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Researchers Make Bendable Concrete
karvind writes "PhysOrg is reporting that scientists from University of Michigan have developed a new type of fiber-reinforced bendable concrete. The new concrete looks like regular concrete, but is 500 times more resistant to cracking and 40 percent lighter in weight. Tiny fibers that comprise about 2 percent of the mixture's volume partly account for its performance. Also, the materials in the concrete itself are designed for maximum flexibility. Because of its long life, the Engineered Cement Composites (ECC) are expected to cost less in the long run, as well." Michigan roads must make the perfect test cases for this stuff, and I look forward to their improvement.
How quaint!
Now finally we can see buildings that bend and shift better under harsh weather conditions such as wind and rain.
The benefits of this extend greatly beyond that as well however.
It will be intresting to see where this goes...
How about a concrete jumping castle?
I've bent many a rim here...
Michigan roads must make the perfect test cases for this stuff
Except that roads crack because water infiltrates under the surface and freezes over. I don't know many material, even 500x stronger concrete, that can withstand the force of expanding freezing water.
I think the material is more targeted toward seismic-proof constructions.
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
I remember reading an article that talked about differenct concrete compounds, for example they had made a spring out of concrete.
-- Error: SIG not found.
I wonder if this new concrete may enhance the concrete submarine programme for deep submersibles.
Being in something with a bit more toughness, and better tensile strenght might be more reassuring. A little less like going to sea in an eggshell.
Maybe a flexible road may not be able to stop the water penetration, but might be able to return (or be pounded) back into its original shape? A small crack stays small, even after many ice expansion cycles, rather than turning into a massive pothole?
If the material won't bend/stretch at all, it might shatter, this new elastic concrete supposedly kand bend at least a little, so it could withstand the freezing expanding water. At least I think that the freezing expansion is not enough to stretch the new concrete to it's limits.
-Is the meaning of life vanity, or is vanity the meaning of life?
Imagine the BSDM^H applications! Seriously, though--interesting stuff. Curious as to how well it'd stand up under pressure.
means this is going to be really fucking expensive.
Tiny fibers in concrete seem very similar to compounds that used asbestos.
As the concrete is degraded these fibers will be released to the environment, and tiny fibers tend to make very good respiratory tract irritants (to say the least).
BTW, I bet demolition crews will hate the stuff...
why? because nobody makes the first jump. (shameless matrix refrence)
Doesn't say in the article, but wouldn't this be useful in making buildings that would fare better in absorbing the shocks of an earthquake, instead of crumbling down?
this one can be solved with bending - Bender Bending Rodriguez
Why not link to the source at the U of M News Service:
U-M researchers make bendable concrete
Technocrat.net had this article earlier today, and without the extra advertising.
interesting stuff!
Michigan roads must make the perfect test cases for this stuff, and I look forward to their improvement.
Does anyone else here hate highways that are made with concrete? They have them here around Salt Lake with asphalt segments every now and then. Every time I go from concrete to asphalt I realize just how much quieter the car is and smoother the ride feels. It's almost painful to go back to concrete.
I guess concret must have some advantage if it's used all over, but it seems like asphalt is better for roads. It expands and contracts easier, and when a pothole forms in concrete it always seems to get real big and deep a lot faster than with asphalt. Not sure, but maybe all the salt they dump on the roads around here in the winter is bad for asphalt?
"What do you despise? By this are you truly known." --Princess Irulan, Manual of Muad'Dib
/)
The article fails to state whether the ductility of the concrete results in elastic (returns to its original shape when load is relieved) or plastic (stays in the shape you bent it) deformation.
One would hope for the former, since structures made out of this material may look strangely 'bent' over time if it readily undergoes plastic deformation.
And one last note: is this material going to be more cost-effective than steel?
I'm Trappped at Berkeley.
...can it withstand the impact of a jet airplane?
And is it safe to inhale the fibers if said airplane makes a big ol' mess?
We dont have that here and I never understood why you would rather use conrete than asphalt on roads. Well, I guess it could be that its cheaper but is it really better and safer?
Don't go to the loo at the top!
even if you replaced 2% of the volume with vacuum, you could only make it 2% lighter
how the hell do they come up with this 40% figure?
They say this concrete is plyable. Can it cushion my face hitting it at roughly 3 metres a second as I accidentally catch my foot in the spokes? Or is it mainly to be used to stand up to Boeing 777's in a 650 knot vertical dive? Either way, I don't want to have my face turn out more useless than Rambus... Ouch.
