沥青混合料车辙变形的离散元数值模拟

采用Burgers模型描述沥青基质的粘弹性，根据实验数据确定Burgers模型参数。借助数字图像处理方法建立试件几何模型，利用离散元法开展了车辙变形的离散元数值模拟，研究了沥青混合料在不同骨料分布、不同载荷和不同温度条件下的车辙深度变化情况。结果表明：温度对车辙变形的影响在沥青软化点附近较大，在离开软化点的范围较小；当温度较低时，混合料的整体性比较好，骨料分布对局部车辙变形的影响比较小，超载引起的车辙增量不太明显，而当温度达到或超过沥青软化点时，混合料的整体性明显下降，骨料分布对局部车辙变形的影响非常突出，超载引起的车辙增量也非常显著。因此，当超载和高温组合到一起时，车辙变形会大幅度增加，将给路面安全带来严重隐患。

Discrete Element Numerical Simulation on Rutting Deformation of Asphalt Mixture

Rutting is one of the main failure modes of asphalt pavement. It is very important to study the rutting deformation evolution for the anti-rutting design of pavement. Burgers model is adopted to describe the viscoelasticity of asphalt matrix, and the model parameters are determined according to the laboratory data. The geometric models of test-pieces are built with the help of the digital image processing method. The discrete element method is used to investigate the rutting depth variation of asphalt mixture with aggregate distribution, load and temperature. It is found that temperature has an evident effect on rutting deformation near the softening point of asphalt but only a slight effect when far away from the softening point. At lower temperature, the mixture behaves good integrity, the aggregate distribution has a tiny effect on local rutting deformation, and the rutting increment caused by overloading is unobvious. However, when the softening point is reached or exceeded, the integrity of the mixture declines distinctly, the aggregate distribution has a significant effect on local rutting deformation, and the rutting increment caused by overloading is pretty remarkable. Therefore, rutting deformation will increase markedly when overloading and high temperature are combined, which can pose serious potential hazards to asphaltpavement.