Missouri Department of Transportation (MoDOT) officials and contractor, Fred Weber Inc., will place a new type of concrete on a section of Route 141 between Ladue Road and Olive Boulevard in St. Louis on Oct. 24 at 10 a.m.
Crews will lay concrete with a photo-catalytic additive of titanium dioxide (TIO2), according to a MoDOT news release. This additive absorbs smog, uses sunlight to break it down, and releases it as nitrogen and carbon dioxide. MoDOT managers stated in the release they believe this additive, which has been used in Europe, is being tested here for the first time in the United States.
Workers will use a process called two-lift paving to place this section of concrete. In this process, crews will lay down a thick layer of concrete and then immediately place a second, thinner “lift,” or layer of concrete on top of that thick layer. Concrete placed using this method is as strong as that used on standard concrete pours.
This process lets the department place two different concrete mixtures. according to MoDOT spokespersons. Since the titanium dioxide additive is expensive, this paving technique lets the department use the additive in the thinner top lift while still getting the benefit of a thick slab of concrete.
MoDOT employees will test a 1,500-foot section of the new Route 141 with this smog-eating concrete. The test period for the concrete will start when Route 141 opens up to traffic in mid-2012.