氯盐环境下混凝土内钢绞线的锈蚀特性试验研究

预应力钢筋的锈蚀特性是研究预应力混凝土结构耐久性失效及防治的基础，为此，分别采用内掺盐和外浸盐两种方式在自然气候条件下作了如下三组混凝土内钢筋锈蚀的对比试验：钢绞线与热轧带肋钢筋、钢绞线与热轧光圆钢筋、钢绞线中心钢丝与热轧光圆钢筋。通过对锈蚀过程中锈蚀电流密度的测试以及试验完毕后的破形观察与称重对比和分析，得到如下结果：钢筋外表面锈蚀程度在面向保护层侧明显严重于背向保护层侧；钢绞线及其中心钢丝外表面锈蚀相对最不均匀，具有严重的局部锈蚀——坑蚀形态，带肋钢筋次之，光圆钢筋相对最均匀、全面；钢绞线内表面发生类似于空气中的相对全面、均匀的锈蚀；钢绞线的平均外表面锈蚀率小于热轧带肋钢筋的与热轧光圆钢筋的，但严重的局部锈蚀对其受拉性能极其不利。另外，还对上述锈蚀特性进行了电化学机理分析。

Experimental study on corrosion characteristics of steel strands in concrete under chloride salt environment

The corrosion characteristics of prestressed steel bars are the basis for studying the durability failure and prevention of prestressed concrete structures. Therefore, two methods, internal salt addition and external salt immersion, were used to conduct comparative tests on the corrosion of steel bars in three groups of concrete under natural climate conditions: steel strand and hot-rolled ribbed steel bars, steel strand and hot-rolled plain round steel bars, steel strand center steel wire and hot-rolled plain round steel bars. Through testing the corrosion current density during the corrosion process and comparing and analyzing the broken shape observation and weighing after the experiment, the following results were obtained: the degree of corrosion on the outer surface of the steel bar is significantly more severe on the side facing the protective layer than on the side facing the protective layer; The corrosion on the outer surface of the steel strand and its central steel wire is relatively uneven, with severe local corrosion - pit corrosion morphology, followed by ribbed steel bars, and smooth round steel bars are relatively the most uniform and comprehensive; The internal surface of the steel strand undergoes relatively comprehensive and uniform corrosion similar to that in air; The average external surface corrosion rate of steel strands is lower than that of hot-rolled ribbed steel bars and hot-rolled plain round steel bars, but severe local corrosion is extremely detrimental to their tensile performance. In addition, electrochemical mechanism analysis was conducted on the above corrosion characteristics