亚热带海洋全浸泡环境下钢筋混凝土劣化规律研究

Study on the deterioration patterns of reinforced concrete under full immersion environment in subtropical ocean

针对亚热带海洋环境混凝土中钢筋锈蚀问题,通过模拟亚热带海洋环境,对不同强度等级和阻锈剂掺量的钢筋混凝土试件进行全浸泡侵蚀试验,利用电化学无损检测、氯离子含量测试,结合微观检测分析了钢筋混凝土的腐蚀劣化规律。研究结果表明:混凝土强度等级的提高和阻锈剂掺量的增加均能明显提升钢筋混凝土的耐腐蚀性能。其中,C30混凝土抗锈蚀性能最差,120 d时,腐蚀电流密度为0.118μA/cm^(2),极化电阻为220 kΩ·cm^(2),混凝土电阻为87.3 kΩ·cm^(2),钢筋-混凝土界面区转移电阻为77.3 kΩ·cm^(2),达到脱钝状态;混凝土强度等级提高至C50时,腐蚀电流密度减小了58.47%,极化电阻增加了3.82倍,混凝土电阻增加了44.56%;阻锈剂掺量为6 kg/m3时,腐蚀电流密度减小了47.45%,极化电阻增加了2.81倍,钢筋-混凝土界面区转移电阻增加了72.43%。

Aiming at the corrosion problem of steel bars in concrete in subtropical marine environment,the full immersion corrosion experiments of reinforced concrete specimens with different strength grades and rust inhibitor contents were carried out by simulating the subtropical marine environment.The macroscopic indexes such as chloride ion content were tested by electrochemical non-destructive testing,and the experimental results were verified by microscopic detection methods.The corrosion degradation patterns of reinforced concrete was analyzed.The results show that the improvement of concrete strength grade and the increase of rust inhibitor content can significantly improve the corrosion resistance of reinforced concrete.Among them,the corrosion resistance of C30 concrete is the worst.At 120 d,the corrosion current density is 0.118μA/cm^(2),the polarization resistance is 220 kΩcm^(2),the concrete resistance is 87.3 kΩcm^(2),and the transfer resistance of the steel-concrete interface area is 77.3 kΩcm^(2),reaching the passivation state.When the concrete strength grade is increased to C50,the corrosion current density is reduced by 58.47%,the polarization resistance is increased by 3.82 times,and the concrete resistance is increased by 44.56%;when the amount of rust inhibitors is 6 kg/m3,the corrosion current density is reduced by 47.45%,the polarization resistance is increased by 2.81 times,and the transfer resistance at the reinforcement-concrete interface is increased by 72.43%.