海水拌和与偏高岭土对铁铝酸盐水泥水化的影响

Effect of Mixing with Seawater and Metakaolin on Hydration of Ferroaluminate Cement

铁铝酸盐水泥具有优异的抗海水侵蚀性能,在海洋工程应用中具有突出优势。研究了海水拌和与掺入偏高岭土对铁铝酸盐水泥浆体的流动度、凝结时间、水化热、电阻率、内部温度、化学收缩、抗压强度和水化产物的影响。结果表明,掺入偏高岭土减小了水泥浆体的流动度,缩短了凝结时间,72 h化学收缩、24 h电阻率均减小,浆体内部温度峰值降低。偏高岭土掺量小于20%时可加快早期水化放热速率、化学收缩和电阻率,并可促进钙矾石生成。海水拌和能加快水泥水化,使得水泥浆体的流动度显著降低,凝结时间显著缩短,并生成水化产物Friedel盐。海水和适量的偏高岭土拌和促进了更多的钙矾石生成,提高了铁铝酸盐水泥浆体的抗压强度。各试样的180 d抗压强度与淡水拌和时相比提高48.6%~80.2%。

Ferroaluminate cement has an effective resistance to seawater erosion due to its advantages in the application of marine engineering.The effect of mixing with seawater and metakaolin on the fluidity,setting time,heat of hydration,electrical resistivity,internal temperature,chemical shrinkage,compressive strength,and hydration products of ferroaluminate cement paste was investigated.The results indicate that the addition of metakaolin reduces the fluidity and shortens the setting time of the cement paste.The chemical shrinkage at 72 h,electrical resistivity and internal temperature peak at 24 h all decrease.However,the heat release rate,chemical shrinkage,electrical resistivity and the formation of ettringite at early age can be accelerated when the content of metakaolin is less than 20%.When the cement is mixed with seawater,the hydration of cement can be accelerated and the fluidity and setting time can be decreased.The formation of the Friedel’s salt can occur.The mixing of seawater and appropriate amounts of metakaolin in ferroaluminate cement promotes more ettringite,thus increasing the compressive strength of ferroaluminate cement paste.The compressive strength of different specimens mixed seawater at 180 d is improved by 48.6%–80.2%,compared to that of the sample mixed with fresh water.