Construction of Road 1. Subgrade : It is the soil foundation on
which the road pavement rests and provides
adequate and uniform support to the pavement.
2. Sub-base course : lt is a layer of granular
material provided in between the subgrade and the
base course in a road surface.
3. Base course : It is a layer of boulders or
over burnt bricks provided over the sub-base
course or over sub-grade, if sub-base course is not
4. Base coat : It is the layer of hard stones
provided in between the base course and the
5. Wearing course : It is the top most layer
of a road pavement which is directly exposed to