Brittle vs. ductile behavior of concrete beams reinforced with steel rebars and fibers

The flexural behavior of hybrid concrete beams, reinforced with both traditional rebars and steel fibers, is investigated in this paper. Specifically, the study concerns the post-cracking response of lightly reinforced members, and consists of an experimental campaign performed on beams in three point bending. Beams were cast using conventional concrete constituents that were reinforced with different combinations of steel rebars and hooked-end steel fibers. In addition, also the use of a special high-performance self-compacting fiber-reinforced concrete mixture, with and without the rebars, was analyzed. As a result, the brittle/ductile response, obtained from the experimental load-deflection curves, indicates the optimal hybrid reinforcement for static reasons (i.e., the most advantageous content of fibers and rebars).