钢筋在混凝土模拟液中的电化学腐蚀行为

Electrochemical Corrosion Behavior of Reinforcing Steel in Simulated Concrete Pore Solution

通过测定HPB235,HRB335和HRB400这3种钢筋在不同pH值和不同氯离子浓度模拟混凝土孔隙液中的稳态电位、腐蚀速率和阳极极化曲线,分析了腐蚀参数的变化规律,并对三者的腐蚀性能进行对比.结果表明:随着模拟混凝土孔隙液的pH值减小,HPB235,HRB335和HRB400耐受氯离子侵蚀的能力变弱.模拟混凝土孔隙液的pH值相同时,氯离子浓度对材料的腐蚀行为也有很大的影响:孔隙液pH=13.6时,这3种钢筋暴露在高浓度氯离子(0.30mol/L)环境下,材料仍能保持良好的耐蚀性;孔隙液pH=12.5时,微量的氯离子浓度(0.05mol/L)破坏了钝化膜,导致3种钢筋均发生严重的孔腐蚀;孔隙液pH=10.0时,3种钢筋未能形成钝态而导致其耐蚀性差.在相同介质下,HPB235耐蚀性能最佳,HRB335次之,HRB400最差.

Through determining the stable electric potential, the corrosion rate and the anodic polarization curve of three types of reinforcing steel HPB235, HRB335 and HRB400 in simulated concrete pore solution at different pH value and chloride ion concentration, the variation rule of corrosion parameters were ana- lyzed, and the corrosion properties of the three types of reinforcing steel were compared. The results show that the ability against chloride ion erosion of the three types of reinforcing steel becomes weak with de- creasing pH value of the simulated concrete pore solution. For the same pH value of simulated concrete pore solution, chloride ion concentration has great influence on the material corrosion behavior. In the pore solution with pH= 13.6, the three kinds of reinforced steel exposed to high concentrations of chloride ion （0.30 mol/L） can still keep good corrosion resistance. However, in the pore solution with pH=12.5, the trace chloride ion contents（0.05 mol/L） can destroy the passive film and seriously corrode the materials. The three types of steel have a high corrosion tendency because they can＇t form a passive film in the con- crete pores solution with pH = 10.0. Among the three kinds of reinforcing steel under the same ambient condition, corrosion resistance of HPB235 steel is the best, and HRB335 is the next, HRB400 steel is the worst.