利用三维随机模型分析沥青混合料的蠕变行为

将沥青混合料看作由粗骨料和沥青砂组成的两相复合材料,根据给定的级配生成凸多面体骨料,然后利用随机投放算法建立沥青混合料试样的三维随机模型.采用广义Maxwell模型刻画沥青砂的本构行为,其参数通过单轴蠕变实验获得.在对三维随机模型的有效性进行验证之后,采用参数化建模方法建立包含不同骨料分布、含量和级配的沥青混合料有限元...

Analysis on Mechanical Properties of Asphalt Mixture with 3D Random Model

Asphalt mixtures are described as a two-phase composite material consisting of asphalt sand and coarse aggregates in the paper. A three-dimensional random model can be generated by packing randomly aggregates from the aggregate base created in accordance with an actual grading curve. The constitutive relationship of asphalt sand can be obtained by extending the generalized Maxwell model into three-dimension and the material model parameters are calculated by fitting the axial relaxation experiment data with nonlinear fitting method. The proposed model is validated by comparing the creep simulation and test results of asphalt mixture with a particular gradation. With the method, the finite models of asphalt mixtures with different aggregate volume fraction and gradations are created, and then the nonlinear numerical simulations are conducted on them. The result shows that the instantaneous elastic modulus increases with the increasing volume fraction of aggregate and ranges from Paul’s bottom to top bound. Within certain bound of aggregate size, the resisting ability of asphalt mixture increases with the increasing aggregate size.