The Influence of Using Recycled Waste Aggregates and Adding TiO2 Nanoparticles on the Corrosion Resistance of Steel Reinforcement Embedded in Cementitious Composite

The aim of this paper was to examine the effects of adding TiO2 nanoparticles to cementitious compositions and partially substituting natural aggregates with recycled aggregates consisting of glass, brick, slag, or textolite, and to examine the material’s ability to resist corrosion under the action of chloride ions existent in the environment that attack the steel reinforcement. The results show that the changes in the cementitious composite when it comes to the composition and microstructure influence the formation of the oxide passivating layer of the reinforcement. The addition of TiO2 nanoparticles and recycled aggregates impacts the kinetics and corrosion mechanism of the reinforcement. An addition of 3% TiO2 was found to be optimal for reinforcement protection. Electrochemical impedance spectroscopy confirmed the results obtained by open-circuit potential and linear polarization tests. The classification of favorable conditions indicates that compositions with recycled aggregates and 3% TiO2 are the most effective, with compositions in which the natural aggregates were partially substituted with slag being the most effective.