[ Building Structures and Materials ]
Journal of Asian Architecture and Building Engineering - Vol. 15, No. 3, pp.581-588
ISSN: 1346-7581 (Print) 1347-2852 (Online)
Print publication date 30 Sep 2016
Received 01 Oct 2015 Accepted 11 Jul 2016
DOI: https://doi.org/10.3130/jaabe.15.581

Fire Behavior of Full-Scale CFRP-Strengthened RC Beams Protected with Different Insulation Systems

Kun Dong1 ; Kexu Hu*, 2 ; Wanyang Gao3
1Ph.D. Candidate, Research Institute of Structural Engineering and Disaster Reduction, Tongji University China
2Professor, Research Institute of Structural Engineering and Disaster Reduction, Tongji University China
3Postdoctoral Fellow, Department of Civil and Environmental Engineering, Hong Kong Polytechnic University China

Correspondence to: *Kexu Hu, Professor, Research Institute of Structural Engineering and Disaster Reduction, Tongji University, 1239 Siping Road, Shanghai, China Tel: +86-021-65986236 E-mail: kexuhu@tongji.edu.cn


In this paper, a series of experimental studies conducted to investigate the fire behavior of insulated full-scale carbon-fiber-reinforced polymers (CFRP)-strengthened reinforced concrete (RC) beams is presented. Four CFRP-strengthened RC beams, respectively insulated with a thick coating system, ultrathin coating system and calcium silicate board system, were tested under ISO834 standard fire exposure. The test results revealed that satisfactory fire endurance for CFRP-strengthened concrete beams can be obtained with the protection of the three systems. The major role of fire insulation materials is to delay the failure of adhesive in the early stage and reduce the performance degradation of concrete and internal reinforced bars after the bond failure of the CFRP–concrete interface. In addition, it was indicated that effective anchorages of CFRP and reasonable anchoring constructions of the insulation system played important roles in ensuring the fire-resistant capability of CFRP-strengthened concrete beams. Further, a detailed finite element model was developed as an alternative to the standard fire test. The predicted temperature and deflection results were in good agreement with the measured ones. Based on the case studies, insulation thickness, insulation thermal conductivity, CFRP amount and load ratio were proven to be the main influences of the fire resistance of insulated CFRP-strengthened beams.