The architects, contractors, and construction workers of the Petronas towers in Kuala Lumpur simultaneously shout, "D'oh!"
Bart: But we want... More asbestos! MORE ASBESTOS!
/^[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}$/i
bendover and start a flappin my wings and a flyin with my flapable concrete wings attached to my flapable steel.
Chick0en Tonight.
...I believe the technical term for this is "Gray Rubber".
Authority questions you. Return the favor.
The columns of some cathedrals - built before people understood roof trusses - are slightly but definitely bent if you sight along them. The percentage strain is very low, so they don't crack.
When I am king, you will be first against the wall.
Would it make a better material for building elevated highways and bridges? It needs to tolerate both weak and strong vibrations (small cars and trucks) all day and night. It needs to be water-proof that cracks don't become serious issue, either.
Some roads are built with concrete as the foundation and asphalt is then laid on top. On some surfaces, the concrete is necessary to give the road strength for soft ground like areas where it is more sand like or is soft. Also roads that carry heavy trucks tend to have such a concrete base (if not plain concrete). Bridges must be concrete, but asphalt can be laid on top to make it "quieter". When they lay concrete or asphalt or both, the engineers decide based on environmental factors also, not just cost or because it is nice. Another major factor is distance to a major city or repair point. If a particular stretch of road is heavily traveled and is far from a city, concrete might be better as the constant repair costs of asphalt might prove to be expensive, compared to a one time fix.
TFA
Is bendable concrete going to make it difficult to demolish structures built using it as the main material?
Me lost me cookie at the disco.
Is bendable concrete going to make it difficult to demolish structures built using it as the main material?
I don't think buildings made out of this stuff will survive a large enough explosion. Besides, concrete is really easy to break apart and chip (hence why you need to use rebar frames for serious construction), so just whacking away with chisel-tipped jackhammer should work for small jobs.
I'm Trappped at Berkeley.
transparent concrete? I seem to recall something about that in /.
I prefer the "u" in honour as it seems to be missing these days.
I see 150 year old brick streets in a lot of towns still. Seems like that's a pretty good building material for slower traffic too :).
How much does this road bend, also what kinda of deformation would we see from traffic. The current roads currently get grooves in them. But make a road that actually felxes, wht kind of effect would that have on the surface of the road? This to me would mean MORE maintaining the road, not less.
Also, what effects would this have on gas mileage of vehicles. If the road was givein way a little as say a semi or large vehicle was driveing over the road, to waht degree would it "sink" into the road? Would you be wanting to run more air pressure in the tires of the vehicle on these types of roads, to compensate for the flex inherant in this road? And over time, what effect would this have on gas. Another valuable resource.
Also, adding fibers into a road, could effect it's traction. Current roads, are rather random. If (through wear) all these fibers were to orientate themselves one way would this effect the grip these roads provided? Also, now does this fiber react after years of abuse, and oil contamination? If oil were to cause these fibers to swell, or if they were to absord it, I would imagine it would have negative effects.
But what the heck, it may just work. Imagine, no ccracks in the slab of your home anymore. All for only a few side effects (and probably 3x the cash).
- Ice_Hole
"I couldn't give him (Bill Gates) advice in business and he couldn't give me advice in technology." Linus Torvalds
I wonder if this stuff could be used to make buildings more invulnerable to earthquakes. If the foundations and a couple of lower levels were flexible, maybe the building would just wobble rather than shaking itself to bits - the equivalent to putting suspension in a car?
Was going to post this infamous "If only all metal were FLEXON"-ad that distraught New Yorkers found in their mailboxes when they came home on 911, but it was nowhere to be found... Good censorship job!
The article doesn't mention anything about the stresses this concrete can take. It just says it looks exactly like concrete and cracks less.
I don't think this kind of concrete is the kind builders would want to make lower-level walls of very tall buildings with. Sure it can handle tensile stresses very well and is extremely flexible, but how will this "concrete" react to compressive stresses? Flexible concrete means less force is required to make it buckle and warp.
Will this concrete be appropriate for floors of condomunium and office towers? Will the concrete floor warp if a heavy copier is moved into the office, or if someone moves in a piano?
Maybe because it's lighter, concrete floors can be made thicker, and thus less prone to warping, but I really think something like this would be better suited in bridges, roads, houses, and maybe their foundations.
