OPTIMAL THICKNESS OF ASPHALT OVERLAY FOR COMPOSITE PAVEMENTS

Reflective cracking is a big problem for asphalt overlays on existing concrete pavements (AC/PCC). It is uneconomical to completely prevent reflective cracking from occurring only by increasing the thickness of asphalt overlay, and in fact the method is not practical. Therefore, it is necessary to study the thickness of asphalt overlay. The paper analyzed the effect of thickness of asphalt on reflective cracking utilizing the three-dimensional finite element. Based on the result of the mechanistic analysis, the critical thickness between the single reflective cracking and couple reflective cracking was recommended, and the concepts of optimal width of delamination and optimal thickness of asphalt overlay are introduced. Furthermore, the results of test roads not only validate the above mechanistic analysis, but also show that the width of couple reflective cracking is equal to the thickness of asphalt overlays. Based on the results of both mechanistic analysis and test roads, the thickness of asphalt is suggested. For the covering abstract see ITRD E109276.