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A Study on the Application of FRP Hybrid Bar to Prevent Corrosion of Reinforcing Bar in Concrete Structure

콘크리트구조물 중의 철근 부식 저감을 위한 FRP Hybrid Bar의 적용성 연구

  • Lee, Seung-Tae (Department of Civil Engineering, Kunsan National University) ;
  • Park, Kwang-Pil (Department of Civil Engineering, Kunsan National University) ;
  • Park, Ki-Tae (Korea Institute of Construction Technology, Smart Cities Research Center) ;
  • You, Young-Jun (Korea Institute of Construction Technology, Smart Cities Research Center) ;
  • Seo, Dong-Woo (Korea Institute of Construction Technology, Smart Cities Research Center)
  • 이승태 (군산대학교 토목공학과) ;
  • 박광필 (군산대학교 토목공학과) ;
  • 박기태 (한국건설기술연구원 스마트시티연구센터) ;
  • 유영준 (한국건설기술연구원 스마트시티연구센터) ;
  • 서동우 (한국건설기술연구원 스마트시티연구센터)
  • Received : 2019.02.11
  • Accepted : 2019.05.03
  • Published : 2019.05.31

Abstract

Recently, the infrastructure of the marine environment has been increasing. Therefore, there has been increasing interest in increasing the durability of structures. The FRP Hybrid Bar with improved durability against corrosion was developed in recent years. On the other hand, studies that evaluate the corrosion resistance are insufficient. In this study, the corrosion resistance according to the type of rebar in concrete was assessed and analyzed. The experiment used steel bars and FRP Hybrid Bar. The corrosion test method was a galvanic current and half-cell potential method. The accelerated corrosion test was carried out by four levels (0%, 1.5%, 3%, and 6%) of chloride added to the concrete. The galvanic current measurements revealed no corrosion current in the FRP Hybrid Bar. The half-cell measurement also showed the corrosion resistance of the FRP Hybrid Bar. Therefore. FHB can be used as an alternative steel for structures where a marine environment and steel corrosion are predicted.

최근 해양환경의 대형 SOC구조물 증가에 따른 구조물 내구성 증진에 관심이 증가되고 있다. 내구성 증진을 위해 개발된 FRP Hybrid Bar의 구조적 성능은 검증 되었으나 부식에 대한 저항성을 평가한 연구는 미흡하여 본 연구를 수행 하였다. 본 연구에서는 콘크리트 중의 철근 종류에 따른 철근부식 저항성을 평가하였다. 평가를 위하여 철근은 일반철근과 FRP hybrid Bar을 사용하였다. 시험방법은 갈바닉전류(Galvanic)와 반전지법(Half-Cell)을 사용하였으며, 철근부식 촉진을 위하여 콘크리트 내부에 염분을 0%, 1.5%, 3%, 6% 첨가하였다. 그 결과 갈바닉전류측정에서 FRP Hybrid Bar는 부식전류가 측정되지 않았다. 반면 일반철근에서는 시험 직후 부식이 발생하는 결과를 나타내었다. Half-Cell측정 결과에서도 4단계의 염분 함유량의 차이와 광물질혼화재료를 사용한 콘크리트와 일반콘크리트에 관계없이 FRP Hybrid Bar의 부식 저항성이 우수하게 나타났다. 따라서 FRP Hybrid Bar는 해양환경 및 철근부식이 예측되는 구조물용 대체 철근으로 사용이 가능하나 부착성능, 탄성계수, 절곡부의 강선 노출에 대한 처리 방법 등이 개선되면 염해로부터 철근부식 저항성 확보를 요구하는 구조물에 사용 할 수 있는 우수한 소재로 판단된다.

Keywords

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Fig. 1. FHB Production Process

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Fig. 2. FFB Configuration

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Fig. 3. Types of bars used for Test

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Fig. 4. Galvanic corrosion current Composition

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Fig. 5. Half-Cell Test Concrete Specimen

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Fig. 6. Half-Cell Test Composition[14]

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Fig. 7. Galvanic currents of Steel and FHB(3.5% NaCl, 30days)

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Fig. 8. Galvanic currents of Fig. 7 ‘O’part(3.5% NaCl, 1day)

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Fig. 9. Galvanic Current Test(3.5% NaCl, 28d)

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Fig. 10. Steel Comparison of half-cell potential(Chloride 0%, 6%)

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Fig. 11. FHB Comparison of half-cell potential(Chloride 0%, 6%)

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Fig. 13. Comparison of half-cell potential by binder type

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Fig. 12. FHB & Steel Comparison of half-cellpotential (Chloride 6%)

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Fig. 14. Comparison of Half-cell Potential by binder type and type of rebar(Chloride content 6%)

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Fig. 15. Comparison of half-cell potential by Chloride content

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Fig. 16. Result of half-cell potential by Chloride content (OPC&SGC)

Table 1. Mix proportions of concrete

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Table 2. Corrosion condition related to half-cell potential[14]

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