Influence of steel fiber on bending behaviors of RPC based on X-ray CT and mesoscopic numerical simulation

Mechanical properties and fracture mechanism of quasi-brittle material are considered largely relied on the mechanical properties of meso-components and the structure of how these components are combined together. In recent practice of numerical simulation, it has become a trend to consider the real structure of materials as accurately as possible. In this paper, macroscopic and mesoscopic bending behaviors of steel fiber reinforced reactive powder concrete (RPC) slabs with fiber volume content between 0.0% and 2.5% were investigated with both experimental tests and numerical simulations. Images obtained from X-ray CT were input into a program named RFPA3D-CT to build a modified 3D FEM model. The results indicate that the steel fibers can help to convert a brittle failure pattern of RPC into a ductile one. Compared with the specimen without fibers, the crack tortuosity and the bending strength of the specimens fiber content of 2.5% are increased by 20.25% and 308.80%, respectively. The bending performance of the numerical results obtained by the modified model are in good agreement with the experimental results, and the relative error values of the tortuosity and bending strength in the simulation compared with those in the experiment are all less than 15%. Moreover, AE parameters and AE curves obtained in RFPA3D-CT can be used to reveal the initiation and propagation process of cracks in RPC.