Life-cycle assessment of titanium dioxide coatings

The use of Titanium Dioxide (TiO 2) ultrafine particulates as coating for concrete pavement have received considerable attention in recent years as these coatings can trap and absorb organic and inorganic air pollutants by a photocatalytic process. Despite these promising benefits, the promotion of TiO 2 coatings based on a single factor such as air quality does not provide a complete evaluation of this technology and may omit critical environmental factors that should be considered in sustainable material selection decision-making process. The objective of the research reported in this paper was to determine the life-cycle assessment of TiO 2 coating technology. To achieve this objective, a life-cycle inventory (LCI) that quantifies the energy, abiotic raw material inputs, and emission of TiO 2 coatings from cradle to grave was developed. Based on this inventory, life-cycle impact assessment of TiO 2 coatings for concrete pavement was determined using the BEES impact assessment model. Results showed that the use of titanium dioxide coating reduces the environmental impact of four main categories: acidification, eutrophication, criteria air pollutants, and smog formation. However, during production phases and due to the consumption of fossil energy, titanium dioxide will cause an increase in global warming, fossil fuel depletion, water intake, ozone depletion, and impacts on human health. Based on the overall environmental performance of this product, life cycle assessment shows that titanium dioxide coating has an overall negative score of -0.70 indicating that theaddition of this surface layer will have an overall positive effect on the environment. © ASCE 2009