Innovative Photocatalytic Cementitious Road Materials

Photocatalytic cementitious road materials represent a new frontier in air quality improvement research, thanks to photocatalysts ability to accelerate natural reaction of oxidation, favouring the pollutants decay. This paper presents some findings that contribute to a better understanding of the effectiveness of photocatalytic road materials, evaluating the synergetic effect of cement and photocatalysts, mainly titanium dioxide, in reducing air pollutant concentrations in urban area, guaranteeing, at the same time, the surface characteristics usually required by a road pavement wearing course. Two different types of concrete road surfaces were studied, choosing the proper selection of titanium dioxide and cement: photocatalytic paving blocks and bituminous open grade filled with photocatalytic cementitious mortar. Results from a large amount of laboratory tests and pilot projects as well are described to demonstrate the enhancement of air quality through these innovative pavements, focusing on nitrogen oxides degradation into inert substances. Besides, concerning the pavement combining asphalt concrete and photocatalytic mortar, other aspects were accounted for in the analysis and a large database of laboratory testing was developed to assess the influence of titanium dioxide on material features, such as fluidity, compression resistance and shrinkage.