Method Of StatementTack Coat and Asphalting

 

Materials

The major materials used for tack coat & asphalt work, but are not limited to the following.

• Asphalt Concrete (Binder Course )
• CRS 1

Equipment

The major equipment used for tack coat & asphalt work, but are not limited to the following.

• Asphalt Pavers – 5.5 m width
• Pneumatic Tyred Rollers – 10 Tone
• Tandem Roller – 8 Tone
• 2.5 T roller
• Plate Compactor
• Tractor & Trailer
• Asphalt Cutter & Breaker
• Tractor with Broom – 2 m Wide
• Dump Trucks – 3.5 Cube
• Sampling & Testing Equipment
• Sprit Level
• Compressor – 125 cfm
• Tack coat sprayer
• Straight Edges
• Water bowser
• Other minor tools

Man Power

Man power used for tack coat & asphalt work, but are not limited to the following.

• Civil Forman (Asphalt)
• Safety Officer
• Lab technician
• Surveyor Assistant
• Supervisors
• Rake Men
• Skilled Labours
• Unskilled Labours

Responsibility of work carried out lies on every person involve for the job. Site management team, Materials Engineer and Surveyor collectively bear responsibility in guaranteeing the quality of finished product.

Safety Management and Tra.ffic Control

Safety precaution will be taken complying with the Traffic and Safety Plan. Every precaution will be taken to avoid any accidents & damages to adjoining properties, workers, and road users.

All workers will be advised to wear helmets, boots, and gloves while working. There will be a stand by vehicle near site always if needed in case of accident.

The safety officer visits several times to inspect safety matters.

Method and Procedures

Generally tack coat & Asphalt works will be done when the existing surface is dry or sufficiently low in moisture and normally the atmospheric temperature is above the 15 ^oC or as instructed by the Engineer. Before starting Tack Coat & Asphalt Works, the area will be demarcated & safety signs will be properly arranged. Single lane traffic will be managed so that no vehicle commuters suffer unnecessary delay.

Placing to shoulders                                                                Final rolling

Tack Coat & Regulating Course

The surface will be cleaned and removed loose and deleterious material from the existing road with the help of compressed air. Request will be made for checking the surface prior to applying the tack coat on existing road.

Tack coat will be applied at required rate 0.25 -0.55 L/m2 on cleaned existing road surface and spray record sheets will be submitted to the engineer on a daily basis for Engineer’s approval.

Asphalt concrete will be mixed with the approved job mix formula in the Asphalt plant Mixing, transporting, trucks & other machineries, and the physical condition of the asphalt mix will be in accordance with the specification requirements. Loading & transportation will be co-ordinate and spreading, compacting and finishing will be completed during daylight hours unless otherwise adequate illumination will be provided in order to minimize darkness. Night work will be done only due to accepted reason with the Engineer approvals. Delivering of asphalt to the paver will be at a minimum temperature of 135 C as per the specification.

Longitudinal edge will be set along the center line and also the lateral joint will be set staggered. Longitudinal and transverse joints will be made in a careful manner so that well bounded sealed joints are provided for full depth of course.

Asphalt paving will be start immediately after transporting, using asphalt paver, which is capable of spreading, finishing, and providing initial compaction to the asphalt mix such that the surfacing shall be finished to the required lines, grades, levels, dimensions, cross sections or as per the Engineer’s instructions. Manual spreading will be applied where Asphalt paver operation not applicable.

Immediately after the asphalt mix is spread rolling will be commenced with out under displacement or cracking. The transverse joint, Longitudinal joint, breakdown rolling done by static weight roller and intermediate rolling and final rolling will be done by pneumatic rollers. The final rolling will be completed before the temperature of the mix falls below 90 C.

Newly laid asphalt edge will be hand tampered simultaneously with the break down rolling.

Section of the newly laid asphalt layer will be protected from traffic until the mix has sufficiently hardened and traffic will normally not be permitted over newly laid surface at least for 12 hours after laying or until the temperature of the newly laid surface has achieved the ambient temperature.

The density of all samples taken from the compacted surface course will not be less than 97% of the Marshall Density at the point appropriate to the locations and air void will be the 3 to 7.

Quality Control

Certain inspections, verifications, and tests will be carried out, to ensure the quality and durability of the product as described in the above procedures, as per the requirements given in specifications.

Guide lines for site requirements will be set while continuing the asphalt laying depending on the condition such as roller passes etc, as a rule of thumb.

Measurement Control

Regulating course (Binder Mix) will be measured by tonnage. Certain inspections, verifications, and tests will be carried out, to ensure the quality and durability of the product as described in the above procedures, as per the requirements given in the specification. Approval will be obtained from Engineer for material (Asphalt) delivery sheet daily.