The strength and toughness of cement reinforced with bone-shaped steel wires

In this study, we have experimentally evaluated the effectiveness of bone-shaped short (BSS) steel wire reinforcement in improving the mechanical properties of cement. Results from four-point bending tests revealed that BSS-steel-wire-reinforced cement is substantially stronger, tougher, and more crack resistant than conventional straight short (CSS) steel-wire-reinforced cement and unreinforced cement. The BSS steel wires provided effective crack bridging by a combination of their ductility and the mechanical interlocking between their enlarged spherical ends and the cement matrix. In the BSS-wire-reinforced cement specimens, multiple cracks formed along the length of the specimen before final failure, whereas in the CSS-wire-reinforced cement and unreinforced cement specimens, a single central crack initiated and propagated across the specimen. Some BSS wires bridged the main crack and were eventually plastically deformed to failure. Secondary matrix cracks also radiated away from the main fracture surfaces, providing significant contributions to the toughness of the composites. In contrast, the bridging CSS wires were easily pulled out of the matrix without much deformation in the wire itself and surrounding cement. Therefore, they were not nearly as effective in bridging cracks and improving toughness as the BSS wires.