The influence of natural and synthetic fibers on low temperature mixed mode IÂ +Â II fracture behavior of warm mix asphalt (WMA) materials

In this contribution, low temperature crack growth resistance of Warm Mix Asphalt (WMA) mixtures reinforced with two types of fiber, namely natural Jute fiber and synthetic Polyolefin-Aramid (FORTA) fiber is investigated experimentally. Using semi-circular bend (SCB) specimen, the influence of different fiber weight percentages (0.3%, 0.5% and 0.7%) and test temperatures (0°, −10° and −20 °C) on mixed mode I + II fracture toughness values (i.e. KIc and KIIc) are studied. It was shown that both fibers can increase in general the fracture resistance of WMA concrete relative to the control mixture. Moreover, modes I and II fracture toughness and effective fracture toughness (Keff) values are increased by decreasing the test temperature or increasing the fiber content. The FORTA fiber provided better crack growth resistance characteristics than the Jute fiber for the WMA mixtures. The effects of both natural and synthetic fibers on enhancing the performance of the tested WMA mixtures was more pronounced for dominantly pure mode I loading case.