Impact response of various concretes at 2.8-second drop shaft

Abstract

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.