Method Statements (Road works) Methodolody

CONTENTS


1. Introduction

2. Clearing and Grubbing

3. Earthworks

4. Granular Sub Base Course

5. Wet Mix Macadam

6. Prime Coat

7. Tack Coat

8. Bituminous Macadam

9. Dense Bituminous Macadam

10. Bituminous Concrete (Wearing Course)


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1. INTRODUCTION


1.1 SCOPE

This document outlines the procedure for the method of construction of major items of Road works true to the lines, grades, shapes and cross sections as per approved drawings and specifications of the Project.

The Standard Specifications for Road and Bridge Works of Ministry of Shipping, Road Transport & Highway (MoSRTH) shall be consulted for the details which are not covered in this document.


1.2 FIELD OF APPLICATION

1. Clearing and Grubbing

2. Earthworks

3. Granular Sub Base Course

4. Wet Mix Macadam

5. Prime Coat

6. Tack Coat

7. Bituminous Macadam

8. Dense Bituminous Macadam

9. Bituminous Concrete (Wearing Course)


1.3. REFERENCES

1. Concessionaire Agreement

2. MoSRTH Specifications for Road and Bridge Works



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2. CLEARING AND GRUBBING



2.1 OBJECTIVE:

To out line the procedure for method of construction of Clearing and Grubbing to the required dimensions and levels conforming to approved drawings and project specifications.


2.2 CONSTRUCTION EQUIPMENT:

• Bull Dozer

• Excavator

• Motor Grader

• Soil Compactor

• Wheel Loader

• Water Tanker

• Dump Trucks


2.3 CONSTRUCTION METHODOLOGY:

The following sequence of activities shall be carried out for Clearing and Grubbing work:


a The original ground level at every 20m interval longitudinally and 3m transversely and also at CL, edge of shoulder and toe of the existing road shall be recorded. In widely varying terrain and in sharp curve portions the longitudinal spacing may be reduced to 10m.

b The toe width with respect to finish road level shall be calculated & marked it on the ground with an additional margin on both sides of carriageway.

c The centerline of proposed road shall be marked from the given reference point on ground with pegs.

d Grubbing, uprooting of vegetation, grass, bushes, shrubs, top organic soil not exceeding 150mm in thickness (201.1), rubbish, etc. shall be cleared and removed with the help of dozer, grader & excavator.

e All trees, stumps, etc., falling within excavation and fill lines shall be cut to such depth below ground level that in no case these fall within 500 mm of Subgrade. All branches of trees extending above proposed roadway shall be trimmed.

f All excavations below the general ground level arising out of the removal of trees, stumps, etc., shall be filled with suitable material and compacted thoroughly so as to make the surface at these points conform to the surrounding area.

g Minor undulations and pits shall be cut and filled to obtain clean & clear bed matching to the road profile.

h The moisture content of each layer of soil at the time of compaction shall be from +1% to –2% of optimum moisture content. (305.3.5.2)

i Watering and rolling shall be carried out for bed / foundation layer with vibratory roller having 80 - 100 KN static weight (305.3.6) to achieve 95% relative compaction with respect to laboratory dry density found as per Modified Proctor Method (Table:300-2). In case of pits or uneven ground surface where compaction can not be done with vibratory roller, mini tandem rollers or tamping compactors shall be used.

j The compaction control of bed shall be exercised as per Sub section 903.2.2 of MoSRTH Specifications.

k After compaction of the bed, the levels at an interval as mentioned at para (a) above shall be taken before placing of embankment/Subgrade layer.

l All materials arising from clearing & grubbing operations shall be disposed of by the Concessionaire as per Concession Agreement or as directed by the Engineer.


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3. EARTH WORKS



3.1 OBJECTIVE:

To out line the procedure for method of construction of Embankments, Subgrades, Earthen Shoulders and Miscellaneous Backfills to the required lines, grades and cross sections conforming to approved drawings and project specifications.


