Bonded whitetopping overlay design considerations for prevention of reflection cracking, joint sealing, and the use of dowel bars

Hundreds of bonded portland cement concrete (PCC) overlays of hot-mix asphalt (HMA) pavements are being constructed in the United States and around the world. Increasing interest in this rehabilitation method has led to a need to define further the most common forms of distresses, quantify the extent of influence of design parameters on performance, and develop rational design guidelines. This study evaluates the performance of in-service pavements to establish criteria for when reflection cracks might develop. Reflection cracking is dictated by the thickness of the PCC overlay and HMA layer, panel size, climatic conditions, and accumulated vehicle loads. When the relative stiffness of the PCC overlay and HMA layer (defined during the coldest month of the year) falls below the critical value one, reflection cracking develops. The rate of development is a function of the load-related stress in the overlay. The performance analysis of the in-service pavements also verify the benefits of joint sealing and the use of small diameter dowel bars for high volume roadway applications.