环境与荷载耦合作用下钢筋混凝土结构的锈胀开裂过程与服役可靠性研究

This project focuses on the corrosion cracking problem of reinforced concrete structure in the coupling of environment factors, such as temperature, humidity, chloride invasion, carbonation, and loading. The time-dependent service performance degradation of reinforced concrete structure due to corrosion cracking will be revealed. And the microstructure of concrete will be employed to explore the coupling effect of the corrosive mediums during their transportation and diffusion in concrete. Then a model on the time-dependent performance of concrete will be proposed. The corrosion process and corrosion state of reinforced bars in the coupling of environment and loads will be investigated. In considering the development of damage in concrete, the corrosion cracking process of reinforced concrete structure will be analyzed. Furthermore, the influence of corrosion cracks on the corrosion of reinforced bars and time-dependent damage of concrete will be discussed to investigate the service performance degradation of reinforced concrete structure in the coupling of environment and loads. Finally, a prediction model will be established to evaluate the service performance reliability of reinforced concrete structure. In this project, theoretical analysis, numerical simulation and experimental research will be used to analyze the corrosion cracking of reinforced concrete structure in the coupling of environment and loads, and evaluate the influence of complicate environment on the service performance of concrete structure. This project aims at predicting the failure risk of reinforced concrete structure based on the real engineering project which will significantly promote the durability investigation of reinforced concrete structure. As a result, the project has great theory significance and applicable engineering value.

本项目立足于温度、湿度、氯盐侵蚀、碳化等环境因素与荷载耦合作用下钢筋混凝土结构的锈胀开裂问题，分析锈胀开裂过程中钢筋混凝土结构服役性能退化的时变规律；以混凝土微观结构为桥梁，研究各种介质在混凝土内部传输扩散过程中的耦合作用机理，构建混凝土时变性能分析模型；研究环境与荷载耦合作用下钢筋的锈蚀过程与锈蚀状态，揭示混凝土的时变损伤规律，分析钢筋混凝土结构的锈胀开裂过程；研究锈胀裂缝对钢筋锈蚀与混凝土时变损伤的影响，揭示环境与荷载耦合作用下钢筋混凝土结构服役性能的退化规律，建立钢筋混凝土结构的服役可靠性预测分析模型。本项目采用理论分析、数值仿真和试验研究相结合的方式分析环境与荷载耦合作用下钢筋混凝土结构的锈胀开裂过程，评估各种复杂环境条件对钢筋混凝土结构服役性能的影响，根据工程情况预测钢筋混凝土结构的失效风险，将极大促进结构耐久性的研究，同时也具有非常重要的理论意义与广泛的工程应用价值。

为了研究复杂环境作用下混凝土结构服役性能的退化问题，本课题研究了温度、湿度、氯盐侵蚀、碳化以及荷载等环境因素的耦合作用对混凝土结构锈胀开裂过程的影响，并对混凝土结构的可靠性进行了评价。本课题首先分析水泥水化过程中微观结构的时变发展规律，基于水泥水化的微观信息，采用Krstulovic-Dabic水化反应动力学方程式，构建了水泥水化度与微观结构之间的联系，建立了改进的水泥水化动力学模型；考虑混凝土硬化过程中的水化放热及水分消耗作用，以及孔隙率对湿度扩散系数的影响，构建早龄期混凝土温湿度耦合作用模型并基于多孔介质多场耦合基本理论，考虑水泥基材料的碳化机理，结合水泥水化模型得到的碳化初始状态下可碳化物质的含量、孔隙率、饱和度等参数，建立了水泥基材料碳化理论模型；基于数字图像相关（DIC）技术，采用数字散斑图像的匹配追踪分析方法，揭示氯盐环境中外加电流加速锈蚀条件下钢筋混凝土梁表面广义主应变场的时变演化规律。基于对混凝土结构的服役性能的动态评价，建立了混凝土结构施工工艺的多目标定量化优化方法，通过对混凝土结构施工工艺的量化控制，提高混凝土结构的耐久性。相关研究成果已经应用于金丽温高速公路以及龙庆云景高速公路的工程建设中。在本课题的资助下，共发表SCI论文2篇，EI论文4篇，授权国家发明专利4项。相关的研究成果为促进混凝土结构耐久性研究，进一步建立混凝土结构全寿命设计理论奠定了基础。