Strain Behaviour of Concrete Slabs under Impact Load

Abstract

This paper presents drop tower experiments. In order to analyse the behaviour of concrete slabs under high strain rates, an impact mass is dropped from a maximum height of 9 m onto square concrete slabs with a side length of 1 m. Slabs of different concrete strengths are tested and the behaviour of standard concrete slabs is compared to that of high performance concrete (HPC) and ultra-high performance concrete (UHPC). Furthermore, the influence of an additional strengthening layer of fabric reinforcement is analysed. For this, steel cord fabric and carbon cord fabric are applied to a slab group. The concrete strain on the slab top and the steel strain on the slab bottom are monitored. Based on the analysis of the concrete strain and the steel strain, the local behaviour and global behaviour due to the impact load can be identified. In addition to the measurement results, slab perforation and damage effects due to impact load are evaluated qualitatively. Comparing the concrete specimen with and without additional fabric strengthening, substantial advantages in the resistance to the impact load and to the penetration of the impactor are seen for slabs with a strengthening layer.