Evaluation of Failure Characteristics and Self-Healing Potential of Modified Asphalt Mixtures under Repeated Loading

One of the inherent characteristics of asphalt mixtures, related to the viscoelastic properties of bitumen, is called self-healing. Due to the self-healing property, minor damages caused in the asphalt mixture during a loading process can be repaired to some extent during the rest period, and some of the original properties of the mixture can be restored. This study aimed to evaluate the factors affecting the failure characteristics and the self-healing phenomenon in modified asphalt mixtures by conducting tests on semicircular samples (SCB). The results obtained in this research showed that the fracture resistance and fracture energy in modified polymer asphalt mixtures are significantly higher than in the control sample (without modifier). Among the investigated additives, APAO polymer was more effective in increasing strength and failure energy, while SBS polymer showed the least increase in these properties. However, the flexibility index in the sample modified with APAO was lower than in the other investigated mixtures. Investigation of the fatigue behavior and self-healing phenomenon in asphalt mixtures showed that increasing the rest time from 0.8 seconds to 2.5 seconds increased the number of loading cycles until sample failure, indicating the self-healing characteristic of asphalt mixtures. Moreover, among the tested mixtures, the mixture modified with APAO polymer showed the best fatigue performance and self-healing behavior, followed by the mixtures containing SBR and SBS polymers, which performed better than the control mixture.