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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模型,通过数值模拟研究骨料分布、含量和级配对沥青混合料蠕变行为的影响.结果表明:骨料分布对沥青混合料力学性质的影响较小;沥青混合料瞬时弹性模量随骨料含量的增加呈近似线性增大,而且弹性模量与骨料含量之间的关系曲线处于Paul上下边界内;在计算考虑的粒径范围内,骨料平均粒径越小,沥青混合料抵抗变形的能力越强.
The asphalt mixture is regarded as a two-phase composite material composed of coarse aggregate and tar sands, convex polyhedron aggregate is generated according to given gradation, and then three-dimensional stochastic model of asphalt mixture sample is established by random placement algorithm. Maxwell model is used to characterize the constitutive behavior of asphaltic sands, and its parameters are obtained by uniaxial creep experiments.After validating the validity of the three-dimensional stochastic model, a parametric modeling method is used to establish a model with different aggregate distribution, content and grading The finite element model of asphalt mixture was used to study the influence of aggregate distribution, content and gradation on the creep behavior of asphalt mixture by numerical simulation. The results show that aggregate distribution has little effect on the mechanical properties of asphalt mixture; The modulus increases linearly with the increase of aggregate content, and the relationship between elastic modulus and aggregate content is within Paul’s upper and lower boundaries. The smaller the average particle size of aggregates within the calculated particle size range, The stronger the ability of asphalt mixture to resist deformation.