Flexible Pavement Thickness Design

The thickness design of highway pavements requires the following large number of complex factors to be considered. (1)The magnitude and number of repetitions of the applied wheel loads and the contact area between the tyre carrying the load and the road surface.(2)The stiffness, stability, durability, the elastic and plastic deformation and resistance to fatigue loading of the pavement layers.(3)Volumetric changes in the subgrade due to climatic changes, the deformation of the subsoil under load and the ability of the pavement layers to reduce the stress imposed on the subsoil by the wheel loads.(4)The severity and incidence of frost and rainfall.