氯离子环境下混凝土钢筋坑蚀深度的随机性研究

Study on the randomness of pitting corrosion depth of steel bar in concrete under the chlorine ion environment

以Fick第二定律为基础,推导了考虑氯离子扩散系数时变性的预测混凝土中钢筋最大坑蚀深度的随机时变模型,并以人工气候氯盐环境下的试验结果为例,分析了影响钢筋最大坑蚀深度的主要因素及其敏感性;以Monte Carlo方法,分析了人工气候氯盐环境下混凝土内钢筋最大坑蚀深度的概率分布特性,并预测了不同暴露时间内钢筋的最大坑蚀深度。结论表明,混凝土的保护层厚度对钢筋最大坑蚀深度的影响最大,钢筋的最大坑蚀深度服从正态分布;人工气候氯盐环境下混凝土内钢筋的最大坑蚀深度随侵蚀时间的增长而呈近似线性增大,且与试验结论相符。

Based on the Fick＇ s second law and the time dependent performance of chloride ion diffusion coefficients, a random time dependent prediction model of the maximum pitting corrosion depth of steel bar was derived, and according to the corrosion test results of concrete under the artificial climate environment, main influence factors of the maximum pitting corrosion depth of steel bar and sensitivity of factors were analyzed. Based on the Monte Carlo method, the probability distribution characteristics of the maximum pitting corrosion depth of steel bar in concrete under artificial climate environment were studied, and the maximum pitting corrosion depths of steel bar in the difference exposure time were predicted. The analysis results indicate that the most important influence factor of the maximum pitting corrosion depth is the thickness of the concrete cover, and the distribution type of the maximum pitting corrosion depth follows normal distribution. The corrosion pit depth increase nearly linearly with the exposure time under the artificial climate environment, and this result is in correspondence with the test data.