• 한국세라믹학회지
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• 제48권6호
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• pp.504-509
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• 2011

In this study, the effect of superplasticizers on the dispersibility and hydration properties of cement with silica fume were investigated. Superplasticizers are used Naphthalene type, Ligno-sulfate type and polycarboxylate type. Compared with plastic viscosity of cement paste without superplasticizers(Plain), plastic viscosity of cement paste with superplasticizers are reduced and yield stress of cement pastes with each superplasticizer is increased rather than Plain. And then, plastic viscosity of cement paste with Naphthalene type superplasticizer was the least of all types. Compared with other two types, setting and hydration of cement paste with Polycarboxylate type(PC) superplasticizer is very fast. At compressive strength after 3-day, PC is higher than other two types, But, compressive strength of after 7-day and 28-day, PC is smaller than other two types.

• 한국세라믹학회지
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• 제48권6호
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• pp.510-515
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• 2011

In this study, as a material used to replace silica fumes for high strength concrete, nano-silica compound with organic functional group for dispersion and with inorganic silica group that can cause a pozzolan reaction is synthesized, These nano silica compound is divided into IC, which is nano size $SiO_2$ with irregularly combined hydroxyl group and carboxyl group, and RC, which is nano size $SiO_2$ with regularly combined hydroxyl group and carboxyl group. The effects of these nano silica compound on the hydration of cement are reviewed. As a result, all of synthesized nano-silica compounds have excellent dispersion on the cement flow, we think that dispersion property is the effect of air entraining by synthesized nano-silica compounds. The result of the microstructure observation showed that the particle size of the synthesized nano-silica is smaller than silica fume and spread evenly among the cement particles. In initial The phenomenon of strength decreasing occurred due to delayed hydration reaction by the synthesized nano-silica with carboxyl(-COOH) and hydroxyl(-OH) functional group.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 춘계 학술논문 발표대회 학계
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• pp.239-242
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• 2009

As the high-rise building increase due to the gravitation of population to big cities recently, it requires high quality and high performance of Concrete. As a result, people are keenly interested in Meta-kaolin as new admixture favorable from an economic perspective, which has strength and endurance with admixture at the same level like Silica-fume. Accordingly, as to Meta-kaolin, this study was to set by three levels like domestic one, foreign one, and Silica-fume, the water-binding material ratio 25%, and four level substitute like 0, 10, 20, and 30(%) in order to compare and analyze the quality durability of high-concrete according to the substitute of Meta-kaolin applicable with replacement of Silica-fume. As a result of performing experiment it was found that when water-binding material ratio increases, resistance of neutralization, carbonation, salt damage and sulfate decrease, and when replacement ratio of mineral admixture increases, depth of accelerating carbonation gets greater. Also, the combination of SF and MK-B favored resistance to chloride ion penetration better than MK-A, and it was found that when replacement ratio of binding material increases, the resistance to sulphuric acid increases. Therefore, based on this study, it was understood that meta-kaolin is useable in replacement of silicafume.

• 콘크리트학회논문집
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• 제22권3호
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• pp.305-311
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• 2010

최근 국제적으로 급속한 경제성장으로 인한 산업부산물이 기하급수적으로 늘어가고 있다. 현재 국내 산업부산물은 매립, 소각, 저장과 같은 1차원적인 처리에도 그 한계를 드러내고 있는 실정이다. 따라서 이 연구에서는 자원재활용을 목적으로 산업부산물을 이용한 고성능 숏크리트용 최적 배합비를 도출하고자 한다. 이 연구에서는 경제적 재활용, 장기강도 및 내구성 향상을 위해 콘크리트에 다양하게 적용되고 있는 혼화재인 산업부산물(플라이애쉬, 실리카퓸)를 적용하여 숏크리트 현장에 적용할 수 있는 적정 배합비에 대한 변수를 설정하여 압축강도 실험을 수행하였고, 외부 환경 변화에 따른 내구성능을 평가하기 위하여 촉진염소이온침투시험 및 염화물확산계수측정시험을 실시하여 외부환경에 대한 내구특성을 평가하였다. 실험 결과 모든 실험에서 국내외 기준을 만족하였고, 내구성에서는 기존 숏크리트 보다 뛰어난 것으로 나타났다.