?? I think this will have a great impact on space building, reading about crazy plastic/concrete/steel mixtures of materials in sci-fi and you will see.
This could be the start of pour your own space home!
rar.
#hostfile 0.0.0.0 primidi.com 0.0.0.0 www.primidi.com 0.0.0.0 radio.weblogs.com
Headlines Plane hits building....
Today the newly launched Airbus was hijacked by an unknown group of radical loons just before 3.00pm EST. After the terrorists seize control of the cockpit they flew the plane into the side of the world tallest building 'the humgo ercto 'standing over 675m in height built in 2006 housed in a flexible concrete sheath. The building stood the attack, bystanders claim the plane hit the build folding into a pile of scrape metal. One claimed the building swayed a full football fields length as it took the blow. The bad news is as the ball of molten steel fell from the sky it took out the 3 Skyscrapers below ;(
Great! Now instead of the concrete overshoes the mafia can go modern and use concrete running shoes!
This results in higher build and repair costs for roads and bridges and explains the poor maintenance of many US highways.
The article is essentially saying that, at last, someone is prepared to experiment with ECCs in the US on a small scale following a test in a difficult area. Meanwhile, advantage has been taken of these materials in the Far East for a number of years.
This is important because in many ways the US is becoming depressingly conservative. It is no longer a world leader in innovative building. Ford and GM have just seen their shares reduced to junk status as the Japanese and Daimler-Chrysler increase their share of the US auto market. And the whole IP/copyright thing is basically about trying to protect what you have rather than innovate and create new markets. If this little experiment is a sign that someone is getting brave enough to risk trial lawyers (my client tripped over a kerb as a result of using this unproven concrete technology...) perhaps it's a green shoot.
Panurge has posted for the last time. Thanks for the positive moderations.
because the concrete is thinner, not because the concrete is lighter. This discerned from RTFA. We poured a pad for a picnic pavilion at the yacht club using concrete that is reinforced with polyethylene fibers. It allowed us to pour a large pad that will not crack without having to use tiebacks. Which brings to mind something I've often wondered about...
With concrete, when it's pre or post stressed in compression, it's much less likely to crack. Traditionally this is done by tensioning the steel prior to pouring or tensioning cable or rod 'tiebacks' after partial curing. Now this is very nice but... It should be possible to engineer a fiber that will shrink as it ages and bonds well as an aggregate. If the shrink time could be matched up reasonably well with the cure time of the concrete it would simplify many types of construction.
World Trade Center made of bendable concrete: 262m $US
747: 5m $US
Razor Blade to hijack plane: 2.95 $US
The look on Osama's face as the plane bounces off the building: priceless.
Concrete wheels and rubber roads! What next?
Was the guy who invented the seedless watermelon somehow involved in the project?
I wouldn't use fiber glass as an example of a safe fiber. People do stupid things with it. When I was looking for houses, I saw more than one house with loose fiberglass dumped all over the attic. I figured it would cost thousands to have it cleaned up. The real estate agent mentioned it was illegal in California. But people do that kind of stuff because they believe anything not illegal and banned must be perfectly safe, even if you ignore the dumbed down safety instructions.
FYI: I think the script that makes TFA too irritating to read is the one that comes from
- uk.intellitxt.com
...I know that I won't read any crap from PhysOrg ever again.
I'd expect that buildings and roads made of this stuff would be better than normal concrete in earthquake zones. Though thats just a hunch
Professor Karmadillo Songs of Science
construction, but scaled composites, USA company, has done some rather innovative work. Space ship one, voyager, ...
Innovative is not always practical. Building construction is about cost. Steel reinforced aggregate is still the least expensive in most applications. Especially when you can pour at 5AM and 24 hours later pull your forms off 3000+ PSI material.
I know a company in Georgia that puts up chicken coops using a robot. They erect a jig, the robot sprays and trims a foam form and then sprays concrete on the interior and exterior. A friends machine shop makes the spray guns, which were designed in his shop.
I think the main reason for slow adoption is not so much the codes, as the lobbying against change on the part of established companies. This is changing as the old boys are retiring in droves. Hawaii recently approved bamboo for use in resdential construction...finally. This is old technology that is good, especially where termites are such a big problem.
... fiber-reinforced bendable concrete.
Does that mean this thing is a load of shit?!
Run search on umich and ECC and you'll find all sorts of interesting stuff they've been doing there. Now off to walk dog over tob watch the tail end of a concrete pour on a midrise that's going up about a mile from the house.
