Bearing capacity of reactive powder concrete reinforced by high-strength steel spirals

High-strength steel spiral is used to confine the anchorage zone of reactive powder concrete (RPC) to avoid the brittle failure of RPC anchorage zone, so that the aim of improving the ductility and increasing the bearing capacity of anchorage zone may be achieved. Based on three fundamental parameters including the ratio of the net pressure-bearing area to the bearing plate area, the ratio of the bearing plate area to the core concrete area and the ratio of steel spirals, 12 RPC blocks reinforced by steel spiral with 970 MPa strength were tested for their locally axial bearing capacity. According to test results, for one half of specimens, stress in steel spirals exceeded the proportional limit when they failed, indicating that the strength of high-strength steel spirals may be sufficiently exploited. The specimens may even crack under small load, but the development of surface crack was slow before the failure occurred. Large-width cracks and spallation might appear at the loading ends, but the specimens remained as an integral whole. The influences of three fundamental parameters were evaluated. Furthermore, combined with the experimental results of unreinforced RPC, a practical calculation method of bearing strength is proposed for RPC reinforced by high-strength steel spirals.