混凝土桥梁构件耐久性数值模拟

项目名称： 混凝土桥梁构件耐久性数值模拟

项目编号： No.50878145

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 数理科学和化学

项目作者： 陈艾荣

作者单位： 同济大学

项目金额： 35万元

中文摘要： 本项目针对混凝土结构常见的两种耐久性退化过程：氯离子侵蚀和混凝土碳化展开研究工作。研究主要着眼于建立这两种退化机理的细观层面数值模拟方法。为此，项目首先研究并建立了基于积累分布函数的三维球形骨料生成算法，采用了在三维空间中随机生成混凝土细观模型，然后随机截取平面做后续计算分析的方法。其次，项目研究了宏观层面上的氯离子对流扩散过程的数值模拟方法，着重对数值求解的稳定性问题做了分析，并通过引入Petrov-Galerkin方法降低求解稳定性对网格密度的要求。第三，项目在已有研究成果的基础上，建立了简化的混凝土碳化数值模型，并将其与可靠度理论结合，用于混凝土构件耐久性设计和评估中，实现了多种修补措施的计算机模拟。第四，在试验研究的基础上，采用修正物质扩散系数的方式来考虑应力状态对氯离子侵蚀和混凝土碳化等耐久性退化过程的影响。最后，项目将上述研究成果进行了整合，建立了细观层面的混凝土耐久性数值模拟方法，着重讨论了骨料对物质扩散行为的影响，并将方法应用于混凝土配合比以及骨料级配的优化设计中。在研究的基础上，项目编写了钢筋混凝土桥梁耐久性数值模拟系统(NSSCD)。

中文关键词： 混凝土;耐久性;细观模型;数值模拟

英文摘要： This project is aiming to study two common durability deterioration processes of concrete structures, i.e. chloride penetration and concrete carbonation. The research work is mainly focused on the mesoscopic simulation method of these two deterioration processes. In order to achieve this goal, an algorithm of random aggregate generation based on the cumulative distribution function is firstly developed. In this algorithm, the random aggregates are generated in three-dimension, and several cross sections of the 3D model are obtained for further analysis. Secondly, the simulation method of chloride diffusion-convection process on macro-scale is studied. The focus of this study is mainly on the solution stability. The Petrov-Galerkin finite element method is adopted to lower the requirement of the solution stability on the density of mesh. Thirdly, based on current research achievements, a simplified numerical model of concrete carbonation is developed. Combined with the reliability theory, this model is used in the durability design and evaluation of concrete structures. The numerical simulation methods of several common repaire measures are also established. Fourthly, based on the current experimental research, the influence of stress condition on the durability deterioration process is considered via modifying the diffusion coefficient of substances. Finally, the above research work is integrated, and the mesoscopic simulation method of concrete durability is established. The influence of aggregates on the substance diffusion behavour is studied.This simulation method has been already used in the optimization design of concrete proportion and aggregate grading. Based on the above research, a computer program called Numerical Simulation System of Concrete Durability (NSSCD) is developed.

英文关键词： Concrete; durability; meso-scale model; numerical simulation