• Title/Summary/Keyword: silicafume

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Influence of Superplastisize Types on Hydration of Cement with Silica Fume (고성능 감수제 종류에 따른 실리카흄이 혼입된 시멘트 수화 특성)

  • Kang, Hyun-Ju;Song, Myong-Shin;Park, Jong-Hun;Song, Su-Jae
    • Journal of the Korean Ceramic Society
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    • v.48 no.6
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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.

Influence of Nano Silica Dispersant on Hydration Properties of Cementitious Materials (시멘트의 수화특성에 대한 유·무기 복합 나노실리카의 영향)

  • Kang, Hyun-Ju;Song, Myong-Shin;Park, Jong-Hun;Song, Su-Jae
    • Journal of the Korean Ceramic Society
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    • v.48 no.6
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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.

An Experimental Study on the Properties of Durability of High Strength Concrete Using Domestic.Foreign Meta-kaolin (국내.외산 메타카올린을 사용한 고강도 콘크리트의 내구특성에 관한 실험적 연구)

  • Lee, Kang-Pil;Lee, Seung-Min;Lee, Sang-Soo;Song, Ha-Young
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2009.05b
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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.

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Evaluation of Durability Characteristics of High Performance Shotcrete Using Fly Ash (폐석탄회를 이용한 고성능 숏크리트의 내구특성 평가)

  • Park, Cheol-Woo;Lee, Hyeon-Gi;Kang, Tae-Sung
    • Journal of the Korea Concrete Institute
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    • v.22 no.3
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    • pp.305-311
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    • 2010
  • The industrial by-product market has increased at a geometric rate worldwide with the rapid economic growth. At present time, conventional disposal methods of industrial by-products in Korea including landfill, incineration and storage already have reached their limits. In this study, the industrial by-products such as fly ash and silicafume were used as mineral admixtures, which are commonly added to concrete mix to inhance the economic efficiency, long-term strength and durability of concrete, to determine the optimized mix proportion of high performance shotcrete. Through the series of tests (compressive strength test, accelerated chloride ion penetration test, measurement of chloride diffusion coefficient). The results of the study showed that the proposed mix proportions satisfied the requirements of domestic as well as international guidelines for shotcrete, with a higher durability than the existing shotcrete.