Journal of the Korea institute for structural maintenance and inspection (한국구조물진단유지관리공학회 논문집)

Korea Institute for Structural Maintenance Inspection (한국구조물진단유지관리공학회)
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Durability of GFRP Rebar with Ribs Containing Milled Alkaline Resistant Glass Fibers

알카리저항 초단유리섬유를 리브에 사용한 유리섬유 보강근의 내구성능

  • 문도영 (경성대학교 토목공학과) ;
  • 오홍섭 (경남과학기술대학교 토목공학과)
  • Received : 2010.07.13
  • Accepted : 2010.12.03
  • Published : 2011.01.30
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Abstract

GFRP rebars could be deteriorated by concrete alkalinity. This paper focuses on the investigation of durability of GFRP rebars with ribs exposed to alkaline environment of concrete. It has been reported that the milled E-glass fibers in the ribs of GFRP rebar can increase bond strength between GFRP rebars and the concrete. In this study, the effect of milled alkaline resistant glass fibers (milled AR glass) and milled E-glass in the ribs on the durability of GFRP rebar is investigated through ISS tests and moist absorption tests of the bare rebar. To accelerate the effect of the alkalinity, high temperature($40^{\circ}C$) was applied. According to the test results, mix ratio of milled glass fibers in the ribs by weight had significant effect on durability of GFRP rebars with ribs. It is because that the high mix ratio may leads more voids in the ribs due to lower workability and formability. On the other hand, changing fiber type in the ribs from E-glass to AR-glass had no improvements on ISS strength of the GFRP rebar. Therefore, it is found that determination of proper mix ratio of milled glass fiber in the mixture for the formation of the ribs of the GFRP rebar is important.

GFRP 보강근은 콘크리트의 알칼리성분에 의해 손상 받을 수 있다. 본 논문은 이형 GFRP 보강근의 알칼리에 대한 내구성을 증진시키기 위한 방법에 대한 실험적 연구이다. 기존 개발된 이형 GFRP 보강근의 표면물질에 삽입되는 초단유리섬유는 콘크리트와의 부착성능을 향상시키는 것으로 알려져 있다. 본 논문에서는 초단 알칼리저항섬유(AR-glass)와 E-glass 섬유를 표면이형의 구성물질로 활용하였을 때, 보강근의 내구성능에 미치는 영향을 흡습시험과 ISS 실험을 통하여 규명하고자 하였다. 혹독한 실내실험조건을 위하여 $40^{\circ}C$의 온도가 적용되었다. 실험결과, 표면성형을 위한 레진과의 합성물로써, E-glass와 AR-glass를 사용하였을 때, 내구성능에 큰 차이는 없는 것을 확인하였다. 오히려, 레진과 섬유의 혼합비가 작업성과 성형성에 영향을 미치고, 이것이 표면 이형부에 공극을 만들게 됨으로써, 큰 영향을 미치는 것으로 나타났다. 따라서, 장기적인 내구성능 확보를 위해서 혼입률의 결정에 주의를 기울여야 한다.

Keywords

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