Enhancement of the bond behaviour between sand coated GFRP bar and normal concrete using innovative composite anchor heads

Anchor heads could efficiently address the bond weakness between Fibre-Reinforced Polymer bars and concrete. This experimental study enhanced the bond behaviour between GFRP bars and concrete using three innovative anchorage systems made from glass fibre cloth and epoxy resin. A direct pullout test was used to study the bond-slip performance between the bar and the concrete. Test variables were GFRP bar diameter (3 diameters), concrete compressive strength (20.4 and 40.2 MPa), and anchor system (three different types). Based on the test results, in low-strength concrete (i.e. 20.4 MPa) samples, the anchor system efficiency was not promising, and the failure occurred between the concrete and anchors. However, for higher strength concrete (i.e. 40.2 MPa) samples, the ultimate developed tensile load increased between 14 and 68% for different bar sizes and anchorage systems compared to the unanchored control specimens.