Impact testing of fibre-reinforced concrete stair treads

Abstract

Synopsis The note reports a laboratory investigation into the effects of the inclusion of fibrillated polypropylene and two types of steel fibre in reinforced concrete stair treads upon transient strains and cracking behaviour during impact loading. Tests were carried out on 24 specimens of which 12 were made with normal-weight and 12 with lightweight concrete. Within each group of 12 specimens, 3 replicas were made for each of the fibre types and 3 which did not include any fibre reinforcement. The results showed that cracking due to the impact loading was initiated in all specimens by a small drop (100 mm) of the small test mass (4 kg). The fibre inclusion did not delay first cracking, but it did affect the subsequent cracking behaviour, and the steel fibres were more effective in this respect.