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Concrete That Purifies the Air

samzenpus posted more than 4 years ago | from the clean-roads dept.

Earth 88

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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Old News? (1, Informative)

Anonymous Coward | more than 4 years ago | (#32839312)

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.

Re:Old News? (2, Informative)

Trails (629752) | more than 4 years ago | (#32839996)

You're right. In fact, I saw this on slashdot in 2006.

Re:Old News? (2, Funny)

StikyPad (445176) | more than 4 years ago | (#32841442)

What's slashdot?

Re:Old News? (1)

NotBornYesterday (1093817) | more than 4 years ago | (#32842566)

A political discussion forum.

Re:Old News? (1)

camelrider (46141) | more than 4 years ago | (#32840108)

Wasn't NOx one of the major pollutant problems in the early 1960s? IIRC the culprits were detergents that ended up in waterways causing algae blooms that used up oxygen and prevented light penetration, thus being very detrimental to aquatic life.

If this is the case it might not be good to have it running into the canals and rivers and into the North Sea.

Re:Old News? (2, Informative)

lxs (131946) | more than 4 years ago | (#32840480)

You're thinking of phosphates. NOx causes smog.

Re:Old News? (1)

russotto (537200) | more than 4 years ago | (#32840488)

Wasn't NOx one of the major pollutant problems in the early 1960s?

No, nitrates -- salts containing the NO3- ion -- were. Nitrates are actually a byproduct of this air-cleaning concrete; ideally you'd want only nitrogen and oxygen to result, but it never works out that cleanly.

Please remember... (4, Funny)

JustinRLynn (831164) | more than 4 years ago | (#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.

Re:Please remember... (1)

dimethylxanthine (946092) | more than 4 years ago | (#32839494)

Hey, they could recycle these into Poppers! Hard Pop is coming to your town (thank God it's not the moving sidewalks...)

Hippie Crack (1)

RevWaldo (1186281) | more than 4 years ago | (#32840006)

Just don't let the Nitrous Mafia [villagevoice.com] find out. They'll want a cut of the action.

(Of course, since it's concrete the MAFIA Mafia might have something to say about that...)

.

Old news, AND (1)

dimethylxanthine (946092) | more than 4 years ago | (#32839360)

they want to install moving sidewalks [slashdot.org] ...

But at what cost. (1)

Mechanist.tm (1124543) | more than 4 years ago | (#32839380)

Another eco product with no mention of cost. Cost being an obvious important factor

Re:But at what cost. (2, Informative)

Mechanist.tm (1124543) | more than 4 years ago | (#32839392)

ah its 10 % more expensive.

Re:But at what cost. (2, Insightful)

camelrider (46141) | more than 4 years ago | (#32840140)

ah its 10 % more expensive.

That's big money in a road project!

Re:But at what cost. (1)

Opie812 (582663) | more than 4 years ago | (#32840612)

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.

Re:But at what cost. (1)

tophermeyer (1573841) | more than 4 years ago | (#32840696)

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!

Re:But at what cost. (1)

phoenixwade (997892) | more than 4 years ago | (#32841794)

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?

Re:But at what cost. (1)

sleeping143 (1523137) | more than 4 years ago | (#32841008)

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 (4, Funny)

IndustrialComplex (975015) | more than 4 years ago | (#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.

Re:Sounds good (1)

TapeCutter (624760) | more than 4 years ago | (#32839498)

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:Sounds good (0)

Anonymous Coward | more than 4 years ago | (#32839708)

not to be a pedantic, but titanium(IV) oxide or titanium dioxide is the basis for nearly all paint.

Re:Sounds good (1)

vlm (69642) | more than 4 years ago | (#32839798)

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:Sounds good (1)

dpilot (134227) | more than 4 years ago | (#32843266)

> 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.

Re:Sounds good (1)

budgenator (254554) | more than 4 years ago | (#32851530)

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.

Basic ingredient in white paint.. (0)

Anonymous Coward | more than 4 years ago | (#32843006)

Did you get that off the label? I formulated paints and coatings for 40 years. TiO2 is a white pigment that provides hiding when dispersed to a specific particle size. Too small and it is transparent. To large and it looks lumpy. Typically one gallon contains up to 2 pounds of Tio2 (rutile form). Add too much more and flocculation occurs and hiding does not improve and can actually drop. Adsorption of materials on the surface of TiO2 is limited.

Re:Basic ingredient in white paint.. (1)

TapeCutter (624760) | more than 4 years ago | (#32845650)

"Did you get that off the label?"

The "scrubbing" part? - Came from a flakey science show in the 90's, a slashdot AC is probably a better source...

