• 자연과학논문집
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• 제4권
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• pp.95-102
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• 1991

규산삼석회$(C_3S)$의 수화반응에 있어서 $T1_2CO_3$의 농도변화에 따른 영향에 대해서 Isothermal microcalorimeter 등을 이용하여 조사한 결과, $T1_2CO_3$의 존재로 인하여 $C_3S$의 수화반응은 촉진되고 $C_3S$의 농도가 급격히 감소된다. 또 $T1_2CO_3$의 농도증가로 인해서 수화반응속도도 증가하고 있다. $T1_2CO_3$ 첨가에서 수화된 $C_3S$의 분석결과로는 반응초기에 $CaCO_3$가 나타나고 있으며, $T1_2CO_3$의 촉진작용이 수화반응의 초기에 있어서만 더욱 분명하게 나타나고 있음을 $C_3S$의 비휘발성 수분함량과 수화도로서 알수 있고 $C_3S$ paste와 접촉하고 있는 액상의 조성은 $T1_2CO_3$의 존재로 인하여 $Ca^(++)$이온과 $OH^-$ 이온의 농도가 상당히 변화하고 있음을 알 수 있다.

• 한국세라믹학회지
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• 제21권2호
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• pp.143-148
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• 1984

In this study we mainly dealt with the effects of organic retarder(calcium lignosulfate) on the early hydration process of clinker minerals. From a consideration of the hydration process of tricalcium silicate $(C_3S)$ tricalcium silicate $(C_3S)$-tricalcium aluminate $(C_3A)$ tricalcium silicate $(C_3S)$-tetracalcium aluminof-errite $(C_4AF)$ systems with calcium lignosulfate the following results were obtained. 1. when 0.25wt% of CLS was added to $C_3S$ the hydration process was progressed normally but adding of 0.5wt% its hydration was greatly retarded. 2. The hydration of $C_3S$-$C_3A$ system was progressed normally up to 0.5wt% but by adding gypsum its hydration was retarded slightly. 3. The hydration of $C_3S$-$C_4AF$ system was greatly retarded even with 0.25wt% of CLS but by adding gypsum its hydration process was recovered normally.

• 한국세라믹학회지
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• 제11권2호
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• pp.17-21
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• 1974

Miscibility of barium sulfate in tricalcium silicate was investigated by firing 3CaCO3·SiO2 mixture containing barium sulfate at 1530℃. Added amount of barium sulfate to the mixture was zero to 5 mole % with intervals of 1 mole %. Lattice parametres were also calculated. Results were as follow; 1) Dissolution of barium sulfate in tricalcium silicate does not alter the symmetry in room temperature, but influences it's polymorphic transition forms, temperatures and thermal effects; modification triclinic Ⅱ is stabilized in room temperature. 2) Barium sulfate dissolves about up to 2 mole % in tricalcium silicate and more than this amount, tricalcium silicate formation is inhibited. 3) Unit cell volume of tricalcium silicate is slightly decreased with dissolution of barium sulfate, mainly because of contraction in c axis.

• 한국분말재료학회지
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• 제26권6호
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• pp.493-501
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• 2019

In this work, ultra-fine calcium oxide (CaO) powder derived from eggshells is used as the starting material to synthesize mineral trioxide aggregate (MTA). The prepared CaO powder is confirmed to have an average particle size of 500 nm. MTAs are synthesized with three types of fine CaO-based powders, namely, tricalcium silicate (C3S), dicalcium silicate (C2S), and tricalcium aluminate (C3A). The synthesis behavior of C3S, C2S and C3A with ultra-fine CaO powder and the effects of C₃A content and curing time on the properties of MTA are investigated. The characteristics of the synthesized MTA powders are examined by X-ray diffraction (XRD), field emission-scanning electron microscope (FE-SEM), and a universal testing machine (UTM). The microstructure and compressive strength characteristics of the synthesized MTA powders are strongly dependent on the C3A wt.% and curing time. Furthermore, MTA with 5 wt.% C3A is found to increase the compressive strength and shorten the curing time.

