Authors: Challa Prasad, Sk.Abdulkareem
Abstract: Concrete is the most widely used construction material in the world, but its inherent brittleness and low tensile strength often limit its performance in structural applications. To overcome these limitations, the addition of fibres into the concrete mix has emerged as an effective technique to improve mechanical properties such as tensile strength, ductility, toughness, and impact resistance. This study investigates the mechanical behaviour of hybrid fibre-reinforced concrete (HFRC) incorporating a combination of steel fibres and polypropylene fibres. Steel fibres are known for their high tensile strength and crack-bridging capacity, while polypropylene fibres enhance post-crack behaviour and resistance to plastic shrinkage cracking. The experimental program includes the preparation of various concrete mixes with different proportions of hybrid fibres, followed by testing for compressive strength, split tensile strength, and flexural strength. The results demonstrate that the synergistic effect of steel and polypropylene fibres significantly enhances the mechanical performance of concrete compared to conventional plain concrete and single-fibre mixes. The research highlights that an optimal hybrid fibre ratio exists, which maximizes strength and ductility without compromising workability. The study provides valuable insights for structural engineers and researchers aiming to improve the durability and performance of modern concrete structures.