3.2 CONSTRUCTION EQUIPMENT:

• Bull Dozer

• Excavators

• Motor Graders

• Soil Compactors

• Wheel Loader

• Water Tankers

• Dump Trucks


3.3 MATERIAL:

The materials used in embankments shall be soil, moorum, gravel, a mixture of these or any other material approved by the engineer. These materials shall be free of logs, stumps, roots, rubbish or any other ingredient likely to deteriorate or affect the stability of the embankment.

The maximum laboratory density of material used for embankments up to 3 m height and not subjected to extensive flooding shall not be less than 15.2 K.N/cu.m; and for embankments exceeding 3 m height or embankments of any height subject to long periods of inundation shall not be less than 16.0 K.N/cu.m; and for subgrade and earthen shoulders / verges / backfilling shall not be less than 17.5 KN/cu.m. It shall be ensured prior to actual execution that the material to be used in the subgrade satisfies the requirements of design CBR of 10.

The size of the coarse material in the mixture of earth shall ordinarily not exceed 75 mm when being placed in embankment and 50 mm when placed in the subgrade.


3.4 SOURCE APPROVAL:

Suitable borrow areas shall be identified and samples taken from borrow areas shall be tested for its suitability in Embankments / Sub-grade construction as per specification requirements.


3.5 CONSTRUCTION METHODOLOGY:

The following sequence of activities shall be carried out for construction of earth works:


a After the site has been cleared the limits of embankment shall be marked by fixing pegs on both sides at regular interval as guides before commencing the earthwork.

b The embankment / subgrade shall be built sufficiently wider than the design dimension so that surplus material may be trimmed, ensuring that the remaining material is to the desired density and in position specified and conforms to specified side slopes.

c If the foundation of the embankment is in an area with stagnant water the same shall be removed by bailing out or pumping and the area of the embankment foundation shall be kept dry. Where embankment / backfilling is to be placed under water, only acceptable granular material or rock shall be used.

d Original ground, where necessary, shall be leveled to facilitate placement of first layer of embankment, scarified, mixed with water and then compacted by rolling so as to achieve minimum dry density as per specification i.e. 95% of Lab MDD and 97% of Lab MDD in case of Sub-grade.

e If the difference between the subgrade top level and ground level, in case, is less than 0.5 m and the ground does not have 97% relative compaction with respect to Lab MDD, the ground shall be loosened up to a level 0.5 m below the subgrade level, watered and compacted in layers to not less than 97% of Lab MDD.

f The embankment / Sub-grade material shall be spread in layers of uniform thickness not exceeding 200 mm compacted thickness over the entire width of embankment by mechanical means, finished by motor grader having hydraulic control to achieve specific slope and grade and compacted to achieve required density. Successive layers shall not be placed until layer under construction has been thoroughly compacted to specified requirement and approved by engineer.

g Where the embankment is to be placed over an existing road surface, the work shall be carried out as per Sub Section 305.4.3 of MoSRTH Specifications.

h When the existing embankment and/or subgrade is to be widened and its slopes are steeper than 1 vertical on 4 horizontal, continuous horizontal benches, each at least 300 mm wide, shall be cut into the old slope for ensuring adequate bond with the fresh embankment/subgrade material to be added. The material obtained from cutting of benches shall be utilized in the widening of the embankment/subgrade.

i When the existing slope against which the fresh material is to be placed is flatter than 1 vertical on 4 horizontal, the slope surface may only be ploughed or scarified instead of resorting to benching.

j Moisture content of the soil shall be measured by moisture meter before taking up compaction of each layer as per IS 2720 (Part-2). If the moisture content is less than the designed OMC plus due allowance for evaporation losses as per IS 2720 (Part-2), water shall be sprinkled from a water tanker fitted with c controllable rate of flow to variable widths of surface uniformly without any flooding. After adding required amount of water, the soil shall be processed by means of graders, harrows, rotary mixture or any other method in practice until the layer is uniformly wet.

