RESEARCH ON PREVENTING REINFORCING BAR CORROSION IN CONCRETE STRUCTURES CAUSED BY CHLORIDES IN SEA SAND

1.亚硝酸根离子/氯离子摩尔比（1）摩尔比的阈值随着混凝土中氯化物含量的增加而增加。(2)当氯离子与钢筋的摩尔比大于等于1时，钢筋的锈蚀可以得到防止，而与氯离子的含量无关.亚硝酸盐不均匀分布对防腐蚀的影响（1）当混凝土中存在一个不含亚硝酸盐离子的小区域时，由于宏电池腐蚀，阳极部位的腐蚀加速。(2)当亚硝酸根离子以0.5或更高的摩尔比分布在整个混凝土中时，没有观察到由于亚硝酸根离子浓度差引起的腐蚀加速。当亚硝酸根离子以摩尔比为1或更大的浓度分布在整个混凝土中时，即使浓度不均匀，也能充分抑制钢筋的腐蚀。亚硝酸根离子的渗透缓蚀剂的低压注入法使亚硝酸根离子快速、大范围地渗透混凝土。但在潮湿环境下，缓蚀剂的渗透性较差.钢筋腐蚀的修复方法使用亚硝酸盐腐蚀抑制剂的低压注射法对于混凝土表面出现微小裂缝的腐蚀状态下的钢筋防腐非常有效和实用。

1. Nitrite Ion/Chloride Ion Molar Ratio above which Corrosion is Prevented(1) The threshold value of molar ratio increases as the chloride content in concrete increases.(2) Corrosion of reinforcing bar can be prevented with the molar ratio of 1 or more independent of the chloride content.2. Effect of Nonuniform Distribution of Nitrite on Corrosion Prevention(1) Acceleration of corrosion on the anodic sites due to macrocell corrosion is observed when a small zone without nitrite ions exists in the concrete.(2) No corrosion acceleration due to differential nitrite ion concentrations is observed when nitrite ions are distributed throughout the concrete with the molar ratio of 0.5 or more. Corrosion of reinforcing bar is sufficiently inhibited when nitrite ions are distributed throughout the concrete at the concentration of molar ratio of 1 or more, even if the concentrations are not uniform.3. Permeation of Nitrite IonsThe low-pressure injection method of corrosion inhibitor enables nitrite ions to permeate concrete fast and in a wide range. However, corrosion inhibitor cannot permeate much in wet condition.4. Repair Method for Corrosion of Reinforcing BarsThe low-pressure injection method using nitrite corrosion inhibitor can be very effective and practical for corrosion prevention of reinforcing bars in a state of corrosion in which minute cracks are occurring on the surface of concrete.