Fracture Properties of Steel Fibre Reinforced High-Performance Concrete Containing Nano-SiO2 and Fly Ash

In this article, we study the effect of steel fibre on the fracture properties of high performance concrete (HPC) containing fly ash and nano-SiO₂. The results reveal that the addition of appropriate content of steel fibre helps improve the fracture properties of HPC. Steel fibre improves the fracture parameters of initial fracture toughness, unstable fracture toughness, fracture energy and critical crack opening displacement of the beam specimen of HPC. The results also show that steel fibre has major effect on the fracture curves of the three-point bending beam specimen. The fracture toughness and fracture energy increase gradually, and the area under the fracture relational curve becomes larger when the steel fibre content increases from 0.5% to 2%. However, these fracture parameters begin to decrease and the area under the fracture relational curve becomes smaller when the steel fibre content exceeds 2%. This indicates that steel fibre helps improve the fracture properties of HPC containing nano-SiO₂ and fly ash only when its fibre content does not exceed 2%.