Hydration in the System of Anhydrite II-Blastfurnace Slag

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J. Korean Ceram. Soc. > Volume 34(8); 1997 > Article

Journal of the Korean Ceramic Society 1997;34(8): 861.

무수석고-고로슬래그계의 수화반응

송종택, 고상열, 노재성¹

단국대학교 재료공학과
¹충남대학교 화학공학부

Hydration in the System of Anhydrite II-Blastfurnace Slag

ABSTRACT

In order to investigate the reaction in the system of anhydrite II-blast furnace slag, the paste hydration which made up with a liquid/solid ratio of 0.45 for 1, 3, 7, 14, 28days by the addition of accelerators to 10~30wt.% slag with natural gypsum calcined for 1hour at 500/$700^{circ}C$ was studied by combined water determination, XRD, DTA, DSC and SEM. As a result of this experiment, it was found that hydration rate was faster in the system calcined at 50$0^{circ}C$. Therefore the anhydrite was converted to calcium sulfate dihydrate in the hydration for 1day but the slag was not almost reacted. For the gypsum calcined at $700^{circ}C$, the hydraton rate in the system of K2SO4 addition was faster than others in the earier period, but the activated effect of the system of Al2(SO4)3 addition was regarded as the highest over 3days. As the amount of slag was increased, they dydration rate was delayed and ettringite was observed in the case of K2SO4 system. However both Al2(SO4)3 and AlK(SO4)2 systems showed calcium sulfate dhydrate only as hydrated products.

Key words: Anhydrite II, Blastfurnase slag, Paste hydration, Combined water, Ettringite