氯盐环境下混凝土中钢筋锈蚀发展全过程的极化动力学行为研究

Steel corrosion is the major form of failure of durability of concrete structures. With the development of corrosion processes, environmental factors in the concrete (saturation, temperature, and so on) and the corrosion rate changing will have an effect on steel corrosion polarization dynamics. Therefore, the key point is to get exact kinetic parameters of steel corrosion polarization dynamics that reflect the polarization control process change, which is the basic work for testing and monitoring of steel corrosion, residual service life prediction and durability redesign. Combined with early work, in micro level, an accurate model descripting polarization dynamics of steel corrosion in concrete at whole corrosion process basically, especially the concentration polarization induced by the hysteresis effect in the transportation of reacting substance and reaction products; in macro level, by optimizing the polarization curve testing technique for reinforced concrete, polarization characteristics of steel under different interior environmental conditions and corrosion state will be accurately described by polarization curve testing to quantify the transformation of control step. Based on polarization dynamics equations of steel corrosion built and accurate polarization curve testing, the models of polarization kinetic parameters influenced by interior saturation and temperature and corrosion rate (reflecting corrosion development in concrete) will be established, which modifies the calculation model of parameter B of Linear polarization method for steel corrosion testing in concrete.

钢筋锈蚀是混凝土结构耐久性失效的主要表现形式。随着锈蚀发展，混凝土内环境因素（饱和度、温度等）以及锈蚀率的变化均会对钢筋锈蚀极化动力学行为产生影响。准确获取反映钢筋锈蚀极化动力学控制过程转变的极化动力学参数是钢筋锈蚀监/检测、结构剩余使用寿命预测以及耐久性再设计等工作的基础。结合前期工作，本项目在细微观层面，构建准确描述混凝土中钢筋锈蚀全过程的极化动力学模型，特别是考虑钢筋锈蚀过程中由于阴阳两极反应物和反应产物传质滞后引起的浓差极化效应；在宏观层面，优化混凝土中钢筋极化曲线的测试技术，以准确表征钢筋在不同内环境条件和锈蚀状态下的宏观极化特征，对腐蚀反应中的控制步骤转变过程进行量化。基于建立的钢筋锈蚀极化动力学方程与准确的极化曲线获取，建立混凝土不同饱和度、内部温度以及钢筋锈蚀程度（反映锈蚀发展过程）对极化动力学参数的影响模型，最后修正混凝土中钢筋锈蚀检测的线性极化法参数B的计算模型。

钢筋锈蚀是混凝土结构耐久性失效的主要表现形式。随着锈蚀过程的发展，混凝土内环境因素（饱和度、温度等）以及锈蚀率的变化均会对钢筋锈蚀极化动力学过程产生影响。因此，准确获取反映钢筋锈蚀极化动力学控制过程转变的极化动力学参数是钢筋锈蚀监/检测、结构剩余使用寿命预测以及耐久性再设计等工作的基础。结合前期工作，本项目在微观层面构建了准确描述混凝土中钢筋锈蚀全过程的极化动力学模型，特别是考虑钢筋锈蚀过程中由于阴阳两极反应物和反应产物传质滞后引起的浓差极化效应；在宏观层面，优化了混凝土中钢筋极化曲线的测试技术，利用电化学极化曲线准确表征钢筋在不同内环境条件和锈蚀状态下的宏观极化特征，对腐蚀过程的控制步骤转变过程进行了量化。基于建立的钢筋锈蚀极化动力学方程与准确的极化曲线获取，回归并建立了混凝土不同饱和度、内部温度以及钢筋锈蚀程度（反映锈蚀发展过程）对极化动力学参数的影响模型，最后修正了混凝土中钢筋锈蚀检测的线性极化法参数B的计算模型。