Mechanical performance of Strain-Hardening Cementitious Composites (SHCC) with hybrid polyvinyl alcohol and steel fibers

Abstract Recently, hybridizing fibers with distinct properties in cementitious materials has gained much attention due to their advantage over single-type fiber reinforcements. However, for Strain-Hardening Cementitious Composites (SHCC), most existing studies only compared hybrid-fiber SHCC (HySHCC) with conventional concrete or introduced additional steel fibers into mono-fiber SHCC, rather than keeping the total fiber dosage constant to show the positive synergetic effect. This study aims to explore the benefits of using hybrid steel/polyvinyl alcohol (PVA) fibers in SHCC with a fixed total fiber dosage of 2.5 vol% by evaluating the mechanical, economic and environmental potentials. The mechanical performance of HySHCC was comprehensively tested under compression, tension, static three-point bending and cyclic four-point bending. The crack pattern under uniaxial tension was digitally captured, and the static three-point bending performance was numerically simulated using a finite element method. While HySHCC generally showed slightly lower ultimate tensile strain and higher environmental impacts than PVA-SHCC, the crack control ability, compressive strength, modulus of elasticity and flexural toughness were superior. The findings of this study offer a new insight on the design and selection of fiber-reinforced cementitious composites for structural applications.