NUMERICAL CHARACTERIZATION OF THE TENSILE STRENGTH OF CONCRETES WITH RECYCLED CERAMIC SANITARY AGGREGATES AND REINFORCED WITH POLYPROPYLENE AND STEEL FIBERS

Pursuing innovative, efficient, and sustainable construction materials is a priority for international agendas. In this context, materials such as recycled aggregate concrete (RAC) and fiber-reinforced concrete are key to these goals. However, the practical application of these innovative materials in construction is still challenging due to the lack of proper characterization of their tensile behavior and detailed design provisions to predict their tensile strength. Some researchers have characterized specific matrices of recycled concrete with polypropylene fibers. However, a wide variety of new RAC matrices, based on different recycled materials, have been recently proposed and remain uncharacterized. Therefore, this study characterizes the tensile strength of particular RACs, based on recycled aggregates from ceramic sanitary waste, reinforced with polypropylene fibers (PFRC) and steel fiber (SFRC). The main variables analyzed were the effect of recycled aggregate content (RA) and fiber type on the toughness and tensile strength of a particular RAC mixed with a partial replacement of recycled aggregates. The analysis was conducted numerically using the Finite Element Method (FEM), employing a softening function obtained through the inverse analysis technique to reproduce the desired experimental behavior. The results from the numerical models showed acceptable accuracy when compared to the experimental test data, indicating that the proposed model strategy is suitable for predicting the properties in question. After validating the numerical models, parametric analysis is conducted to explore different design parameters. The parametric analysis revealed a trend of improved compressive strength with increasing recycled aggregate content. Steel fibers demonstrated better performance compared to polypropylene fibers, with an improvement of more than 20% in flexural tensile strength. Thus, recycled concrete aggregates can be improved for structural applications by using fibers.