Flexural behaviors of GFRP-reinforced Engineered Cementitious Composite (ECC)-concrete composite beams

Abstract

The use of Fiber-Reinforced Polymer (FRP) bars as an alternative to steel bars addresses corrosion challenges in conventional concrete structures. However, the lower elastic modulus of FRP bars typically leads to excessive deformation and crack widening. This study investigates the synergistic effects of combining glass FRP (GFRP) bars with Engineered Cementitious Composites (ECC) to enhance the flexural performance of concrete beams. Seven beams were tested, including concrete, full-ECC, and composite beams with varying reinforcement ratios and configurations. Results demonstrated that ECC integration significantly improved load-bearing capacity (up to 6.2 % in composite beams), ductility (1.5 times higher than concrete beams), and crack control (crack widths reduced by 83 % in composite beams). A sectional analysis model accurately predicted flexural behavior, revealing that the tensile contribution of ECC diminishes at higher reinforcement ratios (>1.84 %), thereby serving as a safety reserve. An optimal ECC layer-to-beam height ratio of 0.3–0.4 was proposed to balance performance. This work advances the understanding of GFRP-ECC systems, offering practical insights for the design of durable and high-performance structures.