复掺矿物掺合料对氯氧镁水泥耐水性能的影响

为了更好地促进氯氧镁水泥(MOC)的工程化应用,研究了原料配比、单掺不同磷酸盐改性剂、复掺磷酸与矿物掺合料改性剂对MOC耐水性能的影响。采用抗折强度、抗压强度(力学性能),变异系数(强度随改性剂掺量变化的稳定性),耐水系数(耐水性能)综合评价了改性剂对MOC耐水性能的改善效果,并结合扫描电子显微镜分析耐水性能改善机理。结果表明:当原料摩尔比n(MgO):n(MgCl₂):n(H₂O)=7:1:15,且1.0%磷酸和60%硅灰(占MgO的质量分数)复掺时,MOC的耐水性能改善效果最佳,改性后MOC的耐水系数在1.1以上;微集料填充效应、火山灰效应、强度相(P5)稳定性的增强效应共同提升了MOC的耐水性能。

Effects of Compound Mineral Admixtures on Water Resistance of Magnesium Oxychloride Cement

In order to better promote the engineering application of magnesium oxychloride cement (MOC), the effects of raw material ratio, single mixing of different phosphate modifiers, combined mixing of phosphoric acid and mineral admixture modifiers on the water resistance of MOC were studied. The improvement effect of modifier on the water resistance of MOC was comprehensively evaluated by using flexural strength, compressive strength (mechanical properties), variation coefficient (strength stability with modifier dosage) and water resistance coefficient (water resistance), and the improvement mechanism of water resistance was analyzed by scanning electron microscope. The results show that when the molar ratio of raw materials is n(MgO):n(MgCl₂):n(H₂O)=7:1:15, and 1.0% phosphoric acid and 60% silica fume (mass fraction of MgO), the water resistance of MOC is the best, and the water resistance coefficient of modified MOC is above 1.1. Microaggregate filling effect, pozzolanic effect and enhancement effect of strength phase (P5) stability together improve the water resistance of MOC.