RC beams, CFRP-strengthened, fire protection; fire test, numerical model


  • ACI Committee 440. (2008). Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures. Farmington Hills, MI, USA: American Concrete Institute.
  • Arioz, O. (2007). Effects of elevated temperatures on properties of concrete. Fire Safety Journal, 42(8), pp.516-522.
  • Ahmed, A., & Kodur, V. (2010). Performance of FRP-strengthened reinforced concrete beams under design fire exposure. In Structures in Fire: Proceedings of the Sixth International Conference (p. 328). DEStech Publications, Inc.
  • Ahmed, A., & Kodur, V. (2011a). The experimental behavior of FRP-strengthened RC beams subjected to design fire exposure. Engineering Structures, 33(7), pp.2201-2211.
  • Ahmed, A., & Kodur, V. K. R. (2011b). Effect of bond degradation on fire resistance of FRP-strengthened reinforced concrete beams. Composites Part B: Engineering, 42(2), pp.226-237.
  • Bakis, C., Bank, L. C., Brown, V., Cosenza, E., Davalos, J. F., Lesko, J. J. & Triantafillou, T. C. (2002). Fiber-reinforced polymer composites for construction-state-of-the-art review. Journal of Composites for Construction, 6(2), pp.73-87.
  • Blontrock, H., Taerwe, L., & Vandevelde, P. (2000). Fire tests on concrete beams strengthened with fibre composite laminates. In Proceedings of the International PhD Symposium in Civil Engineering, Vienna (Austria), 5-7 October 2000/ed. Konrad Bergmeister. -Volume 2, pp.151-161.
  • Bisby, L. A., Green, M. F., & Kodur, V. K. R. (2005). Modeling the behavior of fiber reinforced polymer-confined concrete columns exposed to fire. Journal of Composites for Construction. 9(1), pp.15-24.
  • Chowdhury, E. U., Bisby, L. A., Green, M. F., & Kodur, V. K. (2008). Residual behavior of fire-exposed reinforced concrete beams prestrengthened in flexure with fiber-reinforced polymer sheets. Journal of Composites for Construction. 12 (1), pp.61-68.
  • Chowdhury, E. U., Eedson, R., Bisby, L. A., Green, M., & Bénichou, N. (2011). Mechanical Characterization of FRP Materials at High Temperature. Fire Technology, 47(4): 063-1080.
  • Chowdhury, E., Bisby, L., Green, M., Bénichou, N., & Kodur, V. (2012). Heat transfer and structural response modelling of FRP confined rectangular concrete columns in fire. Construction and Building Materials, 32, pp.77-89.
  • Cooke G M E. (1988). An introduction to the mechanical properties of structural steel at elevated temperatures. Fire Safety Journal, 13(1), pp.45-54.
  • Dai, J. G., Gao, W. Y., & Teng, J. G. (2014). Finite element modeling of insulated FRP-strengthened RC beams exposed to fire. Journal of Composites for Construction, 19(2), 04014046.
  • Deuring, M. (1994). Fire tests on strengthened reinforced concrete beams. Research Rep. No. 148'795, Swiss Federal Laboratories for Materials Testing and Research, Dubendorf, Switzerland.
  • Firmo, J. P., Correia, J. R., & França, P. (2012). Fire behavior of reinforced concrete beams strengthened with CFRP laminates: Protection systems with insulation of the anchorage zones. Composites: Part B, Vol. 43, No. 3, pp.1545-1556.
  • Gamage, J. C. P. H., Wong, M. B., & Al-Mahaidi, R. (2005). Performance of CFRP strengthened concrete members under elevated temperatures. In Proceedings of the international symposium on bond behavior of FRP in structures, pp.7-9.
  • Griffis, C. A., Masumura, R. A., & Chang, C. I. (1981). Thermal response of graphite epoxy composite subjected to rapid heating. Journal of Composite Materials, 15(5), pp.427-442.
  • Hawileh, R. A., Naser, M., Zaidan, W., & Rasheed, H. A. (2009). Modeling of insulated CFRP-strengthened reinforced concrete T-beam exposed to fire. Engineering Structures,31(12), pp.3072-3079.
  • Hu, K., He, G., & Lu, F. (2007). Experimental study on fire protection methods of reinforced concrete beams strengthened with carbon fiber reinforced polymer. Frontiers of Architecture and Civil Engineering in China, 1(4), pp.399-404.
  • Kankanamge N D, Mahendran M. (2011). Mechanical properties of cold-formed steels at elevated temperatures. Thin-Walled Structures, 49(49), pp.26-44.
  • Kodur, V. K. R., Bisby, L. A., & Green, M. F. (2006). Experimental evaluation of the fire behaviour of insulated FRP-strengthened reinforced concrete columns. Fire Safety Journal, 41(7), pp.547-557.
  • Lie, T. T., & Irwin, R. J. (1990). Evaluation of the fire resistance of reinforced concrete columns with rectangular cross-sections. Canada: NRC Publications Archive.
  • Mouritz, A. P., & Gibson, A. G. (2007). Fire properties of polymer composite materials. Springer Science & Business Media.
  • Netinger, I., Kesegic, I., & Guljas, I. (2011). The effect of high temperatures on the mechanical properties of concrete made with different types of aggregates. Fire safety journal, 46(7), pp.425-430.
  • Schaffer, E. L. (1992). Structural fire protection. New York: American Society of Civil Engineers.
  • Williams, B. (2004). Fire performance of FRP-strengthened reinforced concrete flexural members. Ph.D. thesis, Queen's University, Kingston, ON, Canada.
  • Williams, B., Bisby, L., Kodur, V., Green, M., & Chowdhury, E. (2006). Fire insulation schemes for FRP-strengthened concrete slabs. Composites Part A: Applied Science and Manufacturing, 37(8), pp.1151-1160.
  • Williams, B., Kodur, V., Green, M. F., & Bisby, L. (2008). Fire endurance of fiber-reinforced polymer strengthened concrete T-beams. ACI structural Journal, 105(1): 60-67.