Application of the Weibull distribution to assess fracture resistance of rubberized epoxy asphalt mixture with SCB specimens

• Weibull-based crack resistance characterization of rubberized epoxy asphalt mixture. • Sensitivity evaluation of Weibull-based crack indicators regarding various loading conditions. • Correlation analysis between Weibull and load–displacement-based crack indicators. This study employs the probability density function of the Weibull distribution to model the fracture energy damage density derived from force–displacement curves in semi-circular bending (SCB) tests of epoxy asphalt mixtures containing crumb rubber (CR). Key Weibull parameters—β and η—along with derived indices (IBS, CBS, Entropy, and Weibull CRI ), were analyzed to evaluate crack resistance across varying CR contents, temperatures, and loading rates. The results indicate that increased CR content enhances ductility and fracture energy but reduces stiffness, while higher temperatures promote viscoelasticity and decrease failure load. The shape parameter β reflects failure mechanisms, with higher values indicating brittleness. Whereas, the scale parameter η correlates with damage propagation and toughness. A critical transition in mechanical behavior occurs at 4 % CR, characterized by a shift from an aggregate-dominated to a rubber-dominated response. Compared to conventional indicators, the Weibull-based fracture indices are more sensitive to variations in material composition and loading conditions. Correlation analysis shows that η and Weibull CRI exhibit strong positive correlations (r > 0.94) with toughness indices (TI, CRI, CRI pre ), confirming their reliability as indicators of crack resistance. In contrast, β and IBS correlate strongly with stiffness-related parameters but negatively with flexibility metrics. Entropy moderately relates to toughness variability, while CBS shows weak predictive utility. This study establishes η and Weibull CRI as robust indicators for evaluating fracture performance, providing a quantitative framework for optimizing rubber-modified asphalt mixtures under diverse service conditions.