Distribution of dissipated pseudo-strain energies and temperature effect on fatigue cracking resistance in asphalt mixtures under destructive tensile loading

摘要

This paper studies the effect of temperature on the resistance of asphalt mixtures to fatigue cracking by calculating the parameters of the modified Paris' Law more accurately at multiple temperatures in the basis of separating the DP SE components. Firstly, the repeated direct tensile (RDT) tests with two strain levels were performed on four types of asphalt mixtures to obtain the mechanical properties in the non-destructive and destructive stage under 5 sets of temperatures including 0 degrees C, 10 degrees C, 20 degrees C, 30 degrees C and 40 degrees C.The results show that energy ratio to develop fatigue cracking (DPSEF) increases first and then decreases with the temperature increasing, while energy ratio to develop permanent deformation (DPSEP) decreased continuously. If only considering for the relative proportion of the two destructive effects, it was found that the dominant damage mode is fatigue cracking in the 0 degrees C to 20 degrees C interval. The dominant damage mode at 40 degrees C is permanent deformation, and the dominant damage mode at 30 degrees C depends on material types. This finding helps to understand the development and distribution of fatigue cracking and permanent deformation at different temperatures.Then the DPSEF is further introduced to the modified Paris' Law to derive the coefficients A(JR) and n(JR). The logarithmic form of A(JR) and n(JR) at different temperatures follow the same linear relationship while remaining consistent model fitting coefficients. The damage density follows a good linear relationship with the logarithmic form of the parameter n(JR) which is independent of temperature. Parameter n(JR )can reflect the level of cracking resistance performance which is not limited by material type and temperature conditions.