Mechanical, physicochemical, microstructural and self-cleaning performance of nano-titanium dioxide containing photocatalytic cement mortars exposed to elevated temperatures

Abstract

In this study, the effect of thermal exposure on the mechanical, physicochemical, microstructural and self-cleaning properties of photocatalytic cement mortars was investigated. 1%, 2%, 3% and 4% of the ordinary Portland cement weight was replaced with nano-TiO2 particles. Mortars were heated at a rate of 2 °C/min to 200 °C, 400 °C, 500 °C, 600 °C, 700 °C and 800 °C. Compressive and flexural strengths, mass, water porosity, ultrasonic pulse velocity, optical microscopy, scanning electron microscopy, X-ray diffraction and thermogravimetric analysis tests were conducted before and after heating the mortars. The experimental results showed that nano-TiO2 particles have a significant influence on the residual properties of the mortars. The addition of TiO2 increased the resistance of the mortars to thermal deteriorations and preserved the residual mechanical, physicochemical and microstructural properties of the mortars. Additionally, for the first time, the influence of thermal exposure on the photocatalytic performance of cement composites was evaluated in this study by evaluating the degradation of rhodamine B. The photocatalytic performance was unaffected up to 400 °C, however, further heating deteriorated the photocatalytic performance of cement mortars.