Evaluation of changes in surface temperature of TiO2 functionalized pavements at outdoor conditions

Abstract

Surface temperature of ten different materials (combination of different commercial TiO-based photocatalysis on different types of substrate) located outdoors have been recorded for a 12-hours period using an infrared thermography camera after 2 years of exposure to environmental conditions. Twin conventional pavement‘s substrates (asphalt, and three kinds of tiles) were also evaluated as a reference. A detailed optical, chromatic, and textural characterisation was performed and statistical analysis was carried out to further understand the significance of the parameters that control the surface temperature changes. It generally seems that the mean daily surface temperature and temperature range of the TiO modified materials are lower than their corresponding conventional material. The observed differences on the thermal behavior does not seem to be directly related to the TiO photocatalytic effectiveness. The emissivity values do not show significant variations by the application of the nano-TiO additives. A multivariable correlation has allowed to deduce that main contribution to the lower temperature in the photocatalytic pavements is due to the smoother surface induced by the addition of the photocatalyst.