偏高岭土对羟乙基甲基纤维素改性砂浆性能影响

Influence of Metakaolin on the Properties of Hydroxyethyl Methyl Cellulose Modified Mortar

分别以0%,5%,10%,15%(质量分数)的偏高岭土等量取代羟乙基甲基纤维素改性砂浆中的水泥,通过调节用水量控制浆体稠度,研究偏高岭土对新拌及硬化砂浆性能的影响.结果表明:随偏高岭土取代量增加,水胶比提高,新拌砂浆在保持良好保水性及施工性的同时,凝结时间偏长的现象得到改善;偏高岭土能明显提高硬化砂浆的抗压强度和抗渗性能,并使硬化砂浆的孔径分布得到优化,但偏高岭土对硬化砂浆抗折强度的影响相对较小;偏高岭土取代量由5%提高到15%时,硬化砂浆干燥收缩值降低.当偏高岭土取代量为10%时,硬化砂浆能获得最佳的性能.

By replacing the cement with metakaolin in hydroxyethyl methyl cellulose modified mortar in 0 %, 5 %, 10 % and 15 % （by mass）and controlling the fresh mortar consistency by regulating the water demand, the effects of metakaolin on properties of fresh and hardened mortars were investigated. The results show that the higher the replacement ratio of metakaolin, the higher the mass ratio of water to binder, the shorter the setting time of fresh mortar become while its good water retention and workability maintain. By replacing the cement with metakaolin, the compressive strength and impermeability of hardened mortar increase with an optimized pore diameter distribution. The effect of metakaolin on the flexural strength is little. The dry-shrinkage value decrease with the increase of the replacement ratio of metakaolin from 5 % to 15 %. When the replacement ratio of metakaolin reaches 10%, the hardened mortar could obtain its best performance.