Fluidity Changes of Cement Paste added Superplasticizer and Inorganic Fine Powders for Cement Admixture

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J. Korean Ceram. Soc. > Volume 37(8); 2000 > Article

Journal of the Korean Ceramic Society 2000;37(8): 751.

고유동화제와 시멘트 혼화용 무기미분체가 첨가된 시멘트 페이스트의 유동성 변화

김도수, 정흥호, 박병배, 노재성¹

충남대학교 대학원 공업화학과
¹충남대학교 공과대학 정밀공업화학과

Fluidity Changes of Cement Paste added Superplasticizer and Inorganic Fine Powders for Cement Admixture

ABSTRACT

Effects of the dosage change, from 0 to 2.0 wt% based on cement weight, of naphthalenic (NSF) and polycarboxylic(NT-2) superplasticizers, on the fluidity of cement paste substituted by 10 wt% II-anhydrite and fly ash respectively as well as II-anhydrite and fly ash itself were investigated. Dispersion properties between particles in suspension were investigated by zeta potential test. Initial fluidity and slump loss in the paste system were observed through mini-slump and apparent viscosity changes with elapsed time. Zeta potential on the particle surface was a tendency to increase according to increasing of NSF dosage. Especially, zeta potential of fly ash has the highest value among all particles equivalent to NSF dosage. In the fluidity of cement paste substituted by inorganic particles, the specimen with substitution of 10 wt% II-anhydrite and fly ash for cement was more effective than cement itself to improve initial fluidity and retain stable fluidity of cement paste. In addition, effect of NT-2 and NSF to improve the fluidity of cement paste, addition of 1.0 wt% NT-2 was more effective than 1.5wt% NSF.

Key words: II-anhydrite, Fly ash, Zeta potential, Slump loss, Apparent viscosity, Superplasticizer