Final Report on Road Construction

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 , Jagadhri Page 1

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.


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 as an 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 :-

It is a liquid asphalt which is a blend of asphalt and petroleum solvents such as gasoline and kerosene ). A cutback asphalt can be mixed and placed with little or no application of heat. 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.


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 Maharishi Ved Vyas Engineering College , Jagadhri Page 4



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 Maharishi Ved Vyas Engineering College , Jagadhri Page 5

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 designation in accordance with IS:73. Thus 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 hard material 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 Contractor’s 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 a g e n 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 Maharishi Ved Vyas Engineering College , Jagadhri Page 6

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.




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


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 subbase 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 Maharishi Ved Vyas Engineering College , Jagadhri Page 9

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 ½ : 3 (1 cement : 1 ½ 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 Maharishi Ved Vyas Engineering College , Jagadhri Page 10

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 Maharishi Ved Vyas Engineering College , Jagadhri Page 11

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 a standstill and is thus based on speed, driver reaction time and skid resistance. The distance covered during the driver’s reaction period


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 KN weight 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.




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 for consolidation). 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-base/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 m o r e Maharishi Ved Vyas Engineering College , Jagadhri Page 14

t h a n 1 0 0 m m f o r G r a d i n g 1 a n d 7 5 m m f o r G r a d i n g 2 a n d 3 , a s Wherever possible, approved mechanical devices such as aggregate spreader shall be u s e d t o s p r e a d the aggregates uniformly so as to minimise the need for manual r e c t i f i c a t i o 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 roller shall 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 be discontinued 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 shall 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 .


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 time of application. Dry rolling shall be done while the screenings are b e i n g s p r e a d s o t h a t v i b r a t i o n s o f t h e r o l l e r c a u s e t h e m t o s e t t l e i n t o t h e v o i d s o f t h e c o a r s 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, handbrooms or both shall accompany this. In no case shall the screenings be applied so fast and thick as to form cakes or ridges on the surface in such a manner as would prevent filling of voids 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 day’s operation. Maharishi Ved Vyas Engineering College , Jagadhri Page 16

 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 rolling operation shall be continued, with additional 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 shall be taken to see that the base or sub-grade does not get 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 attains adequate strength, as directed by the Engineer.

 Application of binding material:After the application of screenings and the binding material where it is required to be used shall be 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 Maharishi Ved Vyas Engineering College , Jagadhri Page 17

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 final compaction of water bound macadam course, the p a v e m e n t s h a l l b e a l l o w e d t o d r y o v e r n i g h t . Sprinkled with water if necessary and rolled. Not t r a f f i c s h a l l b e a l l o w e d o n t h e r o a d u n t i l t h e m a c a d a m h a s s e t . T h e E n g i n e e r s h a l l h a v e t h 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 allowed to completely dry and set 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 require a new mix design, 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.  Mixing :Premixed bituminous materials, including bituminous macadam, dense

bituminous

macadam,

semi

dense

bituminous

concrete

and

bituminous concrete, shall be prepared in a hot mix plant of adequate capacity and capable of yielding a mix of proper



LAYING : Weather and seasonal limitations: Laying shall be suspended while free standing water is present on the surface to 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 o r w h e n t h e w i n d s p e e d a t a n y t e m p e r a t u r e e x c e e d s 4 0 k m / h a t 2 m h e i g h t u n l e s s specifically approved by the Engineer.  Cleaning of surface:The surface on which the bituminous work is to be laid shall be c l e a n e d of all loose and extraneous matter by means of a mechanical b r o o m o r a n y o t h e r approved equipment/ method as specified in the contract. The use of high pressure air jet from a c o m p r e s s o r t o r e m o v e d u s t o r l o o s e m a t t e r s h a l l b e a v a i l a b l e 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:Except in areas where a mechanical paver cannot access b i t u m i n o u 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 supplied continuously 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

continuously.

Hand placing of premixed bituminous materials shall only be per m i t t e d i n t h e f o l l o w i n g circumstances. 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.


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 adjustment

of

level,

shall

only

be

permitted

in

the

following

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.  Cleanliness and overlaying: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

achieved.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 soon as possible after laying

compaction shall besubstantially

completed before the temperature falls 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 o m , t h e s u r f a c e . The initial or breakdown rolling shall be done with 8-10 tons dead weight smooth wheeled rollers. The intermediate rolling 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 Maharishi Ved Vyas Engineering College , Jagadhri Page 21

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 dropping 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


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

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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 to ensure 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 College ,Jagadhri


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.

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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 ,Jagadhri


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 :-

 I. II.

FEATURES:AN ATTACHMENT ON TRUCK, TRACTOR & JEEP. CHASSIS AND LINKAGE HOLDER ARE ENTIRELY MADE OF STEEL.

III.

BOTH HEATING SYSTEM, WOOD FIRE BHATTHI & BURNER SYSTEM.

IV.

2.5 TON CAPACITY.

V. VI.

SAFE & EASY OPERATION. HAND SPRAY SYSTEM. ,Jagadhri


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:,Jagadhri


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 .

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Final Report on Road Construction

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