nhdp funding, flexible and rigid pavement layerwise details

8/11/2019 NHDP FUNDING, FLEXIBLE AND RIGID PAVEMENT LAYERWISE DETAILS

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Bibhuti B. Bhardwaj

144104041

M.Tech (1stSemester)

Presented By-

NHDP FUNDING, FLEXIBLE AND RIGID

PAVEMENT LAYERWISE DETAILS


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Phase Details Funding allocated Present expenditure

Phase I Golden Quadrilateral Rs. 42,000 crore Rs. 52,434 crore

Phase II NS-EW corridor

Phase III Upgradation of High traffic density

NHs

Rs. 55,000 crore Rs. 65,197 crore

Phase IV Widening of NH (excluding Phase I, II,

III)

Rs. 25,000 crore Rs. 27,800 crore

Phase V Six laning of selected highways Rs. 17,500 crore Rs. 41,210 crore

Phase VI Development of expressways Rs. 15,000 crore Rs. 16,680 crore

Phase VII Improvement of City road network Rs. 15,000 crore Rs. 16,680 crore


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Government of Indias Gross Budgetary Support (GBS) and Additional Budgetary Support

(ABS)

Private financing under PPP frameworks

Ploughing back of toll revenue including toll collection, negative grant, premium and

revenue share deposited by NHAI into Consolidated Fund of India and in turn equivalent

amount released to NHAI for development, maintenance and management of NationalHighways entrusted to it.

External Assistance in respect of International Institutions (World Bank; ADB; JBIC)

funded projects allocated through Union Budget.

Accruals under the Central Road Fund (share in the levy of cess on fuel) allocated through

Union Budget.


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SEAL COAT

Type A seal Coat: Liquid seal coat comprising of an application of a layer of

bituminous binder followed by a cover of stone chips.

Composition:The aggregate should be sand or grit and should consist of clean, hard rocks. The

aggregates should pass 2.36 mm sieve and be retained on 180 micron sieve. The

quantity used for spreading should be 0.06 m3per 10 m2area.

Construction: The binder should be heated in boilers of suitable design. The

aggregates should be dry and heated to 1500 to 1650 C in a mixer. The mix is then

transported to the site and spread uniformly on the bituminous surface followed by

rolling with smooth wheeled roller of 8-10 tonne weight.

Functions:

1) To water-proof the surface 2) To provide skid resistance.


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Type B seal Coat:Premixed seal coat comprising of a thin application of fine

aggregate premixed with bituminous binder.

Composition:

The quantity of bitumen per 10 m2 should be 6.8 kg; when bituminous

emulsion is used as a binder quantity required is 10.5 kg.

Construction:

Bitumen should be heated to 1500 to 1630 C and sprayed. Immediately after its

application, stone chips should be spread by means of mechanical grit

spreaders. After that, rolling is done with a 8-10 tonne smooth wheeled roller.

SEAL COAT


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TACK COAT

Composition:

The binder used for tack coat should be bitumen emulsion complying with IS 8887

of a type and grade as specified in the contract. Cutback bitumen can also be used

per IS 217 for places with sub-zero temperatures.

Construction:

The surface on which tack coat is applied should be swept clean with a mechanicalbroom in order to make it free from dust and clean. The rate of application of tack

coat generally varies from 0.20 to 0.40 kg/m2. The tack coat should be left to cure

until all the volatiles have evaporated before any subsequent construction is started.

Function: To ensure proper bonding between the new construction and old surface


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PRIME COAT

Composition:

The quantity of liquid bituminous material per 10 m2varies from 6 to 9 kg for low

porous surface, 9-12 kg for medium and 12-15 kg for surfaces with high porosity.

Construction:

The surface is first prepared by sweeping clean of dust and loose particles without

disturbing the interlocking of aggregates. A primed surface should be allowed to

cure for at least 24 hours.

