Effectiveness of Two Reflection Crack Attenuation Techniques in Asphalt Pavements

The performance of new asphalt concrete overlays is often jeopardized by existing cracks in the pavement to be rehabilitated. These existing cracks propagate, or reflect, through the new asphalt concrete to the surface of the new overlay. Once reflection cracks appear on the surface of the new pavement, water and debris can enter the pavement structure affecting pavement strength and reducing the life of the overlay. Therefore, reducing the rate at which these reflection cracks propagate to the surface of the pavement is desirable. The research reported in this paper studied the effectiveness of two new reflection crack attenuation techniques. One technique is a grid reinforcing system, the other, a polymer modified asphalt-rich interlayer system. Each system included a control section where no reflective crack attenuation treatment was used. Performance of the two systems was evaluated for six years by measuring cracking semi-annually and comparing this to the cracking present before rehabilitation. After six years significant differences in performance between the controls and the attenuation systems have appeared. Results of this research provide new information regarding tools that may help extend the life of asphalt overlays placed on cracked substrate pavements.