished profile.

Consolidation:-

The sub-grade shall be consolidated with a power road roller of 8 to 12 tonnes. The roller

shall run over the sub grade till the soil is evenly and densely consolidated and behaves as an

elastic mass (the roller shall pass a minimum of 5 runs on the sub grade). All undulations in

the surface that develop due to rolling shall be made good with material or quarry spoils as

the cases may be and the sub-grade is rerolled.

GRANULAR SUB BASE :-

The materials to be used for the work shall be natural sand, gravel, crushed stone,

or combination there of to satisfy the following requirements:

a) The mix shall be as per the specified grading. The Engineer has to specify a particular

grading from the six gradings. In some special cases, the Engineer may specify a

modified grading other than the above six gradings as has been adopted in some APSHP

Works.

b) The material in the mix shall have a 10 percent fines value of 50 KN or more

(for sample in soaked condition) .

c) The material passing 425 micron (0.425mm) in the mix when tested according

to 1S: 2720(Part 5) shall have liquid limit and plasticity index not more than 25% and 6%

respectively. (APSS138 specifies even stiffer limits of 20% and 6% respectively).

d) The mix shall produce the required laboratory CBR values on 4 day soaked sample

Spreading coarse aggregates :-

The coarse aggregates shall be spread uniformly and evenly upon the prepared

sub grade/sub-bas e/base to proper profile by using templates placed across the road

about 6 M apart, in such quantities that the thickness of each compacted layer is n o t mor e



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than 100 mm for Grad ing 1 and 75 mm for Grad ing 2 and 3 , as Wherever

possible, approved mechanical devices such as aggregate spreader shall be u s ed t o sp re ad

t he a gg re ga te s u ni fo rm ly s o a s t o m in im is e t he n ee d f or m an ua l

r ec t i f i c a t io n afterwards. Aggregates placed at locations which are inaccessible to the

spreading equipment, maybe spread in one or more layers by any approved means so as

to achieve the specified results .The spreading shall be done from stockpiles along the side of

the roadway or directly from vehicles. No segregation of large or fine aggregates shall be

allowed and the coarse aggregate, as spread shall be of uniform gradation with no pockets of

fine material .The surface of the aggregates spread shall be carefully checked with templates

and all high or low spots remedied by removing or adding aggregates as may be required.

The surface shall be checked frequently with a straight edge while spreading and

rolling so as to ensure a finished surface as per approved drawings. The coarse

aggregates shall not normally be spread more than 3 days in advance of the

subsequent construction operations.

Rolling :-

Immediately following the spreading of the coarse aggregate, rolling shall be

started with three wheeled power rollers of 80 to 100 KN capacity or tandem or vibrator

rollers of 80to 100 KN static weight. The type of roller to be used shall be approved by the

Engineer based on trial run .Except on super elevated portions where the rolling shall proceed

from inner edge to the outer ,rolling shall begin from the edges gradually progressing towards

the centre.

First the edge/edges shall be compacted with roller running forward and backward.

The rol ler sha ll then move in ward parallel to the centre line of the road, in successive

passes uniformly lapping preceding tracks by at least one half width .Rolling shall bediscontinued when the aggregates are partially compacted with sufficient void space in them

to permit application of screenings. However, where screenings are not to be applied ,as in

the case of crushed aggregates like brick metal, laterite and kankar, compaction

sha ll be continued until the aggregates are thoroughly keyed. During rolling, slight

sprinkling of water maybe done, if necessary. Rolling shall not be done when the sub-grade is

soft or yielding or when it causes a wave-like motion in the sub-grade or sub-base course .



