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Earth Transportation Science

Concrete That Purifies the Air 88

Posted by samzenpus from the clean-roads dept.
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."
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Concrete That Purifies the Air More

Concrete That Purifies the Air

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  • Old News? (Score:1, Informative)

    by Anonymous Coward

    Saw this back in 2006 ... business week article [businessweek.com]

    Still seems like a good idea though, as long as you're not trading one set of problems for another.

  • Please remember... (Score:4, Funny)

    by JustinRLynn ( 831164 ) on Thursday July 08, 2010 @09:03AM (#32839334)
    Nitrogen oxides go into stone (if there is concrete evidence of this, har har) while nitrous oxide (N2O) [wikipedia.org] gets you stoned.

    ...of course, someone will still confuse the two later in these comments.
  • they want to install moving sidewalks [slashdot.org]...
  • Another eco product with no mention of cost. Cost being an obvious important factor

    • Re: (Score:2, Informative)

      by Mechanist.tm ( 1124543 )
      ah its 10 % more expensive.

      • Re: (Score:2, Insightful)

        by camelrider ( 46141 )

        ah its 10 % more expensive.

        That's big money in a road project!

        • Re: (Score:1)

          by Opie812 ( 582663 )
          That's big money in a road project!

          I say take it out of the kick-backs, bribes and union-mandated funny business. There wouldn't necessarily be any increased cost to the tax-payer if the will existed.

          • That's big money in a road project! I say take it out of the kick-backs, bribes and union-mandated funny business. There wouldn't necessarily be any increased cost to the tax-payer if the will existed.

            If we did that, the roads would never get built. That just how America works!

            • If we did that, the roads would never get built. That just how America works!

              Didn't you mean that's how America "Doesn't" work?

    • Along with cost, durability needs to be taken into consideration. If it costs more, but lasts longer, it isn't too much of a problem. If it breaks apart more easily, especially in colder climates, you could be looking at replacing a road more frequently and at a higher cost.

  • Sounds good (Score:5, Funny)

    by IndustrialComplex ( 975015 ) on Thursday July 08, 2010 @09:06AM (#32839388)

    So who owns the patent, how much extra does it cost, are there any materials not normally used in concrete that we should be concerned about.

    With the way things are going, it will probably work out like this:

    Monsanto owns the patent, it costs less than what we use now, but it has asbestos, and 10 years after installation if we don't treat it with a special chemical (patented by Monsanto) the asbestos is released spontaneously.

    • It's been common knowledge for quite some time that titanium oxide can scrub some pollution from the air, it's also commonly used as the basic ingredient in white paint.

      • Re: (Score:2)

        by vlm ( 69642 )

        Next "eco discovery" reported will be titanium refining and distribution is worse for the environment than trace concentrations of mixed nitrogen oxides.

        There is probably a catalyst poisoning effect, just like every other catalyst out there. Just because the stuff works when its fresh doesn't mean it'll work in 25 years. But the environmental costs of producing and disposing of it are "forever", vs the gains of removing a small amount of oxides for a small number of years.

        • Re: (Score:2)

          by dpilot ( 134227 )

          > Just because the stuff works when its fresh doesn't mean it'll work in 25 years.

          Show me a road that lasts 25 years - at least in the US.

        • Titanium dioxide is one of the safest, most bio-inert substances around. Titanium is used for dental and medical implants because it's oxide coating is completely bio-compatible. It's also the primary pigment in every paint your likely to see, it's why white paint is white; if there were any environmental problems with it, they would have shown up decades ago.

  • Is this the same chemical reaction that is causing limestone facades all over Europe to dissolving in polluted cities?

    http://www.windows2universe.org/milagro/effects/property.html [windows2universe.org]

  • Concrete roads are shit (Score:4, Interesting)

    by drinkypoo ( 153816 ) <drink@hyperlogos.org> on Thursday July 08, 2010 @09:13AM (#32839486) Homepage Journal

    They're nice so long as you don't have any heavy weather, ground settling, or seismic activity. Then they go straight to hell and turn into the light version of Ice Crusher in Jet Moto, where you skip from slab to slab with a solid thump with each transition. Even in my MBZ it is enough to turn the stomach. The biggest problem with concrete is that you cannot repair it gracefully as you can with tarmac. If the ground settles under tarmac you plane the highs and fill the lows, then resurface a section of road (hopefully all lanes, but only the affected area in terms of distance.) If the ground settles under 'crete you grind the highs and pray. And if California is any indication, you probably cover it with some tarmac :p

    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.

    Anyone know how much CO2 is produced in the production of the concrete as compared to tarmac?

    Side note: irony is a concrete company called tarmac. Fuckers did it just to confuse people.

