• 콘크리트학회논문집
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• 제12권3호
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• pp.3-10
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• 2000

In this study, we compared a plain mortar with the CAS-system shrinkage compensation mortar for Ondol that is Korean traditional heating system. The Ondol mortar is necessary to have properties as non-crack, fine flatness and stability for thermal changes. especially, mortar'crack prevention is to be most important property in Ondol mortar. To develope the stable material on the crack-prevention, we used to calcium-sulfo-aluminate(CSA)system in shrinkage compensation mortar. And so, we confirmed the effects of calcium-sulfo-aluminate(CSA) system for mortar's physical properties such as setting time, compressive strength and expansion ratio for crack prevention. The initial and final setting time of the CSA mortar is faster than plain mortar about 2hours. And, Compressive strength increased about 20% that plain mortar. The crack length per unit area, plain mortar is 0.426∼0.481m/m2. The Results of apartment construction field test, the shrinkage compensation mortar is excellent about the crack-reduce effect.

• 에너지공학
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• 제27권1호
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• pp.33-39
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• 2018

In this paper, we reviewed briefly about the barrier materials for the radioactive waste disposal. The primary concept of the radioactive waste disposal is safety. The goal of the radioactive waste management is to assure that the environment is not adversely affected and also public. There are a wide variety of materials are available for the radioactive waste disposal or storage. Among those coal fly ash is one of the significant materials are used as a barrier material. Here we reported, the Calcium sulfo aluminate (CSA) from coal fly ash is effectively suitable for the radioactive waste disposal. This is one of the ways of utilization of waste and manufactured the valuable materials for future indeeds.

• 한국세라믹학회지
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• 제23권3호
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• pp.27-34
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• 1986

The hydration of flyash-$Ca(OH)_2-CaSO_4$.$2H_2O$ system was stuedied with varing mixing ratio of flyahs $Ca(OH)_2$ and caSO4.2H2O The samples were steam-cured for 1-7 days at 9$0^{\circ}C$. The optimum mixing composition was flyash : Ca (OH)2=65:35 with 15% $CaSO_4$.42H_2O$ added which produced the hardened material having the best compressive strength (300kg/$cm^2$) Also the low specific gravity(1, 2) of the hardened paste suggests the possibility that it can be used as a light-weight building material. The added $CaSO_4$.42H_2O$ constituted calcium-sulfo-aluminate hydrates which activates the formation of C-S-H hy-drates. Both hydrates developed the strength of hardened paste. The amount of calcium-sulfo-aluminate hydrates was increased when the $CaSO_4$.42H_2O$ was added over 15% however the increased amount did not help the development of strength because of the individually grown calcium-sulfo-aluminate hydrates.

• 시멘트 심포지엄
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• 통권40호
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• pp.55-63
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• 2013

• 대한금속재료학회지
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• 제46권7호
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• pp.437-442
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• 2008

The synthesis and hydration of Calcium Sulfo Aluminate[$3CaO{\cdot}3Al_2O_3{\cdot}CaSO_4(C_4A_3{\overline{S}})$, CSA cement utilizing secondary steelmaking refining slags is studied for recycling the discarded steel plant wastes to meet the environmental requrations imposed on the steel industry. Raw materials of secondary refining slag, lime sludge, gypsum and bauxite were prepared to be sintered at $1,250^{\circ}C$. The sintered samples were hydrated for 1, 3 and 7 days to evaluate the mineralogical and physico-mechanical properties. The hydration products evaluated with the aid of SEM and XRD analyses confirmed the formation and the continuing growth of ettringite phase with the further hydration times, which plays a role in developing the early strength and the expansion properties of cements. The physico-mechanical properties of hydrated CSA products employing the recycled steelmaking refining slags determined in terms of compressive strength and linear expansion of hydrated products are found to be superior to those of the Ordinary Portland Cement(OPC) or the other commercial CSA cements.

