关键词: 沥青混合料, 不连续特征, 永久变形, 离散元法, 虚拟单轴蠕变试验, 时温等效

Abstract:

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.

Key words: asphalt mixture, discontinuous feature, permanent deformation, discrete element method, virtual uniaxial creep test, time-temperature superposition