矿物掺合料对氯氧镁水泥早期水化行为的影响

摘要

研究了矿物改性氯氧镁水泥前期水化行为,绘制了各矿物掺合料氯氧镁水泥水化电阻率-时间曲线,测试终凝时间以及ld抗弯与抗压强度.结果表明,矿物掺合料能够延缓氯氧镁水泥水化速度,并随着矿物掺合料掺量的提高,其水化速度逐渐变慢.同等掺量下硅灰延缓反应时间的作用最为明显,其次是石粉与粉煤灰.硅灰的掺入延缓氯氧镁水泥水化速度,大幅度提高其初终凝时间,降低早期强度,其掺量不宜超过20％.粉煤灰与石粉氯氧镁水泥初终凝时间均在规范要求以内,对早期抗弯拉强度与抗压强度影响幅度相对较小.添加粉煤灰与石粉试样晶体较掺硅灰试样结晶程度更高.%Early hydration process of magnesium oxychloride cement with mineral admixture was studied.The electrical resistivity,setting time and 1 d strength was tested.The results showed that mineral admixture delayed reaction rate of magnesium oxychloride cement.The more mineral admixture,the lower hydration reaction rate.With the same content of mineral admixture,hydration reaction rate of magnesium oxychloride cement from big to small order is silica fume,limestone powder and fly ash.Silica fume delayed reaction rate of magnesium oxychloride cement,extended setting time,and reduced early strength largely.The content of silica fume should not be more than 20％.Fly ash and slag powder have smaller effect on setting time and strength.Sample with fly ash and slag powder have higher crystal degree than sample with silica fume.