Fibres for enhancing of the bond capacity between GFRP rebar and concrete

• Fibres are added for improving the weak bond capacity between GFRP rebar and concrete.
• The various fibres show positive hybrid effect on the bond effect between GFRP and concrete.
• The bond capacity of GFRP in concrete with fibres is better than that of steel rebar in concrete.
• The hybrid use of different macro fibres provides also cost benefit.

The effect of steel fibres (SF) and macro-polypropylene fibres (PPA) on the bond capacity between GFRP rebar and concrete has been studied in this work. A novel method using the equivalent bond strength to evaluate the bond toughness is proposed. In comparison with the bond property of GFRP rebar in plain concrete (PC) matrix, the investigation indicates that adding macro mono fibres or hybrid fibres into concrete can enhance both the bond strength and the bond toughness. Especially, the hybrid use of SF and PPA demonstrates a significant positive synergetic effect on the bond behavior of GFRP rebars in concrete. The results show that the bond capacity of GFRP rebars in concrete reinforced by hybrid fibres can be equivalent to that or better than that of steel rebar in plain concrete.