Finite element investigation of GFRP-reinforced concrete beam flexural performance

Abstract This study numerically investigates and compares the glass fiber–reinforced polymer (GFRP) reinforced concrete beams flexural behaviour with four concrete types: geopolymer concrete (GPC), ordinary Portland cement concrete (OPC), and fiber-reinforced geopolymer concrete (FRGC), fiber-reinforced concrete (FRC). Despite increasing interest in sustainable and advanced material systems, particularly those integrating polypropylene fibers with FRP reinforcement, comprehensive design provisions remain limited, and GFRP-reinforced fibrous geopolymer concrete has been insufficiently explored. No new experimental testing is conducted. Instead, the study develops high-fidelity finite element models calibrated and compared with previously published experimental data by the authors. The primary contribution centers on numerical modeling and interpretation. The validated models accurately capture load-deflection response, strain distribution, cracking, stiffness loss, deformability, and failure modes for all material systems. The applicability of ACI 440.11-22 provisions is also assessed. While the code yields conservative predictions of flexural capacity, the finite element analysis (FEA) results indicate strong agreement with experimental outcomes. Including fibers increases flexural capacity by up to 20% and deformability by 24–28% versus non-fibrous versions. The study demonstrates that validated numerical modeling can reliably assess emerging FRP-concrete systems and support future code development for sustainable structures.