Response of initially stressed concrete targets under high rate of loading

Prestressed concrete is a highly being used material in the construction of strategic and important structures such as nuclear containments, bridges, storage structures and military bunkers. It is highly durable, fire and corrosion resistant and nonporous. In order to study the influence of prestresing on the ballistic characteristics of concrete targets ballistic experiments have been carried out against ogival nosed (3 CRH) hard steel projectiles. The projectile of 0.5 kg mass were normally impacted on 80 mm thick presstressed concrete targets of plan size 450 mm x 450 mm. The unconfined compressive target strength of concrete was designed 48 MPa. An initial stress of 10% magnitude of compressive strength was induced by 4 mm diameter high tensile strength (1700 MPa) steel wires in prestressed concrete targets. A grid of 8 mm diameter steel bars were inserted in the reinforced and prestressed concrete targets to enable the straight comparison between these concretes. The prestressing in concrete has been found to be effective in reducing the volume of scabbed material as well as the ballistic resistance of prestressed concrete targets. The ballistic limit of prestressed concrete with 10% induced stress was found to be 10.2 % higher than that of the reinforced concrete and 14% higher than the plain concrete target, respectively.