钢筋在新拌混凝土砂浆中的电化学行为

Electrochemical Behavior of Reinforcing Steel Embedded in Fresh Concrete Mud

采用恒定电流的计时电位法研究了钢筋在新拌混凝土砂浆中不同氯离子浓度状态下的电位－时间响应关系，并在超低氯离子浓度下测定了具有代表性的７种外加剂（减水剂、早强剂、缓凝剂、高效减水剂等）的电化学行为，证实ＪＣ４７５－９２标准规定的检测方法的正确性和有效性；证明了微量氯离子浓度对钢筋在混凝土中的钝性具有明显破坏作用，某些外加剂的加入可抑制氯离子对新拌混凝土砂浆中钢筋的破坏作用。

The Potential vs time curves of reinforcing steels embedded in fresh concrete mud containing trace amount of Cl- have been measured by galvanostatic method with anodic current density of 50μA/cm2. The effect of 7 kinds of additives (water reduced agent, fast strengthening agent, inhibits solidifing agent and high performance water reduced agent, et al) on electrochemical behavior of the embedded steels in low concentration of Cl- has been investigated. The results show that the correct and effective testing method in the Standard JC 475-92 is proved,and trace amount of Cl- is detrimental to the passivity of the steel tendon embedded in concrete. The additives tested are beneficial to inhibition the breaking up of passive film by Cl- for reinforcing steels embedded in fresh concrete mud.