利用三维随机模型分析沥青混合料的蠕变行为  

ANALYSIS ON CREEP BEHAVIOR OF ASPHALT MIXTURE WITH 3D RANDOM MODEL

作　　者：杨圣枫[1] 杨新华[1] 陈传尧[1] 

机构地区：[1]华中科技大学土木工程与力学学院,武汉430074

出　　处：《固体力学学报》2011年第4期390-397,共8页Chinese Journal of Solid Mechanics

基　　金：国家自然科学基金项目(10672063和10872073)资助

摘　　要：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.By regarding asphalt mixtures as a two-phase composite material consisting of asphalt sand and coarse aggregates, a three-dimensional random model can be generated by packing randomly convex aggregates created in accordance with an actual grading curve. The constitutive relationship of asphalt sand can be described by the generalized Maxwell mode and the material model parameters are calculated by fitting the axial creep 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 numerical simulations are conducted on them to investigate the influence of aggregate distribution, content and gradation on creep behavior of asphalt mixture. The result shows that the aggre- gate distribution doesn＇t greatly influence the mechanical behavior of asphalt mixture. The instantaneous elastic modulus increases with the increasing volume fraction of aggregate and ranges from Paul^s bottom to top bound. Within the considered bound of aggregate size, the resisting ability of asphalt mixture increases with the increasing aggregate size.

关 键 词：沥青混合料 沥青砂 蠕变行为 三维随机模型 骨料级配 

分 类 号：U414[交通运输工程—道路与铁道工程]