THE SYNERGISTIC EFFECTS OF STEEL FIBERS AND SILICA FUME ON THE MECHANICAL PROPERTIES OF HIGH-STRENGTH CONCRETE

Compressive strength, durability, and environmental resistance make high-strength concrete (HSC) essential in modern construction. With increasing urbanization, the demand for resilient infrastructure necessitates advancements in concrete performance. Despite its numerous advantages, high-strength concrete (HSC) faces challenges such as brittleness, susceptibility to chemical attacks, and shrinkage cracking, especially in extreme environmental conditions. This study analyzed how steel fibers and silica fume improve HSC mechanical properties. To optimize durable high-strength concrete, this paper evaluates the enhancement of compressive, tensile, flexural, bonding, and shear strength by various compounds. Researchers tested six concrete mix designs containing 7.5% silica fume and 0.5% to 5% steel fiber by cement weight, measuring strengths at 7 and 28 days using a Universal Testing Machine. Results indicate that steel fibers notably improve mechanical properties, with a 2.0% fiber content yielding a 13.06% increase in compressive strength at 7 days and 19.69% at 28 days. Maximum improvements in tensile and flexural strengths also occur at this fiber content, while shear and bond strength enhancements plateau beyond 2.0%. Additionally, silica fume reduces porosity, further increasing strength. The study concludes that optimal use of steel fibers (up to 2.5%) and silica fume enhances the durability and stability of high-strength concrete, though excessive fiber may impair workability and ultimate strength, necessitating careful mix design.