基于劲度模量分析的橡胶沥青混合料疲劳寿命研究

为了准确地预测橡胶沥青混合料的疲劳寿命（N_f），分析N_f与劲度模量衰减量（SMD）、劲度模量衰减量相对变化率（SMDR）的相关性，根据累积劲度模量衰减量相对变化率（CSMDR）分别建立了其与疲劳荷载次数的函数关系式和损伤模型，基于SMDR与损伤演化速率的相关性分析建立了疲劳方程。结果表明:应用SMD不能很好地预测N_f，SMDR表征了产生损伤变形的劲度模量衰减量占总衰减量的比例，可用于损伤演化分析和N_f预测；建立的函数关系式和损伤模型能分别准确地刻画CSMDR的变化特征和非线性损伤演化规律；建立的疲劳方程能准确地预测橡胶沥青混合料的N_f。

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

To accurately predict the fatigue life(Nf)of rubber asphalt mixture,the correlations between Nf 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 Nf 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 Nf of rubber asphalt mixture.