Abstract

In order to improve the prediction accuracy of the theoretical model on steel corrosion degree, the multiple correction coefficient method was used to establish a piecewise constitutive model based on electrochemical signal of stressed reinforcement. Through “micro fault microstructure” analysis, the non-uniform local corrosion surface characteristics and evolution mechanism of rapid propagation of micro cracks and “Transgranular failure” of stressed reinforcement were deeply revealed. The “external macro surface characteristics and internal micro crystal structure” of corroded reinforcement were related. Based on micromechanics theory and failure criterion of macro deformation, the micro mechanism of micro crack propagation under the coupling effect of internal and external factors (e.g. micro defects, stress state) were revealed, and the essence of macro “low stress brittle fracture” was induced. The influence factors of time-varying and material heterogeneity of the real bridge were introduced, and the “random time-varying model” of mechanical properties of corroded reinforcement under the coupling effect of stress corrosion and material heterogeneity was constructed. Combined with previous visualization method, the “electrochemical signal non-uniform corrosion characteristics mechanical property degradation” was related to form a “three-dimensional time-varying model,” which provided guidance for engineering application.

摘要

为提高理论模型对钢筋锈蚀程度的预测精度，采用多重修正系数法建立基于受力钢筋电化学信号的分段本构模型。通过“微断层微观结构”分析，深入揭示了微裂纹快速扩展和受力钢筋“穿晶破坏”的不均匀局部腐蚀表面特征及演化机制。锈蚀钢筋的“外部宏观表面特征与内部微观晶体结构”有关。基于微观力学理论和宏观变形破坏准则，揭示了内外因素（如微观缺陷、应力状态）耦合作用下微观裂纹扩展的微观机制，并诱发宏观“低应力脆性断裂”的本质。介绍了真实桥梁时变和材料异质性的影响因素，构建了应力腐蚀与材料异质性耦合作用下锈蚀钢筋力学性能的“随机时变模型”。结合以往的可视化方法，将“电化学信号非均匀腐蚀特性力学性能退化”相关联，形成“三维时变模型”，为工程应用提供指导。构建了应力腐蚀与材料非均质性耦合作用下锈蚀钢筋力学性能的“随机时变模型”。结合以往的可视化方法，将“电化学信号非均匀腐蚀特性力学性能退化”相关联，形成“三维时变模型”，为工程应用提供指导。构建了应力腐蚀与材料非均质性耦合作用下锈蚀钢筋力学性能的“随机时变模型”。结合以往的可视化方法，将“电化学信号非均匀腐蚀特性力学性能退化”相关联，形成“三维时变模型”，为工程应用提供指导。