Abstract: In order to investigate the effect of aggregate size on the anti-penetration ability of concrete targets subjected to high-velocity fragments, a two-stage light-gas gun as the accelerate facility and laser light barrier measurement system were employed to conduct the penetration experiments for plain concrete targets and steel fiber-reinforced concrete targets, and the projectile pose and the dynamic damage process of targets were recorded by a high-speed camera. In the experiments, three different aggregate sizes on 5～10 mm, 10～15 mm and 15～20 mm were involved. The results of penetration depth, crate volume and debris spall processes indicate that the large aggregate size corresponds to the increase of anti-penetration ability for plain concrete targets, but the target with 10～15 mm of aggregate size has the optimum efficiency in terms of anti-penetration ability when comparing to the other two kinds of concrete targets for steel fiber-reinforced concrete targets with 1% steel fiber in volume. Considered the effect of aggregate size on the fracture energy of concrete materials, it indicates that there exists an optimum ratio between the content of steel fiber and aggregate size, and under the optimum ratio, the ability of anti-penetration of concrete targets can reach the maximum value. The results in this paper is very beneficial to the design of protection engineering.

Key words: mechanics of explosion, anti-penetration ability, aggregate size, high-velocity fragment, crate volume