United Kingdom Overlay Design of Flexible Pavement: Determination of the Important Parameters

Abstract

Pavement overlay is the most efficient form of material sustainability in road rehabilitation. In the United Kingdom and, perhaps, in most countries there is no standard approach for calculating the residual life of an existing pavement that can then be used to calculate the required overlay thickness to cope with future traffic loading. This paper will discuss the process for determining most of the important parameters used in overlay design. These parameters are traffic loading, layer thickness, stiffness modulus, interface condition, and fatigue properties. The discussion is aimed at critiquing the practice in the evaluation of these parameters by many designers. The paper draws attention to the common practices and methodology in the United Kingdom. It may not present a full rational approach but will certainly enhance the thinking in the field.