骨料不规则程度对混凝土单轴受压性能影响的数值研究

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中图分类号：034；TU528 文献标志码：A

Abstract：In order to determine the influence of aggregate irregularity on the mechanical properties and failure morphology of concrete，Python programs were developed to generate randomly distributed aggregate models with diferent sharpness in ABAQUS，and the O-thickness cohesive element and variable-thickness solid interface transition zone（ITZ）were established respectively.First，the reliability of model was determined by changing mesh size and friction coefficient between the loading pad and concrete compared with the experiment.Then，the quality of two ITZ modeling methods was analyzed.Finally，the uniaxial compression mechanical behavior of the three-dimensional meso-concrete model was analyzed from the aspects of stres-strain curve，fracture propagation，and energy disipation.The simulation results show that the O thickness cohesive ITZ and the solid thickness ITZ model can predict the compressive strength of concrete， and the stress-strain curve and failure morphology of the ITZ model with solid thickness are more consistent with the experiment.The fracture propagation of concrete is obviously afected bythe shape parameters of aggregate.The interior and surface of the spherical aggregate model are penetrating cracks.The strain energy of polyhedral aggregate model is larger，and there are many micro-cracks in the concrete，the possibility being compressed and destroyed into more fragments is higher.With the increase of aggregate irregularity，the compressive strength of concrete increases slightly，but the peak strain is not affected.

Key words ：3D mesoscale concrete ；aggregate;cohesive element； numerical simulation； crack propaga-tion

混凝土本身是一种非均质材料，内部存在骨料、孔隙、砂浆和界面过渡区（interfacial transition zone，ITZ）等，所以在受力过程中的破坏形式具有很大的随机性，其中骨料的随机分布导致混凝土破坏机理难以通过常规实验进行分析。（剩余15158字）