k The compaction shall be done with the help of vibratory roller of 80-100 KN static weight with plain or pad foot drum or heavy PTR of adequate capacity capable of achieving required compaction.

l Where the width of the widened portion is insufficient to permit the use of conventional rollers, compaction shall be carried out with the help of small vibratory rollers/plate compactors/power rammers or any other appropriate equipment.

m The measurement of field dry density of each compacted layer my be done either by a nuclear moisture / density meter calibrated to provide test results identical to that obtained in accordance with IS 2720 (Part-28) or by sand replacement method as per IS 2720 (Part-28).

n Subsequent layer shall be placed only after the finished layer has been tested and accepted by the Engineer.

o When the embankment / subgrade reaches top position, finishing operations like the work of shaping and dressing the shoulders/verge/roadbed and side slopes shall be done to conform to the alignment, levels, cross sections and dimensions shown on the drawings subjected to the surface tolerance as per Sub Section 902 of MoSRTH Specifications.

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4. GRANULAR SUB-BASE



4.1 OBJECTIVE:

To out line the procedure for the method of construction of Granular Sub-base on prepared subgrade to the required lines, grades and cross sections conforming to approved drawings and project specifications.


4.2 CONSTRUCTION EQUIPMENT:

• Motor Graders

• Soil Compactors

• Water Tankers

• Dump Trucks


4.3 MATERIAL:

The material to be used for the work shall be natural sand, moorum, gravel, crushed stone or combination there of depending upon the grading requirements. Materials like crushed slag, crushed concrete, brick metal and kankar shall be allowed to use only with the specific approval of the engineer. The material shall be free from organic or other deleterious constituents and conform to Grading-I of Table 400-1 of MoSRTH Specifications.

Table 400-1 Grading-I for Close Graded Granular Sub base Materials

IS sieve Designation Percent by weight passing the IS sieve

GRADE-I

75 mm 100

53 mm 80-100

26.5 mm 55-90

9.5 mm 35-65

4.75 mm 25-55

2.36 mm 20-40

425 micron 10-25

75 micron 3-10


Physical Requirements:

• The water absorption value of the coarse aggregate shall be determined as per (IS-2386 Part-3). If this value is grater than 2% then soundness test shall be carried out on the material.

• Minimum CBR value for the GSB material for Grade-I is 30%.

• The material passing through 425 micron sieve of GSB material when tested in accordance with IS 2720 part-5 shall have liquid limit and Plasticity Index not more than 25% and 6% respectively.


4.4 SOURCE APPROVAL:

Suitable borrow areas shall be identified and samples taken from borrow areas shall be tested for its suitability in Granular Sub-base construction as per specification requirements.


4.5 CONSTRUCTION METHODOLOGY:

The following sequence of activities shall be carried out for construction of GSB works:


a Immediately prior to laying of GSB material for Sub-base, the subgrade already finished shall be prepared by removing all vegetation and other extraneous matter, lightly sprinkled with water if necessary and rolled with two passes of 80-100 KN smooth wheeled roller.

b The GSB material of Grading-I shall be spread on the prepare surface of subgrade with the help of a motor grader to the required slope and grade.

c Moisture content of loose material shall be checked in accordance with IS:2720 (Part 2) and suitably adjusted by sprinkling additional water from truck mounted water tank uniformly and at controlled quantities to variable widths of surface so that at the time of compaction it is +1% to -2% below the optimum moisture content.

d After water has been added, the material shall be processed by mechanical or other approved means like disc harrows, rotavators until the layer is uniformly wet.

e Immediately after fulfillment of moisture content requirements, rolling shall be started. If the thickness of the compacted layer does not exceed 100 mm a smooth wheeled roller of 80 to 100 KN weight may be used. For a compacted single layer up to 225mm thickness, the compaction shall be done with the help of a vibratory roller of minimum 80 to 100 KN static weight with plain drum of pad foot-drum or heavy pneumatic roller capable of achieving the required compaction. Each pass of the roller shall uniformly overlap not less than the one third of the track made in the preceding pass. The speed of the roller shall not be exceeded 5KM per hour.

