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为了从细观角度模拟分析沥青混合料的低温开裂行为,选取了4种集料类型、4种矿料级配类型,运用颗粒流程序PFC2D内置“Fish”语言,重构了包含沥青砂浆和粗集料在内的沥青混合料细观数字试件,采用离散元方法实施了虚拟劈裂试验。研究结果表明:离散元模拟得到的劈裂抗拉强度与室内试验结果的匹配程度较好;试件在加载至峰值荷载前,内部已萌生一定数量微观裂纹,极值点荷载后微观裂纹数量大幅增加;高强度集料组成的混合料基本沿着集料与砂浆的界面发生破坏,低强度集料则部分会被裂纹贯穿;基于颗粒流程序的虚拟劈裂试验可以作为研究沥青混合料断裂特征的辅助手段。
In order to simulate and analyze the low temperature cracking behavior of asphalt mixture from the microscopic point of view, four kinds of aggregate types and four kinds of mineral gradation types were selected. By using PFC2D built-in “Fish” language, And coarse aggregates, including the bituminous mixture mesoscopic digital specimen, using the discrete element method to implement the virtual splitting test. The results show that the splitting tensile strength obtained by discrete element simulation is well matched with the indoor test results. Before the specimen is loaded to the peak load, a certain number of microcracks have been sprouted inside. After the extreme point load, the number of micro-cracks Increase; the mixture composed of high-strength aggregates basically broke along the interface of aggregates and mortar, while the low-strength aggregates were partially cracked; the virtual splitting test based on the particle flow program can be used as a study of fracture characteristics of asphalt mixture Auxiliary means.