Experimental and simulating investigation of flexural behavior of geopolymer coral aggregate concrete beam reinforced with stainless steel rebar

Abstract Using geopolymer and coral aggregates in concrete preparation not only significantly reduces the economic and time costs associated with transporting construction materials for island projects, but also lowers carbon emissions and enhances resistance to sulfate ion erosion in seawater. Simultaneously, stainless steel rebar effectively safeguards against the corrosion of steel bars induced by chloride ions in marine environments. In practical engineering, reinforced concrete members frequently undergo flexural loading. Therefore, in this study, six geopolymer coral aggregate concrete beams (GCACB) with different reinforcement ratios were prepared and subjected to the four‐point bending test. Firstly, the flexural behavior of these beams was analyzed, including the failure pattern, load–deflection curve, concrete strain, ductility, toughness, and cracking moment. Subsequently, the constitutive relationship for geopolymer coral aggregate concrete (GCAC) and stainless steel rebar was obtained through experimental tests, respectively. The equivalent rectangular section coefficients were derived, and the ultimate moment was calculated based on the GCAC compression constitutive relationship. Finally, a finite element (FE) model of GCACB comprising detailed material and geometric modeling is developed utilizing Abaqus. The results indicate that cracks of GCAC initially appear in the aggregate. The cracking moment of the beams was calculated following three design codes, and it closely correlated with the experimental results. The FE model effectively replicates the failure pattern and crack propagation observed in the specimen beam test. The discrepancies in ultimate load, maximum displacement, and initial stiffness are all within the ranges of 15%, 10%, and 10%, respectively, affirming that the model analysis results align well with the experimental findings. In addition, simulation tests were extended to various types of concrete beams to assess the material properties of GCAC. The comparison reveals that the bending performance of GCACB closely resembles that of ordinary concrete‐stainless steel rebar beams, suggesting its potential for practical engineering applications.