Experimental and numerical investigation of flexural behavior of sustainable self-compacting geopolymer RC beams

Abstract This study presents a comprehensive experimental and numerical investigation into the flexural behavior of sustainable self-compacting geopolymer concrete ( SCGC ) beams incorporating granite waste and slag powder. While the environmental benefits of geopolymer concrete are widely studied, its structural performance, particularly when utilizing industrial wastes, remains underexplored. To address this gap, six reinforced concrete beams (100 × 150 × 1500 mm), including five SCGC beams and one Portland cement concrete ( PCC ) control beam, were tested under four-point bending. The investigation systematically evaluated the influence of key parameters: the longitudinal reinforcement ratio (0.85%, 1.34% and 2.0%) and the shear span-to-depth ratio (4.27, 4.48 and 4.7). Experimental results demonstrate that the cracking load, yield load, and ultimate flexural capacity of the SCGC beams increased with a higher reinforcement ratio and a lower shear span-to-depth ratio. Notably, the SCGC beams exhibited a higher moment capacity compared to the conventional PCC beam. A nonlinear finite element model, validated against the experimental data, provided accurate predictions of the load–deflection response and ultimate strength. The findings confirm that SCGC incorporating granite waste is a structurally viable and superior alternative to conventional concrete, with the developed model serving as a reliable tool for future design and analysis.