• 한국세라믹학회지
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• 제16권3호
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• pp.164-168
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• 1979

In the previous paper, it was reported that formation of desirable calcium alunimate(CA) in clinker was considerably affected by sulfur-contaminated alumina which was prone to form a disadvantageous mineral, $C_4A_3S$. In this study, however, sulphate-free alumina cement was made from sulfur-free alumina refined from alunite and corresponding materials. The major minerals in the clinker were identified by X-ray diffraction patterns as calcium aluminate (CA), calcium dialuminate $(CA_2)$ and dicalcium alumino silicate $(C_2AS)$. The formation of CA was more effective with decreasing contents of silica to 2 per cent or less and sulfur in the refined alumina. Physical properties of prepared alumina cement such as setting time, stability and compressive strength were measured. The values were similar to those of commercial alumina cements.

• 시멘트
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• 통권59호
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• pp.26-38
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• 1975

본고는 일본 소야전Cement Co.의 중앙연구소주임연구원으로 있는 Hiroshi Uckikawa 박사가 일본의 Ceramics-Japan지(''74.10)에 기고한 것을 번역한 것으로서 그 내용에 의한 목차는 다음과 같다. 즉 근년에 개발된 새로운 cement로서는 1. 속경성 cement 2) 초속경 cement(jet cement, regulated set cement) 2) Alumina cement 3) 초조강 cement 4) 급경 cement 2. 고강도 cement 3. 내구성 cement 1) 내유산균 cement 2) 내화 cement (1) alumina cement 계 (2) barium, strontium 계 cement (3) 인산 aluminium 계 cement 3) 방사선차폐용 cement 4. 팽창 cement 1) alumine 산, 유산 calcium 수화물의 생성에 의한 것 2) 수산화 calcium의 생성에 의한 것 3) 기타 5. 시공성을 개선한 cement (예: 유정용 cement, 도장용 cement) 등이 있다. 머지 않아 우리나라에서도 cement 품종의 다양화가 필연적인 문제로 대두될 것을 생각하여 본번역문이 다소나마 도움이 되기를 바란다.

• 대한치과의사협회지
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• 제22권4호통권179호
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• pp.313-322
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• 1984

This study was designed to observe the marginal leakage of three permanent cements affected by three temporary cements. The temporary cements used in this study were Zinc oxide-eugenol, Non-eugenol, and Calcium hydroxide cements and the permanent cements were Zinc phosphate, Polycarboxylate and Alumina reinforced EBA cements. To measure the dye penetration into permanently cemented zone, the experimental specimens were treated with the temporary cements for a week. An analysis of the data obtained from 120 specimens resulted in the following conclusions: 1. Regardless of the types of the permanent cements used, using Calcium hydroxide cement as temporary cement showed higher marginal leakage than other temporary cements. 2. Using Polycarboxylate cement as permanent cement showed less marginal leakage than other permanent cements. 3. The marginal leakage in zinc phosphate cement was similar to Alumina reinforced EBA cement regardless of the types of the temporary 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.

• 한국세라믹학회지
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• 제27권2호
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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.

• 한국세라믹학회지
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• 제12권4호
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• pp.3-8
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• 1975

Hydration processes of the rapid hardening cement clinkers, which were synthesized from domestic alunite for major alumina source, limestone, kaolin and fluorite, were investigated by means of x-ray diffraction analysis, thermal analysis and microscopic observation etc. The clinkers were composed mainly of alite, calcium fluroaluminate (C11A7.CaF2) minerals. While the hydratio processes of the clinkers are altered by concentration of SO3 in the paste, calcium aluminate hydrates such as C4AH13, CAH10 and calcium monosulfate hydrate (C3A.CaSO4.12H2O) are formed at first and then some of them are transformed into ettringite(C3A.3CaSO4.32H2O) within 30~60 min. when the concentration of SO3 in the paste are enough. However the formed ettringite are changed slowly into calcium monosulfate hydrate as the concentration of SO3 become lowered, and the paste is hardened with these close-packed minerals. When the content of SO3 in clinker is so enough, calcium sulfoaluminate hydrates are found without any addition of anhydrite or hemi-hydrite.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 가을학술발표대회논문집
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• pp.183-184
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• 2023

Considering the actual marine environment construction, this paper monitors the mechanical properties (Flexural, Compressive strength) by exposing alumina cement to seawater. As a result of the experiment, it was confirmed that the strength decreases by about -25% when curing in seawater, but the target strength of the product is met, so it is believed that exposure to the actual marine environment will not be significantly affected.

• Computers and Concrete
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• 제24권5호
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• pp.453-458
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• 2019

Today, concrete remains the most important, durable, and reliable material that has been used in the construction sector, making it the most commonly used material after water. However, cement continues to exert many negative effects on the environment, including the production of carbon dioxide (CO2), which pollutes the atmosphere. Cement production is costly, and it also consumes energy and natural non- renewable resources, which are critical for sustainability. These factors represent the motivation for researchers to examine the various alternatives that can reduce the effects on the environment, natural resources, and energy consumption and enhance the mechanical properties of concrete. Geopolymer is one alternative that has been investigated; this can be produced using aluminosilicate materials such as low calcium (class F) FA, Ultra-Fine GGBS, and high calcium FA (class C, which are available worldwide as industrial, agricultural byproducts.). It has a high percentage of silica and alumina, which react with alkaline solution (activators). Aluminosilicate gel, which forms as a result of this reaction, is an effective binding material for the concrete. This paper presents an up-to-date review regarding the important engineering properties of geopolymer formed by FA and slag binders; the findings demonstrate that this type of geopolymer could be an adequate alternative to ordinary Portland cement (OPC). Due to the significant positive mechanical properties of slag-FA geopolymer cements and their positive effects on the environment, it represents a material that could potentially be used in the construction industry.

• 청정기술
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• 제3권2호
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• pp.87-93
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• 1997

본 실험은 알루미나 시멘트와 산화칼슘을 이용해 염기성 조건에서 질산염을 침전시킴으로써 오염수를 처리하는 공정에 관한 것이다. 시중에 시판되고 있는 알루미나 시멘트 중 알루미나 함량이 낮은 시멘트가 높은 질산염 제거를 보였다. 알루미늄과 칼슘의 성분비는 침전반응에 가장 중요한 요소임을 알 수 있었다. 고농도의 질산염 폐수의 처리를 위해 다단계의 침전반응이 효과적이었다. 질산염 뿐만 아니라 황산, 인산 및 염소의 제거에도 침전반응에 의한 제거가 가능하였다. 반응 후에 탄산나트륨의 첨가와 산을 이용한 중화를 포함한 후처리로 처리수내에 용출된 알루미늄과 칼슘의 제거가 가능하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.289-290
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• 2009

본 연구는 알루미나 시멘트 콘크리트(CAC)를 이용하여 염화물의 대한 철근 부식의 저항성을 압축 강도, 염분 침투, 부식을 각각 실험을 통하여 측정하였다. 알루미나 시멘트가 보통 포틀랜드 시멘트(OPC)보다 철근 부식 저항성이 뛰어난 결과가 나왔다.