Experimental research on shear fatigue characteristics of asphalt mixture based on repeated uniaxial penetrating test

Abstract

Shear fatigue properties of asphalt mixture were investigated in this research. First of all, repeated uniaxial penetrating test (RUPT) was designed based on the composite modification of flow number test and uniaxial penetrating test (UPT), with which the failure mode of permanent deformation of asphalt mixture subjected to vehicle load was simulated in the lab. And shear fatigue life (SFL) of asphalt mixture was defined according to the failure criteria of RUPT test. Then, a type of AC-13 mixture with original asphalt binder content of 4.8% was selected as the control mixture and a loading level of 0.7 MPa was used as the control load for the RUPT test. By changing the loading level, binder content and binder type, a series of RUPT tests were performed and the relationship between SFL of asphalt mixtures and the influencing factors was analysed based on the data obtained from RUPT tests. Results indicate that SFL decreases with the increase in loading level, modified asphalt as mixture binder can significantly improve the SFL of asphalt mixture, and there is an optimal air void value corresponding to the maximum SFL of asphalt mixture. Based on the analysis results, a prediction equation of SFL of asphalt mixture was proposed.