Viscoelastic fracture mechanics-based fatigue life model in asphalt-filler composite system

Asphalt-based composites gradually reach the end of their life as the service time increases, which directly leads to fatigue failure of the pavement structure. However, there is currently a lack of a fatigue life model for asphalt-based composites that has a clear physical interpretation. To address this issue, a viscoelastic fracture mechanics-based (VEFM) fatigue life model is proposed to predict the fatigue failure life for asphalt-based composites in this study. The VEFM fatigue life model was established within a viscoelastic fracture mechanics framework and was applied to two types of asphalt-filler composite systems (AFCS). To obtain the model parameters and verify the proposed model, various tests including linear amplitude sweep tests, time sweep tests at low -stress levels and high-stress levels, as well as surface energy tests were conducted on AFCS. The results indicate that the established VEFM fatigue life model can be expressed as a function of the loading level, viscoelastic fracture parameters, initial shear modulus, and surface energy. The initial edge flow of AFCS increases with the temperature and has minimal effect on the fatigue life throughout the fatigue process. A critical fatigue failure point is defined by the curve of damage rate and damage density. The fatigue life of AFCS increases with the temperature while decreasing with the loading level.