Avaliação do uso de polímero reforçado com fibra de carbono associado a uma camada de compósito cimentício como reforço estrutural em vigas

Abstract

Two structural reinforcement techniques that have gained prominence are the application of a layer of Ultra High-Performance Concrete (UHPC) and the application of Carbon Fiber Reinforced Polymer (CFRP) in the tensioned regions of the reinforced concrete structures. However, the appearance of shear stresses at the interface with the substrate characterizes a premature failure mode that prevents the maximum use of the reinforcement. As the emergence of these tensions can be attributed to the difference in the order of magnitude of the modulus of elasticity of the two materials, the objective of this study is to evaluate whether the application of a layer of UHPC between the two elements helps in the transmission of these forces at the interface between the materials. For this, 24 beams were made, in a reduced model, which compare the performance of the following groups: beams reinforced with cement composite, beams reinforced with CFRP, beams reinforced with an intermediate layer of cement composite between the existing concrete and the CFRP and reference beams, which do not have any type of intervention. The analysis was carried out through the four-point bending test, which allowed the evaluation of the values of the breaking loads and the loads that originated the first crack in each sample. It was not possible to compare the performance between the groups of beams in relation to failure stress, since the reduced models failed by shear. However, the analysis of the load at the onset of the first crack of each sample made it possible to conclude that the cement composite layer associated with the CFRP was the control group that most delayed the appearance of bending cracks, followed by the reinforcement groups with CFRP and reinforced with cement composite.