由HRB 400钢筋电极在含不同浓度D-葡萄糖酸钠模拟混凝土孔隙液中添加不同浓度 NaCl的开路电位变化曲线，当氯离子浓度为0时，钢筋电极的开路电位均处于-0.2~-0.3 V_SCE之间，说明经过预钝化之后，钢筋表面生成了一层钝化膜。随着氯离子的浓度不断增加，钢筋电极的开路电位呈现出逐渐减小的趋势，当氯离子浓度增大到一定程度时，开路电位有一个突然的下降，一般认为该浓度为钢筋的临界氯离子浓度。此时，钢筋表面的钝化膜被破坏，钢筋由钝化状态转变为活化状态。添加D-葡萄糖酸钠浓度，能够提高临界氯离子浓度值，且随着缓蚀剂浓度的增大，临界氯离子浓度值显著提高。D-葡萄糖酸钠浓度为2 mM时对应的临界氯离子浓度为0.32 M，将钢筋电极在含2mMD-葡萄糖酸钠模拟混凝土孔隙液中添加0.28M NaCl ，进行电化学阻抗测试。

From the open-circuit potential change curve of HRB 400 rebar electrode in the simulated concrete pore solution containing different concentrations of sodium D-gluconate with the addition of different concentrations of NaCl, the open-circuit potential of the rebar electrode are in the range of -0.2~-0.3 VSCE when the concentration of chloride ions is 0, indicating that after pre-passivation, the surface of the rebar generates a layer of passivation film. With the increasing concentration of chloride ions, the open-circuit potential of the rebar electrode showed a gradually decreasing trend, and when the chloride ion concentration increased to a certain degree, the open-circuit potential had a sudden drop, which is generally regarded as the critical chloride ion concentration of the rebar. At this time, the passivation film on the surface of the rebar is destroyed, and the rebar is transformed from a passivated state to an activated state.Addition of D-gluconate concentration was able to increase the value of critical chloride ion concentration and the value of critical chloride ion concentration increased significantly with increasing concentration of corrosion inhibitor. The concentration of D-gluconate of 2 mM corresponded to critical chloride ion concentration of 0.28 M. The value of critical chloride ion concentration was 0.28 M. The value of critical chloride ion concentration was 0.28 M. The value of critical chloride ion concentration was 0.28 M, Electrochemical impedance tests were carried out by adding 0.32 M NaCl, to the rebar electrode in a simulated concrete pore solution containing 2 mM D-sodium gluconate.