Abstract：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.
2011, Vol. 32 
