The brilliant white concrete of the new Jubilee Church in Rome is expected to stay clean for the ages thanks to a photocatalytic additive to the concrete.

Concrete Additives:
Self-Cleaning Concrete!

Concrete Decor is typically filled with ideas you can use right away. Instead of stashing this article in your tool bag for on-the-job reference, however, take it to the beach this summer and read it when you have time to think about the future of our industry. For while photocatalysts have exciting potential for decorative concreting, they are still in the technology-transfer phase of moving from laboratory to commercial reality.

Strong sunlight or ultraviolet light decomposes many organic materials in a slow, natural process. You have seen this process, for example, in the way the plastic dashboard of your truck fades and gets brittle over time. Photocatalysts speed up this process and, like other types of catalysts, stimulate a chemical transformation without being consumed or worn-out by the reaction.

When used on or in a concrete structure, photocatalysts decompose organic materials that foul the surface. The organic compounds affected by photocatalysts include dirt (soot, grime, oil and particulates) biological organisms (mold, algae, bacteria and allergens), air-borne pollutants (VOCs including formaldehyde and benzene; tobacco smoke; and the nitrous oxides (NOx) and sulfuric oxides (SOx) that are significant factors in smog), and even the chemicals that cause odors. The catalyzed compounds break down into oxygen, carbon dioxide, water, sulfate, nitrate and other molecules that are either beneficial to or at have a relatively benign impact on the environment. Most inorganic pollutants and stains, including rust, are not catalyzed.