Punching shear and flexural performance of ultra-high performance fibre reinforced concrete (UHPFRC) slabs

Ultra-High Performance Fibre Reinforced Concrete (UHPFRC) is a high-performance cementitious composite that is characterised by superior mechanical properties, high energy absorption capacity and enhanced durability. The mechanical characteristics of UHPFRC and more specifically the enhanced tensile strength and the signifi-cant energy absorption and crack resistance make it a very popular material, especially for extreme loading conditions or in cases of thin load bearing elements. UHPFRC has been recently introduced in applications such as bridge decks, and thin slabs and for the strengthening of existing elements. However, the punching shear performance and the effect of the fibres on the punching shear strength of UHPFRC have not been sufficiently studied. Also, there is a lack of provisions for the punching shear design of UHPFRC, which limits the extensive application of UHPFRC in thin elements especially when there are concentrated loads. In this study, extensive experimental work has been conducted on slabs with different geometries and various mixes and valuable results are presented for the flexural and the punching shear capacities of UHPFRC. Also, methodologies for the calculation of the punching shear and the flexural capacities of UHPFRC slabs have been examined and important conclusions have been drawn.