Minimizing reflection cracking of pavement overlays

Reflection cracks are fractures in a pavement overlay that are the result of, and reflect, the crack of joint pattern in the underlying layer. Reflections cracks can cause early deterioration of an overlay, thereby increasing maintenance costs and decreasing the useful life of the overlay. Methods to minimize reflection cracking of asphalt concrete overlays include (a) greater thickness of overlay, (b) changes in the viscosity of the asphalt, (c) additives incorporated into the asphalt concrete mix, (d) treatments to the existing pavement before overlaying and (e) incorporating stress relieving layers. The results of the various tests using these methods are presented.