Development Length and Bond Behavior of Steel Bars in Steel Fiber–Reinforced Concrete in Flexural Test

Abstract

The bond between concrete and steel bars defines the structural behavior of reinforced concrete—each is the complement of the other. The bond allows for the compatibility of strains, transmission of stresses, and good mechanical behavior, with less possibility of the concrete cracking; this can result in the protection of the reinforcement and a higher structural durability. This study investigates (1) the bond behavior between concrete and steel bars, and (2) the development length of steel bars in steel fiber-reinforced concrete (SFRC). For the tests, the bars had diameters of 8 and 12.5 mm with full development lengths (lb), and with reductions of 50% (0.5·lb) and 25% (0.75·lb). The volume fraction of steel fibers (Vf) had values of 0.0%, 0.5%, and 1.5%. In the results, the flexural ultimate loading for SFRC was higher than for nonfiber-reinforced concrete. For samples with a Vf of 1.5%, the bond strength was higher than that found in other concretes, confirming that the use of steel fibers improved the bond between concrete and reinforcement and the effectiveness of the proposed test system.