模拟混凝土孔隙液中碳素钢筋与不锈钢筋耐蚀性试验研究

Experimental Study on Corrosion Resistance of Carbon Rebar and Stainless Rebar in Simulated Concrete Pore Fluid

针对海洋环境中普通钢筋混凝土结构的易锈蚀和耐久性退化问题,文章利用pH为12.6的碱溶液和氯离子溶液模拟氯盐污染的无碳化普通混凝土孔隙液,测试分析模拟液中HRB400碳素钢筋、奥氏体316不锈钢钢筋、双相型2205不锈钢钢筋、双相型2506不锈钢钢筋的电化学指标变化规律,并综合极化电阻和腐蚀电流的突变规律得到钢筋点蚀时的临界氯离子浓度,为不锈钢筋的工程应用提供科学依据。研究结果表明:双相型2506不锈钢钝化膜形成情况优于奥氏体316不锈钢、优于双相型2205不锈钢、更优于HRB400碳素钢;发生点蚀时2506双相型不锈钢的临界氯离子浓度为2.0~3.5 M,奥氏体316不锈钢的临界氯离子浓度为1.5~2.0 M,双相型2205不锈钢的临界氯离子浓度为0~0.05 M,碳钢HRB400的临界氯离子浓度为0.01~0.02 M。双相型2506不锈钢和奥氏体316不锈钢更为适用于严酷海洋环境下的混凝土基础设施建设。

In view of the problems of rust and durability degradation of ordinary reinforced concrete structures in the marine environment,this article used the alkali solution and chloride ion solution with pH =12.6 to simulate the chloride-contaminated ordinary concrete pore fluids,then tested and analyzed the changing law of electrochemical index for HRB400 carbon rebar,austenitic 316 stainless steel,biphase 2205 stainless rebar,and biphase 2506 stainless rebar in simulated liquid,then obtained the critical chloride ion concentration during rebar pitting corrosion by combining the sudden variation law of polarization resistance and corrosion current,thereby providing the scientific basis for the engineering application of stainless rebar.The research results showed that the passivation film formation of biphase 2506 stainless rebar is better than austenitic 316 stainless rebar,better than biphase 2205 stainless rebar,and much better than HRB400 carbon steel; and during pitting corrosion,the critical chloride ion concentration of biphase 2506 stainless rebar is 2.0 ~3.5 M,the critical chloride ion concentration of austenitic 316 stainless rebar is 1.5 ~2.0 M,the critical chloride ion concentration of biphase 2205 stainless rebar is 0 ~0.05 M,and the critical chloride ion concentration of carbon steel HRB400 is 0.01 ~0.02 M.thus biphase 2506 stainless rebar and austenitic 316 stainless rebar are more suitable for the construction of concrete infrastructure in harsh marine environments.