New laboratory equipment for study of reflective cracking in asphalt overlays

One of the current road maintenance problems continues to be the appearance of reflective cracks in asphalt overlays. It would be of real benefit if laboratory equipment were available during the design stage to allow the best solution to be selected for site laying. A new piece of laboratory equipment is reported on for the process known as the wheel reflective cracking (WRC) test based on the traditional wheel-tracking device. The WRC apparatus allows the chief failure mechanisms leading to the phenomenon of reflective cracks to be simulated in the laboratory. Initial results obtained with it on several overlay sections are consistent with the current Spanish experience in full-scale test sections. The WRC test can also be of help to researchers in this field since it enables test parameters to be varied for the purpose of carrying out sensitivity studies. In addition, it allows the loss of structural capacity and the shape of the cracks to be monitored beyond the mere comparison between different overlay sections.