Experimental and numerical characterization of the bond behavior of steel fibers recovered from waste tires embedded in cementitious matrices

This work investigates the mechanical behavior of recycled steel fibers recovered from waste tires and, then, suitable to produce eco-friendly fiber-reinforced concrete. Particularly, the results of an experimental investigation aimed at understanding the tensile response of the aforementioned steel fibers and their bond behavior when embedded in cementitious matrices are reported and discussed. Moreover, as a case study, a fracture-based plasticity formulation for simulating the overall pull-out behavior of fibers embedded in cementitious matrices is also employed. This formulation is based on assuming a discontinuous response between interface bond stresses and the corresponding relative displacements. Then, an extensive comparison between numerical predictions and the corresponding experimental results of the pullout behavior of recycled steel fibers embedded in concrete is presented for validating and calibrating the model. A satisfactory agreement was observed between the numerical and experimental results: it demonstrates the soundness of the interface formulation.