Dynamic mechanical properties and energy dissipation analysis of rubber-modified aggregate concrete based on SHPB tests

Abstract

The fluctuation of the waveform curves in the Split Hopkinson Pressure Bar (SHPB) test can provide a more intuitive reflection of the material's dynamic deformation process, with different strain rates resulting in varying damage states and σ-ε curves. A Φ120×100 mm size SHPB experiment was conducted to study the dynamic mechanical properties of new rubber-modified aggregate concrete (RAC). Based on the different characteristics of waveform and σ-ε curves, combined with high-speed photography technology, the typical failure modes and dynamic compressive strength of rubber-modified aggregate concrete under different loading rates were analyzed. Furthermore, the energy dissipation capacity and mechanism of rubber-modified aggregate concrete at different stages was discussed. The reflected wave of RAC shows a "double-peak" trend of "first high and then low" instead of "first low and then high" of normal concrete due to its exceptional capacity of energy absorption and dissipation. As strain rate increases, a plateau period appears in the reflected wave before first peak. The evolution process is dominated by the energy storage mechanism until it hits the limit, then by the energy dissipation mechanism. These findings can help us design and use RAC materials under dynamic stress.