Pervious Concrete with Titanium Dioxide as a Photocatalyst Compound for a Greener Uraban Road Environment.

摘要

The United States is facing the problem of trying to control air pollution from vehicle emissions, especially in growing urban areas. This study innovatively investigates applying the photocatalytic effect of titanium dioxide (TiO2) onto pervious concrete pavement to remove some of these pollutants from the air, so that pervious concrete pavement can be installed for two sustainable applications: storm water management and air pollutant removal. The photocatalyst, TiO2, activates with UV radiation to oxidize air pollutants, such as nitrogen oxides (NOx) and volatile organic compounds (VOCs). This study compared different methods to apply TiO2 onto the surface of pervious concrete and measured the photocatalytic activity of the concrete, the infiltrating characteristics of the pervious concrete, and its ability to withstand environmental weathering. A brief analysis on each application method with respect to material cost is also presented. High pollutant reductions were seen with a driveway protector mix, a commercial water-based TiO2 preparation, TiO2 in water, a cement-water slurry with low cement concentration, and the commercial PURETI coating. It was found that nitrogen oxide (NO) was efficiently removed with each of these treatments, while VOCs displayed more variability in removal efficiency. The PURETI coating had the least effect on reducing the infiltration rate of the pervious concrete. The driveway protector mix had the highest resistance against deicing chemical and freeze-thaw testing. When pervious concrete was compared to traditional concrete, pervious concrete showed higher NO reductions, whether the sample had TiO2 coating on it or not.