掺防冻剂混凝土中亚硝酸盐的长期阻锈效果

Study on long-term inhibiting effectiveness of nitrite ion in concrete mixed with anti-freezing admixtures

含防冻剂混凝土加速钢筋腐蚀时确定了氯离子和亚硝酸根的迁移行为,并确定了混凝土中钢筋底部临界NO-2/Cl-摩尔比的变化。试验结果表明,含氯盐和亚硝酸盐防冻组分的混凝土由于泌水作用钢筋底部氯离子与亚硝酸根离子浓度较高,而NO-2/Cl-摩尔比随龄期变化不大,说明含氯盐混凝土中只要掺入足够NO-2/Cl-摩尔比的亚硝酸盐,可以保证亚硝酸盐的长期阻锈效果。

The measurements of contents of chloride and nitrite by accelerated corrosion method of the reinforcing bars embedded in concrete containing anti-freezing admixtures were conducted to determine the variations of molar ratio of NO^-_2/Cl^- that inhibits reinforcing bars from corrosion.This study confirmed that the anti-freezing admixtures containing nitrite salt and chloride salt in concrete results in higher ion concentrations at steel bottom than other measuring point because bleeding of water is caused.But NO^-_2/Cl^-ratios tend to be relatively constant after 28 days. So if the nitrite ion with abundant NO^-_2/Cl^- ratios supplied in concrete,the long-term effectiveness can be ensured conclusively.