Influence of curing regime and steel fibres on the mechanical properties of UHPC

The effect of accelerated curing and steel fibre volume on ultra-high performance concrete (UHPC) is the focus of this paper. The compressive strength and microstructural properties of UHPC were evaluated under water, steam and heat curing. The results show that heat-cured samples have higher mechanical properties than those undergoing the other curing techniques. Experimental studies were conducted on heat-treated specimens with different steel fibre volumes and aspect ratios (2·5% and 2·0% of 13 mm and 6 mm length fibres of diameter 0·16 mm) to examine stress–strain behaviour, tensile behaviour and flexure behaviour. The stress–strain behaviour of UHPC was evaluated by uniaxial compression tests on cylinders to propose a new stress–strain model for UHPC under compression. Size-dependent and size-independent fracture energies were determined as per the Rilem procedure and the P–δ tail correction method. Flexural and residual strengths were evaluated under four-point bending.