Journal of the Korean Recycled Construction Resources Institute (한국건설순환자원학회논문집)

Korean Recycled Construction Resources Institute (한국건설순환자원학회)
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Resistance to Chloride Attack of FRP Hybrid Bar After Freezing and Thawing Action

동결융해 이후의 FRP Hybrid Bar의 부식 저항성

  • Ryu, Hwa-Sung (Hanyang Experiment and Consulting, Hanyang University ERICA) ;
  • Park, Ki-Tae (Korea Institute of Civil engineering and building Technology) ;
  • Yoon, Yong-Sik (Department of Civil Engineering, Hannam University) ;
  • Kwon, Seung-Jun (Department of Civil Engineering, Hannam University)
  • 류화성 (한양 E&C) ;
  • 박기태 (한국건설기술연구원 구조융합연구소) ;
  • 윤용식 (한남대학교 건설시스템공학과) ;
  • 권성준 (한남대학교 건설시스템공학과)
  • Received : 2018.02.14
  • Accepted : 2018.03.20
  • Published : 2018.03.30
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Abstract

RC(Reinforced Concrete) structures are exposed to various exterior conditions, and the performances of both chloride resistance and freezing/thawing action are evaluated for those exposed to corrosive environment-sea shore. Recently developed FRP Hybrid Bars which is coated with glass fiber and epoxy with core steel has an engineering advantage of higher Elasticity than FRP rod. In this work, corrosion resistance, weight loss, and bond strength are evaluated for the FRP Hybrid Bar tested through freezing/thawing action for 300cycles. The double coated FRP Hybrid Bar shows the least weight loss without defection due to freezing/thawing action. Bond strength in FRP Hybrid Bar increases to 120% of normal steel through torturity effect with Si-coating. Bond strength in normal steel shows 0.86~0.89times in 3-day corrosion acceleration and 0.35~0.38times in 5-day corrosion acceleration, however, that in FRP Hybrid Bar shows little changes in bond strength before and after freezing/thawing action.

콘크리트 구조물은 다양한 환경에 노출되며, 부식환경인 해안가에서는 매립 보강재의 부식저항성 및 동결융해 저항성이 함께 평가되어야 한다. 최근 개발된 FRP Hybrid Bar는 내부에 강재가 있으며 유리섬유와 에폭시가 코팅된 보강재인데, 기존 FRP Bar보다 탄성계수가 높은 장점이 있다. 본 연구에서는 FRP Hybrid Bar에 대하여 동결융해 300 cycle 시험을 수행한 뒤, 내부식특성과 중량결손율, 및 부착특성을 평가하였다. 300 cycle 이후 2번 에폭시를 코팅한 경우에 규사의 손실이 가장 적었으며, 외관의 결함이 관측되지 않았다. 부착강도는 규사코팅에 따른 조도의 증가로 FRP Hybrid Bar의 경우 일반철근의 120 % 수준을 나타내었다. 또한 일반철근을 가진 시편의 부착력은 부식시간 3일에서는 0.86 ~ 0.89 배, 5일에서는 0.35~0.38 배로 크게 감소하였으나, 동결융해 전후의 FRP Hybrid Bar를 가진 콘크리트 공시체는 부착강도의 감소가 발생하지 않았다.

