Development of glass/carbon/basalt hybrid FRP rebars for reinforced-concrete beams under bending

FRP rebars have been considered as an alternative solution to conventional steel rebars in concrete reinforced elements. There are still several challenges to overcome in order to make it more widely used, namely in what concerns rebars production process, mechanical properties and feasibility. This research work presents the development and characterization of a new type of hybrid FRP rebars combining glass, carbon and basalt fibres and analyses its application as tensile reinforcement on concrete beams tested under bending loading. Modifications on the standard pultrusion process were proposed (dual heat sections) leading to less voids and more homogeneous rebars. Twenty-three beams were used in the experimental campaign comparing beams reinforced with commercially available GFRP rebars, three different types of developed hybrid FRP rebars and beams with steel rebars. The bending performance was evaluated as well as load-deflection behaviour using two reinforcement ratios. In bending tests, Hybrid67 rebars outperformed GFRP with 36 % higher moment capacity and 49 % greater ductility, offering a promising alternative for durable, corrosion-resistant concrete structures. The best hybrid solution achieved tensile strengths up to 1013 MPa and improved bond and ductility. Experimental results were compared with analytical models described in American and Canadian standard models. A consistent overestimation, around 30 %, of the cracking moment was observed.