外加电源式再碱化处理的耐久性探究

摘要

In order to investigate the durability performance of the electrochemical realkalization treatment using impressed current, artificially carbonated reinforced concrete slabs, after an 8. 5 d treatment, were firstly stored 540 d in air conditioned laboratory and then 360 d under natural aging. During this period, some analytical methods (phenolphthalein indicator tests, quantitative pH measurement by powder sus-pension and atomic absorption spectroscopy) were used to quantify the realkalization of concrete cover, and simultaneously some electrochemical techniques (rest potential, linear polarization resistance and electro-chemical impedance technique) were also applied to evaluate the corrosion activity evolution of steel re-bars. The results indicate that after realkalization treatment using impressed current, the concrete cover is more alkaline, and this concrete realkalization is durable upon time. However, the slowdown of corrosion activity of steel rebars is only clearly observed during 360 d. 900 d after treatment, the corrosion activity of steel rebars seems to return to its initial state before treatment%为了探究利用外加电源方式对钢筋混凝土进行再碱化处理的耐久性效果,人工碳化钢混板经过8.5d的再碱化处理后,在恒温恒湿实验室里存放540 d,然后在室外自然老化360 d.期间,采用多种分析化学方法(酚酞指示剂法；混凝土粉样测试法；原子吸收光谱法)对混凝土的再碱化程度进行量化分析,同时应用多种电化学技术(自由电势、线性极化电阻技术、电化学阻抗技术)对钢筋腐蚀的活性变化进行评估.实验结果表明:采用外加电源方式对碳化钢筋混凝土进行再碱化处理后,混凝土保护层可在一定程度上被有效的再碱化,且具有很好的耐久性,但钢筋腐蚀的活性只在短期内(360 d左右)有效下降,900 d后,其活性又恢复到处理前的水平.