Slashdot Mirror
Plastic Roads Sound Like a Crazy Idea, Maybe Aren't
schwit1 writes with news that the Dutch city of Rotterdam is looking at partnering with a company called VolkerWessels to test a prototype plastic road for safety and durability. "They envision pulling waste plastic out of the oceans, and then processing it into prefabricated sections of road with integrated utility channels and drainage. The composition and structure of the plastic makes it more durable than traditional asphalt, and VolkerWessels estimates that their plastic roads should last about three times as long as traditional roads." The roads are manufactured at a factory, and then hauled in a mostly finished state to where they'll end up. This could dramatically reduce the time during which drivers are inconvenienced by road construction efforts.
I've read the assertion that plastic roads sound like a crazy idea elsewhere, too. I don't think this ideas is crazy at all. Why would it be? We currently pave roads with asphalt which we get from crude oil. It makes sense to me that if we process the crude (or some other oil or source of hydrocarbons; say, recycled plastic) we can make something that works similarly well or even better.
Please correct me if I got my facts wrong.
How will these plastic road segments hold up to the kinds of expansion and contraction roads undergo during especially hot or cold days?
Will they be have to be melted together to prevent cracks between segments for weatherproofing against rain, snow and ice? (Water expands when frozen, remember)
And how well will they stack up against some idiot driving along on a rim with no tire?
Will they be fireproof? One flaming car wreck and you've got a wall of fire that goes on for miles, spewing toxic smoke.
Anyone see what just happened in California? Can't imagine the practical road damage and amazing environmental damage of tons of plastic on fire.
Unless you're the company selling the idea in the first place. What it sounds like to me is expensive and pointless. Isn't asphalt reusable? Scoop it up, reheat it, pave with it again? By all means have someone start cleaning up the oceans and recycling all the plastic waste out there, but not this way.
Are YOU using the TOOL, or is the TOOL using YOU? Think about it!
Unless these road pieces are chemically altered in some way, traction on plastic roads would be awful. And shards of the roads that break off under wear and tear are going to be blown out into nature, poisoning the environments they land in over time.
I'm all for cleaning out the oceans, but this seems like moving toxic, nature-insoluble trash from one environment to another. Permanently ridding ourselves of the plastic is the right path.
Finally a car analogy I can understand.
Sounds like a great idea. Lets hope the details will add up.
TFA:
The things that aren't addressed by the available information are safety and cost.
Nor is winter & studded tyres mentioned. Studded tyres eat through asphalt & the stones in it quite quickly. How about this plastic?
Perhaps this is only for warm climates. Rotterdam seems to not average sub-zero temperatures even in February, so I guess studded tyres are not used there? Any duch person to confirm?
Pothole in plastic? Pour molten plastic in? Buy a new section of road?
Potholes form in asphalt when water settles into slight depressions. The water softens the asphalt, and then traffic deepens the depression, allowing more water to settle. Freezing and thawing makes it even worse. The plastic road in TFA is perforated, so water drains into a series of tubes. So potholes should not form in the first place. Even with asphalt, potholes can be greatly reduced with proper grading, and by adding fiber.
But I don't think this plastic road is a serious proposal. They may build a few hundred meters as a PR stunt. You cannot collect plastic from the sea cost effectively, and you aren't going to make a good road surface out of random trash.
The idea of pulling plastic out of the oceans is senseless to anyone who gives the idea a minute of thought. Do these people have any idea how big the ocean is and how small the particles of plastic can be?
Even if we assume that they have magically found a way to get and recycle the plastic garbage in a few bazillion cubic meters of ocean, they'll still have to do better with the end result than experiments so far. The Morrison Bridge in Portland OR has a skid resistant polymer deck that is already coming apart after just a couple years. I wouldn't write this idea off a priori but there major problems to overcome.
http://www.theoceancleanup.com... is the curent page for the project Boyan Slat started that got some coverage back arround 2013 http://www.dailymail.co.uk/sci...
Shamelessly lifted from the comments on the iEEE article, is a link to India using plastic as binder in asphalt.
This seems like a much more practical step towards using lots of plastic in roads, and the article hints that it may help prevent potholes which would mean the road would be usable longer. They've already been testing it on real roads for a year.
