Stato-dynamic response analyses through semi-circular bending test: Fatigue life prediction of asphalt mixtures

This study established a relationship between static and dynamic fracture properties of asphalt mixtures to predict fatigue performance, and hence quantify crack propagation phenomenon to understand the overall fatigue cracking process. Fracture toughness (KIC) of eight different asphalt mixtures were determined covering two conventional and six modified mixes with varying materials properties using static semi-circular bending (SCB) tests. Further, the study delivered a methodological development of the dynamic SCB test, which potentially advances the current state-of-the-art pertinent to fatigue evaluation of asphalt mixtures. Based on the dynamic SCB test, modified gap-graded mixtures had higher fatigue lives than conventional dense-graded. A correlation between KIC and fatigue life indicated that with increasing KIC, modified mixtures showed higher fatigue lives but conventional mixes showed lower fatigue life. The fatigue cracking mechanism explained by crack mouth opening displacement (CMOD) of asphalt mixtures illustrated that modified mixtures had endured crack propagation phase compared to the conventional mixes. Thus, it was adjudged that CMOD is a promising parameter that explains the fatigue cracking mechanism of conventional and modified asphalt mixtures.