Corrosion resistance of strain-hardening steel-fiber-reinforced cementitious composites

Abstract

This study investigated the corrosion resistance of strain-hardening steel-fiber-reinforced cementitious composites (SH-SFRCs) in a chloride environment. Two types of steel fibers, hooked and twisted, were added (2% by volume) to a high-strength mortar matrix (90 MPa). All the specimens were exposed to cyclic wetting in a 3.5% chloride solution followed by drying. The corrosion resistance of SH-SFRCs was then evaluated by measuring the direct tensile resistance after the chloride cycles. The strain capacity and toughness of all the SH-SFRCs decreased significantly after 105 chloride cycles, whereas a slight reduction was observed in their post-cracking strength. The corrosion resistance of SH-SFRCs after the chloride cycles was strongly dependent on the width of multiple microcracks when the SH-SFRCs were pre-cracked by tensioning until 0.1% tensile strain. The addition of calcium nitrite (CNI) was successful in improving the corrosion resistance of the pre-cracked SH-SFRCs in the chloride environment.