利用虚应变分析沥青混合料的粘弹性质

Analysis on Viscoelasticity of Asphalt Mixtures Using Pseudo Strain

沥青混合料是典型的粘弹性材料之一,其行为特性较为复杂,利用虚应变则可以简化沥青混合料的粘弹性分析过程。对Superpave13沥青混合料进行了不同条件下的复数模量试验,并将试验结果转化为沥青混合料松弛模量的Prony系列表达式;分别进行了半正弦荷载试验和恒应变压缩试验,利用松弛模量计算了虚应变,并对采用虚应变的沥青混合料粘弹性本构关系进行研究。结果表明,利用虚应变可以消除粘弹性材料的应力-应变滞后效应和对荷载作用速度或时间的依赖性,而且应力-虚应变呈线性关系,从而可以利用广义弹性-粘弹性对应原理对混合料的行为特性进行分析,达到简化粘弹性分析的目的。

As a typical viscoelastic material, asphalt mixtures behave in a complex way. The concept of pseudo strain can be utilized to simplify the analysis. Complex modulus tests were conducted under various conditions for a superpave13 mixture, and the test results were converted to Prony series of relaxation modulus. Havesine loading tests and constant crosshead tests were performed for the mixture and pseudo strains were calculated on the base of the relaxation modulus. Viscoelastic constitutive relationships were studied, and the results show that hysteretic effects and influences of loading time or loading rate on viscoelastic materials can be removed by using pseudo strain. There is a linear relationship between stress and pseudo strain, thus extended elastic-viscoelastic correspondence principle can be used to analyze the behavior of asphalt mixtures.