Photocatalytic NO removal of concrete surface layers intermixed with TiO2

The combination of TiO2 with cementitious materials to develop functional photocatalytic products (PCP) has garnered considerable attention on a global scale. In practical application, a wide variety of admixtures will be introduced to the PCP. The present study evaluated the effects of a number of factors on the photocatalytic NO removal performance of the PCP. The results showed that the photocatalytic NO removal rate of concrete surface layers increased when glass cullets were used as a replacement of sand. Compared to samples with light green glass cullets, those concrete surface layers with transparent glass cullets displayed a slightly elevated NO removal ability. In addition, it was observed that the concrete surface layers prepared with white cement (WC) and ground granulated blastfurnace slag (GGBS) had a slightly higher photocatalytic NO removal compared with those prepared with WC and metakaolin (MK). Furthermore, adding different coloured pigments into the concrete surface layers significantly reduced the NO removal rate. It was also found that harsh abrasion exerted no obvious deterioration to the TiO2-intermixed concrete surface layers with respect to the photocatalytic NO removal.