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Experimental Study on the Spalling Properties of Ultra High Strength Concrete containing Amorphous Metallic Fiber

비정질강섬유를 혼입한 초고강도콘크리트의 폭렬특성에 관한 실험적 연구

  • 최경철 (충남대학교 사회기반시설기술연구소) ;
  • 김규용 (충남대학교 건축공학과) ;
  • 김홍섭 (동경대학 대학원공학계연구과 건축재료연구실) ;
  • 황의철 (충남대학교 사회기반시설기술연구소) ;
  • 남정수 (충남대학교 건축공학과)
  • Received : 2019.02.27
  • Accepted : 2019.04.05
  • Published : 2019.05.01

Abstract

This study examined the effect of amorphous metallic (AM) fibers on the spalling properties of ultra high strength concrete. Six specimens with concrete strengths of 100 MPa and 150 MPa were evaluated with mix proportions of polypropylene (PP) fibers of 0.15% by concrete volume, and proportions of AM fibers of 0.3% and 0.5% by concrete volume. These specimens were then heated in accordance with the ISO-834 heating curve. The movement of water vapor through a pore network formed by molten PP fibers was found to be a dominant factor controlling the spalling of high-strength concrete. Spalling control was not found to be significantly affected by the addition of 0.3% AM fibers; however, when 0.5% AM fibers was added, cracking was limited and so were paths for water vapor migration, increasing the likelihood of a moisture clog and creating the differential internal pressure often blamed for concrete spalling.

본 연구에서는 비정질강섬유의 혼입이 초고강도콘크리트의 폭렬특성에 미치는 영향이 실험적으로 검토되었다. 콘크리트는 압축강도 100과 150 MPa의 초고강도콘크리트가 사용되었다. 폴리프로필렌섬유는 0.15 vol%, 비정질강섬유는 0.3 및 0.5 vol%가 혼입되었다. 시험체는 콘크리트의 압축강도와 섬유혼입 조건에 따라 6수준이 제작되었고, ISO-834 가열곡선에 의해 가열되었다. 결과로써 폴리프로필렌섬유와 비정질강섬유가 혼입된 초고강도콘크리트의 폭렬제어에 있어서는 용융된 폴리프로필렌섬유가 형성하는 공극네트워크를 통해 수증기가 이동하는 효과가 지배적인 것으로 나타났다. 또한, 비정질강섬유 0.3v ol% 혼입률에서는 폭렬제어에 큰 영향을 미치지 않지만, 0.5 vol%의 비정질강섬유가 혼입될 경우에는 수증기가 이동할 수 있는 균열의 발생이 억제됨으로써 콘크리트 폭렬의 원인으로 지적되고 있는 수분막힘층(moisture clog)가 형성될 가능성이 높은 것을 확인할 수 있었다.

Keywords

References

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