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This work aims to demonstrate the effective use of fibre reinforcement in thin plate elements made of UHPFRC under projectile impact loading. The use of fibre reinforcement is very efficient in case of ballistic loading, as fibres are evenly distributed over the entire volume of the material body and possible damage to the plate is thus suppressed in all points of the plate element equally. The aim of this study is therefore to provide data on the residual flexural capacity of plates that have been significantly damaged by the impact of the projectile and to demonstrate the benefits of using fibre reinforcement for localized impact loading.

This paper presents experimental testing of various types of concrete under impact loading by using a 2.8-second drop shaft. The drop shaft is located in the Josef Underground Laboratory and allows dropping a projectile from 40 meters that results in a maximal velocity of 100 km/h. Three basic types of concrete were used in the framework of this study. This was normal strength concrete, fibre-reinforced concrete, and high-performance fibre-reinforced concrete. The slabs were constructed 1700 mm × 500 mm × 70 mm in size and the clear span of the impacted slab was 1500 mm. Damage of the slab was recorded and the velocity of the projectile was measured with the high-speed camera before and after the impact. It was demonstrated that high-performance fibre-reinforced concrete has a higher ability to absorb and dissipate the kinetic energy of the impact that their lower strength counterparts.