Evaluation of cracking resistance of healed warm mix asphalt based on air-void and binder content
Tam Minh Phan, Tri Ho Minh Le, Dae-Wook Park
Abstract
This paper investigates the effects of air-void and binder content on the cracking mechanism of asphalt concrete by using induction heating. Semi-circular bending test was used to evaluate the cracking resistance of induction asphalt mixture, including fracture energy index, crack velocity, crack resistance index, and flexibility index. Compaction energy index was computed to evaluate the influence of the additive agents on the workability of asphalt mixture. Even though the healing level of asphalt mixture recovered up to 80%, cracking resistance declined greatly after one damage-healing treatment. It was observed that air void plays a major role in both healing capacity and cracking resistance, while the impact of asphalt content is milder. Furthermore, analysis results from Matlab® image processing demonstrated that the crack shape of samples was retained after induction healing, the crack area expanded approximately 18% compared to the virgin sample. The analysis also indicates that aggregate crack failure not only causes low healing level but also deteriorates cracking resistance of induction healed sample.