    • Re:Concrete roads are shit (Score:5, Informative)

      by nordee ( 104555 ) on Thursday July 08, 2010 @09:16AM (#32839556)

      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...

      • New England has similar weather to England, it seams. What happened? Did you get nostalgic for the motherland? If only Birmingham was there and not in Alabama... Then you could have your own set of Black Country folk [bbc.co.uk]

      • Re: (Score:2)

        by Kozz ( 7764 )

        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...

        I've lived in Wisconsin all my life. New highway/interstate/city construction is most frequently concrete, not asphalt (although county roads are mostly asphalt). And it's safe to say that we get plenty of snow, and we salt the hell out of the roads when it's necessary. So why do we have concrete? Is it different/treated to be more resilient? Is it cheaper (to install) than asphalt? [I thought concrete was more expensive.] Is it not really concrete but some other kind of material that looks similar?

        • louder, more expensive, better traction, lasts longer.

          I believe the salt damage issue can be mitigated by using a different mix and allowing lots of curing time. After all, asphalt sidewalks are exceedingly rare, but salted even more heavily than roads in high-traffic areas.
          • Amazingly louder, actually. As a transplant from the NE to the midwest, the concrete roads here are stunningly loud.

            I'm surprised that people put up with it, really.
      • I live in northern MN and the decision to use asphalt or concrete is based on many factors, none of which are the deterioration sure to salt. Frost heaves, and snow plows do most of the damage. The damage from salt is negligible in comparison. Many times cost is the major factor. The standard plan for highways is about 5 years and then replace. If they start with concrete then after 5 years they can grid it up and use it as a base for asphalt. 5 more years and they strip it down to the ground and start

      • Re: (Score:2)

        by dcw3 ( 649211 )

        Maybe there are none in NE, but there are plenty of northern states with concrete highways. I'd be interested to see some stats on the difference in potholes between those with and without.

        • The concrete road beds start flat and each slab stays flat but may heave slightly compared to it's contiguous neighbors; also the seems are vulnerable to freeze/thaw damage. Asphalt flows smoothly without slab heaving doesn't have much freeze/thaw damage, but it displays plastic deformation so it tends to trough with wheeled traffic. What I'm seeing installed on our expressways is a thick concrete base that's rolled like asphalt rather than poured, which is then laminated with an asphalt top-layer to seal t

      • None in New England? I can immediately think of two stretches of highway in Connecticut that are concrete and quite a few bridges that are surfaced in concrete.

      • Not true.

        There are plenty of concrete roads in Canada. I remember a large one going in Quebec. You have to treat it for the conditions, just like everything. The same reason road beds are way thicker in colder climates to fight frost.

        http://www.cement.ca/index.php/en/Highways/Building_Sustainable_Highways_in_Canada.html [cement.ca]

        The problem is Concrete is 2x the price to construct. Industry points out it lasts longer, but project costs trump long term stuff many times.

        I would also bet that the CO concrete is even mor

    • Luckily FTFA:

      "The air-purifying concrete contains titanium dioxide, a photocatalytic material that removes the nitrogen oxides from the air and converts them into harmless nitrate with the aid of sunlight. The nitrate is then rinsed away by rain."

      "For roads where an asphalt surface is preferred the air-purifying concrete can be mixed with open asphalt,"

      Guess it won't be as good in very dry climates though unless they actively wash the .roads.

      And I'm not convinced that "nitrates" is harmless to humans and an

    • Re: (Score:2, Informative)

      by Gazoogleheimer ( 1466831 )
      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 spe

      • I usually explain concrete vs. asphalt with a reverse-car analogy. Concrete is digital; asphalt is analog.

        With a concrete surface, you have two states: good or bad. In the 1 (good) state, it's smooth and durable. In the 0 (bad) state, it crumbles away to nothing.

        Asphalt, though, has many values: smooth and flat, a bit bumpy, kinda rutted, cracked, nearly-gravel, and "wasn't there a paved road here once?" The transition between states is gradual, unlike concrete where one day you're driving just fine, and

      • Re: (Score:2)

        by Scaba ( 183684 )

        Concrete typically is more durable and lasts longer if properly laid

        <aolmode min_year="1993" max_year="2005">Me too!</aolmode>

    • Here in S. Texas you find the majority of new roads are concrete. Mainly due to they last longer and have you ever seen what 100+ F temps does to an asphalt road? It turns it into a soft mess. It's not uncommon to see weak asphalt roads that have grooves in them due to the high temps and heavy trucks.

    • Re: (Score:1, Informative)

      by Anonymous Coward

      What do you think is under that tarmac?

      Typically you concrete first. 6-8 inches depending on traffic load.

