混凝土保护层的临界锈胀开裂是预测腐蚀钢筋混凝土结构使用寿命的重要临界点。考虑3D锈层形貌等内部真实局部特征的三维锈胀临界开裂研究，比以往大量的二维探索更符合实际，不仅可避免各种假定，还可大幅提高精度。本项目旨在探索内部真实三维锈胀局部特征信息，并由此获得相应的临界开裂指标。利用空间数字化重构等先进测试手段，无损提取并科学表征人工气候和自然暴露试样中的各种真实局部特征“体信息”，利用高阶矩随机理论分析揭示其在空域上的三维分布规律及时域上的时变衍生规律；通过空间解算等方式界定上述局部特征信息中的关键参数临界值，建立临界锈蚀量等函数表达式并拟合反演临界3D锈层轮廓及锈胀压力公式；在搭建细观机制与临界指标之间的理论桥梁后，依照边界条件推导三维应力强度因子并建立失效准则，最终获得基于内部真实局部特征的三维非均匀锈胀临界开裂模型。研究将为准确预测相关结构使用寿命提供基础性理论成果，具有重要的学术价值。

Determination of critical cracking time of concrete cover induced by corrosion is important to predict the service life of reinforced concrete structure.The model considering actual local characteristics such as 3D morphology of corrosion products avoids impractical assumption and is more precise than that only considering the 2D information. This project aims to explore the actual interior local characteristics of 3D corrosion-induced cracking to obtain the corresponding critical cracking index. By using advanced testing methods such as reconstruction technique, real local information from actual environment and laboratory can be extracted and characterized non-destructively.The corrosion development with time and condition will be revealed by high-order-moment random theory; critical key parameters will be determined by solving analytical equations, and then functions to calculate critical corrosion mass will be built to derive the critical 3D profile of rusts and the critical pressure cause the expansion of corrosion products. After the bridge between the microscopic mechanism and critical index was established, the 3D stress intensity factor will be derived and the failure criterion will be determined. Finally, the 3D non-uniform critical cracking model will be built based on the real local characteristics. The results of this research provide a fundamentally theoretical achievement to predict the service life of related structures accurately and have important academic value.