水溶性增稠剂对混凝土中氯盐环境下钢筋耐蚀性的影响

Chloride Corrosion Inhibition Effect of Thickening Agent on Steel Bars in Concrete

为研究氯盐腐蚀环境下水溶性增稠剂对钢筋缓蚀性能的影响,在含不同Cl^(-)浓度的模拟混凝土孔隙液中掺入聚丙烯酰胺(PAM),开展钢筋电极的线性极化、电化学阻抗谱、动电位极化谱等一系列电化学试验,探究了掺入不同浓度PAM对氯盐环境下钢筋耐蚀性的影响。结果表明,掺入PAM能显著提高钢筋氯盐缓蚀性能,并延缓腐蚀启动时间,且缓蚀效果随PAM含量的增加而增强,当PAM浓度为0.15%时,抑制效率最高,约为99%;随着PAM浓度的增加,阳极和阴极的腐蚀电流密度均降低,PAM对钢筋在阳极区的缓蚀作用比在阴极区更显著;当氯化物浓度低于Cl^(-)浓度临界值C_(crit)时,钢筋处于钝化状态,几乎与腐蚀环境隔离,而一旦Cl^(-)浓度超过Ccrit值时,Cl^(-)将击穿钝化膜,到达钢筋表面。

To investigate the effect of water soluble thickeners on the corrosion inhibition performance of steel bars in chloride salt corrosive environments,polyacrylamide(PAM)was added to simulated concrete pore fluids containing dif-ferent Cl^(-)concentrations.A series of electrochemical tests including linear polarization,electrochemical impedance spec-troscopy,and dynamic potential polarization spectroscopy were conducted to explore the effect of adding PAM at different concentrations on the chloride salt corrosion resistance of steel bars.The results show that the addition of PAM can sig-nificantly improve the corrosion inhibition performance of steel reinforcement with chloride salt,delay the corrosion initia-tion time,and the corrosion inhibition effect increases with the increase of PAM content.When the PAM concentration is 0.15%,the inhibition efficiency is the highest,about 99%;As the concentration of PAM increases,the corrosion current density of both the anode and cathode decreases,and PAM has a more significant corrosion inhibition effect on steel bars in the anode region than in the cathode region;When the chloride concentration is lower than the critical value C_(crit) of Cl^(-)concentration,the steel bars are in a passive state,almost isolated from the corrosive environment.However,once the Cl^(-)concentration exceeds the Ccrit value,Cl^(-)will penetrate the passive film and reach the surface of the steel bars.