| 摘要: |
| 将外荷载作用的影响等效为外荷载引起的混凝土孔隙率的改变，来研究其对混凝土中氯离子扩散特性的影响，提出了压缩荷载作用下非均质混凝土氯离子扩散行为的细观模型.首先对混凝土在压缩荷载作用下的力学行为进行模拟分析；然后，将荷载作用后的“结果输出”作为氯离子扩散模拟的“初始输入”条件，以单轴压缩荷载为例，将混凝土看作由骨料、水泥浆体基质及界面过渡区组成的三相复合材料，建立了混凝土在力学与物理耦合作用下的细观模型，研究了压缩荷载对混凝土中氯离子扩散特性的影响，得到了氯离子有效扩散系数与压缩应力水平之间的关系式，揭示了压缩应力水平的影响规律. |
| 关键词: 混凝土 压缩荷载 氯离子扩散 细观方法 数值模拟 |
| DOI：103969/j.issn1007 9629201601011 |
| 分类号: |
| 基金项目:国家重点基础研究发展计划（973计划）项目(2011CB013600); 北京市自然科学基金重大项目(8100001)；国家自然科学基金资助项目（51508011）；中国博士后科技基金资助项目（2015M570105） |
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| Meso scale Simulation of Chloride Diffusivity in Concrete Subjected to Compressive Stress |
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DU Xiuli, JIN Liu, ZHANG Renbo
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Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education,Beijing University of Technology, Beijing 100124, China
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| Abstract: |
| The effect of the external mechanical stress on chloride diffusivity in concrete can be equivalent to the effect of porosity change on chloride diffusivity induced by external mechanical stress. And based on this viewpoint, a meso scale model and analysis method were proposed to study the chloride diffusivity in heterogeneous concrete under compressive stress. In this approach, the mechanical simulation was performed first by using the meso scale finite element method. The outcomes of the mechanical response of concrete were then used as input data for the simulation of chloride diffusivity. The concrete at the meso scale was assumed to be a three phase composite composed of aggregate, cement paste matrix and the interfacial transition zones. The meso scopic numerical model of concrete under uniaxial compressive stress was built to investigate the chloride diffusivity behavior. The effect of compressive stress on chloride diffusivity was explored, and the quantitative relationship between effective chloride diffusion coefficient in concrete and compressive stress level was obtained. |
| Key words: concrete compressive load chloride diffusivity meso scale method numerical simulation |
