基于离散元法(discrete element method,DEM)建立沥青混合料二维劈裂(indirect tensile,IDT)试验模型,研究集料模型、集料形状、空隙率,以及加载方位角等因素对混合料低温劈裂虚拟试验结果(劈裂强度和最大水平拉应力)的影响.结果表明:沥青混合料低温虚拟劈裂试验时,集料模型对数值模拟计算效率、内部结构中的接触力链和裂纹扩展路径等有很大影响;实际边界模型较等效椭圆形与等效多边形模型其数值模拟结果变异性较小;空隙率大小对劈裂强度及水平向最大拉应力有显著影响,随空隙率的增大两者均有不同程度的减小;不同加载方位角下的劈裂试验数值模拟结果呈各向异性.
Influence Factors of Low-temperature Virtual Indirect Tensile Test for Asphalt Mixtures
To investigate the influence factors of low-temperature virtual indirect tensile test for asphalt mixtures.Two-dimensional models of the indirect tensile(IDT)test for asphalt mixtures were developed using discrete element method(DEM),and the effects of aggregate models,aggregate shapes,air voids and loading directions on the simulation results(IDT test strength and maximum horizontal tensile stress)were studies based on these models.Results indicate that during the low-temperature virtual IDT test of asphalt mixtures,the aggregate model has a significant impact on the efficiency of numerical simulation calculation,the contact force chain in the internal structure,and the crack propagation path.Compared with aggregate equivalent ellipse models and equivalent polygon models,the simulation results for actual aggregate boundary models show less variability.Air voids has a significant impact on the IDT test strength and maximum horizontal tensile stress,and the larger the air voids,the smaller the IDT test strength and maximum horizontal tensile stress.The numerical simulation results of IDT test exhibit anisotropy in different loading directions.
road engineeringasphalt mixtureindirect tensile(IDT)testdiscrete element method(DEM)influence factors
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