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Fig Two wheel power roller

Application of Screenings:-

After the coarse aggregate has been rolled to clause Screenings to completely fill the

interstices shall be applied gradually over the surface. These shall not be damp or

wet at the t ime of application. Dry rol ling shall be done while the

screenings a re b e i n g s p r e a d s o t h a t v i b r a t io n s o f t h e r o l l e r c a u s e

the m to set t le in t o the voi ds of the coa rs e aggregate. The screenings

shall not be dumped in piles but be spread uniformly in successive thin layers either

by the spreading motions of hand shovels or by mechanical spreaders, or directly from

tipper with suitable grit spreading arrangement. Tipper operating for spreading the

screenings shall be so driven as not to disturb the coarse aggregate .The screenings

shall be applied at a slow and uniform rate (in three or more applications) soaks to

ensure filling of all voids. Dry rolling and brooming with mechanical brooms, hand-

brooms or both shall accompany this. In no case shall the screenings be applied so fast

and thick as to form cakes o r ridges on the surface in such a manner as would

prevent fil lin g of vo ids or prevent the direct bearing of the roller on the coarse

aggregate. These operations shall continue until no more screenings can be forced into

the voids of the coarse aggregate .The spreading, rolling, and brooming of screenings

shall be carried out in only such lengths of the road which could be completed within

one days operation.



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Sprinkling of water and grouting:-

After the screenings have been applied, the surface shall be copiously sprinkled with

water, swept and rolled. Hand brooms shall be used to sweep wet screenings into

voids and to distribute them evenly. The sprinkling, sweeping and rollingoperation shall be continued, with addit ional screenings applied as

necessary until the coarse aggregate has been thoroughly keyed, well-bonded and

firmly set in its full depth and a grout has been formed of screenings . Care sha ll

be taken to se e that the base or sub-grad e does no t ge t damaged due to the

addition of excessive quantities of water during construction .In case of lime treated

soil sub-base, construction of water bound macadam on top of it can cause excessive

water to flow down to the lime treated sub-base before it has picked up enough

strength (is still green) and thus cause damage to the sub-base layer. The laying of

water bound macadam layer in such cases shall be done after the sub-base

at ta ins adequate st rength, as directed by the Engineer.

Application of binding material:-

After the app lic at ion of screenings and the binding material where it is required

to be used shall b e applied successively in two or more thin layers at a slow

and uniform rate. After each application, the surface shall be copiously

sprinkled with water, the resulting slurry swept in with hand brooms, or

mechanical brooms to fill the voids properly, and rolled during which water shall be



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applied to the wheels of the rollers if necessary to wash down the binding material

sticking to them .These operations shall continue until the resulting slurry after filling

of voids, forms a wave ahead of the wheels of the moving roller.

Setting and drying:-

After the f inal compact ion o f water bound macadam course, the

p av e men t sh a l l b e a l l owe d to d r y o v er n ig h t . Sprinkled with water if

necessary and rolled. Not tr aff ic sh al l be al lo we d on th e ro ad un ti l th e

ma ca da m ha s se t. Th e En gi ne er sh al l ha ve th e discretion to stop hauling

traffic from using the completed water bound macadam course, if in his opinion it

would cause excessive damage to the surface .The compacted water bound

macadam course should be a llowed to co mpletely dry and se t before the next

pavement course is laid over it

GENERAL REQUIREMENTS FOR BITUMINOUS PAVEMENT LAYERS :-

Source of material:-

The source of all materials to be used on the project must be tested to the satisfaction

of and be expressly approved by the Engineer. The Engineer may from time to time

withdraw approval of specific source, or attach conditions to the existing

approval. Any change in aggregate source for bituminous mixes, will

requi re a new mix des ign , and laying trials, where the mix is based on a job mix

design, stock piles from different sources, approved or otherwise, shall be kept

separate, such that there is no contamination between one material and another. Each

source submitted for approval shall contain sufficient material for at least 5 days

work.

M i x i n g : -

Premix ed b i tu min o u s mate r i a l s , i n c lu d in g b i tu min o u s macad am,

d en se b itumin ou s macad am, semi dense b itumin ou s co ncre te an d

bi tuminous concrete, sha ll be prepared in a hot mix plant of adequate capacity

and capable of yielding a mix of proper



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LAYING :-

Weather and seasonal limitations:

Laying shall be suspended while free standing water is present on the surfaceto be covered, or during rain, fog and dust storms. After rain, the bituminous surface,

prime or tack coat, shall be blown off with a high pressure air jet to remove excess

moisture, or the surface left to dry before laying shall start. Laying of bituminous

mixtures shall not be carried out when the air temperature at the surface on which it is

to be laid is below 100C or whe n the win d spe ed at any tem per atu re

exceeds 40 km/h at 2m height unless specifically approved by the Engineer.

