Now available in North America from Italcementi Group subsidiary Essroc Û after a decade of development and testing in Europe Û TX Active is a patented (white or gray) portland cement whose photocatalytic properties enable the product to use energy from ultraviolet rays to oxidize organic and inorganic compounds, removing them from the atmosphere and allowing rain to flush them from exterior surfaces. Its current formulation contains, in addition to portland cement binders, particles of titanium dioxide (TiO2), commonly used as a white pigment by paint manufacturers.
Besides oxidizing nitrogen oxides (NOx) and volatile organic compounds (VOC) Û raw ingredients of ozone Û TX Active renders harmless such inorganic compounds as sulfur oxides, carbon monoxide, and hydrogen sulfide; organic compounds, including alcohol, acids, aromatics; chlorinated compounds; and, pesticides. Studies have shown that the by-products of photocatalytic oxidization are negligible quantities of nitrates and sulfates, which do not contribute significantly to soil and water nitrification.
Product developers anticipate that best results will be observed where pollution is most severe: Estimates for Milan, Italy, where automobile traffic is occasionally shut down by local authorities for a full day due to air quality issues, indicate that 50 percent cleaner air could be achieved by resurfacing 15 percent of buildings and roads with photocatalytic cement products. Currently, cost-effectiveness dictates that best applications include any product used in thin layers or fabricated in a two-stage process, e.g., involving face mixtures. Û adapted from information supplied to Concrete International by Essroc's Marco Barbesta and Dan Schaffer