Innovative technique of using carbon fibre reinforced polymer strips for shear reinforcement of reinforced concrete beams with waste plastic fibres

The extensive production of polyethylene terephthalate (PET) in industries worldwide and the long-term decomposition of this plastic type in nature have motivated researchers to study methods for recycling PET. Meanwhile, another serious problem is the sudden shear failure of conventionally reinforced concrete beams due to corrosion. This issue requires finding new alternatives, such as using fibre-reinforced polymer (FRP) materials to ensure the durability of beams. To address both concerns, this study aims to improve the shear strength of reinforced concrete beams by applying the concept of sustainability. The proposed method will enhance the durability of concrete members. Waste plastic fibres were added with volumetric percentages equal to 0.25%, 0.5%, 0.75%, 1%, 1.25% and 1.5% to produce 14 reinforced concrete beams. These beams were designed to fail in shear. Conventional shear reinforcement was applied to seven beams, whereas the remaining beams were reinforced with carbon FRP (CFRP) strips. Results indicated that shear strength increased by 11.45% and 8.45% for the beams reinforced with CFRP strips and steel stirrups, respectively, at 1% fibre content. Similarly, shear ductility increased by 8.61% and 9.96% for the beams reinforced with CFRP strips and steel stirrups, respectively, with an increase of up to 1.25% in fibre content.