Influences of Strain Rate and Density on the Dynamic Material Properties and Energy Dissipation Characteristics of Iron Tailing Porous Concrete

Iron tailing porous concrete (ITPC) is a type of foamed concrete material that uses iron ore tailings powder to partially replace cement. As a relatively new concrete-like material, only very limited research on the dynamic material property of ITPC under high strain rates has been performed. To supplement the material properties for its practical applications, in this study, splitting Hopkinson pressure bar (SHPB) tests were carried out to measure the dynamic properties of ITPC specimens with a density range of 600 kg/m3–1,200 kg/m3 in a strain rate range of about 120 s−1–250 s−1. The influences of strain rate and density on the impact resistance performance of ITPC were analyzed based on the failure modes, stress–strain relations, compressive strengths, elastic moduli, peak strains, and dynamic increase factors (DIFs). The microstructures of ITPC after impact were also observed and characterized by scanning electron microscopy (SEM). Moreover, the energy dissipation characteristics were discussed and analyzed. The test results indicate that the dynamic properties of ITPC exhibit significant strain rate effects and density dependence. The dynamic compressive strength of ITPC increases quadratically and linearly with density and strain rate, respectively. Moreover, the empirical formulas for dynamic compressive strength, DIF, energy dissipation ratio, and energy dissipation capacity of ITPC as functions of strain rate and material density are proposed based on the experimental data; the variation trends of these key dynamic mechanical parameters of ITPC are analyzed and discussed in detail.