Dynamic failure behaviors of reinforced-concrete based on the split-Hopkinson pressure bar tests

In the present study, using the pulse-shaping technique and high-speed photography, large-dimension (Ф120 mm × 100 mm) Split-Hopkinson Pressure Bar (SHPB) tests of reinforced-concrete specimens with two types of rebar configurations (Ø and #) were conducted. Three typical failure patterns, denoted as “exterior failure,” “interior failure,” and “complete failure,” were observed. The reflection waves of “exterior failure” all exhibited a “single-peak” followed by a period of approximately constant-strain rate loading. For “interior failure” and “complete failure,” the “double-peaks” phenomenon appeared in the reflection waves of reinforced-concrete, but the “compression wave” of the transmission wave was weakened and gradually disappeared. Meanwhile, for plain-concrete and reinforced-concrete, the postpeak behavior of the stress–strain curves included three stages, that is, stress-drop, stress-buffer, and stress-softening. The main role of the rebars in the reinforced-concrete was reflected in the postpeak behavior of the stress–strain curve, which exhibited plastic flow behavior as the metal materials. The stability of the rebar frame directly affected the efficiency of the rebars. Additionally, the weak interfacial effect of the smooth rebar between the concrete yielded a counterintuitive test result, that is, at the same strain rate, the dynamic compressive strength of the reinforced-concrete was lower than that of the plain-concrete. However, owing to its toughness and deformation ability, the rebar frame provided good protection of the internal concrete.