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为研究西部氯盐渍土介质中混凝土的氯离子扩散性,采用实验分析、微观扫描、理论预测相结合的方法,分析混凝土中氯离子含量与分布规律、氯离子对流区深度与峰值含量、表层氯离子含量时变规律以及试件表层微观形貌,预测既定混凝土保护层厚度处达到钢筋锈蚀临界氯离子浓度所需时间。研究结果表明,沿扩散深度混凝土中自由氯离子含量与总氯离子含量均呈现出先增长后降低的趋势,二者具有很好的线性关系;存在明显的氯离子含量峰值,随浸泡时间的变化较小;随着浸泡时间的增加,对流区深度逐渐加大,表层氯离子含量逐渐增加,混凝土中Friedel’s和Cl元素逐渐增多。理论分析结果显示,氯离子扩散系数随着扩散深度增加而增大,随浸泡时间增加而减小,使用寿命预测结果与工程实际混凝土结构腐蚀情况吻合较好,预测模型可用于西部氯盐渍土介质中混凝土结构使用寿命预测与分析。
In order to study the chloride diffusion of concrete in western saline-saline soil, the content and distribution of chloride ion in concrete, the depth and peak content of chloride ion convection zone, The time-varying law of chloride ion content and the microstructure of the surface of the specimen to predict the time required to reach the critical chloride ion concentration of steel corrosion in the thickness of the concrete cover. The results show that the content of free chlorine and total chloride ions in concrete along the diffusion depth show a trend of first increasing and then decreasing, both of which have a good linear relationship; there is a clear peak of chloride ion content, with the change of soaking time With the increase of soaking time, the depth of convection zone gradually increased, the content of chloride ion in the surface gradually increased, and the content of Friedel’s and Cl elements in concrete gradually increased. The results of theoretical analysis show that the diffusion coefficient of chloride ion increases with the increase of diffusion depth and decreases with the increase of immersion time, and the predictions of life expectancy are in good agreement with the actual corrosion of concrete structures. The prediction model can be used in the western saline-saline soil Prediction and Analysis of Service Life of Concrete Structure in Medium.