Experimental study on bonding CFRP to fiber concrete beam considering the effect of using nanographene oxide in improving the mechanical properties of polyamine resin

This research examined the effect of nanographene oxide in enhancing the mechanical properties of polyamine resin for better adhesion of carbon-fiber-reinforced polymer (CFRP) to a fiber-reinforced concrete beam. To this purpose, 33 fiber-reinforced concrete beams retrofitted with CFRP of lengths 50 cm, 35 cm, and 20 cm and widths 3 cm, 6 cm, and 10 cm were experimentally studied. Graphene oxide weight percentages of 1, 2, and 3 percent were considered, and the corresponding cases were compared with the case of a retrofitted beam without graphene oxide. According to the results of experiments on 12 of the beams, as the nanomaterial in the adhesive increases from 1% to 2% and 3%, the values of maximum load-carrying capacity, maximum mid-span deflection, beam stiffness, and beam toughness exhibited 46,19, 27, and 5 percent, respectively, relative to the case of the beam reinforced with CFRP and without graphene oxide. Subsequently, given the close results of the beams reinforced with 2% and 3% graphene oxide, 2% graphene oxide was used in the rest of the samples to investigate the effect changes in the number of layers, length, and width of the CFRP on the mechanical properties of the concrete beam. The results indicated that an increase in the number of layers, length, and width of CFRP results in an increase in the load-carrying capacity and deformability of the fiber-reinforced concrete beam.