Dissolving Buildings in Europe (1)

nordee (104555) | more than 4 years ago | (#32839444)

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]

Re:Dissolving Buildings in Europe (1)

hedwards (940851) | more than 4 years ago | (#32839512)

That's basically acid rain you're talking about. And according to the caption to the picture, yes in a way this is intended to help with that.

Re:Dissolving Buildings in Europe (1)

nordee (104555) | more than 4 years ago | (#32839532)

So what happens to the roads after a few years when the nitrogen dissolves the road surface and you have to re-pave?

Re:Dissolving Buildings in Europe (4, Funny)

chill (34294) | more than 4 years ago | (#32839888)

So what happens to the roads after a few years when the nitrogen dissolves the road surface and you have to re-pave?

Uh..you re-pave? Was that a trick question?

Concrete roads are shit (3, Interesting)

drinkypoo (153816) | more than 4 years ago | (#32839486)

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 (5, Informative)

nordee (104555) | more than 4 years ago | (#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...

Re:Concrete roads are shit (1)

L4t3r4lu5 (1216702) | more than 4 years ago | (#32839866)

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:Concrete roads are shit (1)

Kozz (7764) | more than 4 years ago | (#32840254)

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? Or do the counties / state have a deal with the companies who supply the concrete so they can rebuild them again even sooner after salt damage?

Re:Concrete roads are shit (1)

jackbird (721605) | more than 4 years ago | (#32840288)

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.

Re:Concrete roads are shit (1)

apoc.famine (621563) | more than 4 years ago | (#32842346)

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.

Re:Concrete roads are shit (1)

danmart1 (1839394) | more than 4 years ago | (#32841148)

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 over. However, more recent road construction has begun using a bituminous material for redoing asphalt roads. Either way after 3 or 4 years the roads suck, and by 5 it can be dangerous. They also have to be repaired after every winter due to cracking.

Re:Concrete roads are shit (1)

dcw3 (649211) | more than 4 years ago | (#32841216)

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.

Re:Concrete roads are shit (1)

budgenator (254554) | more than 4 years ago | (#32853076)

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 the expansion joints from freeze/thaw damage.

Re:Concrete roads are shit (1)

MaWeiTao (908546) | more than 4 years ago | (#32842152)

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.

Re:Concrete roads are shit (1)

DarthVain (724186) | more than 4 years ago | (#32850180)

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 more expensive. So when your a Municipality and Asphalt costs 10,000$/Km and CO Concrete costs 40,000$/Km it would be a hard sell for any kind of meaningful project.

I can see some big city doing it in limited areas, as a PR campaign and posting signs all over the place bragging about it. It also likely has limited availability, so not all contractors would be able to bid. Largest cost for Aggregates is transportation also, which would also inflate the price. I guess it really depends on what exactly is involved in turning normal cement into CO cement. Also another factor would be the ability to make it at scale that's useful, if you can only make small amounts its not much good, which would also make it more expensive.

So ya, in summary. $$$.

Re:Concrete roads are shit (1)

clickety6 (141178) | more than 4 years ago | (#32839752)

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 animals, especially if you're washing it into the water systems.

Re:Concrete roads are shit (2, Informative)

Gazoogleheimer (1466831) | more than 4 years ago | (#32839762)

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.

Re:Concrete roads are shit (1)

RobertB-DC (622190) | more than 4 years ago | (#32840618)

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 after the ice storm your lug nuts are flying off.

Which surface is "better" depends on your perception. After all, we got rid of asphalt-like analog TV (some stations come in clearer than others) to concreteish digital TV (you either have a station or you don't), and called that "progress".

Re:Concrete roads are shit (1)

Scaba (183684) | more than 4 years ago | (#32843046)

Concrete typically is more durable and lasts longer if properly laid

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

Re:Concrete roads are shit (1)

mprindle (198799) | more than 4 years ago | (#32840644)

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:Concrete roads are shit (1, Informative)

Anonymous Coward | more than 4 years ago | (#32840828)

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 drive continuously down I80. It gets a 'tad' warm in Nebraska in the summer (100-110 max). Not enough to melt the roads but enough to soften them up a little. Then add in 24/7 75 mph traffic. Then the problem they have is gets cold in nebraska for several months of the year (32 to -10).

Between Lincoln and Omaha they have been quietly replacing that type of road with concrete and a asphalt surface.

The problem with roads is if you make them durable that they do not change they end up being to brittle. If you make them able to handle 'fixing themselves' then you end up with a 'gooie' road and ruts form. So they mix materials to get the 'best' of both.

