Laminated composite based on ramie fibers as an alternative solution for strengthening reinforced concrete beams

Abstract

Carbon fibers-reinforced polymers (CFRP) laminates are widely used to strengthen concrete structures due to their high mechanical performance. However, their production has environmental and economic limitations. This study explores the use of natural ramie fibers (Boehmeria nivea) in epoxy-based laminates (RFRP) as a sustainable alternative for reinforcing reinforced concrete (RC) beams. Composites were produced with 50%, 60%, and 70% fiber content, and mechanical tests showed that the 70% RFRP laminate reached a modulus of elasticity of 35.12 GPa, tensile strength of 113.88 MPa, and maximum strain of 24.8‰. As confirmed through experimental testing and finite element simulations, RC beams strengthened with 70% RFRP (≈5.6 mm thick) presented structural performance equivalent to CFRP laminates (≈1.2 mm thick). These results support the technical feasibility and environmental advantages of RFRP composites as an alternative for structural strengthening applications.