Impact resistance of hybrid-fiber engineered cementitious composite panels

This paper investigates experimentally the impact resistance of a new hybrid-fiber Engineered Cementitious Composite (ECC) material reinforced with 1.75% polyvinyl alcohol fiber and 0.58% steel fibers. The ECC panels were subjected to impact from a small ogive–nose steel projectile, which was fired from a gas gun, travelling with an initial impact velocity ranging from 300 m/s to 657 m/s. A computer controlled high speed camera was used to record the impact process, the track of the projectile during impact, and the residual velocity of the projectile after perforation. The magnitude of the impact damage to the panels was evaluated from the measured damage parameters such as crater diameter, penetration depth and scabbing diameter after the impact testing. To evaluate the impact resistance capability of the new ECC material, the impact response of plain concrete panels, high strength concrete panels and hybrid-fiber ECC panels made of an ECC mix, which was recommended to be the most promising impact resistance material, were also tested. In addition to single impact tests, double impacts were conducted. The present study showed that the new hybrid-fiber ECC material has an excellent impact resistance to projectile penetration, evidenced by a number of capacities such as the greater absorption of the impact energy from a projectile, the higher fiber bridging capability and the better durability under multiple impacts.