Bituminous Surface Treatment

1.0 Introduction
This method statement covers all the procedures to be adopted for asphalt concrete surfacing work consisting of furnishing materials, mixing at a central plant, and spreading and compacting asphalt concrete wearing, binder and regulating course on an approved base course.

2.0 Abbreviation
CM  – Construction Manager
SE    – Site Engineer
SEO  – Safety & Environmental Officer
ME   – Material Engineer
PPE  – Personal Protective Equipment

Man Power Equipment
CM Asphalt Plant (2 nos)
SE Water Bowser
ME Tandem Roller
SEO Dump Trucks
Lab Technicians & Helpers Asphalt Paver
Surveyor Air Compressor
Survey Helpers Tire Roller
Supervisor/Foreman Asphalt Distributor
Operator (A/P Finisher)
Operator (Tandem Roller)
Operators (Tire Rollers)
Driver – Distributor
Driver –  Dump Truck
Skilled & Unskilled laborers

1. The material would be composed basically of graded crushed coarse aggregate, fine aggregate, filler, asphalt material, tack coat (CRS-1) and prime coat (MC-30).
2. The several mineral constituents would be sized, uniformly graded and combined in such proportions that the resulting blend meets the grading requirements for the specific type under the contract.
3. Temperature, Delivery of Mixture : 105º C ~160º C
4. Compaction Temperature: 105º C ~ 135º C

4.0 Methodology

4.1 General
1.  Before construction of asphalt pavement for the section concerned would be completed so that the section DGAB already constructed would be protected against erosion.
2.  DGAB should be done on a prepared and accepted sub-base course or other roadbed in accordance with the specification and specific requirements of the contract in conformity with the required lines, levels, grades, dimensions and cross sections.
3. Quality of the work would be secured through the careful control for the materials.
4.  Adequate safety control measures would be provided to prevent from any damage or danger to the public and the personnel involved in the work.

4.2 Preparation of Existing Surface
1. Prior to application of prime coat the base would be brushed to remove all dust, loose particles and other extraneous material and the surface would be moistened with water just before priming.
2. Where local irregularities in the existing surface, the surface would be brought to uniform contour by patching with an asphalt mixture to be approved by the Engineer.
3. Where the mix is laid over cement concrete pavements, joints and cracks would be cleaned and filled with bituminous material as approved, and any unevenness of the surface would be corrected as required. A tack coat would then be applied to the surface.

4.3 Weather Limitations
1. Asphaltic mixtures would be placed only when the surface is dry, when the weather is not rainy or will not soon be rainy and prepared road bed is in a satisfactory condition.
2. For use in an emergency such as rain, chilling wind or unavoidable delay enough tarpaulin covers would be used for the purpose of covering or protecting any material that may have been dumped and not spread.

4.4 Limitations due to Equipment
1. No work would be carried out when there is insufficient equipment for hauling, spreading, compaction and finishing or insufficient labour to ensure progress at a rate compatible with the output of the mixing plant to ensure a continuous paving operation.
2. Trucks for hauling asphalt mixtures would be tight, clean, and smooth metal beds that have been sprayed with soapy water, thinned fuel oil, paraffin oil, or lime solution to prevent the mixture from adhering to the bed and the amount of sprayed fluid would be kept to the practical minimum.
3. Each load would be covered with a canvas or other suitable material of such size as to protect the mixture from the weather.
4. Any truck causing excessive segregation of material by its spring suspension or that causes undue delays shall, upon direction of the Engineer, be removed from the work until such conditions are corrected.
5. When necessary, in order that the mixture would be delivered to the site within the specified temperature range, a properly fastened insulating cover would be used.
6. Loading and transporting would be such that spreading, compacting and finishing would all be carried out during daylight hours unless satisfactory illumination is provided.

7. The equipment for spreading and finishing would be approved mechanical, self powered pavers, capable of spreading and furnishing the mixture to the lines, grades, levels, dimensions and cross sections.
8. The mixture after spreading and initial tamping by the Paver, would have a smooth surface free of distortions caused by dragging, tearing or gouging.
9. Any defects in the finished surface would immediately be rectified before any rolling takes place and there would be no unnecessary scattering back by hand of material on paver laid work.
10. For keeping all small tools clean and free of accumulation of asphaltic material, suitable means would be provided.

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