Crack resistance of fiber-reinforced asphalt mixtures: Effect of test specimen and test condition

The effect of some important testing conditions including test specimen (SCB and ENDB), fracture mode (I and II), loading rate (0.5, 1.0, and 5.0 mm/min), and temperature (−5°C, −15°C, and −25°C) is evaluated on fracture toughness of asphalt material containing different percentages of fibers (0%, 0.025%, 0.05%, and 0.1% of unit weight). The experimental and numerical results show that the addition of 0.025%, 0.05%, and 0.1% of the polyolefin–aramid fiber in asphalt mixture increases the fracture toughness of the control mixture by about 8%, 17%, and 23% in pure mode I and 7%, 16%, and 24% in pure mode II, respectively; which are among the most promising enhancements compared to other fibers. Results also reveal that fracture toughness at mode I obtained from the SCB and ENDB specimens is similar. However, the mode II fracture toughness obtained from the ENDB specimen is about 12% higher than the corresponding value obtained from the SCB specimen.