RESEARCH ON FATIGUE LIFE OF RUBBER ASPHALT MIXTURE BASED ON STIFFNESS MODULUS

To accurately predict the fatigue life (N_f) of rubber asphalt mixture, the correlations between N_f and stiffness modulus degradation (SMD), as well as stiffness modulus degradation ratio (SMDR) were analyzed. The function between cumulative stiffness modulus degradation ratio (CSMDR) and the amount of fatigue load and the corresponding damage model were proposed respectively based on CSMDR. The fatigue equation was built based on the correlation analysis between the SMDR and damage evolution rate. The result shows that SMD is unable to predict N_f well. The SMDR can characterize the proportion of SMD causing damage deformation, and thus can perform damage evolution analysis and fatigue life prediction. The variation of CSMDR and the non-linear damage evolution can be accurately described by the proposed functional relation and damage model, respectively. The established fatigue equation can accurately predict the N_f of rubber asphalt mixture.