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为了抑制氯离子反向扩散造成钢筋二次腐蚀,进一步延长修复后混凝土结构的服役寿命,在电化学除氯(ECR)基础上提出一种通过电驱动SiO_3~(2-)进入孔隙,与孔隙中的Ca(OH)_2反应生成C-S-H凝胶硬化混凝土/砂浆,并同时去除混凝土/砂浆内氯离子的新型的联合修复方法。由对比试验,通过滴定氯离子,利用自腐蚀电位(Ecorr)、腐蚀电流密度(Icorr)和电化学阻抗谱法(EIS)研究了该方法的修复效果及其修复后的长期耐久性,此外,由压汞法和热重分析探讨了该方法的微观作用机制。结果表明:联合修复方法与电化学除氯具有相近的除氯效率;与电化学除氯相比,联合修复方法能更有效延缓钢筋的二次腐蚀;随着初始氯离子含量的减少,联合修复方法延缓钢筋二次腐蚀的效果更为显著;联合修复方法对钢筋二次腐蚀的抑制源于其致密化作用,经联合修复后砂浆总孔隙率与有害孔数量相比于修复前均有所下降。
In order to restrain the secondary corrosion caused by the back diffusion of chloride ions and further extend the service life of the repaired concrete structure, a method of electrically driving SiO_3 ~ (2-) into the pores on the basis of electrochemical dechlorination (ECR) In the reaction of Ca (OH) _2 CSH gel hardened concrete / mortar, and at the same time to remove concrete / mortar chloride new joint repair method. The effect of this method and its long-term durability after repair were studied by comparing the results with titration of chloride ion, using the Ecorr, the Icorr and the electrochemical impedance spectroscopy (EIS) The microscopic mechanism of this method was discussed by mercury intrusion and thermogravimetric analysis. The results show that the combined method of remediation and electrochemical dechlorination have similar dechlorination efficiency. Compared with electrochemical dechlorination, the combined remediation method can delay the secondary corrosion of rebar more effectively. With the decrease of initial chloride ion content, the combined remediation The method of retarding the secondary corrosion was more significant. The inhibition of the secondary corrosion by the combined repair method was due to its densification. The total porosity of the mortar after the joint repair was decreased compared with that before the restoration .