Road in Quetta
1. Preparation of the existing base course layer
The existing surface is prepared by removing the pot holes or rust if any. The irregularities are filled in with premix chippings at least a week before laying surface course. If the existing pavement is extremely way, a bituminous leveling course of adequate thickness is provided to lay a bituminous concrete surface course on a binder course instead of directly laying it on a WBM.
2. Application of Tuck Coat
It is desirable to lay AC layer over a bituminous base or binder course. A tack coat of bitumen is applied at 6.0 to 7.5 kg per 10 sq.m area, this quantity may be increased to 7.5 to 10 kg for non-bituminous base.
3. Preparation and placing of Premix
The premix is prepared in a hot mix plant of a required capacity with the desired quality control. The bitumen may be heated up to 150 – 177 deg C and the aggregate temper