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.