EFFECT OF BURNT GYPSUM ON SETTING TIME AND STRENGTH OF STEELMAKING SLAG AND BLAST FURNACE SLAG CEMENT

摘要

Slow hydration rate of steelmaking slag and BF slag cement accounts for its longer setting time and lower early strength. In the paper, by employing scanning electron microscope analysis, X-ray diffraction analysis and differential thermal analysis, the structure, nature and hydration mechanism in hydration of steel-making slag-BF slag cement of various gypsum modifications formed by dehydrating gypsum heated at various temperatures (220 - 1,100°C) are studied, and features of moderate dissolution rate and successive dissolving of gypsum at 750°C are presented, which can accelerate hydration process of steelmaking-BF slag cement, improve markedly the early strength of steel-making slag-BF slag cement and shorten setting time.The conclusion provides a basis for study and production of steelmaking slag cement.