Effect of Iron-Doped TiO2 Nanotubes on the Hydration of Tricalcium Silicate

Environmental pollution is one of the most serious and global problems for humans. Photocatalysis is a promising technology to control environmental pollution via the utilization of semiconductor materials as a photocatalyst. In this study, iron-doped TiO2 nanotubes (Fe/TiNTs) with an increased photocatalytic effect at longer wavelengths compared to undoped TiNTs were used, and the effect on the early hydration and mechanical properties of the main clinker phase tricalcium silicate (C3S) was investigated for the first time. Prior to the incorporation of nanotubes into C3S, it was treated with a supersaturated Ca(OH)2 solution. The addition of 1 and 2 wt.% of Fe/TiNTs into the C3S system significantly accelerated the course of hydration. The degree of hydration for the hydration products after 8 h, 1 d and 7 d have improved. The enhancement of compressive strength after 7 d, 14 d and 28 d were observed compared to normal TiO2 nanotubes (TiNTs). Treating Fe/TiNTs with a supersaturated Ca(OH)2 solution revealed a stronger interaction between Ca2+-ions and nanotubes. Fe/TNTs were synthesized via a modified hydrothermal process. The study shows that Fe/TiNTs can be used as a nanomaterial in cement-based building materials due to their enhanced interaction with the system.