Experimental Determination of Mode II Fracture Resistance in Asphalt Concretes

This paper presents a test set-up using semi-circular bend (SCB) specimen for measuring pure mode-II fracture toughness of asphalt concretes. Three-point bend fracture tests were performed on the SCB specimens at low temperature. The results showed that this set-up could be used for conducting mode-II fracture tests on hot mix asphalt (HMA) specimens. Linear elastic fracture mechanics (LEFM) concept was used to study the fracture behavior of cracked asphalt concrete. Mode-II critical stress intensity factor, KIIc, was calculated using the fracture load measured from the three-point bend tests. In addition to pure mode-II tests, similar tests were carried out for pure mode-I loading. Results showed that mode-II critical stress intensity factor was higher than that of pure mode-I loading.