Behaviour of Encased Steel Concrete Composite Beams Using Lightweight Aggregate and Fibers

In this study, the flexural behaviour of encased steel–concrete composite beams using lightweight aggregate and steel fibers is investigated. Steel–concrete composites synergize the robust attributes of steel and concrete. They comprise a steel section in conjunction, thereby delivering augmented load-bearing capability, ductility, fire resistance, and creating a lightweight unit. The hot-rolled I-section is used in the composite section to carry heavy loads with minimal material. Lightweight aggregate is used to reduce weight and minimize structural loads, as well as to reduce shrinkage-related cracks. The lightweight aggregate is used in a volume ratio of 5% in coarse aggregate. According to studies, adding steel fibers to lightweight concrete is a good way to prevent cracks. To examine the impact of the volume ratio of steel fibers on the flexural behaviour, experiments were conducted without steel fibers. Every specimen failed due to the reinforcement yielding in the tension zone and the concrete in the compression zone. Steel fibers with a volume ratio of 1% are used, which increases the ductility coefficient. Concrete’s mechanical characteristics are determined, the compressive strength is satisfied when using lightweight aggregate at a volume of 5% and steel fibers at a 1% volume ratio.