• 한국건설순환자원학회논문집
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• 제3권3호
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• pp.199-205
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• 2015

이 연구에서는 고온의 축열재료로 사용하기 위한 알루미나 시멘트 복합재료의 역학적 및 열적 특성을 파악하고자 하였다. 알루미나 시멘트를 기본 바인더로 하고 플라이애시, 실리카퓸, CSA (calcium sulfo-aluminate) 및 그라파이트의 치환에 따른 고온에서의 물성을 파악하였다. 알루미나 시멘트 기반 복합재료의 역학적 특성으로서 열사이클 전과 후의 압축강도 및 인장강도를 측정하였다. 또한, 복합재료의 열적 특성으로서 열전도율과 비열을 측정하였다. 열사이클링 적용 이후의 잔류압축강도 측정결과, 알루미나 시멘트만을 사용한 배합과 알루미나 시멘트를 실리카퓸으로 치환한 배합의 압축강도가 크게 나타나며, 이 두 배합의 잔류강도 비는 65%를 상회한다. 그라파이트를 혼합한 복합재료의 비열이 가장 크고 이는 그라파이트의 비열이 크기 때문이다. 연구결과는 콘크리트를 고온조건에서의 축열매체로 활용하기 위한 실제적인 기초실험 자료로 활용될 수 있을 것으로 사료된다.

• 한국자원리싸이클링학회:학술대회논문집
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• 한국자원리싸이클링학회 2005년도 추계정기총회 및 제26회 학술발표대회 고분자리싸이클링기술 특별심포지엄
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• pp.203-207
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• 2005

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.397-400
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• 2005

This study is a result that, in order to improve the early stage strength of fly ash, the calciumsulfoaluminate in which the generation of ettringite was very active in the early stage was substituted by some amount, and then the effect on the early stage was analyzed. when fly ash was substituted by 30$\%$, the strength dropped by maximum 54 $\%$ in the 3rd day of aging, compared to the cement mixture, but when CSA was substituted by 8 $\%$ in the fly ash amount, the strength improved at the 86 percent level of cement, it is suggested as an economical and effective method to improve the early-stage strength that CSA should be mixed by 8$\%$ compared to the fly ash amount used

• 한국환경과학회지
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• 제29권6호
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• pp.605-612
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• 2020

To improve the initial strength and stability of lightweight-foamed concrete, which shows suitable sound absorption and insulation characteristics, the effect of CO₂-reduced cement on the properties of the concrete was investigated. Various mixing ratios were applied by substituting a certain amount of slag and Calcium Sulfo Aluminate (CSA) in CO₂-reduced Ordinary Portland Cement (OPC) and the physical properties of the samples were examined using the Korean Standard. The kiln temperatures of the CSA were 100-200℃ ; these values are lower than those of OPC and can lead to energy saving. In addition, the low limestone content reduces greenhouse gas emissions by 20 %. Adding a small amount of CSA in OPC content activates Ca-Al-H₂-based hydrates, and the initial compressive strength of the concrete is improved. As the CSA content increased, the thermal conductivity of the concrete decreased by up to 8% compared to plain concrete, thus indicating an improvement in its insulation. Therefore, the settlement stability was improved as the addition of CSA shortened the setting time.

• 자원리싸이클링
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• 제29권1호
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• pp.53-61
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• 2020

본 연구는 시멘트 대비 산업부산물을 90% 이상 대체한 친환경 결합재를 이용하여 저강도·고유동을 갖는 지반보수용 기포콘크리트 소재를 개발하기 위한 연구로서, 산업부산물을 다량 활용시 발생하는 기포콘크리트의 초기 침하율 및 체적변화를 개선하기 위하여 CSA(Calcium sulfo aluminate)를 소량 대체하여 기초특성을 평가하였다. 기포콘크리트용 친환경 결합재 대비 CSA의 대체율은 2.5, 5, 10%로, 굳지않은 특성, 경화특성, 공극구조 및 수화물을 분석하였다. 실험결과 친환경 결합재 사용시의 높은 침하깊이를 CSA 2.5% 사용만으로도 개선할 수 있었으며, 그로인해 경화 후에도 타설된 시험체의 상중하의 중량편차도 개선되었다. CSA 첨가에 따라 공극구조도 작고 균일한 사이즈의 독립기포 형성에 기여하였으며, 초기강도는 개선되었다. 그러나 CSA의 혼입률의 증가에 따라 장기강도는 감소하였으나, 5% 이하를 사용할 경우 목표강도를 만족하였다. 이로써 산업부산물을 다량 활용한 친환경 결합재에 CSA의 2.5% 첨가만으로도 목표성능의 저강도 고유동을 갖는 지반 보수용 기포콘크리트 제조가 가능한 것을 확인하였다.