f Rolling shall be commenced at lower edge and proceed towards the upper edge longitudinally for portions having unidirectional cross fall and super elevation and shall commence at the edges and progress towards the centre for portions having cross fall on both sides.

g Rolling shall be continued till the density achieved is at least 98% of the maximum dry density for the material determined as per IS:2720 (Part 8).

h All loose, segregated or otherwise defective areas shall be made good to the full thickness of layer and re-compacted.

i All works performed shall be verified to confirm to lines, grades, cross sections and dimensions shown on drawings subject to the permitted tolerance as per Sub Section 902 of MoSRTH Specifications.

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5. WET MIX MACADAM BASE COURSE



5.1 OBJECTIVE:

To out line the procedure for the method of construction of Wet Mix Macadam Base Course on prepared Granular sub-base to the required lines, grades and cross sections conforming to approved drawings and project specifications.


5.2 CONSTRUCTION EQUIPMENT:

• Aggregate Mixing Plant with all assembly

• Mechanical Paver

• Vibratory Rollers

• Water Tankers

• Dump Trucks


5.3 MATERIAL:

• Material intended to use in the construction of WMM are crushed stone aggregates of sizes 53 mm to 6 mm (All-in-aggregate), 20mm, 10 mm, Crusher dust & sand

• The Coarse aggregates shall be conformed to the physical requirement given in table below:

Sl. No. TEST TEST MATERIAL REQUIREMENT

1 *Los Angeles abrasion value or

Aggregate impact value IS 2386 ( Part-IV)


IS 2386 ( Part-IV) or IS: 5640 40% (max)


30% (max)

2 Combined flakiness and Elongation indices (total) IS 2386 (Part-I) 30% (max)

*Aggregate may satisfy requirement of either of the two tests.

• The aggregates shall be conformed to the grading given as below:

IS Sieve Designation % by wt. Passing the IS : sieve

53.0mm 100

45.0 mm 95-100

26.5 mm -

22.40 mm 60-80

11.20 mm 40-60

4.75 mm 25-40

2.36 mm 15-30

600.0 micron 8-22

75.0 micron 0-8

• Materials finer than 425 micron shall have Plasticity Index not exceeding 6.

• The final Gradation approved within the above limits shall be well graded from Coarse to fine and shall not vary from these limits on the sieve to high limits on adjacent sieve or vice versa.

• If the water absorption value of coarse aggregate is greater than 2%, Soundness test shall be done.

• Control on the quality of materials shall be exercised in accordance with Section 900 of MoSRTH Specifications.


5.4 PREPARATION OF WMM MIX:

Preparation of the mix shall be carried out in approved calibrated aggregate mixing plant of suitable capacity having provision for controlled addition of water and forced / positive mixing arrangement like pug mill.


Before preparation of the mix in the pug mill the material shall be filled in four bins as mentioned below.


Bin No-1 All-in-Aggregate

Bin No-2 All-in-Aggregate

Bin No-3 20 mm + 10 mm (Premixed separately in the required ratio)

Bin No-4 Sand & Crusher dust (Premixed separately in the required ratio)


Incase 40 mm aggregate is available the same can be filled in Bin No – 1 & 2


After placing the material in the above manner the mix shall be prepared by adding the required water as per the job mix formula. While adding water, due allowance shall be made for evaporation losses. However, at the time of compaction, water in Wet Mix Macadam should not vary from the optimum value by more than agreed limits. The mixed material should be uniformly wet and no segregation should be permitted.


