Method Statement for Asphalt Works

Document Details (Generic)

• Discipline: Civil

• Trade: Roads & Pavements

• Document Type: Method of Statement (MOS)

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1. Purpose & Scope

The primary objective of this method statement is to provide a standardized, documented procedure for asphalt works. This procedure covers all asphalt-related activities and ensures proper execution across construction sites.

2. Definition & Abbreviation

• Bench mark/Reference point: A surveyor’s mark established on a stationary object of known position and elevation, utilized as a construction reference.

• IFC: Issued for Construction drawings

• ITP: Inspection Test Plan

• CAR: Corrective Action Request

• NSL: Natural Surface Level

• PTS: Project Technical Specification

• MC: Medium Curing

• RC: Rapid Curing

3. References

• IFC Drawings

• Approved Material Submittals

• PTS (Project Technical Specifications)

• AASHTO-M20: Aggregate for Concrete

• AASHTO-M43: Standard Specification for Sizes of Aggregate for Road and Bridge Construction

• AASHTO-M81: Coarse Aggregate for Portland Cement Concrete

• AASHTO-M140: Cement

• AASHTO-M283: Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete

• ASTM 0692: Standard Test Method for Specific Optical Density of Smoke Generated by Solid Materials

• ASTM 01073: Standard Test Methods for Analysis of Calcium Chloride

• ASTM 01241: Standard Test Method for Slake Durability of Shales and Other Similar Weak Rocks

• BS1707 or IS:217: Specification for Copper and Copper Alloy Ingots and Castings

• IS:454: Code of Practice for General Construction of Plain and Reinforced Concrete for Dams and Other Massive Structures

• IS:8887: Specification for Water for Making Concrete

4. Responsibilities

• Project/Construction Manager: Bears overall responsibility for the implementation and continuous monitoring of all asphalt-related activities outlined in this method statement.

• Site Manager: Responsible for overarching direction, coordination, and monitoring of all site execution activities related to asphalt works.

• Site Engineer: Directly plans and executes field activities. Responsible for preparing the asphalt plan, developing the safe work plan, and applying for work permits prior to excavation/paving.

• QA/QC Engineer: Conducts monitoring tests in compliance with the approved ITP. Coordinates with independent testing laboratories and verifies that asphalt works align with the IFC drawings and ITP.

• Foremen: Directs the physical execution of asphalt works. Issues instructions to the workforce, ensures proper use of tools/equipment and PPE, and maintains housekeeping around the active work area.

• Surveyor: Establishes site benchmarks and monitors grade elevations. Assesses asphalt surface smoothness, maintains daily logs, records as-built deviations, and conducts the final survey for handover documentation.

• HSE Engineer/Supervisor: Reviews the Safe Work Plan and work permits before activity commencement. Prepares and submits necessary HSE documentation to the client/customer.

5. Tools & Equipments

• Dozer

• Bitumen Sprayer vehicle

• Pressure Distributes Roller

• Loader

• Motor Grader

• Dump Truck

• Vibrator Roller

• Plate compactor

• Paver Machine

• Water Boozer

• Theodolite with tripod

• Automatic level with tripod and staff rod

• Metal detector / Cable detector

6. Procedure

The execution of asphalt procedures is categorized into the following sequential stages: Sub-Base, Prime Coat, Binder Course, Tack Coat, and Wearing Course.

6.1 Sub-Base Preparation

• Execute grading to achieve the proposed grades as indicated on the approved IFC drawings.

• Check and verify all final levels.

• Conduct density tests at randomized locations, with frequency dictated by specifications, to determine the degree of compaction.

• Ensure aggregate sub-base material is tested and approved by an independent laboratory.

• Place approved sub-base material in layers not exceeding 30 cm, or strictly according to company specifications.

• Spread, level, and compact the sub-base layer using steel-wheel tandem vibratory rollers and pneumatic-tired rollers.

• Verify finalized dimensions and levels on the compacted layer.

• Execute third-party density and compaction tests as specified.

6.2 Prime Coat Application

• Thoroughly clean the full width of the surface using compressed air immediately prior to application.

• Ensure the prime coat material has received preliminary approval.

• Apply bituminous material via spray tankers in a single, uniform layer.

• Maintain an application rate between 0.7 to 1.5 liters/sq.m, adhering to company specifications.

• Keep application temperature below 70°C.

• Allow the sprayed area to cure for more than 24 hours until all excess prime coat has completely evaporated.

6.3 Binder Course Application

• Verify binder quality adheres to AASHO-T182 or IS:73, IS:217, IS:454, and IS:8887.

• Clean the primed surface with compressed air, ensuring it is completely dry before paving.

• Transport hot asphalt mix from the mixing plant using wheel trucks and dump it directly into the asphalt paver.

• Lay the material to the specified thickness and level.

• Commence compaction immediately after spreading.

• Execute breakdown rolling at a temperature of 110-120°C using tandem rollers, followed by pneumatic-tired rollers.

• Begin rolling from the outer edges and proceed toward the center, ensuring each trip overlaps the previous pass by at least 30 cm.

• Keep roller wheels moistened and operate smoothly without backlash to prevent surface tearing.

• Eliminate any waves using heavy tandem rollers.

• Achieve full compaction before the asphalt temperature drops to 100°C.

• Prepare construction joints by vertically cutting the layer with an asphalt saw or jackhammer. Clean the joint, apply compressed air, and coat with tack material on vertical/horizontal surfaces for optimal bonding.

• Compact inaccessible areas using plate compactors or hand tampers.

• Once the base course reaches the top level, dump suitable fill material (dune sand) on the road shoulders, level it, shape it to a 1:6 ratio, and compact to 90% maximum dry density.

6.4 Tack Coat Application

• Apply primarily approved tack coat material at a rate of 0.3 to 0.6 liters/sq.m.

• Maintain temperature not exceeding 54°C above the binder temperature (or per manufacturer specifications).

• Cure the surface until a tacky, sticky surface is visible.

6.5 Wearing Course Application

• Spread the hot asphalt mix over the cured tack coat using an automatic asphalt paver according to the approved profile and thickness.

• Compact the mix as soon as possible after spreading.

• Conduct breakdown rolling at 110-120°C using tandem rollers.

• Continue compaction with self-propelled and tandem rollers starting from the sides and moving toward the center, overlapping previous trips by at least 30 cm.

• Maintain moistened roller wheels, reverse without backlash, and utilize heavy tandem rollers to eliminate any surface waves.

• Complete full compaction before the surface temperature reaches 80°C.

• Restrict all traffic on the newly paved layer for a minimum of 12 hours until it is adequately cooled.

• Repair any core test holes with hot asphalt mix and compact thoroughly using a Marshal Hammer.

7. Inspection & Testing

• Ensure all testing is conducted by an approved, independent third-party site laboratory.

• Carry out all field inspection and testing activities in strict alignment with the approved ITP.

• Maintain and prepare all relevant QC records through the Contractor’s QC Engineer.