The UK pavement design guide has recently been updated to include new options for the construction of flexible composite pavements for heavy traffic. They are summarised in this paper. These new designs, along with those they supersede, are based upon the principal that the flexural strength of the cement-bound roadbase should be greater than the combined traffic and thermal warping stresses experienced during service. The thickness of the asphalt layers is required to limit these stresses and to reduce the severity of reflective cracking.

A study of the construction and maintenance history of in-service flexible composite pavements, which have carried up to about 100 million standard axles, has revealed that the current designs are capable of carrying at least this traffic load. Ongoing studies which should lead to further improvements in the design of these pavements are identified and the results to date summarised.