The effect of NiTi shape memory alloy, polypropylene and steel fibres on the fresh and mechanical properties of self-compacting concrete

Abstract

Abstract Self-compacting concrete (SCC) is the main cementitious material employed in modern constructions, because of its outstanding deformability and high resistance to segregation. In this study, a new nickel-titanium (NiTi) shape memory alloy (SMA) fibre was manufactured to investigate its effects on the fresh and mechanical properties of SMA fibre-reinforced SCC and comparing it with polypropylene (PP) fibre and steel fibre reinforced SCC. Fresh properties tests, including slump flow and J-ring, and mechanical properties tests, including compressive strength, splitting tensile strength, flexural strength and impact, were carried out. The SMA fibre-reinforced SCC displays outstanding fresh properties and ductile performance compared to the PP and steel fibre-reinforced SCC. This is because SMA fibres present outstanding ultimate tensile strength and superelastic characteristics. The combination of the advantages delays initial crack development and narrows the crack gap width, resulting in energy dissipation phenomena which enhance both ductile performance in mechanical experiments and dynamic resistance in impact loading.