• Journal of the Korean Ceramic Society
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• v.23 no.2
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• pp.64-70
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• 1986

In this investigation x-ray diffraction method was mainly studied for quantitative analysis of clinker mineral composition. And also optical microscopic observation and Bogue calculation method were applied to compare with the x-ray diffraction method. In the procedure of x-ray diffraction analysis graphite monochromator automatic divergence slit and spinner for sample holder were used for minimizing the error due to the operation of the equipment. Especially the separation of overlapped peaks were proceeded by micro-processor automatically. The results of x-ray diffraction method for synthesized clinker were consistent with the Bogue value and the results of optical microscopic observation. However the results of quantitative analysis of mineral composition or commercial clinker containing solid solution of minor component were different from the Bogue value. On the other hand they agreed reasonably well with results of the optical mic-roscopic observation.

• Magazine of the Korea Concrete Institute
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• v.5 no.1
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• pp.129-138
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• 1993

프리텐션 방식 원심력 고강도 콘크리트 말뚝[KS F 4306]제조에 관한 실험적 연구로써 고황산염시멘트를 이용한 800kg/$ extrm{cm}^2$이상의 고강도콘크리트 제조시 수화 특성검토와 콘크르트 조직내의 기공율과 압축강도간의 상관식을 도출하여 고강도 발현기구를 규명하였으며 콘크리트 압축 및 휨강도간의 상관식 유도와 내구성 측면에서의 내동해성, 건조수축, 화학저항성등을 보통 포틀랜드 시멘트와 비교 고찰한 결과, 고황상염시멘트의 내구성이 우수함을 확인하였다.

• Journal of the Korean Ceramic Society
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• v.19 no.3
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• pp.236-240
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• 1982

The crystallization of melts with similar composition of Portland cement liquid containing 0-5% $K_2O$ was studied by differential thermal and isothermal reaction. The devitrification of melts was occured in stages, the recognizable amount of CaO was appered at the first step, then proto-C3A was crystallized. The latter showed to occur in both cubic C3A and Ca-ferrite crystallization. Batches lost remarkable amounts of $K_2O$ as a result of volatilization during melting and the solubility of $K_2O$ in the melts was unstable.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.14-18
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• 1995

Since cement is one of materials of concrete and have an important effect upon physical properties of concrete, the quality characteristics of ordinary portland cement in domestic market are evaluated in this study. For this purpose, eight kinds of cement are selected and tested on the specific gravity, normal consistency, setting time, fincness, and compressive strength of cement ranged from 300kg/$\textrm{m}^3$ to 600kg/$\textrm{m}^3$ are tested for each kind of cement. As a result,ordinary portland cement in domestic market are satisfied with physical performance prescribed by KS L 5201(Portland Cement) and when unit weight of cement is 300~600kg/$\textrm{m}^3$, the maximum compressive strength of concrete cylinder is showed to be about 440-540kgf/$\textrm{cm}^2$.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.289-290
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• 2010

This study investigated the high early strength properties of blended cement using cement with high blaine value in order to reduce a construction period.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.714-717
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• 2000

To consider sulfate resistance of cement pastes and motars for 3 types of portland cements which have different $C_3A$ contents an silicate ratio($C_3S/C_2S$), they were immersed in 5% sodium sulfate solution for 400 days. SEM analysis and ($Ca(OH)_2$ contents of cement pastes, and compressive strength and length change of cement mortars, were performed to investigate the effects of ($C_3$ and ($Ca(OH)_2$ contents. According to the results of this study, low heat portland cement pastes, and compressive strength and length change of cement mortars, were performed to investigate the effects of C3A and ($Ca(OH)_2$ contents. According to the results of this study, low heat portland cement had a good sulfate resistances because of a small quantity of gypsum and ettringite due to less ($Ca(OH)_2$ contents. However, ordinary portland cement had an adverse result. This was also confirmed by SEM analysis.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.1041-1046
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• 2003

The most recent building trend is going large, high rise, high strength as overlarge project is developing in domestic construction business. Belite cement has properties like low heat, excellent long term strength, and durability without admixture (fly ash, silica fume). So, Belite cement is suitable for mass structure which is needed high strength, high fluidity and low heat property. This study is to examine the possibility of site adoption microwave-use early strength estimation method. Based on the existed study related the portland cement, the interrelation between Belite cement and microwave-use early strength estimation method is required.

• Journal of the Korean Ceramic Society
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• v.38 no.2
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• pp.152-157
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• 2001

본 연구에서는 고유동, 저발열 및 고강도 특성을 발현하는 belite-rich cement(BRC)에 있어서 카르복실산계 유기혼화제를 사용했을 때 가용성 알칼리의 함량 변화에 따른 흡착거동과 유동특성에 미치는 영향성에 대해 검토하였다. BRC에서 알칼리 0.1~0.2 wt% 및 알칼리 설페이트 0.3~0.5 wt% 첨가시 슬럼프가 증가하거나 손실이 거의 없었으며, 그 이상의 함량을 첨가하였을 때 다시 유동서 저하를 가져왔다. 그러나, 보통 포틀랜드 시멘트(OPC)의 슬럼프 유지능력은 알칼리 및 알칼리 설페이트를 첨가할수록 감소되었다.

• Journal of the Korean Ceramic Society
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• v.38 no.2
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• pp.183-192
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• 2001

산업부산물을 이용하여 3CaO.3Al$_2$O$_3$.CaSO$_4$(C$_4$A$_3$S) 클링커를 합성하였다. 이때, 원료 물질은 산업부산물로 플라이 애쉬, 고로 수쇄 및 괴재슬래그를 $Al_2$O$_3$원으로 그리고 부산석고를 SO$_3$원으로 이용하였으며, CaO원으로 천연석회석을 사용하였다. 제조된 $C_4$A$_3$S 클링커를 CaSO$_4$, CaO를 배합하여 CSA계 팽창재를 제조하였으며, 일반 포틀랜드 시멘트(OPC)에 10 wt.% 첨가하여 수화 및 물성 특성을 조사하였다. 주요 수화생성상은 에트링자이트 및 수산화칼슘이었다. 수화시 에트링자이트의 생성으로 인해 팽창 및 경화체가 치밀화되어 건조수축이 감소되었고, 강도(압출, 인장, 휨)가 향상되었다.

• Journal of the Korean Ceramic Society
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• v.28 no.11
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• pp.917-925
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• 1991

For the present experiment five Portland cement mortars are in order: mortars with two different water/ cement ratios (W/C=0.45 and 0.50, each having no chemical additive), and those with an additive such as superplasticizer, air-entraining agent or water-repelling agent. We fix the W/C ratio of mortars having additive so that their pastes can yield the same workability as that of the cement mortar of W/C=0.50 with no additive. It is shown that the freeze-thaw resistivity depends heavily on the characteristic of wide pores. Despite a good deal of wide pores, the air-entrained specimen shows a good freeze-thaw resistivity due to appropriate air-pores. And also the specimen with water-repelling agent, which proves to cause the microstructure to become hydrophobic, make good resistance to freeze-thaw cycles in spite of its high wide-porosity. Our suggestion is that the freeze-thaw durability of Portland cement mortar/concrete can be more effectively enhanced by using air-entraining agent or water-repelling agent, and simutaneously by taking proper measures against foaming and/or the increased tendency of wide-pore building due to additive.