Experimental and analytical study on flexural strength of corroded reinforced concrete beam containing fly ash

The corrosion of reinforcement is a major concern in reinforced concrete (RC) structures and significantly affects strength and durability. Because of corrosion, RC beams show unpredictable failure mode which leads to the necessity of experimental study and validation of results. This study aims to validate the experimental results of residual flexural strength of reinforced concrete beams with fly ash (FA) subjected to reinforcement corrosion using finite element analysis (FEA) and compare them with an empirical model available in the literature. Twelve sets of 150 × 150 × 1500 mm reinforced concrete beams incorporating FA were produced. Four uncorroded beam sets served as control specimens for three-point bending tests. The remaining eight sets underwent accelerated corrosion by varying corrosion current densities over different exposure periods (0%, 10%, and 15%). Flexural tests were conducted on both uncorroded and corroded beams containing 0%, 10%, 20%, and 30% FA. Half-cell potential measurements were used to assess the corrosion resistance of longitudinal and transverse reinforcement embedded in concrete and results indicate that a 30% FA content provides superior corrosion protection. To determine the extent of corrosion in both longitudinal and transverse reinforcement, rebar samples were extracted from the RC beams. Flexural strength and load–deflection behavior were analyzed for all the RC beams. Incorporating up to 20% FA as a cement replacement enhanced the flexural strength of corroded RC beams. However, a significant reduction in maximum flexural strength was observed when corrosion levels increased from 10 to 15%. Experimental test results of the flexural strengths for corroded and uncorroded beams are validated with the FEA results and results of the analytical model from the literature. Experimental results have shown reasonably good accuracy with FEA and analytical models.