Effects of fiber spacing and inclination on the pull-out behaviors of arc-shaped fibers in brittle SIFCON matrix

This study investigates the effects of fiber spacing and inclination on the pull-out behaviors of arc-shaped steel fibers (A-fiber) and hooked-end steel fibers (H-fiber) embedded in brittle slurry-infiltrated fiber concrete (SIFCON) matrix. To this end,two inclination angles of 0◦ and 45◦ and three fiber spacings of 2 mm, 3 mm and 5 mm, corresponding to three fiber content of 13%, 7%, and 1% are adopted. The results demonstrate that the A-fiber exhibit superior slip capacity than the H-fiber, once the end hooks are straightened. Regardless of the fiber shape, the reduction that of the fiber spacing enhances the bond capacity of the fibers. Raising the fiber spacing reduces fiber interaction, leading to an average bond strength approaching the single fiber specimens. In SIFCON with higher fiber content, the average bonding strength of SIFCON containing A-fiber is higher than that of those containing H-fiber. The fiber bundle about the A-fiber causes significant matrix spalling, while the fiber bundle of the H-fiber enhances the bond capacity and contributes to fiber failure. Regarding inclination, the A-fiber induce substantial matrix spalling, whereas the H-fiber experience direct fracture.