ABSTRACT

The pavement courses of a road, usually the uppermost 200-600 mm, are its main load-bearing component. They dissipate the dynamic forces generated by moving vehicles, so that the stresses imposed on the road foundation-its subgrade-are only a small fraction of those at the surface, and thus well within its bearing capacity. Because these transient stresses diminish rapidly with depth in the pavement, its courses (layers) are stiffest and strongest at the top and may be of lesser quality below. The aim of pavement design is to combine adequate strength, hence resistance to deformation, with a satisfactory riding surface and economy in materials.