FATIGUE EQUATION OF ASPHALT MIXTURE CONSIDERING THE INFLUENCE OF LOADING RATE

In order to establish the relationship between the strength and fatigue behavior of asphalt mixture, the direct tensile strength tests under different loading rates are presented and the power function rule between the strength and loading rate is revealed. Basing on the strength values under different loading rates, the real stress ratios corresponding to the fatigue loading rates of asphalt mixture are obtained. The asphalt mixture fatigue equations based on nominal and real stress ratio are created by fatigue tests. The intersection of fatigue curve characterized by the nominal stress ratio and abscissa axis is much larger than 1. The fatigue curve based on a nominal stress ratio cannot be extended. But the fatigue curve characterized by a real stress ratio can be extended to the strength failure point, whose fatigue life is 1. The strength and fatigue failure behavior are unified. The structure coefficient of tensile strength of asphalt pavement is deduced. The results of the research provide a theoretical foundation for revising the specifications for the design of highway asphalt pavement in our country.