Title: Effect of Fiber Hybridization on Basic Mechanical Properties of Concrete

Author(s): Stamatina G. Chasioti and Frank J. Vecchio

Publication: Materials Journal

Volume: 114

Issue: 3

Appears on pages(s): 375-384

Keywords: direct tension; dog-bone specimen; four-point bending; hybrid steel fiber-reinforced concrete; synergy

DOI: 10.14359/51689479

Date: 5/1/2017

Abstract:
In recognition of the gradual and multi-scale process of cracking, this paper investigates the beneficial effects of fiber hybridization on the basic mechanical properties of concrete. Allowing for these benefits in the mechanical performance may potentially lead to reduced production and construction costs. An experimental investigation was undertaken involving normal-strength concrete in which two types of steel fibers were used: high-strength straight steel microfibers with a length of 13 mm (0.51 in.), and hooked-end macrofibers with a length of 30 mm (1.18 in.). Comparisons between hybrid steel fiber-reinforced concrete (HySFRC) specimens and monofiber counterparts with the same total volumetric ratio highlight its superior performance. Synergy in compression is identified by an enhanced confinement mechanism, in tension by improved post-cracking resistance at both low and high crack openings, and in bending through enhanced fracture toughness. Additionally, a variant of the dogbone-type specimen for tests in direct tension was developed. The novel configuration is more suitable for concrete containing fibers and it is easy to construct and test.