Experimental and numerical study on flexural properties of shredded prepreg carbon cloth waste fibre reinforced concrete

Carbon fibre reinforced polymer (CFRP) is extensively employed across various industries due to its exceptional strength-to-weight ratio, corrosion resistance, and high tensile strength. However, its disposal presents significant environmental challenges, as conventional methods such as incineration and landfilling are becoming increasingly restricted due to environmental regulations. One opportunity for recycling and lessening ecological impact is provided by prepreg carbon cloth waste (PCCW), a byproduct of the CFRP manufacturing process. This study explores the utilization of PCCW, which is mechanically processed into shredded prepreg carbon cloth waste (SPCCW) fibres with lengths ranging from 5 to 40 mm and diameters between 0.1 and 1 mm, for concrete reinforcement. Concrete mixes were designed using C40-grade concrete with SPCCW fibre volume fractions of 0.5 %, 1.0 %, 1.5 %, and 2.0 %. The flexural properties were evaluated through three-point bending tests. Additionally, finite element analysis (FEA) was conducted to simulate stress distribution and crack propagation in SPCCW fibre-reinforced concrete. Specific error margins between the simulated and experimental data are mentioned, such as the 1.9 % error in predicting flexural strength, which highlights the accuracy of the finite element model. In this study, the Visco-polymerization cracking model was selected to simulate the cohesive crack propagation in SPCCW-reinforced concrete alongside the concrete plastic damage model to capture the non-linear behaviour of concrete under both tensile and compressive stresses. The experimental results revealed a marked reduction in slump, with the greatest reduction (81.8 %) observed at higher fibre contents. Optimal mechanical performance was achieved at 1.0 % fibre content, where flexural strength increased by 24.9 %. The inclusion of SPCCW fibres facilitated improved stress redistribution and delayed crack initiation and propagation, which was further validated through numerical simulations. The load-bearing capacity peaked following crack initiation, and the concrete exhibited its highest principal stress capacity at 1.0 % fibre content.