Experimental investigations on the concrete breakout capacity of crimped sleeves in steel fiber-reinforced concrete

Crimped sleeves are anchorages suitable for permanent fastening of structural components to reinforced and unreinforced concrete. These consist of a steel sleeve with an internal thread and are crimped at the end to ensure a defined embedment depth in concrete. In this work, experimental investigations were carried out on the tensile and shear behavior of crimped sleeves in steel fiber-reinforced concrete (SFRC). A selection of four crimped sleeves of the same type (M16 x 60, M16 x 80, M20 x 70 and M20 x 100) were tested in normal strength plain concrete and SFRC with 30 kg/m(3) and 50 kg/m(3) fiber content. The aim was to investigate how these fiber contents contributed to the load-bearing behavior of concrete in tension and shear. In total, 48 crimped sleeves were tested in axial tension and 48 crimped sleeves in shear. The results show, with respect to the embedment depth and diameter, that the steel fibers have a positive effect on the load-deformation behavior of the crimped sleeves. With an improved ductile behavior and the crack bridging by the steel fibers in the SFRC, an optimal utilization of the crimped sleeves can be achieved. A comparison of the present results with further test series from the literature demonstrates that the maximum tensile and shear capacity of concrete can even be increased compared to normal strength concrete.