湿盐砂环境下钢筋混凝土加速锈蚀试验研究

Experimental Study on Accelerated Corrosion of Reinforced Concrete in Wet Salt Sand Environment

针对钢筋混凝土传统通电加速锈蚀试验偏离自然锈蚀过程的问题,提出在砂土中喷洒盐溶液(湿盐砂)作为电解质代替传统盐溶液的通电加速锈蚀试验方法.采用恒电流仪对全埋钢筋混凝土进行通电加速锈蚀,并定期对钢筋混凝土进行裂缝观测和电化学性能测试.加速锈蚀结束后观察锈蚀钢筋、计算通电电流效率、利用X射线光电子能谱仪(XPS)分析钢筋锈蚀产物的组成结构.结果表明:钢筋腐蚀电流密度和腐蚀速率均随通电时间延长逐渐增大,早期增幅较大,后期增幅降低,但仍保持较高的锈蚀水平;所提出的试验方法电流效率较高,锈蚀产物主要为红锈(Fe2O3);以湿盐砂作为电解质通电加速锈蚀钢筋可以较好地模拟钢筋在自然环境下的锈蚀情况,具有更好的适用性.

In view that the traditional accelerated corrosion process of reinforced concrete is not in accordance with the natural corrosion process,an experimental method using wet salt sand as an electrolyte to replace traditional salt solution for accelerated corrosion was proposed.DC power supply was used for electric accelerated corrosion,and the cracks were observed and electrochemical tests were made for reinforced concrete at regular intervals.The corrosion product of steel bars was observed after the accelerated corrosion.The current efficiency of accelerated corrosion was calculated and the chemical composition of the corrosion product was investigated using X-ray photoelectron spectroscopy(XPS).The results show that the corrosion current density and corrosion rate increase with the extension of current time,the early increment is large,the later descend,but still maintain high level of corrosion.The current efficiency of accelerated corrosion is higher,corrosion product is mainly brownish red rust Fe 2O 3.On the whole,application of wet salt sand as an electrolyte for accelerated corrosion of reinforced concrete can better simulate the corrosion of steel bars in the natural environment,with better applicability.