• 시멘트
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• 통권88호
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• pp.31-38
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• 1982

• 한국세라믹학회지
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• 제31권12호
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• pp.1417-1422
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• 1994

Effect of MgO, CaSO4, and CaF2 addition on the formation of clinker minerals in portland cement have been investigated by measuring the amounts of free-CaO and C3S in the fired specimens and analyzing the Mg and S concentration in C3S and C2S. It was found that CaSO4 inhibited C3S formation but MgO addition offset this effect of CaSO4. MgO addition also enhanced the mineralizing effect of CaSO4+CaF2, resulting in the acceleration of C3S formation. It was suggested that Mg might inhibit the formation of sulphate compounds rim around C2S and thus C2S+CaOlongrightarrowC3S reaction was facilitated.

• 한국세라믹학회지
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• 제24권4호
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• pp.385-391
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• 1987

Zeta potential according to the hydration time was studied during the early hydration of C3S with and without CO2 atmosphere. Zeta potential was low as a level of 20mV at the first and second exothermic peaks of heat evolution, but it was rapidly increased up to a level of 300mV. In the CO2 atmosphere, zeta potential was level of 60mV at 10 minutes hydration and it's value became a low gradually according to the hydration time. Zeta potential was also proportioned to the Ca2+ concentration in the liquid phase, i.e., there was positive correlation between zeta potential and Ca2+ concentration. The existence of silicate layer was not found out on the hydrated C3S in the CO2 atmosphere by SEM-EDAX.

• 한국세라믹학회지
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• 제24권2호
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• pp.133-138
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• 1987

The behavior of CaO and SiO2 in the reaction produced which produced in the early hydration of C3S was studied by XRD and thermal analyzer. Polymerization of hydrated siltcates was also studied by TMS method. TMS derivatives were separated by gaschromatography. Cao/SiO2 molar ratios of the produced CSH gel under the air atmosphere were higher than that in the CO2. Dimerization rate of hydrated silicates was very fast in the early hydration stage. Trimer began to appear later than dimer and its increasing rate was very low. The amount of dimer and trimer formed under the CO2 atmosphere was less than that in the air.

• 한국세라믹학회지
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• 제56권4호
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• pp.403-411
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• 2019

In this work, the hydration process and cytotoxicity of lab-synthesized experimental Portland cements (EPCs) were investigated for dental applications. For this purpose, EPCs were prepared using laboratory-synthesized clinker constituents, tricalcium silicate (C₃S), dicalcium silicate (C₂S), and tricalcium aluminate (C₃A). C-A was prepared by the Pechini method, whereas C₃S and C₂S were synthesized by solid-state reactions. The phase compositions were characterized by X-ray diffraction (XRD) analysis, and the hydration process of the individual constituents and their combinations, with and without the addition of gypsum, was investigated by electrochemical impedance spectroscopy (EIS). Furthermore, four EPC compositions were prepared using the lab-synthesized C-A, C₃S, and C₂S, and their hydration processes were examined by EIS, and their cytotoxicity to HPC and HIPC cells were tested by performing an XTT assay. None of the EPCs exhibited any significant cytotoxicity for 7 days, and no significant difference was observed in the cell viabilities of ProRoot MTA and EPCs. The results indicated that all the EPCs are sufficiently biocompatible with human dental pulp cells and can be potential substitutes for commercial dental cements.

• Computers and Concrete
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• 제15권1호
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• pp.89-101
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• 2015

In this paper, Artificial Neural Networks (ANN) and Multiple Linear Regression (MLR) models were discussed to determine the compressive strength of clinker mortars cured for 1, 2, 7 and 28 days. In the experimental stage, 1288 mortar samples were produced from 322 different clinker specimens and compressive strength tests were performed on these samples. Chemical properties of the clinker samples were also determined. In the modeling stage, these experimental results were used to construct the models. In the models tricalcium silicate ($C_3S$), dicalcium silicate ($C_2S$), tricalcium aluminate ($C_3A$), tetracalcium alumina ferrite ($C_4AF$), blaine values, specific gravity and age of samples were used as inputs and the compressive strength of clinker samples was used as output. The approximate reasoning ability of the models compared using some statistical parameters. As a result, ANN has shown satisfying relation with experimental results and suggests an alternative approach to evaluate compressive strength estimation of clinker mortars using related inputs. Furthermore MLR model showed a poor ability to predict.