Development of failure criterion and fatigue model to characterize the fatigue resistance of asphalt binders under controlled-stress time sweep tests

Abstract

The fatigue resistance of asphalt binders is of great significance to the design and maintenance of asphalt pavements. This study aims to develop a fatigue model that is independent of material types for asphalt binders subjected to controlled-stress time sweep tests. The ratio of dissipated energy change (RDEC) method and the normalized stiffness ratio (NSR) method are first evaluated with regard to this objective. It is demonstrated that both methods fail to provide a fatigue model that is independent of material types. A new failure criterion is then developed through analysis of the three phases of the dynamic shear modulus versus load cycles graph. The fatigue life is defined as the load cycle corresponding to the second inflection point on such a graph. In accordance with the plateau value concept utilized in the RDEC method, a new fatigue-related parameter is defined as the RDEC value at the fatigue life determined by the NSR method. Combine the fatigue life with the new fatigue-related parameter in the form of power function yields a new fatigue model, which is then fitted to the data points of all tested asphalt binders. It is found that all of the data points are located at or close to the best-fit line with an R2 value of 0.978. Therefore, this new fatigue model has the potential of being material type independent.