Cleaning of surface:-

The surface on which the bituminous work is to be laid shall be cleaned

o f a l l l oo se a n d e x t ra ne ou s m at t er b y m e an s o f a m e ch an i ca l

b ro o m o r an y o th e r approved equipment/ method as specified in the contract.

The use of high pressure air jet from a c om pr es s or to r em ov e du s t or lo os e

m a t t e r s h a l l b e a v a i l a b le f u l l t i m e o n t h e s i t e , u n l e s s otherwise

specified in the Contract.

Spreading:-

E x cep t in a reas wh ere a mech an ica l p av er can n o t access

b i tu mi n ou s materials shall be spread, leveled and tamped by an approved

self propelled paving machine. As soon as possible after arrival at site, the

materials shall be sup plied con tinuously to the paver and laid without delay The

rate of delivery of material to the paver shall be regulated to enable the

paver to operate con tinuously.

Han d p lac in g o f p remix ed b i tu min o u s mate r i a l s sh a l l o n ly b e p e r

mitted in the followingcircumstances.

1) For laying regulating courses of irregular shape and varying thickness.

2) In confined spaces where it is impracticable for a paver to operate.

3) For footways.

4) At the approaches to expansion joints at bridges, viaducts or other structures.

5) For laying mastic asphalt .

6) For filling of potholes.



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7) Where directed by the Engineer. Manual spreading of premixed wearing course material

or the addition of such material by hand spreading to the paved area, for

adjus tment of l eve l, shal l o nly b e pe rmit ted in the fol lowin g

circumstances.

i) At the edges of the layers of material and at gullies and manholes.

ii) At the approaches to expansion joints at bridges, viaducts or other structures.

Clean l ines s and over lay ing: -

B i t u m i n o u s m a t e r i a l s h a l l b e k e p t c l e a n a n d uncontaminated. The

only traffic permitted to run on bituminous material to be over laid shall be that

engaged in laying and compacting the next course or, where a binder course is to be

sealed or surface dressed, that engaged on such surface treatment. Should

any bituminous material become contaminated the Contractor shall make it good

to the satisfaction of the Engineer.

Compaction:-

Bituminous materials shall be laid and compacted in layers which enable the specified

thickness, surface level, regularity requirements and compaction to be

a c h i e v e d . c o m p a c t i o n o f b i t u m i n o u s m a t e r i a l s s h a l l c o m m e n c e a

s s o o n a s p o s s i b l e a f t e r l a y i n g compaction shall besubstantially

completed before the temperature fal ls below the minimum rolling

temperatures started in the relevant part of these Specifications. Rolling of the

longitudinal joints shall be done immediately behind the paving operation. After this,

rolling shall commence at the edges and progress towards the center longitudinally

except that on super elevated and unidirectional cambered portions, it shall progress

from the lower to the upper edge parallel to the centerline of the pavement. Rolling

shall continue until all roller marks have been removed f r om, th e su r fa ce . The

initial or breakdown rolling shall be done with 8-10 tons dead weight smooth

wheeled rollers . The intermediate roll ing shall be done with 8-10 tonnes dead

weight or vibratory roller or with a pneumatic tyred roller of 12 to 15 tonnes weight

having nine wheels, with a tyre pressure of at least 5.6 Kgs/sqcm, The finish rolling

shall be done with 6 to 8 tonnes smooth wheeled tandem rollers. Bituminous

materials shall be rolled in a longitudinal direction, with the driven rolls nearest the



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paver. The roller shall first compact material adjacent to joints and then work from the

lower to the upper side of the layer, overlapping on successive passes by at least one

third of the width of the rear roll or, in the case of a pneumatic tyred roller, at least

the nominal width of 300mm.In portions with super elevated and unidirectional

camber, after the edge has been rolled, the roller shall progress from the lower to the

upper edge..Rollers should move at a speed of not more than 5Km per hour. The roller

shall not be permitted to stand on pavement which has not been fully compacted, and

necessary precautions shall be taken to prevent dropp ing of oil, grease, petrol

or other foreign matter on the pavement either when the rollers are operating

or standing. The wheels of rollers shall be kept moist with water, and the spray system

