The performance of a self-cleaning cool cementitious surface

• Photocatalytic activity was tested using three TiO2 anatase sources.
• Addition of 5% and 30% of TiO2 in white cement paste was made.
• Dye degradation works better with 30% of TiO2 than 5% for self-cleaning purposes.
• Self-cleaning by photocatalysis can maintain cool properties durability.

Cool surfaces are designed to reflect more sunlight and absorb less heat. Environmental exposure can cause surface darkening. Microbiological growth and soiling can be partially controlled by periodic cleaning. A self-cleaning surface would be a suitable proposal for maintaining adequate reflectance.The aim of this study is to obtain a cool, self-cleaning cement-based surface using TiO2. Three samples of commercial TiO2 (anatase) nanoparticles (P25, US NANO – IV and Millennium – TiONA) were mixed with white cement and water to produce a self-cleaning paste. The cement paste specimens were prepared by replacing 0%, 5% and 30% of the cement (by mass) by TiO2.The powder samples were characterized by X-ray fluorescence spectroscopy (XRF), and the photocatalytic efficiency of the specimens was tested using Congo Red dye degradation under UV and visible radiation. The loss of colour was measured by diffuse reflectance using a UV–vis spectrophotometer.The cement specimens were characterized, before dye degradation, using UV–vis and Raman spectroscopy, and scanning electron microscopy to verify the presence of TiO2 on the surface. The specimens’ characterization demonstrated high levels of TiO2 on surfaces indicating conditions for photocatalytic reactions in case there was a presence of organism growth or deposits of atmospheric pollution.