      As cracks appear you then layer asphalt on top of that recreating a smooth surface again. Asphalt by itself is not strong enough for highway usage. Not unless you *LIKE* pot holes and ruts in the road. And ruts will form. As Asphalt is almost a liquid being a tar petroleum derivative.

      For example in Nebraska between Lincoln and Grand Island is asphalt road. Major ruts from the 18 wheelers that driv

    • Re: (Score:3, Insightful)

      by gknoy ( 899301 )

      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 s

    • Re: (Score:1)

      by men0s ( 1413347 )
      Perhaps this explains why the roads in Michigan are complete shit. The I-75 corridor between Toledo, OH and Detroit, MI was used as a running joke for 18-wheelers: if you need to find out which parts to replace because they're loose, just run I-75 and you'll hear all the rattles.

      A majority of the interstates in southeast Michigan are done in concrete, yet we experience chilly winters, plenty snow, we use rock salt to de-ice the roads, and we have heavy amounts of truck traffic due to a couple internatio

      • The only plus I can see concrete having over macadam is traction in the wet.

        This depends entirely on the composition of the tarmac, mostly the makeup of the macadam. Where I live the roads are super-rough because they're subject to icing and traction is more important than tire wear. Consequently most 40,000 mile tires last 25-30,000 miles in these parts... But traction is generally fantastic. Unfortunately, there's usually not much smoothness to go around, which is why when I moved here from Marysville I (eventually) sold my race-suspension 240SX and bought a 300SD. There's likely

    • California isn't the only one going over concrete with asphalt / tarmac. The Oregon Department of Transportation just resurfaced the Stadium Freeway in Portland (I-405) with blacktop over the original 1960s-era concrete. They are currently doing the same thing with Interstate-84 in the East County / Gresham urban area.

      The worst of both worlds - the settling effect of concrete combined with the low lifetime of tarmac.

    • Re: (Score:2)

      by jbengt ( 874751 )

      You a wrong. Concrete roads are much more long lasting than asphalt.

      I live in a climate with hot summers and cold, snowy winters, and recently rebuilt interstate highways. (Chicago area) Lots of salt is used in the winter. Still, almost all of the busiest, biggest highways are built from concrete. Well, more precisely, the new interstates have been built on a gravel foundation topped with several inches of asphalt, and the reinforced concrete roadway has been set on top of that.

      Asphalt would be much che

    • They're nice so long as you don't have any heavy weather, ground settling, or seismic activity. Then they go straight to hell and turn into the light version of Ice Crusher in Jet Moto, where you skip from slab to slab with a solid thump with each transition. Even in my MBZ it is enough to turn the stomach. The biggest problem with concrete is that you cannot repair it gracefully as you can with tarmac. If the ground settles under tarmac you plane the highs and fill the lows, then resurface a section of road (hopefully all lanes, but only the affected area in terms of distance.) If the ground settles under 'crete you grind the highs and pray. And if California is any indication, you probably cover it with some tarmac :p

      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.

      Anyone know how much CO2 is produced in the production of the concrete as compared to tarmac?

      It's not properly called tarmac typically that refers to airports, it is called asphaltic concrete in most civil materials books, some refer to it as flexible pavement systems (as opposed to rigid portland cement pavement), and in many transportation pay items it is considered bituminous material.

      Asphalt and traditional concrete have significantly different uses and maintenance life cycles. Traditional concrete is used in locations where there is a reasonable expectation of high ESALs (Equivilent Single Ax

  • FTA:

    The air-purifying concrete contains titanium dioxide, a photocatalytic material that removes the nitrogen oxides from the air and converts them into harmless nitrate with the aid of sunlight. The nitrate is then rinsed away by rain.

    So we are going to add fertilizer to the rainwater runoff. I can't see how that could go wrong...

    • Re: (Score:2)

      by macraig ( 621737 )

      What's worse is that paving every road worldwide with this stuff will require HOW MUCH titanium? Since road surfaces WEAR, how often will these tiles have to be replaced with more? What will that do to the price of titanium for everything else? When the price skyrockets, how will we cope with people tearing up these fancy new roads to sell off the titanium, as some scavengers do now with catalytic converters and copper pipes and wiring, etc.?

      Nope, I can't see how tying up the bulk of the world's titanium

      • Re: (Score:1, Informative)

        by Anonymous Coward
        Titanium dioxide is abundant and easy to produce. You're already surrounded by huge quantities of it. Elemental we're not talking about elemental titanium.

      • Re: (Score:3, Informative)

        by mlts ( 1038732 ) *

        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.

