Evaluation of nano-TiO₂ on properties of cementitious mortars

This work deals with the effect in fresh and hardened properties of nano-TiO₂ as addition in cement-based mortars. Three commercial nano-TiO₂ powders were characterized by laser granulometry, XRD, FRX, zeta potential, BET and SEM. Two cementitious mortars were produced with nano-TiO₂, an industrialized and a non-industrialized type; then, these mortars were characterized by flowability, surface roughness, flexural strength and surface fracture. The results showed that the nano-TiO₂ addition reduced the flowability in terms of spread on table of the mortars. For surface roughness, in the industrialized mortars, the nanoparticles resulted in a smoother surface, while in the non-industrialized mortars, the nanoparticles formed a rougher surface. For flexural strength, in the non-industrialized mortars, the higher the nanoparticles amount, the higher the strength, while in the industrialized mortars no tendency was verified. In addition, from SEM analysis, it was noted that the fracture of the samples presented a tortuous aspect and growth through the region between cement paste and aggregates. (author)