I just can't see how the equivalent of potholes in a pure plastic road are anything but disaster - a ton of water gathering in the conduits, and any fragmentation would lead to very sharp shards on the road, or large areas just failing wholesale.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
Argh, copy/paste fail. Let me try that again:
First off, another poster noted plastic is usually significantly less toxic than asphalt. I mean, you probably consume food and beverages from plastic containers all of the time--how would you feel about drinking from an asphalt cup? There might be environmental dangers, but this would be due to the mechanical properties of the plastic (does it break apart into particles or shards?), not the chemical properties.
Which brings us to my next point: "plastic" is not some generic, monolithic thing, which is why so many plastic products will try to use another term to avoid the connotations of cheapness or flimsiness: "resin", "polymer", brand names or genericized brand names (acrylic, nylon, Kevlar, lucite) and, my personal favorite, calling attention to the fiber used to strengthen the plastic (fiberglass, "carbon fiber").
I'm not a plastics chemical engineer, but I have noticed that softer plastics seem to resist shredding or dusting pretty well. It may well be possible to chemically transform unsorted waste plastic into a suitable material, particularly if some kind of fiber or rock aggregate material is added. I'm not going to say this will definitely work, but it's certainly a lot more complicated than you're making it out to be. Plastic is not a catch-all term for cheap stuff that breaks when you use it. Airplanes and boats are made of plastic. Semiautomatic pistols are made of plastic. $3000 bicycles are made out of plastic. Let's keep an open mind here.
The space for cables is a good idea but I wouldn't put pipes in there, at least in colder climates as they would freeze.
I think this would be pretty good for parking lots and sidewalks to start with since you don't seem to need to lay down a thick gravel subsurface.
But I thought all of our roads were going to be glass electricity generating ones!
Here in Arizona we are laying a lot of rubber roads: more durable, quieter, and no more mountains of old tires. It's like driving on carpet. But in accidents, they can catch fire.
This is where it's at: http://www.solarroadways.com/i...
A better headline would be, "Are plastic roads the future?"
Sig: I stole this sig.
One time when I visited Rotterdam (wonderful people and a great city, btw) I saw some street construction near the hotel I stayed in. The street was paved with bricks. Instead of using a jackhammer to get through the street's surface, the workers just dug up the bricks, did their work, smoothed out the surface and re-installed the bricks. When they were done, it looked like they were never there. So it seems more like a matter of replacing those bricks with plastic ones, as bricks are already being used for road surfaces.
They are also a little more dangerous for heavy trucks. A friend drives a 16-wheel dump truck with pushers and a strongarm, and apparently if he has to panic-stop the rubberized-asphalt roads are more prone to surface melting and turning to liquid under the tires, effectively making the truck hydroplane in otherwise dry conditions. Nothing like fifteen tons of uncontrollable truck sliding at freeway speeds toward a stupid motorist that cut-off the truck...
I've also noticed they're not nearly as durable as the hard concrete surfaces they replace. There are stretches on most of the oldest coated roads like the I-17 around the Durango Curve and on the US-60 where it diverges Eastbound from the I-10 where the coating has been scraped off in patches, and there are other sections where the coating has split above the control joints in the underlying concrete, making the road noisy again.
I won't deny they're beautifully quiet when new, but they just don't age very well.
Do not look into laser with remaining eye.
The whole point in just about all construction is to achieve an acceptable, durable result for the lowest possible price. Having to heat the road itself completely negates that, as there's a LOT of road out there.
Roadways start by digging a wide, shallow cut. That cut is lined with some form of crushed stony material or sand, and harder and larger layers are built-up until truly solid layers are applied. In some places they use concrete and coat it with a layer of asphalt, in other places it's just multiple layers of asphalt that are let to cool before the next is put down. Most of the materials used are themselves durable in the local environment so that they wear well. The tar and oil components of the top layer simply act to bind the durable sandy/stony mix together so it stays-put.
The idea of prefabbed sections worries me. If it's a top-layer I worry about water or other liquid getting between it and the substrate on which it sits. If it's anchored with tie-downs into the lower layers, I worry that they'll push up and puncture tires. Ever lost tire pressure at freeway speeds? I have three times. It's scary as hell.
