Influence of Steel Fibres and Matrix Composition on The Properties of UHPFRC

Abstract

The influence of fibre length, volume fraction and composition of matrices on the self-flowing ability and the mechanical properties of ultra-high performance fibre reinforced concrete (UHPFRC) is reported. Four different self-compacting UHPC mixtures with different maximum grain size of 1 mm, 2.5 mm, 4 mm, 8 mm and compressive strength of 190 MPa were used. Two types of steel fibres with length-diameter ratios of 13mm/0.2mm and 20mm/0.2mm were employed to improve the ductility of these UHPCs. The investigations on the mechanical behaviours of the UHPFRCs using critical fibre volumes, which were experimentally determined to ensure the self-compacting properties of the fibres concrete, were carried out. There were no significant effects of the fibres on the compressive strength of the UHPFRCs. For UHPFRCs with maximum grain size up to 4 mm the concretes using the long fibre had a similar modulus of rupture and a better toughness in comparison to the concretes including twice higher volume fraction of the short fibre.