CAMBER AND THE SUPER ELEVATION MUST BE PROVIDED TO THE EARTHEN AS WELL AS THE TREATED ROADS ,SO REQUIRED FOR DRAINAGE OF THE SURFACE WATER.

The structural element of the pavement is the foundation and also called sub base , and the base .It is a soil foundation,the surface of the natural ground,on which the entire road structure rests .The importance of the sub grade lies in the fact that if it fails the performance of the whole road will be affected so the sub grade must be able to resist the effects of both traffic and the weather. As such the soil of formation of road Structure or sub grade should be well borne strata of soil as the traffic load spread on the foundation of the road and thereafter the soling coat is laid over the formation width of the road and the function of this course is to spread the traffic loads and weight of the roadway above base .The soling may consist either base course and the wearing course or may consist the boulders and the wearing course of broken stone aggregates laid over the soling stone as per design and specifications prescribed by the design and scope of the local material available for the major structural components of the road works.The base course is composed of stone aggregates or road metal well consolidated.The main Consideration of the base are ,it's thickness, stability under traffic loads and resistance to the weathering.The stability of the base depends upon the thickness and the thickness of the base construction is mainly a function of the strength of the sub grade and the maximum wheel loads that are anticipated with the intensity of traffic.Some times foundation (soling) and the base are combined and the whole thickness laid over the formation width is called the base .The soling or the base is most commonly placed directly on the sub grade but where the sub grade is of the poor quality or has poor drainage properties, a layer of the granular materials must be interposed between the soling and the sub grade and this layer is known as sub base .A sub base is usually placed under a concrete road .The surfacing is the upper most part of the road structure,it's purpose is to minimise the abrasion of the road by traffic,act as a cushion between the wheel and the base and reduce the adverse effects of climate.By acting as an impervious layer it enables the road to shed storm water that would otherwise damage the road and is the wearing surface.As such road structure depends upon the intensity and nature of the traffic, bearing capacity of the soil /sub grade, climatic conditions and the maintenance.The camber or cross slope and the super elevation must be provided to the earthen as well as the treated roads as per the guidelines and specifications by the codes for construction and when the road has longitudinal gradients greater than 1 in 20 ,flatter cambers may be provided .