초임계 탄산화 반응이 순환잔골재의 품질개선에 미치는 영향

국문 초록 (Abstract)

본 연구는 탄산화 메커니즘을 통해 공극을 채우는 방법으로, 온실가스인 CO₂를 영구히 고정화시키는 동시에, 탄산화 반응에 의해 순환골재 내부에 존재하는 균열 및 공극을 메워, 순환골재의 활용가능성을 높이기 위한 목적으로 진행되었다. 이를 위해 밀폐된 공간에 기체상의 CO₂와 scCO₂를 사용하여 순환잔골재를 반응시켰고, 겉보기 밀도 및 흡수율, 진밀도, pH, FE-SEM 측정 등을 활용해 탄산화 전 후 순환잔골재의 물성을 비교 분석하였다. 이후 탄산화 반응이 진행된 순환잔골재로 모르타르 시편을 제작하여 압축강도 실험을 수행하였다. 실험 결과에 따르면, 고온ㆍ고압으로 진행된 scCO₂와의 반응이 기체상의 CO₂와의 반응에 비해, 겉보기 밀도 및 진밀도의 증가폭이 높은 것으로 나타났다. 또한 용출수의 pH는 기체상의 CO₂보다 초기에 감소하는 폭이 큰 것으로 나타났고, 탄산칼슘 결정의 생성량과 결정형태가 기체상의 CO₂와 반응하는 것에 비해 큰 것으로 나타났다. 압축강도의 상승 폭 또한 scCO₂와 반응한 순환잔골재를 활용한 모르타르에서 가장 크게 나타나, 기체상의 CO₂보다 scCO₂에 의한 품질개선 가능성이 더욱 큰 것을 확인하였다

다국어 초록 (Multilingual Abstract)

The objective of this work is to prove a possibility o f void filling through a carbonation for the purpose of improving the quality of recycled aggregate. Carbonation can permanently immobilize CO₂, which is a greenhouse gas, and thus provides additional benefit on environment. In this work, recycled fine aggregate was reacted using gaseous CO₂ and supercritical CO₂(scCO₂) in a closed chamber, and the changes in physical properties of the recycled fine aggregate before and after carbonation were analyzed using the apparent density, skeletal density, pH, and FE-SEM measurements. Thereafter, a mortar specimen was prepared and a compressive strength was measured. According to the experimental results, it was found that the increase in the apparent density and the true density was higher by the reaction with scCO₂, which was conducted at high temperature and high pressure compared to the reaction with gaseous CO₂. In addition, the pH of the eluted water was found to have a larger initial decrease than that observed with samples from reaction by gaseous CO₂. The shape and amount of calcium carbonate crystals were also found to be larger than that from gaseous CO₂. The increase in compressive strength was the largest when using recycled fine aggregate reacted with scCO₂. It was clear that quality improvement of recycled fine aggregate was higher with scCO₂ than with gaseous CO₂.

목차 (Table of Contents)

• 1. 서론
• 2. 실험계획 및 방법
• 3. 실험결과
• 4. 결론
• References

참고문헌 (Reference)

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