Effective fiber type investigation on the shear behavior of ultrahigh-performance fiber-reinforced concrete beams

Abstract

In this study, the effects of different fiber types on shear behavior (cracking pattern, shear cracking strength, ultimate shear strength, and post-cracking deformability) of ultrahigh-performance fiber-reinforced concrete beams were investigated experimentally. For this purpose, 15 ultrahigh-performance fiber-reinforced concrete beams including different steel fiber types (two straight, two hooked, and one double hooked) with three volume fractions (0.5%, 1.0%, and 1.5%) were casted without shear reinforcement and tested under four-point loading until the failure. In addition to the experimental program, three existing numerical models proposed for the shear capacity of fiber-reinforced concrete beams were investigated to show the applicability of these models to the ultrahigh-performance fiber-reinforced concrete beams. The experimental results demonstrated that the straight fiber of 13 mm is the most effective fiber type in terms of the considered parameters. However, the addition of 13-mm straight fiber with 1.5% by volume into the ultrahigh-performance fiber-reinforced concrete beam changed the failure mode from the shear to flexure without shear reinforcement.