Investigation of fracture failure and water damage behavior of asphalt mixtures and their correlation with asphalt-aggregate bonding performance

The bonding quality of the mixture is critical to the longevity and durability of the asphalt pavement. This paper aims to investigate the influence patterns and intrinsic relationships of various factors including binder, aggregate, moisture, and anti-stripping agents on asphalt-aggregate bonding performance and mixture failure characteristics. Specifically, the influence of various factors on asphalt-aggregate bonding strength was investigated through binder bonding strength (BBS) tests. Next, the disk-shaped compact tension (DCT) and indirect tensile (IDT) tests were used to investigate the influence of different factors on the bonding failure characteristics of mixtures from the perspectives of fracture failure and water damage, respectively, and finally the correlation between the asphalt-aggregate bonding and the mixture failure characteristics was explored. The BBS test results show that crumb rubber significantly deteriorates the bond strength while SBS incorporation shows an insignificant effect on bond strength, and aggregates containing more alkaline components favor bond strength enhancement. The DCT and IDT test results reveal that SBS enhances the fracture and water damage resistance of the mixture, while crumb rubber is detrimental to it. Water causes deterioration of asphalt-aggregate adhesion and reduces the fracture resistance of the mixture. Mixtures containing anti-stripping agents and alkaline aggregates exhibit enhanced resistance to fracture failure and water damage. The fracture energy ratio is preliminarily validated as a new evaluation index for water damage resistance of asphalt mixtures. The correlation analysis shows that the pull-off tensile strength (POTS) correlates well with fracture resistance under consistent asphalt conditions, and the POTS ratio (R_p) could effectively reflect the moisture damage resistance of the mixture. This study provides valuable insights into selecting the optimal material combination for superior bonding performance in engineering practice and enhancing pavement durability.