Tiny fibers that comprise about 2 percent of the mixture's volume partly account for its performance.
Not to be a stickler, but you mean "tiny fibers that compose about 2 percent..."
Just remember, the whole comprises the parts, and the parts compose the whole.
Fitzghon
There have been boats built out of concrete for years, they aren't a new phenomenon, the hull has some flexibility. Replacing the steel reinforcing with fibres is an interesting development.
t +boat&btnG=Google+Search&meta=
To find out more...
http://www.google.co.uk/search?hl=en&q=ferrocemen
Deleted
are you sure you don't mean misuse?
"misusage" is a US-local redundant neologism, and cannot strictly be referred to as English, can it?
The more cynical side of me wonders whether better roads that require less maintenance and have longer life are really what the states want. Highway construction is so full of pork barrel politics.
I thought Switzerland had high quality, long lasting roads, so it is possible...
Stephen
I can't think of a better test case than Michigan roads for this material.
Galloping Gertie was the first large-scale project to incorporate this material.
http://www.ketchum.org/tacomacollapse.html
What exactly does "500 times as flexible" mean? How can a bridge be lighter than concrete?
Read the last point carefully. A self-serving press release based on conjecture. I understand why U. Mich. would write such a thing, but why would physorg.com and
Bad idea.
Some doorknob of a kender would steal it.
Exam 4/C again. Maybe I'll do better this time.
Ok, so they say it looks exactly like concrete. Despite the fact that I don't think it matters what roads look like (as long as their not bright yellow, requiring new traffic markings), I really think looks matter even less in this case.
:P
The real question is, how does it feel? What kind of texture does the outside of it have? Does it have some grit to it, or is it perfectly smooth? If the latter case, can a grit be ground into it, and will it hold that gritty shape? Smooth-surface roads are a Bad Thing (tm).
Yes, I know it says that they have already used it in roads, but both examples listed describe small patches of the stuff. Even further, in the replacement of the expansion joints on the bridge, this stuff is replacing steel, which is also slick. Even with the other road patch they talk about, in most places I've lived, that means that it probably replaced a large steel plate.
Just wondering. Maybe I need to go try to find the actual UofM site that describes it, rather than this news article.
Oxymoron?
...will it have the same (or better) coefficient of friction than normal concrete? Sure it might not crack, but if your tires don't stick to the road, then you're going to have more problems...
Out of six replies to the GP post, valkoinen is the only one who has a clue. No wonder Edison has such disdane for mathematicians!
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
"Tiny fibres" embedded in the concrete? Reminds me of the tiny fibres of asbestos, which get stuck in people's lungs and cause cancer. Are we looking at a possible health risk here as this bendable concrete crumbles off unmaintained buildings, and is gradually eroded off highly used roads?
very slippery when wet
expensive to maintain (probably few/none of the individual bricks are 150 years old)
sometimes makes property more valuable, thus paying for itself in higher taxes at the same tax rate
Exam 4/C again. Maybe I'll do better this time.
If this bendable concrete has the flexibility of asphalt with the durability of concrete, it could indeed be a superior road surface to either.
"If it's real, then it gets more interesting the closer you examine it. If it's not real, just the opposite is true." -
Michigan roads must make the perfect test cases for this stuff
I got a pothole the size of the Grand Canyon that says Ontario would be a better test case.
Adventure City Tours
I was two sentences into this article when I thought about the condition of Michigan's roads. I was already thinking about a post on how ironic it was that it was the Univ. of Michigan that developed this concrete, and look at the road conditions. As the article noted, it is perfect conditions here in Michigan to test this new concrete.
YOU'RE WINNER !
Another lame blog
They've had this for years. We have an entire road about 120 miles long here (toll) that did that. I must say the ride is much smoother but they still have to maintain it from time to time.
Here's a streaming video!
/. effect* :-(
(And here's the original article from the Univ. of Michigan)
*already starts to feel guilty about the
Haven't we invented that years ago?e
http://en.wikipedia.org/wiki/Tacoma_Narrows_Bridg
Ok.. so you build a big "balloon" of this material, laminated with the mylar stuff to make a tough and springy space habitat. assuming you can find water where you are going, it would seriously cut down on your shipping needs.
meh
Michigan has some really bad roads. Lifespan should be measured in months here not years.
Our multiple issues with concrete come from poor installation practices followed by some of the worst maintenance practices known to man. We also have trucks driving around with very high axle loads doing considerable damage.
