Influence of iron doped TiO₂ nanotubes on the hydration of tricalcium silicate

Environmental pollution is one of biggest challenges facing the world. The promising technology to control this problem is utilization of semiconductor materials as photocatalyst. It is well known that normal TiO₂ showing photocatalytic activity in the UV light, so to decrease the band gap and shifting into visible light, titanium dioxide nanotubes was doped with Fe³⁺ ions. The influence of fabricated Fe‐doped TiO₂ nanotubes (Fe/TiNTs) on the hydration of tricalcium silicate (C₃S) have been studied. Addition of 1.0 wt%, 2.0 wt% and 3.0 wt% of Fe/TiNTs into C₃S system significantly accelerated the course of hydration. Study on the hydration products after 8h, 1d and 7d improved the degree of hydration. The enhancing of compressive strength of hydrated C₃S after 7d, 14d and 28d was observed comparing to the normal TiO₂ nanotubes (TiNTs). Also treating both Fe/TiNTs and TiNTs with supersaturated Ca(OH)₂ solution revealed a strong interaction between Ca²⁺‐ ions and nanotubes particularly in the presence of iron (Fe/TiNTs). The specific surface area of hydration products in the presence of Fe/TiNTs was increased. In this study, isothermal calorimetry was utilized for the course of hydration, x‐ ray powder diffraction (XRD) for the phase composition in combination with simultaneous thermal analysis (STA) and gas adsorption (GA) for measuring specific surface area of nanotubes and hydration products.