Quantitative analysis of oxidative aging effects on the fatigue resistance of asphalt mixtures based on the simplified viscoelastic continuum damage (S-VECD) model

Fatigue cracking evolution in asphalt pavement is coupled by the oxidative aging of asphalt binder throughout its lifespan. Identifying the quantitative effects of asphalt binder aging on the fatigue resistance of asphalt mixture is important for the long-life design of asphalt pavements. In this study, two fatigue indexes (D^R and S_app) derived from the simplified viscoelastic continuum damage (S-VECD) model, were used to evaluate the fatigue resistance of laboratory-aged asphalt mixtures. Asphalt binders were extracted from aged asphalt mixtures and tested by using Fourier transform infrared spectroscopy (FTIR) to assess their aging state based on two aging indexes, the carbonyl index and the sulfoxide index. It was found that the aging indexes and fatigue indexes are well related through two power functions. Hence, the relationship between aging evolution and fatigue modelling of asphalt mixtures can be well quantified. It is anticipated that these aging-fatigue functions can assist in modelling and predicting the fatigue resistance for asphalt pavements in the field.