Analytical and Experimental Investigation of the Strength Characteristics of Fiber-Reinforced Quaternary Blended Concrete (Hybrid Fibres)

The pursuit of sustainable and high-performance concrete has led to extensive research on the integration of supplementary cementitious materials (SCMs) and fiber reinforcement. Among emerging advancements, quaternary blended concrete reinforced with hybrid fibers has shown great potential in enhancing strength, durability, and structural performance. This study investigates the mechanical properties of fiber-reinforced quaternary blended concrete (QB-FRC) through experimental and analytical methods. It examines the combined effects of SCMs—fly ash, ground granulated blast furnace slag (GGBS), silica fume, and metakaolin—along with hybrid steel and polypropylene fibers on compressive strength, split tensile strength, and flexural strength. A comprehensive series of laboratory tests was conducted on both control specimens and quaternary blended concrete samples at different curing periods. The results demonstrate notable improvements in strength, durability, and microstructural integrity compared to conventional Ordinary Portland Cement (OPC) concrete. The study concludes by discussing optimal mix design strategies and the complementary effects of SCMs and hybrid fibers. Findings suggest that quaternary blended concrete, combined with hybrid fiber reinforcement, significantly enhances load-bearing capacity, crack resistance, and energy absorption, making it a promising approach for modern sustainable construction.