Mechanical properties of nano SiO2 and fiber-reinforced concrete with steel fiber and high performance polypropylene fiber

Abstract

This research studies the mechanical properties of concrete mixtures containing 1% nano-SiO2 and different content macro-fiber. Steel (ST) fibers and High performance polypropylene (HPP) fibers of the same length and shape were used, a total of 10 concrete mixtures incorporating 1% of nano-SiO2 by weight of the binder and 0.5%, 1%, 1.5% and 2% macro-fiber by volume of concrete were studied. The experimental results show that addition 1% nano-SiO2 leads to an improvement in all of the mechanical properties of concrete and the incorporation of steel fiber and HPP fiber improves the mechanical properties of concrete. Furthermore, the tensile strength of concrete mixed with 2% steel fiber increased by 51.4%, and the flexural strength increased by 32.7%, the tensile strength of concrete mixed with 1% HPP fiber increased by 34.5%, and the flexural strength increased by 22.8%. It was also indicated that when the fiber content is 1 vol%, the HPP fiber can replace steel fiber.