Performance of the Overlay Tester in Cyclic Loading Mode

The premature cracking of asphalt concrete (AC) layers in flexible pavements is one of the major concerns of the pavement community. The overlay tester (OT) is considered by several highway agencies to evaluate the cracking resistance of AC mixes. The variability of OT results is expressed as a major concern in reliably characterizing the cracking potential of AC mixes. The main objective of this paper is to evaluate the variability of the number of cycles to failure (currently the main output parameter of OT test) and propose alternative parameters that can be measured for characterizing the cracking potential of AC mixes. Three AC mixes were used to evaluate the uncertainties associated with the performance of the OT tests. The OT can be employed with more certainty if cracking parameters measured from the first hysteresis loop and load reduction curves are implemented on a data interpretation method.