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为了明确氧气含量对钢筋锈蚀的影响,通过对直接反应钢筋钝化膜状态信息的物理量-钢筋极化电阻的测试,研究了不同氧气含量的混凝土模拟孔隙溶液中钢筋钝化膜破坏的临界氯离子浓度及氧气含量对钢筋锈蚀速率的影响.试验结果表明:当钢筋极化电阻值小于270 kΩ.cm2并持续下降时,钢筋钝化膜开始破坏;在氧气质量浓度为10.5至8.7 mg/L的混凝土模拟孔隙溶液中,当pH值为12.5到13.4之间时,钢筋钝化膜破坏的临界氯离子浓度为Cl-与OH-浓度比值是0.1;当pH值为11.7时,钢筋钝化膜破坏临界氯离子浓度接近为零,钢筋钝化膜几乎不能保持完整.氧气含量的适当降低有效减缓了钢筋钝化膜的破坏速度,但对钝化膜破坏时的临界氯离子浓度未产生影响.
In order to clarify the effect of oxygen content on the corrosion of steel bars, the critical chloride ion (Cr (superscript 2 +)) destroying the steel passivation film in concrete with different oxygen content was studied by measuring the physical quantity of rebar passive film, Concentration and oxygen content on the corrosion rate of steel bar.The results show that when the polarization resistance value of steel bar is less than 270 kΩ · cm 2 and continues to decrease, the passivation film of steel bar begins to destroy; at the oxygen concentration of 10.5 to 8.7 mg / L When the pH value is in the range of 12.5 to 13.4, the critical chlorine ion concentration of the steel passivation film destroyed is Cl- and OH-, the ratio of which is 0.1; when the pH value is 11.7, the steel passivation film is damaged When the critical chloride ion concentration is close to zero, the passivation film barely retains its integrity.The appropriate reduction of oxygen content effectively slows the destruction rate of the passivation film, but it does not affect the critical chloride ion concentration when the passivation film breaks down.