Hybrid effects of carbon nanotubes and steel fiber on dynamic mechanical properties of ultra-high performance concrete

Abstract This study aims to investigate the hybrid effects of carbon nanotubes (CNTs) and steel fiber (SF) on dynamic mechanical behavior ultra-high performance concrete (UHPC) under high-speed loading effects. The functionalized CNTs content varied from 0.0% 0.20%, SF volume was added 0.5% 2.0%. UHPC specimens were tested at strain rates ranging about 60 s-1 240 using split Hopkinson pressure bar. evaluated in terms stress–strain relationships, energy absorption capacity failure patterns. Test results show that compressive properties are strongly sensitive rates. individual addition obviously improves plain UHPC, there exists an optimal 0.10% achieve better improvement increase factor (DIF) is almost unrelated but closely correlated rate variations, which can be well described by a modified empirical formula. Furthermore, it found display more significant reinforcing as specimen with 2.0% exhibits highest strength toughness. Meanwhile, reinforced fibers less high compared UHPC. From microscopic observations, reasonably believed exert synergistic matrix view their respective characteristics, improving interfacial transition zone (ITZ) structure between surrounding matrix. work promotes fundamental understanding for provides effective strategy reinforce multiscale perspectives.