Tolling A Clean, Green Concrete Technology
- Written by CP Staff
With the dedication of a 75-ft.-tall bell tower at Dalton State College in northwest Georgia, Metromont Corp. stands as the first U.S. precaster to fully execute a project incorporating TX Active photocatalytic cement. Project designer Gregg Sims, AIA, recognized the value of TX Active cement for the structure when Metromont's George Spence cited its self-cleaning and pollution-reducing properties upon exposure to sunlight.
Like many other regions, we have some atmospheric pollution that, over time, discolors concrete with an uneven, soot-like coating that distracts from the architecture, explains Sims. Since that darkening is particularly evident on vertical surfaces near the top of structures, the self-cleaning properties of TX Active cement were especially attractive for the new bell tower at Dalton State College Û the tallest structure on campus and highly visible to thousands of drivers daily on adjacent Interstate 75.
Aiming to transform a predominantly utilitarian campus building style, the college chose to introduce a more traditional architectural element in the form of a bell tower as the centerpiece of a new quadrangle. Accordingly, Metromont's Hiram, Ga., plant was enlisted to produce a concrete mix incorporating TX Active and cast the tower. Nazareth, Pa.-based Essroc Cement Corp. Û the North American subsidiary of Italcementi Group Û supplied the photocatalytic cement.
Architectural surfaces formulated with TX Active cement react with sunlight to destroy atmospheric pollutants, notes Essroc's TX Active Product Manager Dan Schaffer. The results are cleaner concrete surfaces and cleaner air. Instead of having to regularly clean the Dalton State bell tower with scaffolding, chemicals and mechanical methods, the college will have pristine surfaces for the life of this beautiful landmark.
Concurrent with the Dalton State bell tower project was another high-profile job incorporating TX Active photocatalytic cement: the I-35 West Bridge spanning the Mississippi River in downtown Minneapolis opened in September 2008. It is bracketed by two 30-ft.-high, white-concrete wave sculptures installed in the median, one at each end of the span. Cemstone Products Co., the primary ready mixed supplier for the bridge, produced a TX Active cement-enriched mix, subsequently formed by Elk River, Minn.-based Stoneworks Architectural Precast to create the gateway elements.
In Europe, the benefits of TX Active cement have been in evidence for more than a decade. Landmarks like Rome's Dives in Misericordia Church, designed by American architect Richard Meier, and Air France headquarters at Charles de Gaulle International Airport in Paris Û two among numerous structures constructed with TX Active-formulated concrete Û remain as clean today as they were at ribbon-cutting, Metromont representatives assert. Besides providing a bright-white color, moreover, the photocatalytic cement inhibits air pollution by promoting conversion of smog-related gases, e.g., CO, nitrous oxides, and SO2, to higher oxidized states at the surface of the structures.