provided with the machine shall be in good working order, to prevent the mixture

from adhering to the wheels. Only sufficient moisture to prevent adhesion between

the wheels of rollers and the mixture should be used. Surplus water shall not be

allowed to stand on the partially compacted paveme



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CHAPTER -4

WATER BOUND MACADAM WITH STONE AGGREGATE

Water Bound Macadam with Stone Aggregate

Stone aggregate of specified size is used. This is a standard sub base/base and is used

where stone aggregate is available at reasonable rates. This consists of clean crushed

coarse aggregate mechanically interlocked by rolling and voids thereof filled with

screening and binding material with the assistance of water, laid on a prepared sub

grade, sub-base, base or existing pavement as the case may be. Water bound macadam

may be used as a sub base, base course or surfacing course.

Quantities of Materials

Maharishi Ved Vyas EngineeringCollege ,Jagadhri Page 23


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Quantities of coarse aggregate, screening and binding material required to be stacked

for 100 mm approximate compacted thickness of W.B.M. for 10 sqm shall be as per

table 16.12 for stone aggregate of the size 90 mm to 45 mm. For stone aggregate of

other size, 63 mm to 45 mm and 53 mm to 22.4 mm quantity of coarse aggregate and

stone screening for 75 mm approximate compacted thickness of WBM base for 10

sqm. shall be as per Table

GENERAL GUIDELINE AND PROCEDURE FOR WATER BOUND

MACADAM:

1) Thickness of a compacted layer should be 100 mm for 90-45 mm, size aggregates

and

75 mm for 63-45 mm or 53-22.4 mm size aggregates.

2) Screenings should generally be of the same material as coarse aggregate. However,

if the use of screenings is not feasible, some other non-plastic material, such as,

moorum

or gravel (other than rounded river borne material) having liquid limit and plasticity

index below 20 and 6 respectively may be used provided fraction passing 75 micron

sieve does not exceed 10 per cent.

3) Binding maternal need not be used if the layer is to serve as base (or is to receive

black topping), or where crushable type of screenings, like, moorum is used.



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4) It is a good practice to lay a sub-base of granular/stabilised material before laying

WBM. This is particularly important where the sub grade is of clayey type.

5) Where the WBM is to be laid directly over sub grade, a 25 mm thick layer of stone

screenings (Grading B) - "inverted choke" - should be spread on the prepared sub

grade before the application of aggregate is taken up. In case of fine sand or silty or

clayey sub grade it is advisable to lay 100 mm thick insulating layer of screening or

coarse sand on the top of fine grained soil. A preferred alternative to inverted choke is

the use of appropriate geosynthetics mesh.

6) Arrangements for water, rollers in working order and templates/ other tools and

equipment for checking the quality of the materials and work must be available at site

before the work of laying is started.

7) The quantities of coarse aggregates and screenings will vary, depending on the

actual grading.

8) Arrangements for lateral confinement of aggregates must be provided. This can

conveniently be done by raising the shoulders in stages equal in thickness to each

layer of WBM.

9) The coarse aggregate should be spread uniformly and evenly on the prepared

subgrade sub-base by using templates placed across the road about 6 m apart. The

thickness of each compacted layer should not be more than 100 mm in grading 1 and

75 mm for grading 2 and 3. Wherever possible, mechanical devices should be used to

spread the aggregates uniformly so as to minimise the need for manual rectification

afterwards.

10) The spreading should be done from stockpiles or directly from vehicles. No

segregation of large or fine aggregates should be allowed.

11) The surface should be checked frequently while spreading and rolling so as toensure the specified regularity of slopes and camber.

12) The coarse aggregate should not normally be spread more than three days in

advance of the subsequent construction operations. Three wheeled power rollers at 80

to 100 kN or tandem or vibratory rollers at 80 to 100 kN static weight should be used

for rolling. Except on supper elevated portions, where the rolling should proceed from

inner edge to outer edge, rolling should begin from the edge gradually progressing



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towards centre. Successive passes should uniformly overlap the proceeding by at least

one half widths.