We get concrete cracks from stress fractures (bad weight/balance) and then follow that up with lots of salt, snow plows and repeated water saturation with rapid freeze/thaw cycles. The state solution is to dump some asphault on it and smack it with a shovel. Needless to say, within 2 weeks the freezing water boots that "patch" out and the problem grows and continues to grow rapidly over time. Smaller, smarter communities will tar these cracks early resulting in longer road life.
As for asphault in our environment. It takes the traffic about 3 weeks to carve ruts into it in high traffic areas. Ruts with rain on the freeway can be a freakishly terrifying feeling. Speaking to some Germans at DaimlerChrysler about our road differences, it seems they resurface their asphault annually. That might make asphault viable here in Michigan, if it was laid on clean road rather than on pothole infested, trashed road that crawls up through the asphault like zombies in a horror film within 8 weeks.
I'll now be watching the construction on that bridge mentioned in the article more careful, as I go under it daily. Maybe they can redo the I-23/I-94 ramps with this stuff if it works... (or Geddes road on the way in to north campus - it's paved but unpaved would be smoother)
I don't know how well this would serve as foundation material for weather-resistant buildings, because I have an inkling of a feeling that under that great a weight, flexing concrete would generate a decent amount of internal heat, and is it really designed to conduct that heat away?
The information that informs this feeling is that that is the same reason why we don't have solid rubber tires, the internal heat generated would melt the tire from the inside out under normal stresses.
In France they make extensive use of Cobblestone streets. The roads last far longer and the whole pop and crack of the cement during winter is really not an issue..
Does anyone know why a Cobblestone system isn't used more in US cities?
Smile.
And would it be really expensive?
-- IV
http://www.LinuxMedNews.com Revolutionizing Medical Education and Practice.
I'd be more interested if they had invented the bendable truth. ;)
The Internet is full. Go Away!!!
They ruined my Asbestos & BBQ restaurant.
I'm concrete, your glue, everything bounces off me and sticks to you! Bendable Concrete? Doesn't that defeat the entire purpose of concrete? Further, what does this do to the metaphor? No more concrete ideas. I need to go rethink my life.
nt
The real question is, how does it feel?
I agree! The most logical use for flexible concrete is a new line of designer clothing!
If I may say so, life is a game, and there's so much to do and so few turns.
-Reiner Knizia
Michigan roads must make the perfect test cases for this stuff, and I look forward to their improvement.
:/
Oh hell yes. I work in Pontiac and go to college in Flint.
However, it's Michigan, so it's more likely we'll see this being used in Hawaii before here.
I wonder what this means for concrete skateparks. Would I crack my skull open or shred my knees on this type of concrete just like the regular stuff?
We can finally make people more comfortable when we toss them off a bridge into the ocean!
Wer mit Ungeheuern kämpft, mag zusehn, dass er nicht dabei zum Ungeheuer wird. --Nietzsche
Thus, the towers stabilize each other and are quite flexible. According to the documentary, if you watch the water in the upper-level toilets on a windy day, you'll see it swooshing around. - In the late 1990's (just before Xmas) I was on the 30th floor of a 32 storey building in Melbourne, Australia. We sometimes get small violent dust/thunderstorms at that time of the year and the view can be pretty awesome from a skyscraper.
We had a clear view over the docks and on this particular day we all started watching what looked like a medium sized dust storm coming our way, it had completely blocked the Westgate bridge from view (eight lane bridge, big enough to fit the huge container ships coming into the nearby Port). When it hit our building you could not see much out of the window except dust, leaves,...wtf...,sticks,...rubbish...,30 storeys up! After a couple of minutes, it felt like the building had turned into a small boat rocking in a gentle sea and I found myself swaying slightly to stay vertical. The blinds were starting to smash against the sides of the window frame and stuff was rolling off the desks here and there.
Some people got half under thier desks or just started crouching down where they stood, people were letting out "oh shiiiit" type of statements, a few of the women let out short jumpy screams when somthing tipped over near them. This went on for about 5-10 minutes, then it stopped just as suddenly as it started. Turned out to be the strongest winds to hit the city for 100yrs, on the streets around the building it had uprooted several old Elm that were planted in the 1800's.
