ASPHALT PAVING, TRANSPORTING, PLACING & COMPACTING Part 01

Preparation of Surface

The layer to be primed shall be cleaned of all loose and deleterious material by means of a rotary broom and/or hand brooms or other approved means. The brushing force shall be sufficient to dislodge all adhering material without damaging the pavement surface. Scale, clay and other foreign material shall be removed by hand where instructed. The exposed surface shall be kept moist up to the time of spraying. If the moisture content is too high to permit full penetration of the prime coat in the opinion of the Engineer the Contractor shall delay prime coat application until the moisture content is satisfactory for full penetration as instructed by the Engineer.

The surface shall be prepared in this manner to expose a hard tight mosaic of large aggregate in the base course. Hardened impervious films or layers of compacted fine material over the larger aggregate shall be removed by approved by the Engineer.

Preparation of road surface for paving with asphalt includes:

• close inspection followed by any necessary correction of the existing surface,
• Cleaning of the surface,
• Pre-treatment of the surface, usually by tack coating and
• Provision for traffic during the course of the work.

Transport and Delivery of the Hot Asphalt Mixture

The method of transport is to be such as to minimize the loss of heat, segregation of the mix and contamination with foreign matter. Delivery should be at a uniform rate within the capacity of the spreading and compacting equipment. Waiting time and delays on the site should be minimized.

Haulage Vehicles

Trucks for transporting the mix should have clean, smooth, metal tipping bodies with a minimum capacity of 6 tones, to conserve heat. They should be providing with heavy duty waterproof covers to further reduce heat losses and to protect the material from rain and also be provided with suitable tailgates to permit controlled discharge without spillage.

When haulage over long distances is required truck bodies may have to be suitably insulated. Trucks should be as large as practicable, and their bodies deep, for better heat retention. The trucks should be filled sufficiently to minimize heat loss and segregation during transport and to reduce costs.

Release Agents

It is important that the internal surfaces of truck bodies be clean to prevent the mix from adhering. Release agents such as diesel or stone dust should be used sparingly. Truck bodies should be tipped before loading to ensure removal of any excess liquid release agents or water.

Organization

Transport operations should be arranged in a manner to allow continuous placing of the mix, having regarded to:

• The number of haulage vehicles available;
• Meal breaks;
• The haulage distance to the work site, and
• The times at which the mix can be placed, due to site availability.

Placing the mix

Placing to shoulders

Asphalt truck had reached to the site that would direct toward asphalting section. Then lay mat bottom of truck opening for collecting wasted asphalt. Then asphalt is supplied to shoulders by means of excavator bucket and placed it around 5m intervals. After that asphalt are spread out by labours. Before use the bucket was applied oil. Manually laid the asphalt over the shoulder according to section

Hand Work

If the paver is adjusted and operated correctly, and the asphalt mix is well designed, little hand work should be required. Shovelling, raking or other disturbance of the surface after machine spreading has taken place should be kept to a minimum. Segregation of the coarser particles is the greatest danger with hand work and care must be taken to ensure the mix is not moved excessively by hand methods. Hand laying should be done by placing the asphalt in position and spreading from the centre using the back of a rake. The asphalt should never be thrown scattered, or raked. Any segregated coarse particles should be removed and not returned to the top of the layer.