• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 봄 학술논문 발표대회
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• pp.91-92
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• 2022

This study is a basic study on carbonation curing technology of concrete using supercritical CO₂, and carbonation curing was carried out by exposing concrete to supercritical CO₂ for a certain period of time. In the case of conventional carbonation curing, long-term curing was performed for several weeks by controlling the concentration of CO₂, but by using supercritical CO₂, more rapid carbonation curing was carried out using constant temperature and pressure conditions to improve durability through surface modification of concrete. This experiment was conducted with the goal of deriving the optimal carbonation curing conditions by measuring the carbonation depth by exposing concrete for a certain period of time to conditions above the supercritical level. As a result, it was confirmed that the carbonation depth increased as the curing time increased, and the curing time could be shortened compared to the carbonation curing according to the existing CO₂ concentration.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.27-28
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• 2022

In this study, the mechanical properties of resource-recycling concrete containing concrete sludge waste as main materials was compared depending on whether supercritical CO2 curing was applied for the realization of CCU technology. After supercritical CO2 curing, the compressive strength of the steam-cured specimen was lowered, but it was confirmed that the compressive strength of the underwater-cured specimen was improved.

• Journal of the Korean Wood Science and Technology
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• 제28권4호
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• pp.41-50
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• 2000

Cement-bonded particleboard is being used as outdoor siding material all over the world, because this composite particularly bears a light weight, high resistance against fire, decay, and crack by cyclic freezing and thawing, anti-shock property, and strength enhancement. Construction systems are currently changing into a frame-building style and wooden houses are being constructed with prefabrication type. Therefore, they require a more durability at outdoor-exposed sides. In this study, the cement hydration property for Korean pine particle, Japanese larch particle and face- and middle layer particles (designated as PB particle below) used in Korean particleboard-manufacturing company was investigated, and the rapid manufacturing characteristics of cement-bonded particleboard by supercritical $CO_2$ curing was evaluated. Korean pine flour showed a good hydration property, however, larch flour showed a bad one. PB particle had a better hydration property than larch flour. The addition of $Na_2SiO_3$ indicated a negative effect on hydration, however, $MgCl_2$ had a positive one. Curing by supercritical $CO_2$ fluid gave a conspicuous enhancement in the performances of cement-bonded particleboards compared to conventional curing. $MgCl_2$ 3%-added PB particle had the highest properties, and $MgCl_2$ 1%-added Korean pine particle had the second class with the conditions of cement/wood ratio of 2.7, a small fraction-screened particle and supercritical curing. On the contrary, the composition of non-hammermilled or large fraction-screened particle at cement/wood ratio of 2.2 was poorer. Also, the feasibility for actual use of 3%-added, small PB particle-screened fraction was greatest of all the conventional curing treatments. Relative superiority of supercritical curing vs. conventional curing at dimensional stability was not so apparent as in strength properties. Through the thermogravimetric analysis, it was ascertained that the peak of a component $CaCO_3$ was highest, and the two weak peaks of calcium silicate hydrate and ettringite and $Ca(OH)_2$ were present in supercritical treatment. Accordingly, it was inferred that the increased formation of carbonates in board contributes to strength enhancement.

• 한국결정성장학회지
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• 제22권5호
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• pp.254-259
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• 2012

순환유동층 연소방식의 화력발전소에서 석탄을 연소시킨 후 발생하는 석탄재 중 탄산화 반응 인자인 Ca 성분을 다량 포함한 비산회를 시멘트에 일정량 치환하여 제조한 인공경량 경화체를 초임계상태에서 이산화탄소($CO_2$)를 고정화하여 골재의 기계적 물성향상을 도모하였다. 초임계 분위기 $40^{\circ}C$ 조건에서 비산회의 치환량을 변화시켜 재령일수별 탄산화를 시행하였다. 비산회 치환량에 따른 탄산화 반응시킨 인공경량골재 경화체의 무게변화율, TG/DTA 분석, 1 % 페놀프탈레인 알칼리성 측정을 통하여 탄산화 진행여부를 확인하였으며 28일까지의 재령 이후 경화체의 압축강도 측정과 비중측정을 통하여 골재의 기계적 물성향상과 인공경량골재의 기준 비중치인 2.0 이하의 비중값을 갖는 탄소고정 인공경량골재 경화체를 얻는 것이 가능할 것으로 판단되었다.

• 한국세라믹학회지
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• 제53권3호
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• pp.354-361
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• 2016

The purpose of this study was to prepare lightweight foamed concrete by mixing coal fly ash of circulating fluidized bed combustion(CFBC) with cement, and to develop uses for recycling by analyzing carbonation behavior resulting from a change in conditions for pressurized carbonation. For concrete, CFBC coal fly ash was mixed with Portland cement to the water-binder ratio of 0.5, and aging was applied at room temperature after 3 days of curing at $20^{\circ}C$, RH 60%. For carbonation, temperature was fixed at $60^{\circ}C$ and time at 1 h in the use of autoclave. Pressures were controlled to be $5kgf/cm^2$ and the supercritical condition of $80kgf/cm^2$, and gas compositions were employed as $CO_2$ 100% and $CO_2$ 15%+N2 85%. In the characteristics of produced lightweight concrete, the characteristics of lightweight foamed concrete resulting from carbonation reaction were affirmed through rate of weight change, carbonation depth test, air permeability, and processing analysis for the day 28 specimen. Based on these results, it is concluded that the present approach could provide a viable method for mass production of eco-friendly lightweight foamed concrete from CFBC coal fly ash stabilized by carbonation.

• 폴리머
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• 제24권4호
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• pp.529-537
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• 2000

본 연구에서는 압출된 PP sheets를 각기 다른 조사량으로 조사 가교시켜, 겔 분율 차이에 따른 세 종류의 샘플을 만든 다음, 회분식 공정을 통해 초임계 유체 (supercritical fluid) 상태의 $CO_2$를 발포제로 사용하여 발포시켰다. 이때, 겔 분율의 차이 및 고압 반응기 내에서 충진 압력과 충진 시간이 셀 구조에 미치는 영향을 관찰하였다. 다음으로, 발포조건에 따른 셀 구조 변화를 알아보기 위해 발포온도와 발포시간을 변화시키면서 실험하였다. 고분자 샘플 내로 침투한 가스의 양은 겔 분율의 차이에 의한 변화가 거의 없었으며, 충진 압력이 2000 psi 이상일 경우 충진 압력의 영향에도 큰 영향을 받지 않았다. 겔 분율이 낮은 샘플은 발포온도나, 발포시간이 증가함에 따라 셀 크기가 불균일하게 증가하였으나, 겔 분율이 높은 샘플은 높은 발포온도와 발포시간에서도 균일하게 셀 크기를 유지하며 안정한 구조를 나타내었다.