• Journal of the Korean Ceramic Society
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• v.33 no.9
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• pp.1024-1030
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• 1996

• Journal of the Korean Ceramic Society
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• v.27 no.2
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• pp.195-200
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• 1990

For the development of low energy cement, the belite cement clinker of calcium sulphoaluminate ferrite type was synthesized at 130$0^{\circ}C$ and containing C2S, C4A3S as the major minerals along with C3A, C4AF, CS by using limestone, dolomite, clay, iron ore, gypsum and alumina as raw materials. At over 130$0^{\circ}C$, C4A3S was decomposed and thus C3A was increased. When hydrated, this cement was hardened, producing ettringite, CSH, etc.

• Journal of the Korean Ceramic Society
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• v.33 no.10
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• pp.1163-1169
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• 1996

The effects of borax on the phase formation of C2S, C4A3 and $\alpha$'-C2S phases. It has negative effects on formation of C4A3 And it lowers the forming temperature of C4AF. It also has been found that borax improves the clinkerization of MBC. In the MBC clinker with borax 3% C2S have larger and more irregular shapes, larger C/S mole ratio and C4A3 have smaller size larger C/ molr ratio than in the clinker without borax.

• Journal of the Korean Ceramic Society
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• v.36 no.7
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• pp.685-690
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• 1999

Modified belite cement clinker containing $\alpha$'-C2S and C4A3 were syntehsized form the mixture of raw materials. $\alpha$'-C2S was stabilized at room temperature by adding borax. Properties of the clinker were charaterized with a XRD, SEM, TEM The additive effects of slag on the hydration properties were also estimated by measurement of compressive strength fluidity and heat evolution. The experimental results exhibited that the addition of slag to the belite cement improves the fluidity and early compressive strength due to the formation of ettringite and C-S-H. The compressive strengths of the mortar with 20% slag after 7, 90 days hydration were 212, 355 kgf/cm2 respectively.

• Journal of the Korean Ceramic Society
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• v.32 no.8
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• pp.873-880
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• 1995

In order to prepare the modified belite (C2S-C4A3S-C4AF-CS) cement with low energy, clinkers were synthesized by converter slag, limestone, gypsum and clay. The synthesized clinkers were characterized and the hydration processes were investigated by XRD, SEM and microconduction calorimetry. The hydrates were mainly C-S-H and ettringite. The needle-like ettringite formed by the hydration of C4A3S at the early stage of hydration was filled in the inner vacant spaces of the hardened body and it might contribute to the rapid-hardening phenomena. The hardened body became stronger due to the hydration of C2S at the later period. The compressive strengths of the cement-3 mortars hydrated for 3, 7 and 28 days were 115, 128 and 211 Kgf/$\textrm{cm}^2$, respectively.

• The Korean Journal of Ceramics
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• v.2 no.3
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• pp.147-151
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• 1996

By adding borax into the raw mix, Modified Belite Cement clinker and cements were prepared. Clinkerization and hydration reactions were investigated in order to better understand. Borax-bearing MBC clinker sintered at 1300℃ for 1 hour showed excellent burnability. Borax stabilized α'and β-C2S at room temperature. In the hydration of the cement prepared with the borax-bearing clinker, ettringite, monosulphate, C-S-H hydrates and CH were formed. The hydration of calcium sulphoaluminate was less reactive than the cement prepared with the controlled clinker at early hydration time. But, as hydration time elapsed, this cement showed more active hydraulicity and higher compressive strength development.

• Cement Symposium
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• no.21
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• pp.47-50
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• 1993

• Cement Symposium
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• no.25
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• pp.66-72
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• 1997

• Journal of the Korean Ceramic Society
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• v.35 no.5
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• pp.479-485
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• 1998

Raw mateials such as limestone quartzite bauxite and anhydrite were used in the production of mod-ified beloite cement. Two kinds of clinker were synthesized with relatively higher content of $C_2S$ than that of $C_4A_3{\={S}}$ Concerning $C_2S$ the main mineral component borax ($Na_2O\;2B_2O_3\;10H_2O$) was added to stimu-late hydraulic reactivity and this would be possible by stabilizing ${\alpha}'-C_2S$ at room temperature. We had in-tended to compare burning and hydraulic characteristics of clinkers with one another by varying the amount of borax addition and to study the appropriate amount of anhydrite addition needed in the strengthening of cement during hydration. It was concluded that the effective amount of borax addition ne-eded for stabilization of ${\alpha}'-C_2S$ was 5 wt% in 60wt% $C_2S$ inclusive clinker and adding anhydrite in the ra-tio of 1.3 of $SO_3/Al_3O_3$ was appropriate in the production of cement by this clinker. Only ettringite was seen to contribute to the strength without additives but C-S-H was found to form along with ettringite with the addition of borax in the initial stage of hydration.

• Journal of the Korean Ceramic Society
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• v.37 no.10
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• pp.949-954
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• 2000

천연원료를 사용하여 $\alpha$-C$_2$S-C$_4$A$_3$S계 시멘트를 제조하였다. 클링커의 특성분석은 XRDd, FT-IR, SEM으로 행하였고 플라이애쉬 첨가에 따른 강도변화와 유동성 및 수화발열속도를 검토하였다. 그 결과 플라이애쉬 첨가시 유동성 증가 및 ettringite와 stratling계 수화물의 생성으로 초기 압축강도가 증진되었다. 플라이애쉬 5wt% 혼합시 7일 모르타르 압축강도가 224kgf/$ extrm{cm}^2$, 90일 강도는 440kgf/$\textrm{cm}^2$ 이였다.