Post-peak fatigue performance of steel fiber reinforced concrete under flexure

The present paper deals with an experimental study on the fatigue behavior under bending of plain and steel fiber reinforced concrete (SFRC). Notched beams were tested under three point bending test: both monotonic and fatigue tests on pre-cracked specimens (in which a fracture process zone was present) were performed. In order to quantify the influence of fiber reinforcement on the fatigue performance of SFRC, two volume fractions of fibers (0.5 and 1.0 %) and three fatigue load levels were adopted. Test results are compared in terms of cyclic creep curves and Wohler diagrams, crack opening rate, toughness and energy dissipation. Experimental results show that the fatigue deformations at failure match the monotonic stress-strain curves with a good agreement. Fibers seem to improve the fatigue life of concrete, whereas their effectiveness tends to decrease under high-cycle fatigue. In both cases, however, the addition of fibers ensures an increase of the energy dissipation at failure.