氯盐对受硫酸盐腐蚀混凝土性能的影响

The effect of chloride on concrete under sulfate attack

通过单一氯盐环境、单一硫酸盐环境以及氯盐和硫酸盐共同环境中混凝土的浸泡腐蚀试验,测试了不同腐蚀环境中混凝土抗压、抗折强度随浸泡时间的变化规律,采用XRD方法对各腐蚀环境中的腐蚀产物进行分析,研究腐蚀环境中氯盐的存在对受硫酸盐腐蚀混凝土性能的影响.结果表明,氯盐的存在可延缓混凝土的硫酸盐损伤进程,氯盐浓度越高,延缓效果越明显;氯离子会与混凝土中水泥水化产物发生化学反应,生成水化氯铝酸钙(3CaO.Al2O3.CaCl2.10H2O),减少了硫酸盐腐蚀产物钙矾石的量,是推迟混凝土出现硫酸盐损伤进程的原因.

The specimens of concrete were immersed into single chloride solution,single sulfate solution and composite solution respectively;the compressive and flexural strength of concrete were tested at different immerse ages,and meanwhile the corrosion products were studied by XRD.The results indicate that the presence of chloride in composite solution can delay the damage of concrete,and the higher the concentration of chloride in composite solution,the more obvious the delayed effect.Chloride ions can react with hydration products of concrete and generate hydrated calcium aluminum chloride（3CaO·Al2O3·CaCl2·10H2O）,whose expansibility is higher than that of ettringite,becoming the reason of the delayed damage of concrete.