Effect of Using Granite and Iron Ore Waste on Flexure Behavior of Ultra High Strength Reinforced Concrete Beams

This study investigates the flexural behavior of ultra-high-strength reinforced concrete (UHSRC) beams produced with the incorporation of granite waste (GW) and iron ore waste (IOW) as sustainable materials. Four beams with cross-sectional dimensions of 120 × 280 mm² and a span of 1500 mm were cast and tested under three-point bending. Each beam was reinforced with three 12 mm diameter high-strength steel bars in the tension zone and two 12 mm diameter bars in the compression zone. The experimental program evaluated ultimate load, crack patterns, failure modes, load–deflection response, and structural ductility. A control mix containing 19% silica fume of the total binder and 2% steel fibers of the total volume was used for comparison. The beams exhibited flexural cracking followed by crushing at the compression zone, with variations in ultimate deflection depending on the mix composition. The beam incorporating GW exhibited enhanced flexural strength compared to the control. The combined use of GW and IOW decreased the flexural strength by 10% this reduction was attributed to impurities in the iron ore waste, but increased ductility by 62%. The G50I0 beam exhibited a 44% higher ductility energy index compared to the control beam. Replacing natural aggregates with GW and IOW in ultra-high-strength concrete saves costs by up to 15% and reduces embodied carbon and energy use by about 70%. Further research is required to determine the optimal mix proportions of IOW and GW for achieving the best performance.