Critical parameters for the penetration depth in cement-based materials subjected to small caliber non-deformable projectile impact

Abstract

It has been recognized that the compressive strength alone cannot accurately describe the penetration depth in cement-based materials subjected to high-velocity non-deformable projectile impact. This paper provides an in-depth investigation with the aim to determine critical effective properties for the penetration depth in cement-based materials across a wide range of compositions and material properties against small caliber non-deformable projectile impact. Compressive strength, elastic modulus, effective hardness index, density, splitting tensile strength, and flexural toughness are considered in the investigation. Cement-based materials investigated include cement pastes, mortars, concretes, ultra-high performance concretes (UHPCs), and engineered cementitious composites (ECCs) with 28-day compressive strengths from 34.2 to 220.2 MPa and elastic moduli from 17.1 to 80.4 GPa. The penetration resistance was evaluated using 300 × 170 × 150 mm3 specimens subjected to the impact of conical-nosed projectiles with a diameter of 8.0 mm and a mass of about 7.8 g at velocities of about 400.0 m/s. Within the range of effective properties considered, the effective hardness index and elastic modulus have the most influence on the penetration depth, as these two parameters characterize the overall contributions of constituent components (e.g. aggregate and matrix). It is also found that UHPCs do not exhibit better impact resistance in terms of penetration depth, in comparison to high performance concretes (HPCs) with coarse aggregate.