Impact resistance of novel geogrid reinforced green concrete under effect of high-speed projectiles

Catastrophic disasters caused by hard/high-speed projectiles represent a significant threat to the integrity of concrete structures. Therefore, the impact resistance of concrete structures must be a critical consideration in its design procedures. This research assessed green concrete mixtures incorporating steel slag and silica fume as by-products that fulfill sustainability criteria, and geogrid reinforcement as reinforcing contenders, tested against modified hard M8 armor-piercing incendiaries at velocities up to 930 m/s. The compressive, tensile, and flexural strength of the proposed green concretes was evaluated. While, the projectile impact resistance was evaluated in terms of the energy absorption capacity, perforation resistance, crack trajectory, projectile deviation length and angle, and fracture diameter at front and rear faces of concrete panels. The results indicated slight static performance improvements and substantial impact resistance enhancements. It was revealed as a 96 % increase in energy absorption, up to 50 % better-cracking resistance, up to 12 % reduction in impact diameter, and up to 200 % improvement in deviation angle and distance compared to normal concrete. A superior impact resistance was achieved by the multiple geogrid-reinforced green concrete panels by fully preventing the perforation of the aforementioned high-speed projectile. The concluded optimum design for overall mechanical properties is steel slag concrete mixtures reinforced by biaxial geogrid meshes. This research achievements pave the way for utilizing such sustainable concrete in critical infrastructures.