• 한국세라믹학회지
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• 제26권5호
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• pp.609-616
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• 1989

For the development of high durable portland cement, it was tested that the some physical properties of ordinary portland cements (OPC) treated with 0.3-1.5wt.% asphalt and 0.5-1.0wt.% carbon black. From the results, the contact angles of water against cements treated with more than 0.6wt.% asphalt were increased over 80 degrees, the initial and the final setting times of cement paste were delayed about 20min. according to the every 0.3wt.% increase of asphalt. The first and the second pick heights of the hydration curve of the cement were considerabely decreased and the induction period of that was increased. And so, the cumulative hydration heat of the cement which was treated with 0.6wt.% asphalt and 0.5wt.% carbon black was lower about 10cal/g than that of ordinary portland cement during 42 hydration times.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 가을학술발표대회논문집
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• pp.191-192
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• 2023

This study, evaluated the effect of changes in the chemical composition of cement on the hydration reaction for carbon neutrality. For this purpose, changes in the chemical bound water and heat of hydration between current cement and past cement were compared. As a result, it was found that both the chemically bound water and heat of hydration of currently used cement decreased.

• 한국세라믹학회지
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• 제36권1호
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• pp.77-81
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• 1999

분말도가 포틀랜드 시멘트의 물성에 미치는 영향을 알아보기 위하여, 서로 다른 분말도(2300, 2500, 3000, 3500, 3500, 4500 $\textrm{cm}^2$/g)를 갖는 5종의 일반 포틀랜드 시멘트를 제조하여, Ca(OH)2 분석, 수화열, 유동성 및 물성 측정을 하였다. 그 결과, 시멘트의 분말도가 낮아짐에 따라 수화속도는 늦어졌고 수화열 및 압축강도는 떨어졌으나 유동성은 개선되었다. 특히 2300$\textrm{cm}^2$/g 시멘트의 경우, 수화열은 3500$\textrm{cm}^2$/g 시멘트에 비교해서 약 15% 감소하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 추계 학술논문 발표대회
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• pp.28-29
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• 2013

When concrete was hardened, it should had considered a crack to make internal stress by hydration heat. For control of crack, admixture was use to change cement because hydration heat was effect to cement. High strength mass concrete had much hydration heat with high volume of cement. It was necessary to reduce hydration heat in construction method. In this study, it evaluates hydration heat, compressive strength of transfer concrete girder regard to field construction type such as separation, whole etc. Also, we test compressive strength of concrete with core and mold specimen.

• 한국세라믹학회지
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• 제30권11호
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• pp.967-973
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• 1993

The effect on the hydration of cement was that Cu and Pb reacted with alkali to form soluble hydrates at theinitial stage and then there followed a slow reaction forming insoluble metal hydroxides. These hydroxides were deposited on the surface of cement particles providing a barrier against further hydration. But as a slow reaction continued, the insoluble layers were eventually destroyed and the hydration reaction resumed. Thereafter, another retardation occured by restricting the polymerization of silicates, shown by FT-IR spectroscopy analysis. In the case of Cr, as its reaction with cement caused H2O, the coordinator of Cr complex, to replace or polymerize with OH-, the formation of Cr complex promoted the leakage of OH- and increased the heat of dissolution. So the total heat evolution during hydration was larger than that in the case of Pb or Cu. The retarding effect of heavy metal ions was in the order Pb>Cu>Cr.

• 한국세라믹학회지
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• 제37권1호
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• pp.70-76
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• 2000

In order to investigate the properties of the blended cement using coarsely ground blasturnace slag blended coements which were substituted from 10 to 70 wt% low Blaine slag powder (2,000 and 3,000 cm2/g) for porland cement clinker were prepared and Cal(OH)2 contents in hydrates hydration heat the fluidity and the compressive strength were measured. As the content of slag was increased the hydration heat and the early strength was decreased and the fluidity of the cement paste was improved. The heat evolution of the cement with 2,000cm2/g slag was lower than that of 3,000 cm2/g slag blended cement. Especially the heat evolution of 60wt% or above slag blended cement was similar to that of belite rich cement.

• Computers and Concrete
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• 제32권1호
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• pp.45-60
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• 2023

Concrete in water environment is easily subjected to the attack of leaching, which causes its mechanical reduction and durability deterioration, and the key to improving the leaching resistance of concrete is to increase the compaction of its microstructure formed by the curing. This paper performs a numerical investigation on the intrinsic relationship between microstructures formed by the hydration of cement and slag and leaching resistance of concrete in water environment. Firstly, a shrinking-core hydration model of blended cement and slag is presented, in which the interaction of hydration process of cement and slag is considered and the microstructure composition is characterized by the hydration products, solution composition and pore structure. Secondly, based on Fick's law and mass conservation law, a leaching model of hardened paste is proposed, in which the multi-species ionic diffusion equation and modified Gérard model are established, and the model is numerically solved by applying the finite difference method. Finally, two models are combined by microstructure composition to form an integrated curing-leaching model, and it is used to investigate the relationship between microstructure composition and leaching resistance of slag-blended cement pastes.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.25-28
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• 2006

This study investigated pre-mixed cement combined with ordinary portland cement, BF and SF, in order to manufacture cement binder, which is possible to produce 150MPa ultra high strength concrete. The BF used in this study reduces and control hydration heat. It can also improve concrete fluidity, while AP increases hydration product and accelerates reaction of BF. SF has micro filler effect and makes pozzolanic reaction. It also fabricates high density internal organization. This developed pre-mixed cement can reduce hydration heat and increase hydration product. It is possible to fabricate high density organization and to secure homogeneity. The mock-up test of ultra high strength concrete showed excellent dispersibility and workability and indicated compressive strength more than 150MPa at 28 days.

• 한국세라믹학회지
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• 제43권9호
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• pp.537-543
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• 2006

Length change, hydration heat, setting time and compressive strength of OPC were measured by adding KCl and replacing limestone powder so as to examine the influence of limestone powder on hydration of the OPC contained much chloride. In general, the chloride modified cement was high in heat of hydration, short in its setting time, low in its fluidity and low in its strength at 28 days due to the sudden hydration in its initial stage. As a result of the experiment, it has been demonstrated that heat of hydration, became low as one replaced limestone powder to the chloride modified cement, and the fluidity and shrinkage rate of mortar decreased without change in setting time; furthermore, the compressive strength at 28 days was improved.

• Journal of Ceramic Processing Research
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• 제21권6호
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• pp.622-631
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• 2020

Fly ash is an industry by-product of thermal power factories that is broadly utilized in the concrete industry. This research shows a framework for evaluating the hydration heat, reaction amount, and strength progress of cement-fly ash binary composite. First, we conducted an experiment to study the isothermal hydration heat of fly ash composite paste with assorted fly ash contents and temperatures. According to the experimental outcomes of cumulative hydration heat, the coefficients of a kinetic reaction model of fly ash were determined. Furthermore, the reaction amount of fly ash was calculated using a fly ash reaction model. We discovered that the reaction of fly ash is considerably improved at elevated temperatures. The reaction amount of fly ash decreases with the growing content of fly ash. Second, in line with the reaction amount of fly ash and cement, we developed a straight-line equation for evaluating the strength progress of binary composite. The strength progress model applies to a number of water-to-binder ratios and fly ash substitution ratios. Summarily, the suggested hydration-heat-strength model is helpful for understanding the material style of fly ash concrete.