Laboratory characterization of cracking-resistance potential of asphalt mixes using overlay tester

• Reflective cracking and fatigue cracking.
• Characterize and rank the cracking resistance potential of 29 different HMA mixes by Overlay Tester (OT).
• Evaluate the OT test protocol’s suitability and variability.

In this study, the Overlay Tester (OT) was successfully utilized to comparatively characterize the cracking resistance potential of various hot-mix asphalt (HMA) mixes with different mix-designs and material characteristics in the laboratory, ranging from fine- to coarse-graded mixes. Due partly to their heterogeneous structure and high air void content/variability, the OT test results indicated poor laboratory cracking performance and higher variability for the open- and coarse-graded mixes. Overall, the study findings substantiated the OT’s potential to rapidly screen and discriminate between good and poor crack-resistant mixes in the laboratory, with a proposed mix pass-fail screening criteria ranging from 30 to 750 OT load cycles.