The idea of taking our roadways' surface area and making it do something useful is appealing, but so far I don't see any ideas that make more sense than using the same old layered-material approach that we've used in some form or another since Roman times. There's simply not enough benefit to outweigh the detriments and costs.
Do not look into laser with remaining eye.
I live in the desert and we have potholes form here too, where it doesn't ever freeze enough for the mild overnight frost to do jack to the roads.
Our roads pothole because enough traffic over time stresses the material, and the expansive soil expands and contracts, causing the road to fracture. Since it doesn't rain much here either, the roads are not designed to drain as well as in other places (ie, no steeply banked crown) and the water finds its way down into the cracked road surface. As vehicles continue to drive on it they push down, and when they let up the pressure pent-up pushes road material up and out of the road surface.
Admittedly this happens more on the roads in less-populated areas at the outskirts of the city more than in the middle where the roads have been resurfaced off and on for 50+ years, but every time it rains I see chunks of asphalt on the roads that were pushed out by the pressure and moisture.
Do not look into laser with remaining eye.
This is ridiculous.
First, the expansion/contraction of plastics is generally MUCH much higher than concrete/pavement.
Second, the "prefab road sections" are absurd; nobody builds roads like this already (of any material) because they would be ruinously expensive (not because of the raw material costs), nothing has come close to the level of durability needed to handle 50-ton trucks repeatedly for decades, and extremely hard to deploy.
Third, the overwhelming majority of plastic in the ocean is 0.1mm or smaller (http://theconversation.com/in-the-ocean-the-most-harmful-plastic-is-too-small-to-see-35336) - the cost/magnitude of scale to sieve this from the oceans is mind-boggling.
Seriously, Dutch, I love you - but that's a mind-blowingly dumb idea.
-Styopa
As this is an article about Dutch roads. Most highways here have a top layer of asphalt; this is a mix of materials which include: rubber, plastics, stone, zand, and a tar like binding agent called bitumen.
It is designed to make highways be able to drain water, have a rough structure for grip on tires and to reduce noise pollution, and handle the temperature and humidity changes of the Dutch climate.
https://nl.wikipedia.org/wiki/Zeer_Open_Asfalt
There are some pictures of the top layers of a Dutch highway. And lots of text in Dutch, but no link to an english page.
As I mention that asphalt layer is only the top 7 cm of a highway, below it are:
- 3 layers of 6 cm each of asphalt/concrete slabs
- 30 cm of unbounded foundation
- 70 cm of sand
Below this a foundation of Styrofoam blocks may be used on very soft ground to reduce sagging.
water drains into a series of tubes
But that's where the internet goes! Will we have a moister, more humid (and therefore more prone to rusting) internet if this technology is implemented?
Hint: It worked for bumpers, why not for roads?
Bumpers are all but useless. My '68 Caprice had bumpers you could use to knock down light poles at 30mph. Not that I would have ever done such a thing. Sober.
You are welcome on my lawn.
I live in New England. We have lots of freeze-thaw cycles during the year. It's rare that you see a proper frost heave in a road (and you certainly know it when you see it). By FAR the most road damage is caused by inexpert patching of the asphalt where the surface needs to be cut for utility work. When inexpertly patched, the surface is no longer remotely planar, and the unevenness right at the (and caused by the) patch increases the wear exactly where it can do the most damage. So, shortly, the patch needs a patch. Which is inexpertly done, and the cycle continues until you get a stretch of crud for surface and the local municipality shells out big bucks to have the road re-surfaced entirely.
Compare this to Southern California (where I lived for a number of years) where the road patches after utility work are 100% as smooth as the original surface. With your eyes closed, you cannot tell that you've driven over a patch. The patch (and especially the transitions from original surface to patch, and back) receives no more or less force than the original road, so there's no focus of wear, and it lasts a very long time.
It baffles me why we can't make proper road patches in New England. It's clearly possible. And I really can't believe that the people working to patch roads in Southern California are that much more talented, so it's either a technology issue, lack of managerial directive, or an out-and-out conspiracy to have a never-ending amount of road resurfacing work.
Put my fist through my alarm clock with its ding-dong death inside my ear. - The Blackjacks.
LA has a freeze cycle. It could even be hours of freezing temperatures in some areas, sometimes....
I have no problem with your religion until you decide it's reason to deprive others of the truth.