论文部分内容阅读
钢筋锈蚀是混凝土结构提前破坏的主要原因,为提高氯盐环境下混凝土结构耐久性并延长其使用寿命,人们采取了包括掺入外加剂、应用高性能混凝土和环氧涂敷钢筋在内的很多方法,这些方法中迁移性阻锈剂(migratory of corrosion inhibitors,MCIs)在作为混凝土添加剂、表面涂敷和结构修补的应用中表现出很大的灵活性。研究了表面涂敷氨基醇和羧酸胺基迁移性阻锈剂(400g/m2)对掺加胶材总量0.5%氯化钠的C30混凝土中钢筋锈蚀的抑制效果及其在混凝土中的迁移性能,监测了涂敷MCIs前后混凝土试件中钢筋的电化学阻抗谱、开路电位、线性极化电阻和腐蚀电流。结果表明:涂敷迁移性阻锈剂60d后钢筋混凝土试件平均腐蚀电流从涂敷前3.77μA/cm2降低为0.104μA/cm2,尤其是涂敷#6阻锈剂腐蚀电流最低可降低到涂敷前的1.1%;渗透浓度前锋线的分析结果表明:在保护层下30～40mm处仍能检测到较高含量的有机氮,表明迁移性阻锈剂确实通过毛细孔和微细裂缝渗透进入了混凝土内部和钢筋表面,即使在氯盐条件下钢筋产生了锈蚀,在硬化混凝土表面涂敷迁移性阻锈剂也能有效抑制钢筋锈蚀发展或使其修复。
Steel corrosion is the main reason for the early destruction of concrete structures. In order to improve the durability and extend the service life of concrete structures in the environment of chloride salts, many people have taken into consideration, including the incorporation of admixtures, application of high performance concrete and epoxy coated steel bars Method in which migratory of corrosion inhibitors (MCIs) show great flexibility in their application as concrete additives, surface coatings and structural repair. The effect of inhibiting the corrosion of steel bars in C30 concrete with 0.5% sodium chloride and 0.5% sodium chloride mixed with aminoalcohol and carboxylic acid amine-based migration inhibitor (400g / m2) was studied, and its migration in concrete The electrochemical impedance spectra, open circuit potential, linear polarization resistance and corrosion current of the steel bars in concrete specimens before and after the application of MCIs were monitored. The results showed that the average corrosion current of reinforced concrete specimens decreased from 3.77μA / cm2 before coating to 0.104μA / cm2 after 60 days of application of migration inhibitor, especially the corrosion current of coating # 6 can be reduced to the lowest 1.1% of pre-deposition; analysis of the penetration concentration front line shows that higher organic nitrogen can still be detected at 30-40 mm under the protective layer, indicating that the migratory rust inhibitor does penetrate into the pores and fine cracks Even in the presence of chloride salt, corrosion of reinforcing bars occurs on the interior of concrete and on the surface of reinforcing steel bars. Applying a migratory rust inhibitor on the hardened concrete surface can effectively suppress or repair the corrosion of steel bars.