Development of Fatigue Failure Criterion for Hot - Mix Asphalt Based on Dissipated Energy and Stiffness Ratio

Fatigue in hot-mix asphalt is the accumulation of damage under the effect of repeated loading. Flexural beam fatigue testing in the laboratory has been used for several decades and is expected to be an integral part of the new superpave advanced characterization procedure. Current fatigue failure criteria are based on a simple relation between the tensile strain in the beam versus the number of load repetitions to failure. Failure in the beam has relied on an arbitrary criterion such as 50 percent reduction of stiffness. This method does not provide a consistent indication of the onset of failure when different modes of loading are used. The dissipated energy approach is a promising technique for fatigue characterization, since it provides a consistent indication of the level of deterioration in the specimen in terms of behavior, accumulated damage or remaining life. As a part of the superpave advanced characterization research, a new fatigue failure criterion for flexure fatigue test was developed in this study using the dissipated energy approach. This approach makes it possible to predict the fatigue behavior of hot-mix asphalt in the laboratory over a wide range of conditions from the results of a few simple fatigue tests. A fundamental energy-based fatigue failure criteria methodology was developed using the dissipated energy approach, which is independent of the type of load control, temperature and mix and binder type.