Specimen type effect on measured low‐temperature fracture toughness of asphalt concrete

Mode I fracture resistance of two asphalt mixtures (control and modified with low‐density polyethylene [LDPE] as binder additive) was studied experimentally and theoretically. The fracture toughness experiments were conducted on edge notch disc bend, edge notch disc compression and semi‐circular bend configurations under two loading rates and two low temperatures. The fracture resistance was increased by increasing the loading rate, reducing the test temperature and adding the LDPE additive. A discrepancy due to the influence of specimen geometry and its loading type was also observed on the measured critical stress intensity factors, demonstrating the effect of specimen type on mode I fracture behaviour. By considering the maximum normal strain value as constant material property and taking into account the effect of T ‐stress, the fracture toughness value for any of the investigated mode I samples was estimated in terms of the fracture results of the other specimens.