Friction coefficient between FRP pultruded profiles and concrete

This paper presents the experimental results of a direct shear test to determine the friction coefficient between fibre reinforced polymer (FRP) pultruded profiles and concrete. The FRP pultruded profile used in this study was glass fibre reinforced polymer (GFRP) I-section. The specimens were composed of a concrete block and a coupon of the GFRP pultruded profile. The experiment was conducted by using the direct shear test method. The parameters investigated included the type of concrete (self-compacting concrete and normal concrete) and the compressive strength of the concrete, as well as the different components (web and flange) of the I-section. The test results verify that the bond behaviour between the concrete and the GFRP pultruded profiles mainly depends on two factors, the friction stress and the adhesion stress. The friction coefficient between the FRP pultruded profiles and the concrete was between 0.5 and 0.6 when the normal stress fluctuated between 0.5 and 2 MPa, and the adhesion stress was about 0.2 MPa. The compressive strength of the concrete and the different components of the I-section have little effect on the friction coefficient, however, the type of the concrete significantly affects this coefficient.