纳米二氧化硅对硅酸盐水泥水化硬化的影响

EFFECT OF NANO-SILICON DIOXIDE ON HYDRATION AND HARDENING OF PORTLAND CEMENT

利用微量热分析、X射线衍射、差热分析、扫描电镜和氮气吸附等手段研究了纳米SiO2对硅酸盐水泥水化硬化的影响。结果表明:纳米SiO2掺量为5%(质量分数)时,其高火山灰反应能大量吸收Ca(OH)2,进而促进水泥水化,提高水化开始时的放热速率,并改善水泥浆体的微观结构,使得水泥石更加均一密实。同时,纳米SiO2的掺入使得标准稠度需水量急剧上升,凝结时间缩短,促进水泥石的中后期强度增长。

The hydration and hardening of cement-based materials containing nano-silicon dioxide of 5% （in mass） were investigated by mieroealorimeter, X-ray diffraction, differential thermal analysis, scanning electron microscope, and nitrogen adsorption. The results show that nano-silicon dioxide can consume large amounts of Ca（OH）2 due to its high pozzolanic activity, so that hydration can be accelerated, the evolution rate of hydration heat in the early period can be increased, the microstructure can be improved and harden cement paste gets more homogeneous and dense. Nano-silicon dioxide can increase water requirement of normal consistency, shorten setting time and enhance compressive strength of cement-based materials, especially at middle period and later period.