粉煤灰对硫氧镁水泥抗氯离子侵蚀性的影响

Effect of fly ash on chloride ion corrosion resistance of magnesium oxysulfate cement

以粉煤灰作为活性掺合料制备硫氧镁水泥(MOS),提高MOS的抗氯离子侵蚀性。研究MOS经不同浓度氯化钠水溶液浸泡后抗压强度、体积稳定性、相组成、微观形貌和孔结构等的变化,分析MOS在海洋工程中应用的可行性。结果表明:MOS净浆的抗水性和抗氯离子侵蚀性较差,浸水和浓度为1%氯化钠水溶液28 d后的强度保留系数分别为0.74和0.77。粉煤灰的掺入提高了MOS体系无定形相的含量,降低了MOS的总孔隙率,优化了MOS的孔径分布,改善了MOS的抗水性和抗氯离子侵蚀性。其中,20%粉煤灰掺量的MOS浸水和浓度为1%氯化钠水溶液28 d后的强度保留系数分别提高至0.89和0.93。

In order to improve the resistance to chloride ion corrosion of magnesium oxysulfate cement(MOS),fly ash was used as active admixture to prepare MOS in this study.The changes of compressive strength,volume stability,phase composition,microstructure and pore structure of MOS soaked in sodium chloride aqueous solution with different concentrations,so as to analyze the feasibility of MOS application in ocean engineering.The results show that MOS paste has poor water resistance and chloride ion corrosion resistance.The strength retention coefficients after soaking in water and 1%sodium chloride solution for 28 d are 0.74 and 0.77,respectively.The incorporation of fly ash increases the content of amorphous phase in the MOS system,which reduces the total porosity,optimizes the pore size distribution and improves the water resistance and chloride ion corrosion resistance of the MOS.The strength retention coefficients of MOS samples containing 20%addition of fly ash after soaking in water and 1%sodium chloride solution for 28 d are 0.89 and 0.93,respectively.