Experimental and numerical investigation on the resistance of steel fiber-reinforced heavyweight concrete slabs against rigid projectile impact

This study presents an inclusive experimental and numerical investigation of the resistance of steel fiber-reinforced heavyweight concrete under the impact of a high-velocity rigid projectile. Thus, concrete specimens were made using hooked-end steel fibers at 0%, 0.5%, 1%, 1.5%, 2%, and 2.5% volume fractions to assess the physicomechanical specifications of heavyweight concrete containing iron ore as fine and coarse aggregates. Also, the compressive and splitting tensile strengths, modulus of elasticity, stress-strain relationship, bulk density, and water absorption capacity of heavyweight concrete specimens were compared to those of the equivalent normal-weight concrete. The penetration tests were conducted on concrete slabs fabricated with normal weight and heavyweight concrete mixes to examine the specimens' failure mode, penetration depth, and spalling volume. The results revealed that normal-weight concrete's compressive and splitting tensile strengths were more susceptible to adding steel fibers. It was also shown that increasing the density and fiber content significantly affected the impact resistance and residual velocity of fiber-reinforced concrete elements. Heavyweight concrete provided better life safety measures against the impact load than normal weight specimens, while the repair and reuse of heavyweight concrete components were feasible. Moreover, numerical modeling was performed using LS-DYNA finite element software, and the predictions were compared to the proposed experimental results and the analytical relations in the literature. There was good agreement between the results.