Flexural behavior of sustainable high-strength RC beams with GGBS and iron filings incorporation

This experimental study investigates the behavior of sustainable high-strength reinforced concrete (HSRC) beams when cement is partially replaced with ground granulated blast furnace slag (GGBS) and sand with iron filings (IF). Eight rectangular HSRC beams were experienced to four-point loading to examine the effects of these substitutions. The cement was replaced with GGBS at three percentages (10%, 30%, and 50%), with and without a 10% substitution of sand by IF. The results showed that substituting 30% GGBS caused a minor reduction in beam strength, while higher GGBS percentages (above 30%) led to a more significant decrease. However, adding 10% IF improved the beams' strength, demonstrating its potential as a reinforcing material. All beams exhibited similar failure patterns under peak loads. Similarly, the load-deflection behavior of all beams showed consistent patterns across different configurations. However, beams of an optimum replacement consisting of 30% GGBS and 10% IF can support larger values of load-carrying capacity, moment-resisting capacity, and energy absorption than those with other mixtures. The study shows that while GGBS could enhance sustainability, it should be judiciously adopted to maintain structural integrity. Contrariwise, IF shows excellent potential in improving the HSRC beams with improvement in sustainability. It tends to create a balance in material substitution to optimize performance and environmental impacts in concrete structures.