混凝土碳化与氯离子侵蚀共同作用研究

Study on Interaction of Concrete Carbonation and Chloride Corrosion

处于除冰盐环境和海洋大气环境中的混凝土结构将受到碳化和氯离子侵蚀的共同作用。通过盐溶液浸泡与碳化交替方式,研究了碳化作用对混凝土中氯离子扩散的影响。结果表明:碳化作用加快了混凝土中氯离子扩散速度,提高了混凝土中的氯离子含量,相对于混凝土碳化对结合氯离子的释放作用,碳化导致的混凝土微观结构重分布对氯离子扩散的加速作用占主导地位。分析了碳化混凝土中的碳化钙分布和碳化深度,结果表明,用化学试剂法测试混凝土碳化深度时,碳化与未碳化交界处位于混凝土部分碳化区,交界处碳酸钙含量变化范围为5.4%～10.8%。

The concrete structures in deicing salt environment and marine atmospheric environment will suffer the dual effect of car-bonation and chloride corrosion. The influence of carbonation on chloride diffusion in concrete was investigated by alternation of immersion and carbonation. The results show that carbonation increases the speed of chloride diffusion and the content of chloride in concrete. The microstructure redistribution of concrete caused by carbonation dominates the acceleration of chloride diffusion com- pared with the release of binding chloride because of carbonation. The distribution of calcium carbonate and carbonation depth in concrete after carbonation was also analyzed. The results show that the boundary between carbonated zone and uncarbonated zone is in the half-carbonated zone of concrete, where the content of calcium carbonate ranges from 5.4% to 10.8% when the carbonation depth is tested by the law of chemical reagents.