Glass Fiber Reinforced Polymer (GFRP) composite rebars are increasingly adopted in reinforced concrete (RC) structures, particularly in aggressive or high-durability environments, due to their superior corrosion resistance and light weight compared to conventional steel reinforcement. However, the inherent differences in material behavior, surface interaction, and manufacturing processes between GFRP and steel lead to complex and often less understood bond behavior. The bond strength and the resulting slip mechanisms between GFRP and concrete dictate the serviceability and ultimate limit states of the structure, governing crack control, load transfer efficiency, and structural robustness. Traditional analytical models and design codes often simplify this complex tri-linear bond-slip relationship (initial stiffness, peak bond strength, and post-peak softening) based on empirical fitting to limited experimental data, failing to capture the nuances introduced by fiber orientation, surface modification (ribs/sand coating), matrix composition, and environmental aging.
Ali Alemi (2025) studied this question.