Experimental research and theoretical prediction on mechanical properties for recycled GFRP fiber reinforced concrete

Abstract

Recycled GFRP fiber has increasingly been reused in concrete, necessitating an improvement in its recycling process and an investigation into its effects on the mechanical properties of concrete to achieve higher recycling values. To this end, this study proposed a novel GFRP recycling method that integrates mechanical recycling, water-vibratory separation, and secondary sieving to efficiently remove impurities from GFRP waste. Three different sizes of recycled GFRP fibers (SF, MF, and LF) were sorted from decommissioned GFRP wind turbine blades using the novel recycling method, and their effects of on the mechanical properties of concrete were investigated. The results show that all three types of recycled GFRP fibers increase the strength and toughness of concrete. With equivalent fiber content, the largest recycled GFRP fiber (LF) yields the most substantial reinforcement effect on the mechanical properties of concrete. Specifically, incorporating 1.0 % LF increases the compressive strength, splitting tensile strength, and flexural strength of concrete by 14.0 %, 16.8 %, and 37.0 %, respectively, while also increasing flexural toughness by 2.9 times. In addition, the mechanical properties of recycled GFRP fiber reinforced concrete were theoretically analyzed in this study, and two strength prediction models for recycled GFRP fiber reinforced concrete were established to achieve rapid prediction of concrete strength.