Function:

To seal the pores by penetrating into it

To coat and bond dust and loose mineral particles

To provide adhesion between the base and superimposed layer


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Functions:

It provides characteristics such as friction, smoothness, drainage,

etc. Also it will prevent the entrance of excessive quantities of

surface water into the underlying base, sub-base and sub-grade,

It must be tough to resist the distortion under traffic and provide a

smooth and skid- resistant riding surface,

It must be water proof to protect the entire base and sub-grade from

the weakening effect of water.

WEARING COURSE:


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Bitumen:It should be paving bitumen of penetration grade complying with IS:

73 Paving Bitumen. As per requirement the bitumen can be modified

bitumen also.

Coarse aggregate: It consists of crushed rock, crushed gravel or other hard

material retained on 2.36 mm sieve. They should be clean, hard and durable.

Fine Aggregate: They should be clean, hard and durable. They consist of

crushed or naturally occurring material or a combination of the two, passing

through 2.36 mm sieve and retained on 75 micron sieve

Bituminous Concrete


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Minimum Stability (kN at 600C) 9.0

Minimum Flow (mm) 2

Maximum flow 4

Compaction Level (no. of blows) 75 blows on each of the two faces of the

specimen

Percent of air voids 3-6%VMA 10-16

%VFB 65-75

Loss of stability on immersion in water at

600

C

Min 75% retained strength

Requirement of the mix

Construction:

The pre-existing surface should be thoroughly swept clean by a mechanical broom, and the

dust removed by compressed air. Except in areas where a mechanical paver cant access,

bituminous material shall be spread, leveled and tamped by an approved self propelled paving

machine.


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Function:

To provide additional load distribution

To contribute to the sub-surface drainage

BASE COURSE

Dense graded bituminous macadam

Composition:

Bitumen:It should be paving bitumen of penetration grade complying with IS: 73 Paving

Bitumen. As per requirement the bitumen can be modified bitumen also.

Coarse aggregate:It consists of crushed rock, crushed gravel or other hard material retained

on 2.36 mm sieve. They should be clean, hard and durable.

Fine Aggregate:They should be clean, hard and durable. They consist of crushed or naturally

occurring material, or a combination of the two, passing through 2.36 mm sieve and retained

on 75 micron sieve


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Minimum Stability (kN at 600C) 9.0

Minimum Flow (mm) 2

Maximum flow 4

Compaction Level (no. of blows) 75 blows on each of the two faces of the specimen

Percent of air voids 3-6

%VMA 10-16

%VFB 65-75

Loss of stability on immersion in water

at 600C

Min 75% retained strength

Requirement of the mix

Construction:

The pre-existing surface should be thoroughly swept clean by a mechanical broom, and the

dust removed by compressed air. When the material on which the DBM is to be laid is other

than a bitumen bound layer, a prime coat shall be applied. The mixture is prepared in a hot mix

plant and carried to the site and is spread over followed by rolling of smooth wheeled roller.


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Functions:

To provide structural support, improve drainage,

To reduce the intrusion of fines from the sub-grade in the pavement structure

If the base course is open graded, then the sub-base course with more fines can serve as filler between

sub-grade and the base course

SUB-BASE COURSE

Composition:

The material to be used for the work shall be natural sand, gravel, crushed stone or their combination

depending on the grading required. The material should be free from organic or other deleterious

constituents

Construction:

The materials selected as per the table are mixed either manually or in mechanically. Moisture content is

suitably adjusted by sprinkling water. After placing the sub-base materials, rolling should start

immediately. Rolling shall be continued till the density the density is at least 98% of the MDD of the

material determined


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FUNCTIONS

To receive the stresses from the layers above

To transfer the entire load coming to it to the earth mass

To provide a good support to the earth structure

SUBGRADE

Composition:

The materials used in subgrade shall be soil, moorum, gravel, a mixture of these or any

other material approved by the engineer provided the materials are free of logs, stumps,

roots or any other ingredient likely to deteriorate or affect the stability of the subgrade.

Construction:

Subgrade is generally built sufficiently wider than the design dimension so that the surplus material may

be trimmed, ensuring that the remaining material is to the desired density and in position, The subgrade

material is then compacted to not less than 97% of the MDD. The compaction shall be done with the help

of vibratory roller of 80 to 100 kN static weight.


