This paper first addresses the effect of steel and forta-ferro fibers on the mechanical properties of highstrength concrete, and then, investigates the effect of silica fume and nano-silica on the mechanical properties of the fiber-reinforced concrete. In total, 230 concrete specimens were produced in two stages and subsequently tested; in the first stage of specimen production, hooked-end steel fibers with Vf of 0.5%, 0.75%, 1%, 1.25%, and 1.5%, and forta-ferro fibers with Vf of 0.2%, 0.35%, 0.5%, 0.65%, and 0.8% were added to concrete mixture, and in the second stage, silica fume with the weight percentage of 8%, 10%, and 12%, and nano-silica with that of 1%, 2%, and 3% were replaced the cement in mixtures with a fixed volume fraction of both fibers. The aim was to study the mechanical properties of the fiber-reinforced concrete including compressive strength, tensile strength, modulus of elasticity, water absorption, and density, and to propose equations for predicting the compressive and tensile strength and the modulus of elasticity of the fiber-reinforced concrete with no pozzolan