In lower California you see lots of concrete as the temps are fairly stable. As you start with that. Wait for cracks to form then asphalt over it. The cracks will come back eventually. But then you scrape off the asphalt melt it up and pour it back on. You need the concrete to absorb the energy from the cars driving over it. Asphalt is not up to that job. At least not long term (10+ years). It may work for your driveway. But put any sort of traffic on it and it would crack and rut very quickly without something supporting it.

Re:Concrete roads are shit (2, Insightful)

gknoy (899301) | more than 4 years ago | (#32841504)

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.

Re:Concrete roads are shit (1)

men0s (1413347) | more than 4 years ago | (#32841736)

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 international bridge crossings and industry to and from Chicagoland area.

The only plus I can see concrete having over macadam is traction in the wet. Down here in northern Virginia during rainy days, torque steer is common in my car (FWD with about 150 ft/lb of torque). Despite being from Michigan, I don't typically drive like a hellion, but I still have to slow down on my right hand turns, on highway interchanges, pulling out into the street, and even taking off from a stop light.

Re:Concrete roads are shit (1)

drinkypoo (153816) | more than 4 years ago | (#32842360)

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 no vehicle better for enjoying a drive on local roads, though a Subaru or similar does make it safer (I had a '93 Impreza for a while and it was fairly amazing... but not so smooth as the MBZ.)

Re:Concrete roads are shit (1)

MachineShedFred (621896) | more than 4 years ago | (#32841836)

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:Concrete roads are shit (1)

jbengt (874751) | more than 4 years ago | (#32842228)

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 cheaper, but not in the long run.

Asphalt is guaranteed to crack, even in permanent good weather with no traffic. This is because the lighter constituents of the asphalt evaporate, so the asphalt shrinks. This is inevitable,

Concrete can buckle in the heat (as can asphalt), but that can be mitigated with proper expansion joints.
Concrete can be damaged by salt (as can ashpalt), but that can be mitigated using epoxy-coated rebars and the right concrete mix.
A lot of winter road damage around here is caused by snowplows. Concrete fares better than asphalt under the plow.
Concrete potholes are harder to fill properly (often cheaply patched with asphalt "temporarily"), but they don't happen as often as in asphalt
Concrete can be grooved to provide better traction in wet weather, not so asphalt.

(As far as the environment goes, asphalt gives off a lot of nasty petrochemicals, requires a lot of heating to be made, transported, and laid. I believe that concrete is less polluting, in production as well as use.)

Re:Concrete roads are shit (1)

JustABlitheringIdiot (1773798) | more than 4 years ago | (#32843536)

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 Axel Loads) because you can use a much thinner section than you can with asphalt. That's not to say agencies don't do it but it is a difference in price and work. In high ESAL areas you will sometimes see rutting in the asphalt (there is a reason they put concrete in where the buses stop). Asphalt gives a quieter ride and can be modified with things like crushed glass or shredded tires to enhance traction, concrete cannot. Asphalt also has a shorter lifespan, depending on the road you can typically expect to get approx. 10+ years from it before it needs to be milled and paved. Concrete you get into the 20+ years before you need to repave. Is it cheaper to repave full depth or mill and top? Well that depends on the agency and their location cost of labor and materials.

It also sounds like you are experiencing some really bad roads or you are describing the expansion joints. If it is truly bad roads there are a number of explanations ranging from age (most likely) to poor construction (shortcuts while finishing) to bad materials (unlikely but possible). It is possible to mill concrete back into near smoothness and it makes a tremendous difference (they just did this last year in NJ on a very heavily traveled route near Philly). If the concrete is cracked beyond repair it was most likely a lack of maintenance and would have happened to asphalt too and this is typically exacerbated by winter conditions (not from the salt directly but from the freeze thaw cycle that comes with using it to melt the snow/ice and then it refreezing later in the cracks). Also it is extremely common to use the concrete as a base layer under asphalt, you get the best of both worlds, thinner section with a smooth quiet ride.

I tried to hit on everything you mentioned. There is no need to avoid concrete, it just depends on your local conditions.

just moving the problem (1)

Original Replica (908688) | more than 4 years ago | (#32839508)

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:just moving the problem (1)

macraig (621737) | more than 4 years ago | (#32839852)

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 supply in road surface could possibly go wrong....

Re:just moving the problem (1, Informative)

Anonymous Coward | more than 4 years ago | (#32841030)

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:just moving the problem (2, Informative)

mlts (1038732) | more than 4 years ago | (#32841222)

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:just moving the problem (1)

macraig (621737) | more than 4 years ago | (#32841350)

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.

Re:just moving the problem (0)

Anonymous Coward | more than 4 years ago | (#32839860)

But just think of the movie possibilities!

It Came From The Ditch coming to a theatre near you!

