In this study, the flexural behavior of structurally deficient reinforced concrete (RC) beams incorporating fly ash partially replacing cement was investigated. Structural deficiencies in RC beams typically arise from causes like old age, poor design, and material deterioration. To understand the performance of these deficient beams, a series of flexure tests were conducted. Nine categories of RC beam specimens, each measuring 150mm x 150mm x 700mm, were cast and divided based on steel reinforcement percentages into three sets: 100%, 70%, and 50% of required steel. Within each set, one specimen contained 0% fly ash (100% cement), another contained 20% fly ash (80% cement), and the last one contained 30% fly ash (70% cement). The study focused on analyzing crack propagation, applied load versus mid-deflection relationships, stress-strain relationships, and normalization curve relationships. The results demonstrated that incorporating fly ash improved the flexural performance of RC beams. Beams with fly ash exhibited enhanced crack resistance and higher load-bearing capacities, particularly with 20% fly ash. Lower steel reinforcement percentages increased flexural deficiencies, but the presence of fly ash mitigated some effects. This research provides a significant understanding of optimizing RC beam design for improved durability and performance, showcasing the potential benefits of using sustainable materials such as fly ash in construction.
