Bond Behaviour of GFRP Bars with Concrete at Normal and High Temperatures


Jahanzaib J., Sheikh S. A., Kharal Z., Almansour H.

10th International Conference on Fibre-Reinforced Polymer (FRP) Composites in Civil Engineering (CICE), İstanbul, Turkey, 8 - 10 December 2021, vol.198, pp.275-286 identifier identifier

  • Publication Type: Conference Paper / Full Text
  • Volume: 198
  • Doi Number: 10.1007/978-3-030-88166-5_23
  • City: İstanbul
  • Country: Turkey
  • Page Numbers: pp.275-286
  • Keywords: Thermal degradation, Bond strength, Pullout specimens, Beam bond strength, Climate change, REBARS
  • Istanbul Technical University Affiliated: No

Abstract

Bond strength of glass fibre reinforced polymer (GFRP) rebars after long-term thermal conditioning was experimentally investigated in this study. In this paper, the results of pullout specimens with 5db embedment length are presented which is part of a much larger study on the effects of climate change on FRP-reinforced concrete structures. Specimens were constructed with 16 mm nominal diameter sand coated GFRP bars and conditioned at 50 degrees C and 80 degrees C for 4 months to investigate the effects of long-term thermal exposure. Relative humidity of 60% was maintained while conditioning the specimens. Long-term thermal exposure induced significant reductions in the average bond stress values of the specimens. Specimens conditioned at 50 degrees C and 80 degrees C observed 10% and 23% reductions in strength, respectively. Overall, the GFRP bars performed reasonably well and the retained average bond stress for specimens treated at 80 degrees C was about 10.5 MPa which is still marginally greater than the minimum code specified limit of 8 MPa for design purposes. The 50 degrees C thermal treatment was designed to study the climate challenges of continuously increasing temperatures and 80 degrees C thermal exposure was devised to replicate the elevated service temperatures. Visual inspection revealed that GFRP bar's core had deteriorated after thermal exposure and the results of this study should be of interest to develop design guidelines to incorporate the thermal degradations.