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."

Why can it only be roads?

[TooMad]

Concrete is used all over the place air ie gas goes everywhere. Where there are cars and roads there are plenty of other places to use the air purifying concrete other than a road.

Re:But at what cost.

[camelrider]

ah its 10 % more expensive.

That's big money in a road project!

Re:Concrete roads are shit

[gknoy]

You can get away with using them for speeds around 25 mph but even that is typically a tragedy. Just say no to concrete highways. Try to avoid using it in civil planning. Even the increased road glare is a hazard.

I've grown up in southern California, where most of our freeways are concrete, though roads are tarmac. I much prefer driving on concrete. I find the glare to be less in the mornings or evenings (though polarized sunglasses help a lot in both cases) than with oily tarmac. Sure, it's likely not so great for a road that doesn't have good maintenance, but for a highway system it is very nice to drive on. I've never encountered the damaged concrete roads that you have, which I think is ironic given that I live(d) in one of the most earthquake-prone parts of the country.

Another advantage of concrete is that they have cut grooves in many parts of the highways (running parallel to traffic) which allow a small amount of water to settle there. The net result is that I can still see where lane markers are, and the road glare from other car's lights is roughly halved. On a tarmac section of road (such as pretty much everything that isn't a freeway here), it's pure hell to see where the lanes are when it rains. This is especially stressful when there is no physical median between each side of the road, or when your 4-lane road has curves in it. When wet, tarmac is like driving on a mirror -- I can't see a damn thing that's useful, and it scares the hell out of me.

As a driver, I'd rather drive on concrete roads ALL the time.

The biggest problem with concrete is that you cannot repair it gracefully as you can with tarmac.... If the ground settles under 'crete you grind the highs and pray.

The ease of repair is a good point, though. I don't know how much time they spend resurfacing concrete roads. On the other hand, the only times I've seen substantial road work on our freeways has been when they're building NEW portions of road, or are re-surfacing tarmac. The concrete seems to last forever, whereas they end up sending new tarmac crews around to various roads every 5-10 years. I believe (but could be wrong) that tarmac degrades faster than concrete, especially under high traffic. The tarmac roads I drive, with the exception of the ones that have been freshly surfaced, are always in worse condition than the concrete highways which are older.