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FUNCTIONS

To provide characteristics such as friction, smoothness, noise control and drainage

To serve as a waterproofing layer to the underlying base, subbase and subgrade

To carry the load stresses

SURFACE COURSE/Concrete Pavement

Composition:Cement: Preference should be to use at least 43 grade or higher.

Admixtures: Conforming to IS: 6925 and IS: 9103 to improve the workability of concrete.

Aggregates:Natural aggregates with IS: 383 but with a Los Angels Abrasion Value lesser than 35%

Coarse aggregate: The maximum size should not exceed 25 mm for pavement concrete. Aggregates

should have water absorption value lesser than 2%.

Fine aggregate: Clean natural sand or crushed stone sand or combination of the two.

Water: It should be clean and free from injurious amount of oil, salt, acid etc.

The proportions of these are determined as per the design strength of the pavement.

Dowel bars and tie bars are also provided at the transverse and longitudinal joints respectively.


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Construction:

The concrete to be used in pavement is prepared in a batching plant and is transported to

the site without delay by means of trucks.

The delay must not exceed 120 minutes when concrete temperature is less than 250C and

90 minutes when the temperature is in between 250 C to 300C.

The mixing and placing of concrete should progress at such a rate as to permit proper

finishing, protecting and curing of the pavement.

While the concrete is still plastic, its surface shall be brush textured.

After 3 hours the pavement, shall be covered by moist hessian and the same shall be

covered by moist hessian and the same shall be kept damp for a minimum period of 14

days after which the hessian can be removed.


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Functions

To provide additional load distribution,

To contribute to drainage and frost resistance,

To provide uniform support to the pavement

To provide a stable platform for construction equipment

To prevent subgrade soil movement due to slab pumping.

BASE COURSE

Water bound Macadam

Composition:

Coarse Aggregate: It should be either crushed or broken stone, crushed slag etc. Los AngelsAbrasion value should be 30% (maximum) and combined flakiness and elongation indices

are 30% (max).

Screenings: Screenings to fill the voids in the coarse aggregate should consist of the same

material as coarse aggregate.


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Construction:

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

subgrade by using templates placed across the road.

Immediately following the spreading of the coarse aggregates, rolling shall be started

with three wheeled power 80 to 100 kN capacity.

After the coarse aggregate has been rolled, screenings to completely fill the interstices

should be applied gradually over the surface. These should not be damped or wet at the

time of applying.

This is followed by sprinkling of water and grouting and the binding material is applied

and left to set and dry.


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Functions:

To provide structural support, improve drainage,

To reduce the intrusion of fines from the sub-grade in the pavement structure

If the base course is open graded, then the sub-base course with more fines can serve as filler between

sub-grade and the base course

SUB-BASE COURSE

Composition:

The material to be used for the work shall be natural sand, gravel, crushed stone or their combination

depending on the grading required. The material should be free from organic or other deleterious

constituents

Construction:

The materials selected as per the table are mixed either manually or in mechanically. Moisture content is

suitably adjusted by sprinkling water. After placing the sub-base materials, rolling should start

immediately. Rolling shall be continued till the density the density is at least 98% of the MDD of the

material determined


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FUNCTIONS

To receive the stresses from the layers above

To transfer the entire load coming to it to the earth mass

To provide a good support to the earth structure

SUBGRADE

Composition:

The materials used in subgrade shall be soil, moorum, gravel, a mixture of these or any

other material approved by the engineer provided the materials are free of logs, stumps,

roots or any other ingredient likely to deteriorate or affect the stability of the subgrade.

Construction:

Subgrade is generally built sufficiently wider than the design dimension so that the surplus material may

be trimmed, ensuring that the remaining material is to the desired density and in position, The subgrade

material is then compacted to not less than 97% of the MDD. The compaction shall be done with the help

of vibratory roller of 80 to 100 kN static weight.


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nhdp funding, flexible and rigid pavement layerwise details

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