Selection on Optimum Overlay Thickness for Asphalt Pavement

This article presents asphalt pavement overlay design method based on Tongji University's research achievements about the performance of new and overlay asphalt pavements,with life cycle cost analysis incorporated in overlay design as well as performancebased overlay design method.The method mainly includes two parts: one is the selection of optimum overlay timing and thickness for new pavements or pavement in good condition.The other is the selection of optimum overlay thickness for pavement in need of overlay which is highlighted in this paper.Optimization of overlay thickness taking into account of lifecycle and one period performance is discussed with several design nomograms of optimum overlay thickness provided.