Influence Law and Mechanism of Asphalt Oxidation Kinetic Aging on Fatigue Performance

Abstract

Asphalt aging and fatigue cause the pavement performance to decline, affecting the service life of the pavement. However, limited research on impact laws and the mechanism of asphalt oxidation kinetic aging on fatigue performance, and no consistent conclusions about this issue as well. In this study, the asphalt aged for different periods, then time sweep tests were performed. The fatigue performance of asphalt at different aging periods was studied through various fatigue life indicators that were determined according to different fatigue failure criteria. It is found that the longer the aging time, the greater the asphalt fatigue life when the strains are 5% and 10%, and the increase rate is faster at the shorter aging time and slower at the longer aging time, while the change rate is relatively small when the strain is 15%. There are strong linear correlations among the various indicators. The quadratic equation model is established to predict bitumen fatigue life by response surface method, and the significance of the model is studied by analysis of variance. The results show that the model is accurate and reasonable. The impact of aging time and strain level as well as their interaction on the model were analyzed. It is found that the effect of aging time on the fatigue life of asphalt is more significant when the strain is small, and the effect of aging time on the fatigue life of asphalt decrease with the increase of strain. The influence of strain level on the fatigue life of asphalt is relatively small when the aging time is shorter, and the effect of strain on fatigue life gradually increases with the increase of aging time.