The UK pavement design guide has recently been updated to includenew options for the construction of flexible composite pavementsfor heavy traffic. They are summarised in this paper. These newdesigns, along with those they supersede, are based upon the principalthat the flexural strength of the cement-bound roadbase shouldbe greater than the combined traffic and thermal warping stressesexperienced during service. The thickness of the asphalt layersis required to limit these stresses and to reduce the severityof reflective cracking.

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