This principle, correcting the shortages in the natural soil under the road so as to strengthen it, is call soil under the road so as to strengthen it, is call soil stabilization and is widely used in modern roadbuilding. It can be used for any or all of the layers’ of a road. In roads carrying heavy traffic the total thickness of the road may reach 45 cm ,but the construction varies greatly with the materials available at the site and with the surfacing chosen .