DESIGN PRACTICE FOR BITUMINOUS PAVEMENTS IN THE UNITED KINGDOM. SIXTH INTERNATIONAL CONFERENCE, STRUCTURAL DESIGN OF ASPHALT PAVEMENTS, VOLUME I, PROCEEDINGS, UNIVERSITY OF MICHIGAN, JULY 13-17, 1987, ANN ARBOR, MICHIGAN

A new method for the structural design of bituminous road pavements has been developed by the Transport and Road Research Laboratory. It is based on the systematic analysis of the performance of a large number of experimental pavements interpreted in the light of structural theory. The sub-base is designed primarily to carry construction traffic. Standard design curves are given for the thickness of roadbase required to carry the traffic expected to use the road during its design life, life being defined in terms of the timing of pre-emptive pavement strengthening. The designs take into account the effect of variability in road performance and there is independent evidence of their validity. Probabilistic criteria for design against pavement deformation and fatigue cracking are established and a new procedure for predicting the internal deformability of bituminous pavement layers is introduced. The method offers the means of adapting the standard designs to take advantage of new materials and design configurations: this is particularly relevant for designs for very heavy traffic and for pavement reconstruction. Examples of developments that are leading towards changes in design practice are given.