自然扩散条件下混凝土中氯离子的沉积

采用浸泡试验方法,通过测定不同条件下混凝土内部不同位置处外渗氯离子的含量,研究了混凝土组成与配比、溶液中氯离子浓度、浸泡方式等因素对自然扩散条件下混凝土中氯离子沉积的影响规律,并采用不同的试验测试方法分析了混凝土中以化学结合、物理吸附或游离方式沉积的氯离子含量.结果表明:较高水胶比(>0.42条件下,水胶比的变化对混凝土表层沉积的氯离子数量无显著影响.混凝士中沉积的氯离子数量随外部环境中氯离子浓度的增加而呈不同程度的增加.相对于一维浸泡方式,三维浸泡的混凝土表层沉积的氯离子有一定程度的提高.与酸溶法相比,混凝土中水溶性氯离子的沉积量约降低30%.

PRECIPITATION OF CHLORIDE ION IN CONCRETE UNDER NATURAL DIFFUSION CONDITION

The amount of soluble and total chloride ions in concrete were measured under immersion conditions. The distribution ofchemical bounds, physical absorption and flee chloride ions existing in concrete were also investigated by different testing methods.The results indicated that the precipitation amount of chloride ion slightly varies with the water to binder ratio when the water tobinder ratio is more than 0.42. The quantity of chloride ions in concrete increased by various rates with increasing concentration ofchloride ion in the solution. Compared with single dimension immersion, the precipitation of chloride ions in the concrete surfacelayer under three dimensions immersion was higher. The amount of chloride ions dissolved by water in concrete was about 30% lessthan that of chloride ions dissolved by HNO3 solution.