CURRENT ISSUES FOR MECHANISTIC PAVEMENT DESIGN

Abstract

The Austroads pavement design guide uses a layered elastic computer program, CIRCLY, to calculate elastic strains at subgrade level and at the underside of asphalt and stabilised layers. This paper discusses the following issues currently faced by designers in using CIRCLY to produce pavement designs that are consistent and appropriate. The Austroads empirical rutting criterion, having been developed for highway loadings will not be fully applicable for the much higher wheel loads used on airfields, docks, container terminals and mine haul roads. Criteria based on pavement performance data that is more relevant in terms of loads and loading patterns are available. Current and proposed Austroads pavement design methods do not consider the fact that critical strains are distributed laterally across the pavement due to vehicle wander. A special version of CIRCLY is now available that rationally incorporates wander into pavement life predictions. The use of full axle rather than half axle loading can produce anomalous design results for some pavement geometries. (a) For the covering entry of this conference, please see ITRD abstract no. E208431.