Journal of the Korea Concrete Institute (콘크리트학회논문집)

Korea Concrete Institute (한국콘크리트학회)
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Characteristics of Pore Structures and Compressive Strength in Calcium Leached Concrete Specimens

칼슘이 용출된 콘크리트의 공극 구조 및 강도 특성

  • Yang, Eun-Ik (Dept. of Civil Engineering, Gangneung-Wonju National University) ;
  • Choi, Yoon-Suk (Dept. of Civil Engineering, Gangneung-Wonju National University)
  • 양은익 (강릉원주대학교 토목공학과) ;
  • 최윤석 (강릉원주대학교 토목공학과)
  • Received : 2011.05.16
  • Accepted : 2011.08.12
  • Published : 2011.10.31
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Abstract

In radioactive waste repositories constructed in underground, concrete member could be in contact with groundwater for a long time. However, this pure water creates concentration gradients which lead to the diffusion of Ca ions from the pore water and the degradation of underground concrete. Therefore, this study is aimed at investigating the alteration of pore structure and loss of compressive strength associated with dissolution. The results showed that as the leaching period became longer, the pore volume within 50 nm to 500 nm in diameter is greatly increased. Also, the volume of pores larger than 200 nm rapidly increased during initial leaching time and those below 200 nm gradually increased. Furthermore, the compressive strength gradually decreased with increase of degraded thickness. The residual strength of the degraded concrete with OPC was in the range of 33% to 58%.

방사성 폐기물 처분 시설과 같은 지하 구조물의 콘크리트 부재가 장기간에 걸쳐 지하수(이온교환수)와 접촉하면 이온교환수와 공극수 사이에 농도구배가 발생한다. 이로 인해 공극수로부터 칼슘이온이 용출되고, 콘크리트의 열화가 진행된다. 따라서 이 연구에서는 콘크리트의 칼슘 용출에 의한 내부공극 구조의 변화를 분석하고, 열화된 콘크리트의 강도 특성을 평가하고자 하였다. 연구 결과, 콘크리트의 칼슘이온이 용출됨에 따라 50~500 nm 크기의 공극들이 상당히 증가하게 되며, 용출 초기에는 200 nm 크기 이상의 공극들이 급격히 증가하고 이후에는 200 nm 크기 이하의 공극들이 증가하는 것으로 나타났다. 칼슘이 용출된 두께가 증가함과 더불어 압축강도는 감소하였으며, 칼슘이 용출된 OPC 콘크리트의 잔류강도는 대략 33~58% 정도로 나타났다.

Keywords

References

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  2. Leaching Behavior of Hardened Cement Paste with Mineral Admixtures in Deionized Water vol.48, pp.1, 2019, https://doi.org/10.1520/JTE20180241