5.5 CONSTRUCTION METHODOLOGY:

The following sequence of activities shall be carried out for construction of WMM works:


a The surface of the base to receive the Wet Mix Macadam course shall be prepared to the specified lines and cross fall (camber) and made free from dust and other extraneous material.

b While constructing Wet Mix Macadam, arrangement shall be made for the lateral confinement of Wet Mix. This shall be done by lying materials in adjoining shoulders along with that of Wet Mix Macadam layer.

c Immediately after mixing, the aggregate shall be spread uniformly and evenly upon the prepared sub-base in required quantities. In no case should these be dumped in heaps directly on the area where these are to be laid nor shall their hauling over a partly completed stretch be permitted.

d The mix shall be spread either by a paver finisher or motor grader. However, in restricted locations and in narrow widths where the paver can not be operated, the manual spreading shall be done. The material shall be spread uniformly all over the surface. The surface of aggregate shall be carefully checked with templates and all high or low spots remedied by removing or adding aggregate as may be required.

e The layer may be tested by depth blocks during construction. No segregation of layer and fine particles shall be allowed. The aggregates as spread shall be of uniform gradation with no pockets of fine materials.

f After the mix has been laid to the required thickness, grade and crossfall / camber the same shall be uniformly compacted to the full depth with suitable roller.

g If the single compacted layer thickness does not exceed 100mm, the compaction may be done with the help of smooth wheel roller of 80 to 100 KN weight. For a compacted single layer upto 200 mm, the compaction shall be done with the help of vibratory roller of minimum static weight of 80 to 100 KN or equivalent capacity roller. The speed of roller shall not exceed 5 Km/hour.

h In portions having unidirectional cross-fall/ super elevation, rolling shall commence from the lower edge and progress gradually towards the upper edge. There after roller should progress parallel to the center line of the road, uniformly overlapping each preceding track by at least one-third width until the entire surface has been rolled.

i In portion in camber, rolling should begin at the edge with the roller running forward and backward until the edges have been firmly compacted. The roller shall then progress gradually towards the center parallel to the centerline of the road, uniformly overlapping each preceding track by at least one-third width until the entire surface has been rolled. Any displacement occurring as a result of reversing of the direction of the roller or from any other cause shall be corrected at once as specified and / or removed and made good.

j Along forms, Kerbs, walls or other places not accessible to the roller, the mixer shall be thoroughly compacted with mechanical tamper or a plate compactor. Skin patching of an area without scarifying the surface to permit proper bonding of the added material shall not be permitted.

k Rolling should not be done when the sub-base is soft or yielding or when it causes a wave like motion in the sub-base. If irregularities develop during rolling which exceed 12mm when tested with a 3mtr straight edge, the surface should be loosened and premixed material added or removed as required before rolling again so as to achieve a uniform surface conforming to the desired grade and cross-fall. Rolling shall be continued till the density achieved is at least 98% of the maximum dry density for the material as determined by the method outlined in IS:2720 (Part 8).

l After completion, the surface of any finished layer shall be well closed, free from movement under compaction equipment or any compaction planes, ridges, cracks and loose material. The finished layer shall be prevented from the movement of vehicles etc. by placing medium size stones to discourage traffic entry. All Care shall be taken to prevent the contamination of laid W.M.M. with foreign unwanted soil, dust, etc.

m All loose, segregated or otherwise defective areas shall be made good to the full thickness of the layer and recompacted.

n After final compaction of Wet Mix Macadam course, the road shall be allowed to dry for 24 hours.

o The control on the quality of works shall be exercised in accordance with Section 900 of MoSRTH Specifications. The levels of the finished WMM layer shall not vary beyond the tolerances of ± 10mm from those calculated with reference to the longitudinal and cross-profile of the road shown on the drawings.

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6. PRIME COAT



6.1 OBJECTIVE:

To out line the procedure for the method of construction of laying Prime Coat on prepared Wet Mix Macadam base to the required lines conforming to approved drawings and project specifications.


