Journal of the Korean Recycled Construction Resources Institute (한국건설순환자원학회논문집)

Korean Recycled Construction Resources Institute (한국건설순환자원학회)
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The Effect of Electrochemical Treatment in Lowering Alkali Leaching from Cement Paste to an Aquatic Environment: Part 2- Microscopic Observation

전기화학적 기법을 통한 시멘트페이스트의 수중노출에 따른 알칼리이온 침출저감 효과: Part 2- 미세구조 분석

  • Bum-Hee Youn (Department of Civil & Environment Engineering, Hanyang University) ;
  • Ki-Yong Ann (Department of Civil & Environment Engineering, Hanyang University)
  • 윤범희 (한양대학교 건설환경공학과) ;
  • 안기용 (한양대학교 건설환경공학과)
  • Received : 2023.04.25
  • Accepted : 2023.05.15
  • Published : 2023.06.30
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Abstract

In this study, microscopic observation was made on the surface of cement paste immersed in an aquatic environment for 100 days at electrochemical treatment to mitigate the leaching of alkali ions. To quantitatively rank the hydration products, unhydrated grains and porosity in the interfacial region, the backscattered electron(BSE) images were obtained by scanninng electron microscopy. As a result, it was found that the porosity on the surface was significantly reduced by the electrochemical treatment, while unhydrated grains were more or less increased presumably limited hydration reaction under electric charge. At electrochemical treatment, Ca2+ ions present in C-S-H gel could be precipitated with OH- to form Ca(OH)2 then to lower C-S-H gel and simultaneously to enhance Ca(OH)2. Substantially, the risk of alkali leaching could be lowered by the limited ionized matrix under electrochemical treatment.

본 연구에서는 알칼리 이온의 침출을 완화하기 위해 전기화학적 처리로 100일 동안 수중 환경에 침지된 시멘트 페이스트의 표면을 현미경으로 관찰하였다. 계면 영역에서의 미수화물 입자와 공극률을 정량적으로 평가하기 위하여 주사 전자 현미경을 통해 후방 산란 전자(BSE) 이미지를 얻었다. 그 결과, 전기화학적 처리에 의해 표면부의 공극률이 크게 감소한 반면, 전하 상태에서 제한된 수화반응에 의해 미수화 입자는 다소 증가한 것으로 나타났다. 전기화학적 처리에서, C-S-H 겔에 존재하는 Ca2+ 이온은 공극수 내의 OH- 이온과 Ca(OH)2 형태로 침전되어 C-S-H 겔을 낮추면서 동시에 Ca(OH)2를 증대시킬 수 있다. 실질적으로 알칼리 침출에 대한 위험성은 전기화학적인 처리 하에서 제한된 이온화 매트릭스에 의해 감소될 수 있다.

Keywords

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