钢筋在碱激发矿渣模拟孔溶液中的钝化及腐蚀性能

采取自腐蚀电位，Mott-Schottky曲线测试技术，研究了钢筋在不同掺量氢氧化钠激发矿渣的模拟孔溶液中钝化膜的生成、钝化膜的半导体性能、氯离子对钝化膜半导体性能的影响、钢筋锈蚀时的临界氯离子浓度。研究结果表明：钢筋在矿渣模拟孔溶液中能生成稳定的钝化膜，但钝化膜的生成时间较长，在18d～26d之间；氢氧化钠激发剂掺量（矿渣质量分数）较低时（2%和4%），钝化膜具有双极性（n-p型）半导体结构特征；氢氧化钠激发剂掺量较高时（6%、8%和10%），钝化膜具有三极性（p-n-p型）半导体结构特征；钝化膜的耐氯离子腐蚀能力随着氢氧化钠激发剂掺量的增加而增强，当氢氧化钠掺量≥6%时，钢筋耐氯离子腐蚀能力好于硅酸盐水泥对比组。其中氢氧化钠掺量为10%时，临界氯离子浓度为0.11 mol/L，而硅酸盐水泥对比组的临界氯离子浓度仅为0.03 mol/L。

Deactivation and Corrosion Resistance of rebar in Simulated Pore Solutions of Alkali Activated Slag

The semiconductor properties of the rebar passive film formed in the simulated pore solutions for different dosages of sodium hydroxide (NaOH) activated slag were investigated with free-corrosion potential, Mott-Schottky plots. The detrimental effect of different chloride ion concentrations on the passive film and the threshold chloride ion concentration were also studied. The rebar passive film formed in the simulated pore solutions of Ordinary Portland Cement (OCP) was also tested for comparative purpose. The results indicate that the passive film formed in the simulated pore solutions of NaOH activated slag needs 18 d~26 d. When the dosage of NaOH is low (2% or 4%), the passive film has the characteristics of bipolar semiconductor structure (n-p). As the dosage of sodium hydroxide increases (6%, 8% or 10%), the passive film is changed to tripolar semiconductor structure (p-n-p). So the corrosion resistance of passive films is improved with the increasing dosage of NaOH. When the sodium hydroxide dosage is higher than 6%, the steel resistance to chlorine ion corrosion ability is better than the contrast group from Portland cement. The threshold chloride ion concentration is 0.11 mol/L when the dosage of sodium hydroxide is 10%, while the control sample formed from Portland cement is only 0.03 mol/L.