13) In case screening are to be applied, rolling should be discontinued when the

aggregate are partially compacted with sufficient void space to permit application of

screening. During rolling slight sprinkling of water may be allowed. Complete rolling

is indicated by a loose stone piece getting crushed under the roller without sinking.

14) After the coarse aggregate has been rolled, screening to completely fill the

interstices should be applied gradually over the surface. Screening should not be

damp or wet at the time of application. These should not be dumped in piles but

applied at a uniform rate, in three or more applications, so as ensure filling of all

voids. Dry rolling should be done while the screenings are being spread so that

vibrations of the roller cause screenings to settle into the voids of coarse aggregate.

Dry rolling should accompanied by brooming. These operations should continue until

no more screenings can be forced into the voids of coarse aggregate.

15) Spreading, rolling and brooming of screens shall be carried out in only such

lengths which are likely to be completed within one day's operation.

16) After screenings have been applied, the surface should be copiously sprinkled

with water, swept with hand brooms and rolled. This operation should be continued

with additional screenings, applied as necessary, until the coarse aggregates has been

thoroughly keyed, well broomed, firmly set in its full depth and a grout has been

formed of screenings.

17) The base or sub grade should not get damaged due to use of excessive quantities

of water. In case lime treated soil sub-base, construction of water bound macadam

should be taken up only after sub-base has picked up enough strength.

18) Apply binding material, wherever required, in a similar fashion as screening.Continue rolling till full compaction is achieved.

19) After the final compaction of WBM course, the pavement should be allowed to

dry overnight. Next morning hungry spots should be filled with screenings or binding

material, lightly sprinkled with water, if necessary and rolled.



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20) No traffic should be allowed on the road until the macadam has set. The

compacted WBM Course should be allowed completely dry and set before the next

pavement course is laid over.

21) WBM work should not be carried out when the atmospheric temperature is less

than 00 C in the shade.

22) Apply binding material, wherever required, in a similar fashion as screening.

Continue rolling till full compaction is achieved.

23) After the final compaction of WBM course, the pavement should be allowed to

dry overnight. Next morning hungry spots should be filled with screenings or binding

material, lightly sprinkled with water, if necessary and rolled.

24) No traffic should be allowed on the road until the macadam has set. The

compacted WBM Course should be allowed completely dry and set before the next

pavement course is laid over.

25) WBM work should not be carried out when the atmospheric temperature is less

than 00C in the shade.



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CHAPTER 5

WET MIX MACADAM

Wet mix macadam:-

Wet mix macadam construction is an improvement over the conventional water bound

macadam providing speedy and more durable construction. It differs from the water bound

macadam in that graded aggregates and granular materials are mixed with predetermined

quantity of water in accordance with the specifications to form dense mass which is spread

and wiled to approved lines, grades and cross-section to serve as pavement course(s).

General guideline and Procedure for Wet mix macadam :-

1) P.I. value of Materials finer than the 425 micron sieve should be less than 6.

2) The mix should be prepared in approved mixing plant of suitable capacity having

provision for controlled addition of water and forced/positive mixing arrangement, like, pug

mill or pan type mixes of concrete batch/plant

3) The mixed material should be uniformly wet and no segregation should be permitted.

4) The mix should be spread uniformly and evenly in required quantities on the prepared sub

grade/sub-base either by a ~elf-propelled paver finisher or a motor grader fitted with blades

having hydraulic control suitable for initial adjustment and maintaining the same. In no case

should the mix be dumped in heaps on the area.

5) The thickness of single compacted wet mix macadam layer should not be less than 75 mm

nor more than 100 mm. However, the compacted thickness of single layer of the sub-base

may be increased up to 200 mm provided vibratory roller of approved type is used for

compaction. The roller speed should not exceed 5 Km / hour.

6) Rolling should continue till density achieved is at least 98 per cent maximum dry density

as per IS: 2720 (Part VIII).7) When surface irregularity of wet mix macadam exceeds permissible tolerance or where the

course is otherwise defective (like, sub grade soil getting mixed with the aggregates), the full

thickness of the layer should be scarified over the affected area, reshaped with added

premixed material as applicable and re-compacted. The area treated in this manner should not

be less than 5 m long and 2 m wide.

8) It is not advisable to lay the wet mix macadam during rains and the tempo of work suffers

during rains.

