中文摘要：

采用不同应力水平和次数对 Q235钢筋进行拉伸疲劳试验，在饱和 Ca（OH）2模拟液中，采用自腐蚀电位法和电化学阻抗谱法测定钢筋锈蚀的临界氯离子浓度，同时通过扫描电镜观察拉伸疲劳作用引起的钢筋显微结构变化。结果表明：在拉伸疲劳作用下，钢筋锈蚀的临界氯离子浓度随着拉伸疲劳应力水平的增大和疲劳次数的增加而减小；拉伸疲劳会使钢筋晶粒细化，晶界、相界增多，并且随着拉伸疲劳应力水平的增大和疲劳次数的增加，这种变化就越明显；钢筋晶粒的细化以及晶界的增多会引发短路扩散，降低钢筋锈蚀的临界氯离子浓度。

英文摘要：

A tensile fatigue experiment was conducted on Q235 reinforcing steels with different stress levels and fatigue cycles. The steels were soaked in a saturated Ca（OH）2 solution, and the chloride threshold level （CTL） for corrosion of reinforcing steels was detected by combining the open-circuit potential with electrochemical impedance spectroscopy. The changes of microstructure caused by the tensile fatigue were observed with a scanning electron microscope （SEM）. The results show that the CTL of steels degreased with the increase of the stress level and fatigue cycles. The grains of the steels became finer and the amounts of grain boundaries and phase boundaries increased after tensile fatigue. This change became more significant with the increase of the stress level and fatigue cycles. The refinement of grains and increase of the amount of grain boundaries will cause short-circuit diffusion and reduce the CTL of steels.