Self-healing of thermal cracks in asphalt pavements

As an intrinsic property of asphalt material, self-healing could reverse the cracking process in asphalt pavements and extend their service life. This study provides quantitative assessment of self-healing of thermally induced damage in asphalt concrete materials using Acoustic Emission (AE) as well as Disk-shaped Compact Tension (DCT) tests. Asphalt concrete specimens were subjected to eight cooling cycles and the effects of resting time between cooling cycles on self-healing were investigated. The AE test results showed gradual degradation in self-healing capability of asphalt mixtures as the material was exposed to increasing number of cooling cycles. In addition, AE results indicated that the 12 h resting time between cooling cycles significantly improved the self-healing by more than 30% and allowed the material to regain most of its self-healing capability. DC(T) results also showed that the fracture energies of asphalt mixtures were increased on the average by 13% due to the 12 h of resting time. DC(T) test results were consistent with the findings from the AE tests indicating that both approaches could successfully capture the effect of resting times on the material fracture properties. (C) 2019 Elsevier Ltd. All rights reserved.