The influence of the carbon fiber sheets dimensions on the behavior of flexural strengthened reinforced concrete beams

Abstract

The need to reinforce a structural element is common, since it is not always able to withstand an increase in the applied load for which it was initially designed. Thus, this work aimed to carry out a study of the technique of structural bending reinforcement, with composite material based on carbon fibers in reinforced concrete beams. Also, verify changes in the behavior of the reinforced beams using different layers and geometries of this material, which adds high strength values without major changes in the cross section of the element. For the objectives of this work to be achieved, an experimental program was carried out, which consisted of three point bending tests on four beams. One without reinforcement, used as a comparison parameter and three other beams reinforced with one, two and three layers of carbon fiber sheets, these having different widths, but with the same area as the reinforcement cross section. According to the experimental results, it is possible to realize the increase of strength and stiffness of the strengthened beams when utilized carbon fibers, when compared with the regular beam. It was also observed a reduction in the rupture load proportional as much as the number of reinforcement layers was increased. The width has also been reduced aiming to keep the same cross-sectional area. Furthermore, it was found that the failure mode for detachment of the reinforcement of the concrete substrate is preponderant in relation to typical flexure failure modes of reinforced concrete beams.