6.2 CONSTRUCTION EQUIPMENT:

• Bitumen Distributor with self-propelled or towed bitumen pressure sprayer

• Hand Sprayers

• Mechanical Broom

• Air Compressor


6.3 MATERIAL:

• Since WMM is considered to be material of low porosity, it is proposed to use Slow Setting Emulsion for Prime Coat. The Slow Setting Emulsion shall comply with IS:8887 and shall be procured from reputed manufacturers.

• Test Certificates shall be obtained from Manufacturer for the material supplied and the same shall be submitted to IC.

• The quantity of bituminous primer to be sprayed per 10 Sq.m shall be kept at 7.5 Kg. The spray rate shall be maintained between limits 6 to 9 Kg per 10 Sq.m.


6.4 CONSTRUCTION METHODOLOGY:

The following sequence of activities shall be carried out for laying of Prime Coat:


a Prior to applying primer on prepared WMM surface, the surface shall be carefully swept clean of dust and loose particles by mechanical broom and air compressor with proper care not to disturb the interlocked aggregate. To achieve this, the WMM surface layer, if required, shall be lightly sprayed with water and surface is allowed to dry to a stage where the surface is slightly moist but no free or standing water shall be present at the time of priming.

b The primer shall not be applied to a wet surface or during a dust storm or when the weather is foggy, rainy or windy or when the temperature in the shade is less than 10° C.

c The bituminous primer shall be sprayed uniformly with bitumen distributor at specified speed. The speed of bitumen distributor shall be so regulated so as to achieve the required rate of spray within tolerance limits. The spray test shall be conducted to check the bitumen spray rate per unit area.

d Where the areas are inaccessible to the distributor or in narrow strips, hand sprayers shall be used for spraying of primer.

e The primed surface shall be cured for 24 hours or such other period as is found necessary to allow all the volatiles to evaporate before any subsequent surface treatment or mix is laid. Any unabsorbed primer shall first be blotted with an application of sand, using the minimum quantity possible. A primed surface shall not be opened to traffic other than that necessary to lay the next course. A very thin layer of clean sand shall be applied to the surface of the primer, to prevent the primer picking up under the wheels of the paver and the trucks delivering bituminous material to the paver.

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7. TACK COAT



7.1 OBJECTIVE:

To out line the procedure for the method of construction of Tack Coat application over primed surface / existing bituminous road surface (preparatory to the superimposition of a bituminous mix) to the required lines conforming to approved drawings and project specifications.


7.2 CONSTRUCTION EQUIPMENT:

• Bitumen Distributor with self-propelled or towed bitumen pressure sprayer

• Hand Sprayers

• Mechanical Broom

• Air Compressor


7.3 MATERIAL:

• The material used for tack coat shall be Rapid Setting Emulsion complying to IS:8887 and shall be procured from reputed manufacturers.

• Test Certificates shall be obtained from Manufacturer for the material supplied and the same shall be submitted to IC.

• The quantity of R.S. Emulsion to be sprayed per 10 Sq.m shall be kept at 2.75 Kg for surfaces treated with primer and at 2.25 Kg for existing bituminous road surface preparatory to the superimposition of a bituminous mix. The spray rate shall be maintained between the limits as specified in the Section 503 of MoSRTH Specifications.


7.4 CONSTRUCTION METHODOLOGY:

The following sequence of activities shall be carried out for application of Tack Coat:


a The surface on which the tack coat is to be applied shall be made clean and free from dust, dirt and any extraneous by mechanical broom and/or air compressor with proper care not to disturb the interlocked aggregate.

b The tack coat shall not be applied to a wet surface or during a dust storm or when the weather is foggy, rainy or windy or when the temperature in the shade is less than 10° C.

c The bituminous emulsion shall be sprayed uniformly with bitumen distributor at specified speed. The speed of bitumen distributor shall be so regulated so as to achieve the required rate of spray within tolerance limits. The spray test shall be conducted to check the bitumen spray rate per unit area.

d Where the areas are inaccessible to the distributor or in narrow strips, hand sprayers shall be used for application of tack coat.

e Tack coat may not be applied over a freshly laid bituminous layer, which has not been subjected to traffic or contaminated by dust, where the overlay is completed within two days.

f The tack coat shall be left to cure for 2 to 4 hours whichever is found necessary to allow all the volatiles to evaporate before any subsequent construction is started.