During the swaying, I kept watching out the window and tried to keep calm by thinking, "I have seen documentaries where people have huricane parties in tall buildings, they are designed to sway around, sit back, enjoy the ride". Then my head would counter with it's own thinking, "It's starting to feel like the build up to a tornado in a hollywod movie, I have seen documentaries about how fragile buildings can be if the lower floors are open-wall car parks, I am ontop of nine floors of car-park, ok, this is getting out of hand, I want the swaying stop now,...Marge, do something,it's not stopping...". The only conclusion I can come too, is that "hurricane parties" are for adrenelin junkies that find the triple loop rollercoaster is just not enough anymore.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
So if the concrete road is flexible, does that mean we can go back to steel wheels like the very first automobiles?
Furthermore, the two towers are located on a relatively 'soft' foundation -- they essentially 'float' on sea of soft land.
Interesting. There's some architectural info, Flash enabled, at PBS also on some of the new buildings (mainly the one at Shanghai), but not much detail.
But even that idea isn't relatively new, I believe it was one of the ideas proposed for the foundation of a nuclear power plant in Meehan's excellent book on this subject, The Atom and The Fault
I can't resist.
:-)
Since this form of concrete is slightly flexible it will allow a certain amount of movement. This would be useful if the construction company almost gets the pour in the right location or someone changes their mind about where it should go. They can now hook up a dozer and pull the slabs in line.
ECC == Error Correcting Concrete
(Tempting as it is, no hotlink done intentionally to help avoid the slashdotting.)
I recommend starting with 03-04 "On Engineered Cementitious Composites (ECC) - A Review of the Material and its Applications" as it includes a nice photo of a bent column.
New concept? I don't know... that Tacoma Narrows bridge swinging in the wind looked pretty bendable to me, and that was way back when they had old cars and everything was black and white.
These two technologies together might constitue a concrete used for roads that is both very flexible and also featured automatic snow and ice removal!
I am not interested in articles about life extension advancements.
I recall seeing automobile coil springs made from concrete years ago (as a demonstration, not a production item). Was that in the Museum of Science and Industry in Chicago (where they also have a whole roomful of things most people would never dream of doing with glass)?
Maybe it was these guys, and it took them 30 years to get it right? I should RTFM...okay, I did, and there's no mention of the spring I saw, so I dunno.
I'll grant that 30 years of research probably makes a significant difference in the result.
NEO CRATERED!
Okay according to TFA:
"the ECC is 37 percent less expensive, consumes 40 percent less energy, and produces 39 percent less carbon dioxide (a major cause of global warming) than regular concrete."
That's fanstastic, but my bull-shit-o-meter is going off... Yup, the very next sentense is:
" based on the assumption that ECC lasts twice as long as regular concrete"
Okay, so lets get out our calculators:
(1-.37) * 2 = 1.26, or 26% more expensive in capital
(1-.4) * 2 = 1.2 or 20% more energy to make and
(1-.39) * 2 = 1.22 or 22% more CO2 emissions to make.
Since the claims of double longevity are speculative, I would base any potential of the system on - at best - an eqiuvalent lifespan.
One item they don't mention is whether they have significantly changed the modulus of elasticity or the yield strength to get their results. I would suspect that the latter is the case, with the tensile allowables getting the only bump.
Most concrete can withstand 3500-4000psi in practice. I would guess 90% of concrete is "spec'd" at 2500-3000psi, and most ready mix plants pad by 500-1000psi to make sure they get the required struength. At a 3000psi alloable, the tensile stress is about 250psi. Increasing that to 3000 through fibers would make the material act more like a traditoinal material.
Actually, that's what happens in concrete for buildings. We don't design for that 250psi tensile strength, we design for 3000psi compression, and then embed steel to take the tension stresses. Using high-tensile steel, prestressed concrete effectively "pre-compresses" the concrete to increaee its capacity. Anyone who believes concrete is not flexible has never seen a "double tee" bridge girder after they cut the prestressing steel and take it out of the forms. The fom nive little arcs. The weight of the bridge topping (road surface) then weights the bema down until it is nearly flat again.
This may have implications in the near term for specialty applications, but I don't really see it as sliced bread for the industry in the near future.
Is it just my observation, or are there way too many stupid people in the world?
This Concrete was already jumping & bending (as well as winning the hearts of scantily clad hotties) in the 80's!
In this town, we have cobbled streets, still going strong from the Middle Ages...
