Experimental study of bond behaviour between concrete and FRP bars using a pull-out test

This paper presents the results of an experimental programme concerning 88 concrete pull-out specimens prepared according to ACI 440.3R-04 and CSA S806-02 standards. Rebars (reinforcing bars) made of carbon-fibre and glass-fibre reinforced polymer (CFRP and GFRP), as well as steel rebars, with a constant embedment length of five times the rebar diameter were used. The influence of the rebar surface, rebar diameter and concrete strength on the bond-slip curves obtained is analysed. In addition, analytical models suggested in the literature are used to describe the ascending branch of the bond-slip curves. To calibrate the analytical models, new equations that account for the dependence on rebar diameter are presented.