Bond strength of FRP bars in recycled-aggregate concrete

Ahmed Godat, Shaima Aldaweela, Hamda Aljaberi, Noura Al Tamimi, Ebtesam Alghafri

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


This study presents an experimental program conducted to investigate the bond strength of FRP bars in recycled-aggregate concrete compared to the one in normal-aggregate concrete for better evaluation of the results. The experimental program contains thirty six specimens that are tested using the direct pull-out test. In this study, glass, carbon and basalt FRP bars are used with 12 mm diameter and bar bond length of 5d, where d is the bar diameter. The FRP bars are casted in different recycled-aggregate concrete strengths of 30, 45 and 60 MPa. The behaviour of bars in natural-aggregate concrete strength of 30 MPa is used as a benchmark and its behaviour is compared with the ones in recycled-aggregate concrete. The impact of the concrete strengths considered is identified based on the gain in the bond behaviour. The experimental results demonstrate the promise of the recycled aggregates as an alternative to natural aggregates in FRP reinforced concrete. In addition, the use of recycled aggregate enlarges the bearing friction behaviour between the FRP bars and concrete. Analytical models proposed in the literature for the bond behaviour of FRP reinforced concrete are compared with the experimental results obtained here. Organgun et al. equation, and the CMR and the BPE models can accurately predict the bond strength, and bond stress–slip behaviour, respectively, of FRP bars in recycled-aggregate concrete.

Original languageEnglish
Article number120919
JournalConstruction and Building Materials
Publication statusPublished - Jan 18 2021


  • Analytical models
  • Bond strength
  • Bond stress–slip relations
  • Direct pull-out test
  • FRP bars
  • Recycled-aggregate concrete

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • General Materials Science


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