Preparation and fracture behavior of annularly aligned steel fiber reinforced cementitious composite: Experiment and simulation

Annularly cement-based structures are widely used in the harsh environments, such as municipal drainage and subway tunnels. The cracks in the structures will provide the penetrate channel of aggressive media, which induces the further deterioration. To prevent cracking and improve durability, an external circular magnetic field is applied in this work to prepare the annularly aligned steel fiber reinforced cementitious composites (ASFRC). The fracture behavior of annularly ASFRC is investigated by three-point bending fracture test. Moreover, the fracture propagation progress is elucidated based on the digital image correlation (DIC) approach. The results reveal that the initial fracture toughness (Kini) and fracture energy (GF) of annularly ASFRC arch notched beams are improved by more than 35% and 100%, respectively, when compared to the steel fiber reinforced cementitious composite (SFRC) with randomly distributed fibers. The development of the strain field produced by the DIC method also demonstrates that aligning steel fibers improves the crack resistance of arch notched beams greatly. Moreover, the effects of steel fiber volume fraction and initial notch ratio on fracture behavior of arch notched beams are further verified and measured based on numerical simulation method. This study can provide guidance for the application and promotion of annularly ASFRC.