Re:just moving the problem (1)

budgenator (254554) | more than 4 years ago | (#32853462)

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.

Ozone (0)

Anonymous Coward | more than 4 years ago | (#32839518)

Isn't ozone good? Could we use it to repair the holes in the ozone layer?

Re:Ozone (0)

Anonymous Coward | more than 4 years ago | (#32839640)

Ozone is good in the right place. high in the atmosphere, it blocks radiation. Low around people, it's a toxin.

Old Story (0, Redundant)

crmarvin42 (652893) | more than 4 years ago | (#32839722)

This story already appeared on /. back in 2006 [slashdot.org] .

This is an update (2, Informative)

Anonymous Coward | more than 4 years ago | (#32839968)

This is an update on the results of the testing.

Also available for roof tiles (1)

firefarter (307327) | more than 4 years ago | (#32839778)

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.

Re:Also available for roof tiles (1)

Mr. Arbusto (300950) | more than 4 years ago | (#32839876)

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.

Re:Also available for roof tiles (1)

wowbagger (69688) | more than 4 years ago | (#32840424)

"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.

Bro, don't take my Nitrous! (0)

Anonymous Coward | more than 4 years ago | (#32839836)

I love that stuff. Get the concrete to get rid of the poison version instead.

Are You Pondering What I'm Pondering? (4, Funny)

Ukab the Great (87152) | more than 4 years ago | (#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.

Re:Are You Pondering What I'm Pondering? (0)

Anonymous Coward | more than 4 years ago | (#32842674)

You're thinking about methane. Humans don't produce NOx as far as I know. The temperatures need are too high.

Regards,
Jason

'Washing way' (1)

RenHoek (101570) | more than 4 years ago | (#32839882)

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?

Since when? (1)

pz (113803) | more than 4 years ago | (#32839936)

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?

Re:Since when? (1)

RockClimbingFool (692426) | more than 4 years ago | (#32840386)

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 cleaner there today due to the emphasis on eliminating N0x, S0x, etc. Even though there an many more cars on the road today than the 70's.

I think the US got it right. We have better technology today to start addressing the MPH performance of cars, starting with a clean burning baseline.

When it comes to fighting pollution (2, Funny)

Nick Number (447026) | more than 4 years ago | (#32840030)

My way is the highway.

Acid Rain (0)

Anonymous Coward | more than 4 years ago | (#32840058)

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

Nitric acid is actually a MINOR constituent of acid rain. The major constituent of acid rain is dihydrogen monoxide. This chemical compound is known to be used by the oil companies, tobacco companies, and the big Wall Street banks in pursuit of their profits.

Banning dihydrogen monoxide would do more to combat acid rain than nitric acid.

Is this supposed to be funny? (0)

Anonymous Coward | more than 4 years ago | (#32842024)

Is this supposed to be funny? After being endlessly repeated, over and over, over and over, over and over, everywhere on the Internet? Why do people who repeat ancient jokes for the hundred thousandth time always think they're the epitome of wittiness?

Re:Is this supposed to be funny? (0)

Anonymous Coward | more than 4 years ago | (#32842154)

Who are you shilling for? Big Oil, Big Tobacco, or Wall Street? Or is it Monsanto?

Re:Is this supposed to be funny? (0)

Anonymous Coward | more than 4 years ago | (#32842462)

I think you're confused. The shill was comparing banning water to using a reportedly effective tool to eliminate the acid part of acid rain.

Re:Acid Rain (0)

Anonymous Coward | more than 4 years ago | (#32842362)

Banning dihydrogen monoxide would do more to combat acid rain than nitric acid.

Yeah, then it would just be acid, instead of acid rain.

Why can it only be roads? (2, Insightful)

TooMad (967091) | more than 4 years ago | (#32840106)

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:Why can it only be roads? (1)

ZeroExistenZ (721849) | more than 4 years ago | (#32840464)

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 where the power is generated instead of spreading it around and trying to extract it from the atmosphere.

Re:Why can it only be roads? (1)

sourcerror (1718066) | more than 4 years ago | (#32845492)

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.

Sounds like another workaround... (1)

jopsen (885607) | more than 4 years ago | (#32840706)

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!

Nitrate in runoff (1)

beth_gis (836679) | more than 4 years ago | (#32843106)

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?

Combine with smog busting paint (1)

G3CK0 (708703) | more than 4 years ago | (#32843600)

I wonder if they have thought of combining this with the smog busting paint [newscientist.com] previously discussed here [slashdot.org] ?

Concrete is not Green (1)

stereoroid (234317) | more than 4 years ago | (#32850060)

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 room, and it's made of concrete.
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