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8. BITUMINOUS MACADAM



8.1 OBJECTIVE:

To out line the procedure for the method of construction of Bituminous Macadam in one or more layers (the thickness of single layer shall be 50 mm to 100 mm) to the required lines, grades and cross sections conforming to approved drawings and project specifications.


8.2 CONSTRUCTION EQUIPMENT:

• Hot Mix Plant of adequate capacity

• Dump Trucks

• Sensor Pave

• Power Broom / Air Compressor

• Self- propelled or towed bitumen pressure sprayer.

• Vibratory Tandem Rollers

• Pneumatic Tyred Rollers

• Steel pegs & thin wire.


8.3 MATERIAL:

The following materials shall be used.


Bitumen: The bitumen shall be paving bitumen of penetration grade complying with IS Specifications for “Paving Bitumen” IS:73 and the penetration grade shall be as specified in the Concession Agreement.


Coarse Aggregate: The coarse aggregates shall be of crushed rock, crushed gravel or other hard material and shall be clean, hard, durable, free from dust or soft or friable matter, organic or other deleterious substances. The aggregates shall satisfy the physical requirements as given in the Table – 8.1.


The aggregate may satisfy the strength requirements of either Los Angeles Abrasion Value or Aggregate Impact Value. The water sensitivity test is only required if the minimum retained coating in the stripping test is less than 95%.


Fine Aggregate: Fine aggregate shall be the fraction passing 2.36 mm sieve and retained on 75 micron sieve, consisting of crusher run stone aggregate or screening sand, or a mixture of both. Fine aggregate shall be clean, hard, durable, dry and free from dust, and soft or friable matter, organic or other deleterious substances.


Filler: Filler shall consist of finely divided mineral matter such as stone dust. The filler shall be free from organic impurities and have a plasticity Index not greater than 4.


Aggregate Gradation: The combined coarse, fine aggregate and filler (when used) shall produce a well-graded mixture and the grading shall fall within the limits given in Table – 8.2 with respect to type and quantity of bitumen and appropriate thickness.



Table – 8.1: Physical Requirements for Coarse Aggregates

Property Test Reference: Specification

Cleanliness (Dust) Grain Size Analysis IS 2386 - Part-1 Max 5% passing 0.075mm sieve

Particle Shape Flakiness and Elongation Index IS 2386 - Part-1 30% max.

Strength 1. Los Angeles Abrasion Value


2. Aggregate Impact Value IS 2386 Part-4


IS 2386 Part-4 Max 40%


Max 30%

Durability Soundness:

1. Sodium Sulphate

2. Magnesium Sulphate

IS 2386 Part-5

IS 2386 Part-5

12% max.

18% max

Water Absorption Water absorption IS 2386 Part-3 2% max

Stripping Coating and Stripping of Bitumen Aggregate Mixer IS 6241 Minimum retained Coating 95 %

Water Sensitivity Retained Tensile Strength AASHTO T283 Min 80%



Table – 8.2: Combined Aggregate Gradation for Bituminous Macadam

Grading 1 2

Nominal Aggregate Size 40 mm 19 mm

Layer Thickness 80-100 mm 50-75 mm

IS Sieve (MM) Cumulative % by weight of total aggregate passing

45 100

37.5 90-100

26.5 75-100 100

19 - 90-100

13.2 35-61 56-88

4.75 13-22 16-36

2.36 4-19 4-19

0.3 2-10 2-10

0.075 0-8 0-8

Bitumen Content % by mass of total Mix 3.1 – 3.4 3.3 – 3.5

Bitumen Grade (pen) 35 or 90 35 or 90



8.4 LAYING TRIALS: