Investigation of cracking resistance of rubberized epoxy asphalt mixture using semi-circular bending (SCB) test

Abstract

The dry-mixed rubberized epoxy asphalt mixture (DREAM) has demonstrated superior mechanical properties. The addition of crumb rubber (CR) improves the damping performance and toughness characteristics of DREAM while offering significant potential for recycling waste materials. However, cracking remains a critical issue for DREAM, necessitating further experimental investigations into its crack resistance performance, especially regarding the sensitivity of evaluation indicators. In this study, semi-circular bending tests were conducted on DREAM with varying CR content under three loading rates and two test temperatures. P-values were utilized to evaluate the sensitivity of nine indicators. Results suggest that not all fracture performance indicators exhibit significant differences due to the varying toughness resulting from the CR content in DREAM. Normalized parameters, such as the pre- and total cracking resistance index (CRI^pre,CRI), tensile stiffness index (TSI), and tensile strength (TS) demonstrate superior performance in distinguishing the effects of CR content and test temperature. Meanwhile, TSI, CRI, and CRI^pre can only significantly distinguish the effects of loading rate in DREAM with high CR content. Moreover, the addition of CR reduces the load-bearing capacity and stiffness of DREAM while increasing its flexibility and crack propagation resistance. Among the effective indicators, TSI is more sensitive to changes in loading rate and test temperature compared to CRI^pre and CRI. This study aims to enhance the understanding of the crack resistance performance and indicator adaptability of DREAM via macro-mechanical experiments and provides guidance for its future applications.