ABSTRACT
Identifying damaging effect of multi axles on asphalt mixture is necessary for evaluating the damage state of the pavement. This research applied the actual loading waveforms that induced by single axle, tandem axle and tridem axle to test the fatigue responses of asphalt mixture. Test results showed that the multi-axle wave results in much lower fatigue lives for the mixture than the single-axle one. The tandem- (tridem-) axle wave generates more damage on the mixture than two (three) independent single-axle waves. The variation rates of stiffness ratio, phase angle and dissipated energy with loading cycles for the mixture under multi-axle wave are also higher that those under single-axle one, which help explain the difference in fatigue lives under different waves. The relationships between the initial dissipated energy (IDE) and fatigue life are uninfluenced by loading waveform. Based on IDE, a unified fatigue model was developed to predict the mixture’s fatigue life under different axle loads.
