MoDOT Selects 141 Improvement Project to Test Smog Absorbent Concrete

October 24, 2011 - Fred Weber, Inc., MoDOT, and various environmental and transportation officials gathered at the 141 Improvement Project near Olive Boulevard to watch FWI crews lay a section of the first ever smog-eating concrete to be tested in the United States.

The concrete, which is treated with a photo-catalytic additive of titanium dioxide (TiO2), will absorb the smog and use sunlight to break it down. It will then be released back into the atmosphere as nitrogen and carbon dioxide. This additive has previously been used in Europe and has proved successful.

Crews used a two lift paving process to place the 1,500 foot test section of concrete. This application consisted of laying a thick layer of base concrete followed by an immediate thinner layer “lift” of concrete which was treated with the additive.

MoDOT officials say that this two layer process helps off-set the cost of the titanium dioxide, and the result is just as strong as standard poured concrete.The test period for the concrete, which has a lifespan of 15-20 years, will begin when Rte 141 opens up to traffic in mid-2012.

"It just acts as a sponge.  It takes those pollutants, holds them in there, and when the sun comes out, the UV rays from the sun activate the cement and it breaks it down into harmless products." - Jesse Jonas, MoDOT Resident Engineer
 

Crews pour second "lift" layer containing smog absorbent additive