甲酸钙对砂浆抗氯离子侵蚀性能的影响

Effect of Calcium Formate on the Resistance to Chloride Ion Erosion of Cement Mortar

采用RCM法、电位滴定法研究了甲酸钙对水泥砂浆中氯离子扩散系数及氯离子含量的影响,通过测定不同浸泡龄期试件的自腐蚀电位、电化学阻抗谱研究了甲酸钙对砂浆中钢筋锈蚀的影响,采用XRD、SEM分析了甲酸钙对砂浆中水泥水化产物及微观形貌的影响。研究结果表明:甲酸钙能使水泥砂浆中的氯离子扩散系数增大,并随着水胶比增大,孔隙液中自由氯离子含量提高,总氯离子含量增大;甲酸钙使水泥砂浆浸泡NaCl溶液后的Friedel盐及Ca(OH)2含量减少,溶液pH值降低,氯离子更易到达钢筋表面,加速了水泥砂浆中钢筋的腐蚀。

RCM method and potentiometric titration method were used to study the effect of calcium formate on chloride diffusion coefficient and chloride content in cement mortar.The effect of calcium formate on the corrosion of steel bars in mortar was studied by measuring the self-corrosion potential and electrochemical impedance spectroscopy of samples with different soaking ages.The effects of calcium formate on cement hydration products and microstructure in mortar were analyzed by XRD and SEM.The results show that calcium formate increases the diffusion coefficient of chloride ions in cement mortar.With the increase of water-binder ratio,calcium formate increases the content of total chloride ions and free chloride ions in pore solution.The content of Friedel′s salt and Ca(OH)2 decreases after the cement mortar soaked in NaCl solution,and the pH value of the solution decreases,and the chloride ions are more likely to reach the surface of the steel bar.Calcium formate accelerates the corrosion of reinforcement in cement mortar.