Enhancing the mechanical properties of fibre-reinforced concrete through sustainable mix design: effects of fibre type and dose

This study investigated the mechanical properties of fibre-reinforced concrete (FRC) by varying fibre content and incorporating supplementary cementitious materials into M20 grade concrete. The research focused on the effects of four types of fibres—hooked end steel, chopped glass, PET fibres from recycled bottles, and jute fibres—introduced at volume fractions of 0%, 1%, 2%, and 3%. Additionally, 30% of the cement was replaced with fly ash, and 25% of the coarse aggregate was substituted with recycled concrete aggregate (RCA) to enhance sustainability. The primary aim of this study was to evaluate the impact of these fibres on the compressive strength, flexural strength, and split tensile strength at various fibre dosages. The results provide valuable insights into optimizing FRC formulations for sustainable construction, emphasizing the benefits of using recycled materials and diverse fibre types to improve concrete performance and durability. The study concluded that the optimal fibre dosage is 3% for steel fibres and 1% for glass fibres. PET fibres improved compressive and split tensile strengths at a 1% dosage but led to a decrease in flexural strength with increasing fibre content. In contrast, jute fibres were found to reduce strength as fibre content increased, supporting previous findings that suggest the optimal dosage for jute fibres is below 1%.