Influence of the properties of polypropylene fibres on the fracture behaviour of low-, normal- and high-strength FRC

• The influence of the polypropylene fibres properties on fracture of FRC is analysed.
• Failure of fibres in FRC depend on its properties and the strength of concrete.
• The ductility of concrete depends on its strength and the properties of the fibres.
• The most suitable fibres for a particular strength of concrete are indicated.

This paper describes a comprehensive experimental study of the influence of the geometrical and mechanical properties of polypropylene fibres on the fracture parameters and ductility of low, normal, and high-strength fibre-reinforced concrete. Three-point bending tests were carried out on 88 notched beams using the simplified boundary effect method of Abdalla and Karihaloo. The influence of the fibre reinforcement was especially felt on the tail of the load–displacement curve, and its effect on the size-independent specific fracture energy of concrete has been subsequently analysed. An analysis of the ductility of the concrete has also been carried out based on the Hillerborg’s brittleness number. The increase in ductility due to the influence of the fibre reinforcement was conveniently analysed for the different mixes. From results, an analysis of the likeliest mechanisms of failure of the fibres reliant on their properties and the strength of concrete was completed. The results showed the most suitable fibres that were used to get the best fracture behaviour for a particular strength of concrete.