A simple fatigue performance model of asphalt mixtures based on fracture energy

A simple fatigue prediction model of asphalt mixtures based on fracture energy was proposed in this study. The fracture energy density obtained from indirect tension (IDT) test was employed in the fatigue model to consider the resisting energy of the asphalt mixtures against fracture damage. Four point bending beam fatigue tests were performed at various strain levels to characterize the fatigue performance of the two different asphalt mixtures with varying binder contents. Using the fatigue tests data, various types of fatigue models were evaluated. Traditional strain or dissipated energy based fatigue models are simple but strongly dependent on the material types and unable to identify fatigue performance for various asphalt mixtures. A fatigue model based on the ratio of dissipated energy change is independent of the material types and shows relatively high levels of prediction accuracy. However, this fatigue model needs cyclic fatigue tests to characterize the model coefficients. Unlike the fatigue models mentioned above, the newly proposed fatigue model is independent of binder types, binder contents, strain levels and volumetric properties. The proposed fatigue model is able to reasonably predict the fatigue lives of various asphalt mixtures without changing the model coefficients. Moreover, the material properties used in the model can be obtained from the simple IDT test.