Specimen size effect on the splitting-tensile behavior of coral aggregate concrete: A 3D mesoscopic study
Specimen size effect on the splitting-tensile behavior of coral aggregate concrete: A 3D mesoscopic study
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样本尺寸对珊瑚骨料混凝土劈裂拉伸行为的影响：3D 细观研究
DOI：
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发表时间：
2021
影响因子：
4
通讯作者：
Haiyan Ma
中科院分区：
文献类型：
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作者：
Zhangyu Wu;Jinhua Zhang;Hongfa Yu;Qin Fang;Haiyan Ma
采用细观方法研究了试件尺寸和应变率对珊瑚骨料混凝土（CAC）在劈拉载荷作用下的强度和破坏模式的影响。一个三维（3D）中尺度模型，假设混凝土为三相复合材料，即，建立了骨料、砂浆和界面过渡区（ITZ）模型，模拟了不同应变速率（10 5 ~ 2 0 0 s 1）下CAC的劈拉行为。通过三维细观模拟，展示了不同尺寸CAC圆柱体的细观变形和破坏模式。重点研究了试样尺寸和应变率对CAC抗拉强度的影响，并用数理统计方法给出了相应的影响规律。数值结果表明，CAC的抗拉强度存在速率硬化效应，当达到临界应变率（1 s-1）时，应变率效应更加显著.考虑到低应变率和高应变率下强度的变化，通过数值计算和已有的试验结果，确定了反映应变率效应的CAC分段公式。根据劈拉强度与试样断裂面积的关系，采用幂函数形式对不同应变率下CAC的尺寸效应规律进行了数学表达，这对CAC的进一步研究和应用具有重要意义。
The paper presents a mesoscopic investigation into the effects of specimen size and strain rate upon the strength and failure modes of coral aggregate concrete (CAC) subjected to splittingtensile load. A three-dimensional (3D) mesoscale model that assumes concrete as a three-phase composite, i.e., aggregate, mortar and interfacial transitional zone (ITZ), was established for simulating the splitting-tensile behaviors of CAC at different strain rates (10 5 ~ 200 s 1). The mesoscopic deformation and failure patterns of CAC cylinders with different sizes were exhibited through the 3D mesoscale modelling. Emphasis was set on the specimen size- and strain-rate effect on the tensile strength of CAC and corresponding effect laws were finally expressed by the mathematical statistical method. The numerical results suggest that there is a rate-hardening effect on the tensile strength of CAC, and the strain-rate effect is more noticeable when the critical strain-rate (1 s 1) is reached. Taking into the varying strengths at low- and high strain rate, the piecewise formulas were determined by the numerical and available test results to represent the strain-rate effect on CAC. In accordance with the relationship between the splitting-tensile strength and fracture area of specimen, the size-effect law of CAC at various strain rates was mathematically expressed using a series of power functions, which is of great significance for future research and application of CAC.