压缩疲劳作用对钢筋锈蚀临界氯离子浓度的影响

Influence of Compression Fatigue on Chloride Threshold Values for the Corrosion of Steels

关键词:  压缩疲劳作用  钢筋锈蚀  临界氯离子浓度  电化学方法  晶粒细化  保护膜

Key words:  compression fatigue  steel corrosion  chloride threshold value （CTV）  electrochemical method  grain refinement  protective film

摘要:

采用08的应力水平对Q235钢筋进行压缩疲劳试验，然后将受到不同疲劳次数作用的钢筋置于饱和Ca（OH）2溶液中，采用阶梯逐级添加方式加入NaCl溶液，通过自腐蚀电位Ecorr和由电化学阻抗谱（EIS）所测得的腐蚀电流Icorr判定导致钢筋锈蚀的临界氯离子浓度（CTV），并利用扫描电子显微镜（SEM）研究疲劳作用引起的钢筋显微组织变化.结果表明：在一定的应力水平和疲劳次数范围内CTV呈现先增后减趋势；压缩疲劳作用下，EIS图谱中钢筋容抗弧半径的变化无明显规律，而未经压缩疲劳作用的钢筋容抗弧随Cl-添加量的增加而单调递减.

Abstract:

Compression fatigue was enforced on Q235 steels with stress level of 08 and different fatigue life cycles. The steels were soaked in the saturated Ca（OH）2 solution, which was used as simulated concrete pore solution. NaCl was chosen as the sources of chloride to corrode the steels. The CTV （chloride threshold value） was detected by combining the open circuit potential （Ecorr） with corrosion current density （Icorr）, which was obtained by electrochemical impedance spectroscopy （EIS）. The changes of microstructure that caused by the compression fatigue were observed by scanning electron microscopy （SEM）. The results show that as the fatigue cycle times increases, the CTV increases at first and then decreases under a certain stress level and range of fatigue life cycles. While the capacitive arc under no compression fatigue decreases gradually, the ones under compression fatigue present no regularity.