        • Re: (Score:2)

          by macraig ( 621737 )

          I know it's very abundant, but is it really *that* abundant? Abundant enough to be used in that kinda ongoing quantity without disrupting the rest of the market for it? I think my titanic apocalypse (pun intended) has some ring of truth.

    • It's going to wash out of the atmosphere anyways sooner or later, I think the unit of measure is dog's pissing on a fire hydrant per fortnight.

  • Old Story (Score:1, Redundant)

    by crmarvin42 ( 652893 )
    This story already appeared on /. back in 2006 [slashdot.org].

  • I'm doing a complete makeover of our new house and was shopping around for new roof tiles.
    I was pretty surprised to see that there are roof tiles available which do exactly this NOx conversion (http://www.braas.de/dachsteine/frankfurter-pfanne-titanox.html). And I asked myself, who exactly would be the target market? I can't imagine the average home owner paying a premium for this.

    • The target market is everyone. After they influence the UBA into spreading their influence to mandate it as an Air Pollution measure for a better environment...a better world.

    • "who exactly would be the target market? I can't imagine the average home owner paying a premium for this."

      The TiO2 not only removes pollutants from the air, but it removes things like bird droppings and "gunk" from the roof (by the same photocatalyzed oxidization) - thus keeping your roof cleaner.

      That is the benefit to the homeowner.

  • Are You Pondering What I'm Pondering? (Score:5, Funny)

    by Ukab the Great ( 87152 ) on Thursday July 08, 2010 @09:38AM (#32839856)

    If you can put up with an uncomfy concrete floor in your bathroom you could save a fortune in the long run on matches and glade plugins.

  • Reminds me of a test they are doing in Rotterdam atm with a length of road to clean micro particles out of the air (10 micrometers) that comes from the exhaust of cars. (http://www.wassendeweg.nl/)

    Maybe a good thing to combine?

  • Although much of the focus of pollution from automobiles centers on carbon emissions ...

    What, did we forget the decades of governmental (EPA) regulation on NOx, SOx, HC and particulate emissions that have utterly ignored CO2 emissions, at least until very recently? The CAFE (Corporate Average Fuel Economy) standards? The reasons that we have, oh, EGR valves, catalytic converters, lambda sensors, lead-free gasoline, and a gazillion other emission control bits on our automobiles? Exactly where is said focus?

    • I think its because there has been a fundamental difference in managing automobile exhaust between Europe and the US.

      US policy historically has been to eliminate all non-CO2 emissions, miles per gallon (mph) be damned. MPH has only recently begun to become an popular issue to address.

      EU policy has been to maximize miles per gallon, and trying to minimize pollutants after the fact.

      I would rather deal with excess CO2 instead of poisons. California in the 70's was horrible. The air is much, much clea

  • When it comes to fighting pollution (Score:3, Funny)

    by Nick Number ( 447026 ) on Thursday July 08, 2010 @09:53AM (#32840030) Homepage Journal

    My way is the highway.

  • 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.

    • Concrete is used all over the place air ie gas goes everywhere.

      What I never understood in the "electrical car"-debate, and it's a bit related to your pointing outof the "gas goes everywhere", is that cars with ignition engines spread around "pollution".

      People flail their arms around: "But, if you go electric they will burn charcoal electro generators and you will have the same polution at some other site!", yet it always seemed to me a way to "filter" in a place very efficiently in a few central locations w

      • Add the increased health of people who don't breath the high concentration pollutants in the cities. If we can choose, let trees have cancer not humans.

  • All this talk about how cars can almost drive themselves, the air can be almost clean and cars almost doesn't need gasoline anymore... Makes me think, what if we just put down iron rails, put power in the rails and a computer run the cars...
    - Yes, it's impossible... because... and... But the technology for clean and safe transport is there just use it!
  • Added nitrate (or nitrite, or ammonia, for that matter) is something to be avoided in storm-water runoff, NOx is something to be avoided in the air. How do we judge this concrete based on these mutually exclusive goals?
  • I wonder if they have thought of combining this with the smog busting paint [newscientist.com] previously discussed here [slashdot.org]?

  • This article appears every year or so:
    A Concrete Solution To Pollution [slashdot.org]
    Green Cement Absorbs Carbon [slashdot.org]
    Dutch Town Lays Air-Purifying Concrete [slashdot.org]

  • So concrete can be tweaked to remove some pollutants from the atmosphere. Yay. However, do these scientists realise just how much CO2 is released in the production of concrete? Lots. This piece [physorg.com] describes the situation well: in cement production, CO2 is released both directly (chemically) and indirectly (burning fossil fuels). The piece also suggest that 5-10% of that CO2 is reabsorbed by the finished concrete, but that's it, and this new "tweak" doesn't make much more of a dent. There's an elephant in the r

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