EXPERIMENTAL DETERMINATION OF PENETRATION COEFFICIENTS OF VARIOUS CONCRETE TYPES UNDER HIGH-VELOCITY PENETRATING OBJECT IMPACT

Abstract

Structural failures of buildings can result from high-velocity impacts on structural elements, such as collisions with vehicles, fragments from explosions, or military projectiles during warfare. These impacts may cause deep penetration and severe damage, compromising the load-bearing capacity of the structure. To estimate penetration depth, empirical formulas are commonly employed, which depend on a material-specific penetration coefficient (K_p) that must be determined experimentally. For certain concrete types, including normal concrete (B22.5) and coral concrete, this coefficient has not yet been established. This study presents experimental investigations of penetration depth in concrete specimens subjected to high-velocity impacts using bullet-shaped projectiles. Based on the test results, the penetration coefficient (K_p) was determined as 20.1·10⁻⁷ for B22.5 concrete and 22.13·10^-7; 24.27·10^-7 (B22.5; B20) for coral concrete. This suggests that normal concrete has a higher penetration resistance than coral concrete, primarily because the coarse aggregates in normal concrete possess higher compressive strength than coral aggregates. These findings provide essential data for evaluating the impact resistance of concrete structures under high-speed object penetration, thereby contributing to the development of a database of K_p coefficients with potential applications in the practical design of structures subjected to high-velocity penetrating objects.