Flexural Performance of Hybrid Fibre-Reinforced Recycled Aggregate Concrete Beams with Steel Fibre-Reinforced Polymer Composite Bars (SFCBs)

With the need for sustainable infrastructure growth, recycled aggregate concrete (RAC) is a promising alternative to solve the shortage of construction raw materials. Compared to natural aggregate concrete, RAC poses a greater risk of inducing corrosion in steel. Hence, there is a need to investigate alternative forms of reinforcement aside from steel fibres and bars. This study investigates the application of a newly developed hybrid fibre-reinforced recycled aggregate concrete (FRRAC) in reinforced concrete beams, using recycled macro-polypropylene fibres and macro-basalt fibres. The flexural behaviour and serviceability performance of four concrete beams (2 RAC and 2 FRRAC) reinforced with steel and steel fibre-reinforced polymer composite bars (SFCBs) were tested. The beams (200 mm in depth and 150 mm in width) were loaded to failure under a four-point bending setup over a span of 1400 mm. The test results, including damage modes, load-deflection curves, concrete and reinforcement strain values, energy absorption and beam ductility, were obtained and analysed. Hybrid fibre addition to SFCB-reinforced RAC beams improved the flexural capacity and energy ductility coefficients by 18.8% and 102.8%, respectively.