沥青混合料三维离散元虚拟单轴蠕变试验

为了从沥青混合料不连续特征的角度研究其永久变形行为,采用离散元方法进行了沥青混合料三维离散元虚拟单轴蠕变试验,生成了包含粗集料、沥青砂浆及空隙的沥青混合料三维离散元虚拟试件,对虚拟试件微观组成成分之间的接触赋予了相应的微观接触模型,并采用基于时温等效原理的方法对粘弹性离散元模型的计算效率进行了优化,最后将三维虚拟试验结果与二维虚拟试验及室内试验结果进行了比较.研究表明:时温等效原理能够大大减少粘弹性离散元模型的计算时间;三维虚拟试验结果与室内试验结果相差无几,二维虚拟试验结果大于三维虚拟试验及室内试验结果,且随着荷载的增大差异也随之增大.

Three-Dimension Virtual Uniaxial Creep Test of Asphalt Mixture by Using Discrete Element Method

In order to investigate the permanent deformation behavior of asphalt mixture considering its discontinuous feature,first,a three-dimension(3D) virtual uniaxial creep test of asphalt mixture was developed by the discrete element method(DEM).Next,a 3D discrete element(DE) virtual specimen composed of coarse aggregates,asphalt mastic and air voids was generated,and the corresponding micromechanical models describing the interactions of micro-scale components of the virtual specimen were assigned.Then,an approach was presented based on the time-temperature superposition(TTS) principle to optimize the computation efficiency of the virtual test.Finally,the results of 3D virtual test were compared with those of the two-dimension(2D) test and the laboratory measurements.It is found that the introduction of the TTS principle in DE viscoelastic model significantly reduces the computation time,that the 3D virtual test results almost accord with the measurement ones,and that the 2D virtual test results are greater than the 3D and the measurement ones,with their difference increasing with the load.