Experimental investigation on bond strength between GFRP rebars and concrete under pullout conditions

Based on the Canadian Standards Association (CSA) criterion, pullout test was used to study the effect of rebar type, rebar component, rebar diameter, rebar surface texture, rib height, rib spacing and rib width on the bond strength between GFRP rebar and concrete. Test results show that there are three failure modes, namely deformation shearing off, deformation desquamation and the crush of the concrete between the ribs. The bond strength of GFRP rebars is about 13-35 percent lower than that of steel rebars. The rebar type, rebar diameter, rebar surface, texture, rib height, rib spacing and rib width has significant effects on the bond strength while the rebar component showed little. The highest bond strength is obtained when rib spacing equaled rebar diameter and rib height is 6 percent of rebar diameter.