Fatigue Performance of Asphalt Mixture under Actual Loading Patterns at Different Pulse Durations

摘要

The fatigue performance of an asphalt mixture under actual loading patterns corresponding to single, tandem, and tridem axle configurations at three different pulse durations corresponding to axle speeds with constant rest periods was examined using an indirect tensile cyclic load test. This research was conducted at two temperatures, 25℃ and 35℃. Considering our sets of variables and three repetitions for each set, in total 54 specimens were tested. The actual loading patterns applied to the specimens were determined using the KENLAYER software program. After testing and data acquisition, the cumulative vertical plastic strain approach was utilized to determine the number of load applications at two points of deformation on the fatigue curves, the hardening and softening starting points. The results at these two points show the following: (1) force repetition depends on loading patterns and, at a constant speed, varies from maximum to minimum with tridem, tandem, and single loading patterns, except at the hardening starting point; (2) force repetitions are strongly related to pulse duration in such a way that fatigue life increases with a decrease in pulse duration; and (3) the effect of temperature depends on pulse durations and loading patterns. It can be stated, in general, that when comparing the effects of different loading patterns, pulse duration must be considered. Based on the findings of this study, at different temperatures the results follow the same trends and are not temperature dependent.