Evaluation of the durability of titanium dioxide photocatalyst coating for concrete pavement

The use of titanium dioxide (TiO2) ultrafine particles as coating for concrete pavement have received considerable attention in recent years as these particles can trap and decompose organic and inorganic air pollutants by a photocatalytic process. In spite of these promising benefits, the durability and resistance to wear of TiO2 surface coating has not been evaluated. The objective of this study was to determine the abrasion and wear resistance properties of TiO2 coatings and its effect on the coating’s environmental performance. To achieve this objective, an experimental program was conducted to measure and compare the environmental performance of titanium dioxide coating before and after laboratory-simulated abrasion and wearing. The environmental efficiency of the coating to remove nitrogen oxides (NOx) from the atmosphere was measured using a newly developed laboratory setup. Microscopic analysis was conducted using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) to determine the distribution of TiO2 particles on the surface before and after wearing. The measured rut depth using the Loaded-Wheel Tester (LWT) was minimal indicating that the use of the coating did not appear to affect the wear resistance of the surface. Wearing of the specimens with 5% TiO2 resulted in a small decrease in the coating NO removal efficiency. In contrast, the wearing of the samples with 3% TiO2 slightly improved the NO removal efficiency. Results presented in this paper support that the use of TiO2 coating as a photocatalytic compound would provide acceptable durability and wear resistance.