The comprehension of the phenomena caused by fast-transient-loading regimes on structures, such as impact or blast, plays a capital role in order to prevent catastrophic failures. In fact, very complex failure modes can occur at these regimes where compression, tensile and shear strengths are involved. The present study investigates the dynamic response of commercial Ultra High Performance Fibre Reinforced Concretes (UHPFRCs) in direct-shear. Four UHPFRCs with different percentages of fibre reinforcement (1%, 2%, 3% and 4%) were tested at the same high strain-rate level. These results were compared with those obtained on their matrix. They showed that increasing the percentage of fibres enhances the direct-shear strength. The experiments were carried out by means of a Modified Hopkinson Bar device installed in the DynaMat Laboratory.
