Fracture Toughness of Warm Mix Asphalts Containing Reclaimed Asphalt Pavement

This paper deals with the fracture toughness of three different asphalt mixtures of HMA (Hot Mix Asphalt), WMA (Warm Mix Asphalt) and WMA-RAP (i.e. mixture of WMA and reclaimed asphalt pavement). Fracture tests were performed on SCB (Semi-Circular Bend) specimens to obtain the fracture properties (i.e. fracture toughness and fracture energy) of asphalt mixtures under three different modes of loading (i.e. pure mode I, pure mode II and mixed mode I/II) at the two test temperatures of −15◦C and 25◦C. The results exhibit that the WMA (i.e. WMA and WMA-RAP) mixtures provide greater fracture toughness than the HMA one under any mode of loading and temperature conditions; however, the WMA-RAP shows the highest fracture toughness. Furthermore, the fracture energies of the WMA and WMA-RAP mixtures are higher than the HMA mixture; however, the WMA mixture demonstrates the greatest value of fracture energy compared to other mixtures. Both the fracture toughness and fracture energy of the mixtures at −15◦C are also found to be higher than those at 25◦C.