Variation of self-cleaning performance of nano-TiO2 modified mortar caused by carbonation: From hydrates to carbonates
Zixiao Wang, Qingliang Yu, Pan Feng, H.J.H. Brouwers
Abstract
Evaluation and quantification of the effects of the carbonation process on photocatalytic activity are essential for the long-term functional assurance of nano TiO2 modified photocatalytic concrete. This work focuses on the photocatalytic self-cleaning performance variation of mortar containing different dosages of nano TiO2 hydrosol at different carbonization duration. The colourimetric analysis is used to evaluate the self-cleaning performances of carbonated mortar samples. The distribution areas of anatase TiO2, hydrates, and carbonates in the mortar surface are characterized by the Confocal Raman Microscopy. The data recorded during the 28 days of carbonation show that the self-cleaning performance of mortar surfaces features a recovery phenomenon during carbonation. The correlations between photocatalytic self-cleaning performance and the possible parameters are analysed. A predictive model is suggested to evaluate the influence of carbonation degree on the photocatalytic self-cleaning ability of nano TiO2 hydrosol modified mortar.