High strength concrete response to hard projectile impact

High strength concrete (HSC) becomes more common in practice and may have advantageous implementations. According to existing penetration formulae HSC is expected to enhance the performance of structural elements that are designed to resist projectile impacts. However, scabbing at the rear face is expected to be more severe in elements that are made of HSC, because of the relatively high material brittleness. Therefore, it is important to enhance the ductility of HSC elements, and one possible direction is to use fibers or wire mesh reinforcement. In order to study the influence of the concrete strength and of the reinforcement type on the elements response, penetration tests were conducted on regular strength concrete (RSC) and on HSC plates, with the following types of reinforcement: 5 mm steel mesh, steel fibers, small diameter steel wire mesh, and woven steel fence mesh of various diameters. The plates were subjected to an impact of a cylindrical hard steel projectile, weighing 120 g, with a conical nose and a 1.5 aspect ration. The projectiles were accelerated by a laboratory gas gun to velocities that ranged between 85 and 230 m/sec, which were measured by an electro-optical device. By comparing the response of these plates to an impacting projectile, the effects of concrete strength and of the reinforcement were studied. Major trends of the elements behavior were studied, their responses were compared and are described herein.