Mechanical properties of concrete reinforced with macro fibres recycled from waste GFRP

Fibre-reinforced polymer (FRP) composites have been widely used in many sectors, such as construction, transportation, energy, aerospace and sports, due to their advantages such as lightweightness, high strength, and excellent durability. A large amount of FRP wastes arises from the production process and at the end-of-life of FRP products, of which 95% is glass fibre reinforced polymer (GFRP) composites. Existing GFRP recycling methods are not economical owing to the low added value of glass fibres and significant degradation of glass fibre properties due to the recycling process. The authors’ research team has previously proposed a mechanical method to process decommissioned wind turbine blades into macro fibres, which can then be used to produce macro fibre reinforced concrete (MFRC). This paper presents an experimental study in which the effects of fibre volume fraction, fibre thickness, fibre length, and concrete mix on the compression and splitting tensile properties of MFRC were investigated. The test results show that the splitting tensile strength of the concrete can be significantly enhanced by the addition of macro fibres, e.g., by 40% when the macro fibre volume fraction in mix 2 concrete is 1.5%. The applicability of existing equations for predicting the splitting tensile strength of fibre reinforced concrete (FRC) to MFRC is evaluated, and a new equation for predicting the splitting tensile strength of MFRC is proposed based on the test data.