Evaluation of rheological properties of mortar with TiO2 addition

Abstract

Adding TiO₂ to coating mortars is carried out to promote self-cleaning through photocatalytic activity. However, this addition influences the workability of the mortar and, consequently, the application stage as the TiO₂ used can present a large number of fine particles and a high surface area, increasing the demand for mixing water, requiring consistency adjustments before coating. In this work, three mortars (two with the addition of different types of TiO₂ and one reference) were developed on a laboratory scale to maintain similar workability, using the flow table test. The amount of kneading water was changed to maintain a spread of 220 ± 10 mm and the content of air-entrained was kept constant, around 25%. The mortars were evaluated using the squeeze flow method. Then, a blind test was performed to assess the mason sensitivity during handling and application of the coating, and all mortars were considered similar. However, the yield of the compositions with TiO₂ addition was lower compared to the reference composition, making it possible to explain the results based on the physical parameters of the formulations and with a more in-depth analysis of the rheological indices obtained by the squeeze flow test.