Experimental investigation on the behaviour of concrete ties reinforced with GFRP bars

Aim of the paper is the evaluation of the bond transfer mechanism and the following cracking behavior for concrete elements reinforced with Glass Fiber Reinforced Polymer (GFRP) bars. At the scope, an experimental survey has been developed on nine 3000 mm long fie-specimens with square cross-section of 150 mm x 150 mm, reinforced with a 4000 mm long GFRP reinforcing bar embedded in the centerline. Besides the reference element reinforced with conventional steel rebar with diameter equal to 16 mm, nine GFRP bars with the same equivalent diameter and different surface treatments (smooth, sand-coated and helical fiber wrapped surfaces) were taken into account. The specimens were subjected to tensile force and the obtained results have shown how the different surface coating may affect the bond behavior at the concrete - GFRP interface, and the following crack pattern