Maharishi Ved Vyas Engineering College,Jagadhri Page 28


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9) After construction of the top WMM layer will need immediate sealing with bituminous

surfacing.

10) Provision of adequate drainage for the foundation area for the construction courses

assumes greater importance in this method of construction.



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CHAPTER -6

ROAD SURFACE DRAINAGE

Road Surface Drainage

Surface Sloping:-

Reducing the erosive power of water can achieved

by reducing its velocity. If, for practical reasons,

water velocity cannot be reduced, surfaces must be hardened or protected as much as possible

to minimize erosion from high velocity flows. Road surface drainage attempts to remove the

surface Water moves across the road surface laterally or longitudinally.

Lateral drainage is achieved by crowning or by in- or out- sloping of road surfaces.

Longitudinal water movement is intercepted by dips or cross drains. These drainage features

become important on steep grades or on unpaved roads where ruts may channel water

longitudinally on the road surface.

The main objective of road drainage is to prevent early damage of the pavement

due to entry of excess of water and preventing saturation up to a depth of 1 meter below

the top of sub grade

Various types of damages arising due to inadequate drainage

1) Reduction in bearing capacity of sub grade soil

2) Pavement failures like potholes, rutting, waviness and corrugation in flexible pavement

3) Reduction in strength of many pavement materials like stabilized soil, WBM and

BT surfacing

4) Damages to shoulder and pavement edges from surface water

5) Considerable erosion of soil from sub strata, slopes ,cut and hill side due to surface water

CHAPTER -7



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EQUIPMENT REQUIRED FOR ROAD CONSTRUCTION:-

1. WET MIX MACADUM PLANT:-

4-BIN FEEDER:-

It is of single chassis construction. At each Bin a radial gate is provided which can be opened

in any position to regulate the aggregate flow. Individual endless belts are provided, below

the gates to discharge material onto the gathering belt.

VIBRATING SCREEN:-

A single-deck vibrating screen is provided on the slinger conveyor to remove oversize

aggregates received from the 4-bin feeder.

SLINGER CONVEYOR

An inclined conveyor with 600 mm wide belt mounted on idlers receives aggregate from the

gathering conveyor and feeds it to the pug mill.



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PUG MILL:-

A twin shaft pug mill mounted on antifriction bearing provides quick, continuous and

homogeneous mix of aggregates and additives.

WATER TANK:-

One / Two Water Tanks of 15 / 20 MT capacity each are provided, fabricated from steel plates

with manhole, flow meter, pump etc.

Figure :- wet mix macadam plant

2.MINI BITUMEN SPRAYER:-

FEATURES:-

I. AN ATTACHMENT ON TRUCK, TRACTOR & JEEP.

II. CHASSIS AND LINKAGE HOLDER ARE ENTIRELY MADE OF STEEL.

III. BOTH HEATING SYSTEM, WOOD FIRE BHATTHI & BURNER SYSTEM.

IV. 2.5 TON CAPACITY.

V. SAFE & EASY OPERATION.

VI. HAND SPRAY SYSTEM.

http://www.kditechnology.co.in/mini_bitumen.htmlhttp://www.kditechnology.co.in/mini_bitumen.htmlhttp://www.kditechnology.co.in/mini_bitumen.html


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3.ROAD ROLLER:-

Road rollers use the weight of the vehicle to compress the surface being rolled (static) or use

mechanical advantage (vibrating). Initial compaction of the substrate on a road project is

done using a padfoot drum roller, which achieves higher compaction density due to the pads

having less surface area. On large freeways a four wheel compactor with padfoot drum and a

blade, such as a Caterpillar 815/825 series machine, would be used due to its high weight,

speed and the powerful pushing force to spread bulk material. On regional roads a smaller

single padfoot drum machine may be used.

Figure Road roller

4.Earth excavation machine:-

http://en.wikipedia.org/wiki/Soil_compactionhttp://en.wikipedia.org/wiki/Soil_compaction


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Earth excavation machine is used in the road construction to excavate the sides of the road .

Earth excavation machine is also used to fill the trucks for transporting the cutting earth for

e.g. JCB .

final report on road construction

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