Slashdot Mirror
Concrete That Purifies the Air
fergus07 writes "Although much of the focus of pollution from automobiles centers on carbon emissions, there are other airborne nasties spewing from the tailpipes of fossil fuel-powered vehicles. These include nitrogen oxides (NOx). In the form of nitrogen dioxide it reacts with chemicals produced by sunlight to form nitric acid – a major constituent of acid rain – and also reacts with sunlight, leading to the formation of ozone and smog. Everyone is exposed to small amounts of nitrogen oxides in ambient air, but exposure to higher amounts, in areas of heavy traffic for example, can damage respiratory airways. Testing has shown that surfacing roads with air purifying concrete could make a big contribution to local air purity by reducing the concentration of nitrogen oxides by 25 to 45 percent."
ah its 10 % more expensive.
Also you can't use salt to de-ice in the winter. Destroys the concrete surface quickly, which is why there are some concrete highways in the Southern US, but none in New England...
still no sig
Concrete highways have both advantages and disadvantages compared to asphalt paving materials. Concrete typically is more durable and lasts longer if properly laid, however is also nigh-impossible to repair without entirely removing it then repouring the slabs. This is why the majority of highways and roads are paved with asphalt but bridges, overpasses, and ramps are often concrete. And if you're in a vehicle with a suspension, you usually can get away with something a good three times your figure for speed.
This is an update on the results of the testing.
You're right. In fact, I saw this on slashdot in 2006.
You're thinking of phosphates. NOx causes smog.
I dug up the link to: http://science.slashdot.org/story/06/11/10/041214/A-Concrete-Solution-To-Pollution
Titanium is pretty common. The hard part with it is getting it into alloy form because it has to be smelted without oxygen present or else you get a bunch of titanium dioxide, a lit fart or two, and not much else.