Improvement of mechanical performance in different concrete applications through use of steel fibers

Abstract

The use of steel fibers improves the brittle characteristics of concrete and provides superior mechanical performance compared to the conventional concrete. Remarkable increase in tensile strength and flexural toughness is obtained when steel fibers are used in conventional concrete, mainly due to the crack arrest effect of these fibers. The use of waste materials, such as scrap tires as a source of steel fibers, as well as the resulting increase in service life and the savings in the life cycle cost make the steel fiber reinforced concrete (SFRC) a sustainable construction material. From this perspective, SFRC offers a strong potential for a more sustainable and more economical alternative to conventional concrete. This paper presents examples of how the addition of steel fibers improves the mechanical performance in two different concrete applications: (1) bond behavior of prestressing strands and (2) flexural behavior of reinforced concrete beams. The first part of the study aimed at investigating the variation in bonding mechanism of prestressing strands when used in plain concrete and in SFRC. Pullout tests were conducted on 12.7 mm diameter prestressing strands embedded in SFRC blocks with four different fiber concentrations. This way, the applicability of the available transfer length and development length formulas for prestressing strands embedded in SFRC was investigated. In the second part of the study, flexural behavior of SFRC beams with various levels of flexural reinforcement ratio was studied. The aim was to identify the influence of steel fibers on the mechanical response of lightly and relatively heavily reinforced SFRC beams. The response of SFRC beams and the companion plain concrete beams were evaluated based on the moment capacity, deformation capacity, and service stiffness. © 2016 International Committee of the SCMT conferences. All rights reserved.