In structural design, it is extremely desirable to use as low-material as possible while keeping integrity and usefulness. Reducing the structure's weight is one strategy for achieving this objective. Steel fibres have recently been added to reinforced concrete beams to increase flexural and shear strength. Fibre
reinforcement in structural elements has drawn considerable interest from the building sector. Steel fibre has received the greatest attention and utilization among all fibre types. When compared to plain concrete, incorporating fibres into concrete may result in better crack management and greater strength. This study examines how two-layer beams made of lightweight steel fibre concrete and recycled aggregate concrete flex under bending loads. Twelve distinct beams with cross sections measuring 100 mm, 150 mm, and 1500 mm (width, depth, and length) are prepared and tested as part of the study. These beams are evaluated under four-point bending. In the tension zone of the lightweight concrete layer, different percentages of steel fibre ranging from 0% to 1.5% by volume were introduced. In the concrete compression layer, recycled block aggregate was substituted for natural coarse aggregate in varying percentages (0%, 25%, and 50%). According to the findings, the flexural strength of beams with a higher steel fibre percentage is higher than that of beams with a higher recycled aggregate component. The study also shows that two- layer beams with higher steel fibre content have superior crack management and deflection behavior than those with lower steel content. The results of the flexural reinforced concrete beam test were contrasted
with the calculated design strength determined using British Standards.