Experimental and numerical evaluation of indirect tensile properties of concrete containing macro fibers processed from waste GFRP composites

With the increasingly widespread use of fiber-reinforced polymer (FRP) composites, the volume of non-biodegradable FRP solid waste is accumulating at a high rate, becoming a significant threat to environmental sustainability. To address this, the authors’ group has developed a novel mechanical recycling method to produce “macro fibers” for use as discrete reinforcement in concrete. In this study, an experimental program was conducted to explore the indirect tensile behavior of macro fiber reinforced concrete (MFRC) with an emphasis on the effect of fiber volume fractions and fiber length. Then, the finite element models (FEMs) of the splitting test and four-point bending test were established. The results reveal that the macro fibers have a limited influence of approximately ±5 % on the compressive strength, while increasing the splitting tensile strength and flexural tensile strength of concrete by 52.2 % and 125.0 % respectively. The comparison analysis indicates that the splitting tensile strength and flexural behavior of MFRC are effectively captured by the finite element models, although some discrepancies or overestimations are observed.