Reinforcing overlay to reduce reflection cracking; an experimental investigation

This study examines the influence of the most important parameters on delaying reflection cracking in geogrid reinforced overlay in bending mode, employing a large scale experimental set up. The objective was to investigate the effects of grid stiffness, tensile strength, coating type, amount of tack coat, overlay thickness, crack width and stiffnesses of asphalt overlay and existing asphalt concrete on reinforced asphalt overlay performance with geogrid interlayer. Results indicate that the cracked layer and overlay moduluses have strongest influence on reduction of reflective cracking. Also, two fatigue life estimation models for reflection cracking were developed, one based on initial strain (fatigue model) and the other by modifying Paris law for fracture mechanic model in mode I. It was found that the coefficient of determination of predicted fatigue lives and measured lives for the two developed models were sufficient. Therefore, both service life models can be used to estimate fatigue life of reflection cracking in bending mode (I).