Keywords

References

  1. ACI 440.1R-06. (2006). Guide for the Design and Construction of Structural Concrete Reinforce with FRP Bars, ACI Committee 440.
  2. American Concrete Institute(ACI) Committee-201. (2008). Guide to Durable Concrete ACI 201R-08; American Concrete Institute(ACI): Detroit, MI, USA.
  3. Baek, S.H., William, X., Maria, Q.F., Kwon, S.J. (2012). Nondestructive corrosion detection in RC through integrated heat induction and IR thermography, Journal of Nondestructive Evaluation, 31, 181-190. https://doi.org/10.1007/s10921-012-0133-0
  4. Bautista, A., Gonzalez, J.A. (1996). Analysis of the protective efficiency of galvanizing against corrosion of reinforcements embedded in chloride contaminated concrete, Cement and Concrete Research, 26(2), 215-224. https://doi.org/10.1016/0008-8846(95)00215-4
  5. Broomfield, J.P. (1997). Corrosion of Steel in Concrete:Understanding, Investigation and Repair, E&FN, London, 1-15.
  6. Choi, S.J., Mun, J.M., Park, K.T., Park, C.W., Kwon, S.J. (2015). Characteristics of flexural capacity and ultrasonic in RC member with corroded steel and FRP hybrid bar, The Journal of the Korea Contents Association, 15(8), 397-407 [in Korean]. https://doi.org/10.5392/JKCA.2015.15.08.397
  7. Choi, Y.S., Won, M.S., Yi, S.T., Yang, E.I. (2012). Characteristics of pore structure and chloride penetration resistance of concrete exposed to freezing-thawing, Journal of the Korea Institute for Structural Maintenance and Inspection, 16(6), 73-81 [in Korean]. https://doi.org/10.11112/jksmi.2012.16.6.073
  8. Chung, L., Jay kim, J.H., Yi, S.T. (2008). Bond strength prediction for reinforced concrete members with highly corroded reinforcing bars, Cement and Concrete Composites, 30(7), 603-611. https://doi.org/10.1016/j.cemconcomp.2008.03.006
  9. European Committee for Standardization(Comite Europeen de Normalisation, CEN). (2000). Eurocode 1: Basis of Design and Actions on Structures; EN-1991; European Committee for Standardization(Comite Europeen de Normalization, CEN): Brussels, Belgium.
  10. Hakan, Y., Ozgur, E., Serhan, S. (2012). An experimental study on the bond strength between reinforcement bars and concrete as a function of concrete cover, strength and corrosion level, Cement and Concrete Research, 42(5), 643-655. https://doi.org/10.1016/j.cemconres.2012.01.003
  11. Hwang, C.S., Park, J.S., Park, K.T., Kwon, S.J. (2017). Mechanical performance evaluation of RC beams with FRP hybrid bars under cyclic loads, Journal of the Korea Institute for Structural Maintenance and Inspection, 21(1), 9-14 [in Korean].
  12. Japan Society of Civil Engineering(JSCE). (2007). Standard Specification for Concrete Structures-Design JSCE Guidelines for Concrete 15; Japan Society of Civil Engineering(JSCE): Tokyo, Japan.
  13. KICT. (2013). Development of Enhancing Life Span Technology for Waterfront Structures using FRP Hybrid Bars.
  14. Mehta, P.K., Monterio J.M. (1993). Concrete; Structure, Properties, and Materials, Prentice-Hall Inc., Englewood Cliffs, New Jersey.
  15. Oh, B.H., Um, J.Y., Kwon, J.H. (1992). An experimental study on corrosion resistance of epoxy coated reinforcements, Journal of the Korea Concrete Institute, 4(4), 161-170 [in Korean].
  16. Oh, K.S., Moon, J.M., Park, K.T., Kwon, S.J. (2016). Evaluation of load capacity reduction in RC beam with corroded FRP hybrid bar and steel, Journal of the Korea Institute for Structural Maintenance and Inspection, 20(2), 10-17 [in Korean]. https://doi.org/10.11112/JKSMI.2016.20.2.010
  17. Oh, K.S., Park, K.T., Kwon, S.J. (2016). Evaluation of Anti-corrosion performance of FRP hybrid bar with notch in GGBFS concrete, Journal of the Korea Institute for Structural Maintenance and Inspection, 20(4), 51-58 [in Korean]. https://doi.org/10.11112/jksmi.2016.20.4.051
  18. Seo, D.W., Park, K.T., You, Y.J., Kim, H.Y. (2013). Enhancement in elastic modulus of GFRP bars by material hybridization, Engineering, 5, 865-869. https://doi.org/10.4236/eng.2013.511105
  19. Shin, S.W., Ahn, J.M., Han, B.S., Seo, D.W. (2006). Effects of reinforcement ratio on concrete beams reinforced with FRP re-bars, Journal of the Architectural Institute of Korea, 22(2), 19-26 [in Korean].
  20. Song, H.W., Back, S.J., Lee, C.H., Kwon, S.J. (2006). Service life prediction of concrete structures under marine environment considering coupled deterioration, Restoration of Buildings and Monuments, 12(4), 265-284.
  21. Yoon, Y.S., Park, J.S., Park, K.T., Kwon, S.J. (2017). Evaluation of tension behavior in FRP hybrid bar affected by UV exposure and freezing/thawing tests, Journal of the Korean Recycled Construction Resources Institute, 5(2), 130-136 [in Korean]. https://doi.org/10.14190/JRCR.2017.5.2.130