偏高岭土对磷酸镁水泥水化特性的影响

EFFECT OF METAKAOLIN ON HYDRATION PERFORMANCE OF MAGNESIUM PHOSPHATE CEMENT

磷酸镁水泥因具有凝结硬化快、早期强度高、低pH环境、良好的生物相容性等特点,在道路修补、固体废弃物固化等方面应用广泛。但磷酸镁水泥原材料成本较高,在一定程度上限制了磷酸镁水泥的推广应用。为降低磷酸镁水泥成本,提高磷酸镁水泥性能,研究采用偏高岭土部分替代氧化镁,研究偏高岭土对磷酸镁水泥工作性能及水化放热特性的影响。结果表明偏高岭土的掺加可以显著延长磷酸镁水泥凝结时间,掺加40%偏高岭土时磷酸镁水泥凝结时间可以从9min提高到24min;但偏高岭土的掺加会降低磷酸镁水泥流动度,当偏高岭土掺量不超过10%时,随着掺量的增加磷酸镁水泥水化放热总量会逐渐增加,进一步提高偏高岭土掺量会降低磷酸镁水泥水化放热总量。

Magnesium phosphate cement is widely used in road repair and solid waste solidification due to its characteristics of rapid setting and hardening,high early strength,low pH environment,and good biocompatibility.How⁃ever,the high cost of raw materials of magnesium phosphate cement limits the promotion and application of magne⁃sium phosphate cement to a certain extent.To reduce the costs of magnesium phosphate cement and enhance its properties,metakaolin is used to partially replace magnesium oxide to study the effect of metakaolin on the working performance and hydration heat release characteristics of magnesium phosphate cement.The results show that the setting time of magnesium phosphate cement is significantly prolonged by adding metakaolin,and the setting time of magnesium phosphate cement increases from 9 min to 24 min by adding 40%metakaolin.However,the addition of metakaolin reduces the fluidity of magnesium phosphate cement.When the content of metakaolin is not more than 10%,the total hydration heat release of magnesium phosphate cement gradually increases with the increase of the content,but further increase of the content of metakaolin reduces the total hydration heat release of magnesium phosphate cement.