Mechanical performance of recycled glass fiber reinforced concrete: An integrated experimental and theoretical analysis

Applying recycled glass fibers (RGFs) derived from waste wind turbine blades as sustainable reinforcing materials in concrete is an effective approach for achieving their resource utilization. In this study, the uniaxial compressive behavior of recycled glass fiber reinforced concrete (RGF-RC) is experimentally investigated, with particular emphasis on the effects of fiber volume ratio and water-cement ratio on its mechanical properties and constitutive response. The results indicate that the incorporation of RGFs significantly influences the strength and deformation characteristics of RGF-RC. As the fiber volume ratio increases from 0% to 0.8%, the compressive strength and peak stress first increase and then decrease, with the optimum performance achieved at a fiber volume ratio of 0.6%. At this optimum dosage, the compressive strength and peak stress are increased by 27.2% and 19.1%, respectively, compared with those of the control concrete (B series). In contrast, due to the beneficial crack-bridging effects of the RGFs, the splitting tensile strength and longitudinal strain at peak stress continuously increase with the fiber volume ratio increases. At a fiber volume ratio of 0.8%, the splitting tensile strength and longitudinal strain at peak stress reach their maximum increments of 36.8% and 18.5%, respectively. Furthermore, the added RGFs results in a more gradual descending segment of the stress-strain curves, indicating the improved ductility and toughness of RGF-RC. Increasing the water-cement ratio adversely affects the compressive strength, tensile strength, peak stress and strain, and elastic modulus of RGF-RC. On the basis of the experimental results, the predictive formulas for the peak stress and strain, Poisson's ratio, and elastic modulus of the RGF-RC are respectively proposed, and the means of the predicted to experimental value ratios range from 0.95 to 1.11. Finally, considering the effects of the fiber volume ratio and water-cement ratio, a new constitutive model for evaluating both the longitudinal and transverse stress-strain curves of the RGF-RC is established, and it demonstrates close match with the experimental curves. The research findings can provide valuable references for the stress analysis and structural design of RGF-RC members, and promote the large-scale application of waste wind turbine blades in civil engineering.