Workability, strength and flexural toughness properties of hybrid steel fiber reinforced SCC with high-volume fiber

Abstract

The purpose of this study was to investigate the effect of total volume fraction and combinations of macro and micro steel fiber on the workability and mechanical as well as flexural performance of hybrid reinforced self-compacting concretes (HFR-SCC). A sum of five fiber reinforced SCC mixtures containing a total volume fraction fiber of 1.00% and 1.50% were designed as two single fiber reinforced mixtures with only macro steel fiber and two hybrid fiber reinforced as well as the control mixture without fiber. To interpret the fresh properties of HFR-SCC, slump flow diameter, T500 and J-ring test were performed. The compressive strength, splitting tensile strength, flexural strength, load-carrying capacity, flexural toughness and ductility were measured to evaluate the mechanical and flexural performance of HFR-SCC. The attained test results for fresh properties revealed that although decrease in the workability of FR-SCC mixtures happened with the increase in total volume fractions of fibers, all steel fiber reinforced SCC mixtures provided the workability limits of EFNARC. The flexural toughness values increased with the total volume fraction of fibers from 1.00% to 1.50%. The hybrid reinforced SCC specimens were exhibited superior the compressive strength, flexural toughness and ductility compared to single fiber reinforced SCC specimens. Also, HFR-SCC mixture with 1.20% macro and 0.30% micro steel fibers gave the best results in terms of mechanical and flexural performance due to increase in macro steel fiber volume fraction and higher fiber reinforced index with 1.04 as well as synergistic blends of macro and micro steel fibers.