Abstract Considering the heterogeneity and strain-rate effects of meso-components, concrete was simulated as a three-phase composite and a 3D meso-scale numerical method was set up. The splitting tensile failure of 315 concrete cubic samples having different side lengths with different aggregate contents and maximum aggregate sizes (MAS) has been explored by using the meso-scale numerical approach. In addition, the effect of aggregate contents and MAS on dynamic mechanical properties and the corresponding dynamic size effect of concrete was analyzed. The simulation results indicate that the size effect on dynamic splitting tensile strength of concrete materials is closely associated with the applied strain-rates. Appropriate enhancement in aggregate contents and MAS can increase the nominal strengths of concrete under different strain-rates. Aggregate contents and MAS present obvious influences on the size effect of splitting tensile strengths under low(er) strain-rates while they perform little effect on the dynamic size effect under high(er) strain-rates. Furthermore, the developed static and dynamic unified size effect law (SD-SEL) for concrete materials can quantitatively predict the size effect on dynamic splitting tensile strength.

中文翻译：

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尺寸对混凝土动态劈裂抗拉强度影响的细观模拟：骨料含量和最大骨料尺寸的影响

摘要 考虑细观构件的非均质性和应变率效应，将混凝土模拟为三相复合材料，建立了三维细观数值方法。已经使用细观尺度数值方法探索了具有不同边长、不同骨料含量和最大骨料尺寸 (MAS) 的 315 个混凝土立方体样品的劈裂拉伸破坏。此外，还分析了骨料含量和MAS对动态力学性能的影响以及相应的混凝土动态尺寸效应。模拟结果表明，尺寸对混凝土材料动态劈裂抗拉强度的影响与施加的应变率密切相关。适当增加骨料含量和 MAS 可以提高混凝土在不同应变率下的标称强度。骨料含量和 MAS 对低 (er) 应变速率下的劈裂拉伸强度的尺寸效应有明显影响，而它们对高 (er) 应变速率下的动态尺寸效应影响不大。此外，为混凝土材料开发的静态和动态统一尺寸效应定律（SD-SEL）可以定量预测尺寸对动态劈裂抗拉强度的影响。