Influence of steel fibre on bending behaviours of RPC based on X-ray CT and mesoscopic numerical simulation

The mechanical properties and fracture mechanism of quasi-brittle materials are considered to be largely reliant on the mechanical properties of meso-components and the structure formed when these components are combined. In recent numerical simulation practice, a trend has developed whereby the real structure of materials is considered in as accurate a way as possible. In this paper, the macroscopic and mesoscopic bending behaviours of steel fibre-reinforced reactive powder concrete (RPC) slabs with fibre volume content between 0.0% and 2.5% were investigated using both experimental tests and numerical simulations. Images obtained from X-ray computed tomography (CT) were input into a program named RFPA^3D-CT to build a modified three-dimensional finite-element method model. The results indicate that the steel fibres can help to convert a brittle failure pattern of RPC into a ductile one. Compared with specimens without fibres, the crack tortuosity and bending strength of specimens with fibre content of 2.5% are increased by 20.25% and 308.80%, respectively. The bending performance according to numerical results obtained by the modified model are in good agreement with the experimental results. Moreover, the acoustic emission (AE) parameters and AE curves obtained in RFPA^3D-CT can be used to reveal the initiation and propagation process of cracks in RPC.