Alternative products have been around for a while. A steel based fiber reinforcement from the same lab @ UofM is commercially available from PolyTorx and offers even better performance in many applications. http://www.polytorx.com/
Actually, this interests me more for countertops than roads. "Countertops?" you ask. If you've never looked at concrete countertops, you really should. Here are some pics. (I am in no way related to the site.) They seem like they have signifigant advantages over granite, namely cheap, easily formed materials, and can look just as good or better (mix in whatever you want!). However, my concern has always been dropping somehting on them and chipping, because you have to replace the whole slab if you want to fix it. Perhaps bendable concrete would be less prone to chipping.
They said to stop passing off their early '90s news articles as new today!
Look for the article "Concrete that Bends", between 1990 and 1992.
The concrete was made with lots of nylon fiber inside.
im a real geek and i didnt get it.
perhaps i need to move back in with my mom?
It looks like concrete. It feels like concrete. But does it taste like concrete?
Sig free since 2/6/2002
You can read Victor Li's paper (PDF). The reinforcing fibers are plastic, which raises a whole host of questions. The work, by the way, has been done at U Mich's Advanced Civil Engineering Material Research Lab.
Uhmm, yeah, lets test out our new road material on a bridge...couldn't we start on a parking lot or a 35 mph road?
It's amazing how shitty surfaces last for 1000 years.
Concrete less resistant to cracking in marine environments minimizes the embarassment of having your stiffs pop to the river's surface some years later after the "cement overshoes" flake off the corpse...
I used to wonder about what would drive people
to built a ferro-cement boat, considering the
surface area/bouyancy required for the weight of
it's construction. This advancement in materials
science makes a smaller (less ark-like) concrete
boat a viable alternative.
I no longer have any excuse for not building a
concrete catamaran, in spite of being nearly 1000
feet above sea-level. No need to wait for that
Canary Islands tsunami for it's launch.
We can only pray. But seriously do you really want the road commission guys applying for jobs were you work?
If you do a poor one, you're gonna have to do it all over again next year (i.e. more money).
The Raven
Less job security for those who repair potholes =(
"I figure you're here 'cause you need some whacko who's willing to stick his finger in the fan. So who are we helping?
In this town, we have cobbled streets, still going strong from the Middle Ages...
That's Europe for ya... thousands of years of history, unbroken by progress..
I keed... I keed...
A Human Right
like crap (on purpose.)
Leave it to neo-Ludites to come and smash it up.
MSBPodcast.com The opinions expressed here are my own. If you don't like 'em... Think up your own stuff.
The streets here in downtown are constantly being torn up and whatever surface there might be is, literally, a holey mess. (I walk with a cane and its an exterience, let me tell you.)
I've often wondered why they bother paving them again when it would probably be smarter to just span the holed with 'arched' concrete segments resting on sidewalk supports that they could just lift out of the way, lay the cables/pipes/whatever and then replace.
It would certainly mean that the street isn't torn up for weeks at a time.
MSBPodcast.com The opinions expressed here are my own. If you don't like 'em... Think up your own stuff.
still not as cool as pykrete
"The direction controls are the same in Nethack as they are in vi." "Yeah, I hardly ever die in vi anymore."
This sounds too complex to have been made by human researchers, so I hereby posit the Bendable Concrete Intelligent Design theory. There must be a higher power.
I remember the civil engineering students demonstrating a flexible concrete snow sled during Engineering Week at my alma mater (UBC) sometime around 1994. They rolled it up and carried it away. (It took four of them to lift it.)
"Anyone that has ever gotten an idea based on any of my work and done something better with it-good for you."--J.Carmack
I've done that! When I was in college, on an internship, one of the other interns thought it would be a cool contest to see who could crash a PC with the smallest amount of code. (This was back in the Windows 3.1 days.) So he wrote a batch file that called itself (or something along those lines), and sure enough, it eventually blew up the DOS stack and crashed. It was pretty small, maybe 20 bytes or so. Being a real programmer, I did this:
COPY CON X.EXE
[Crtl-A][Ctrl-Z][Enter]
Which creates a one-byte file with ASCII character 0x01, which is the smiley face (just to be cute). One of the wonderful things about Win 3.1 and DOS is that they don't do any sanity checking of EXE files. They just jump right in there and start executing. So trying to execute the single smiley-face character did in fact hang the system.
Seems like the big limitation is the foam they use for flotation. Made me wonder if you could embed the microballons in a matrix of metal rather than epoxy. Yes I can imagine the issues.
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
...structural grade applesauce.
A couple of years ago my interest in boating caused me to start looking into composites. Eventually I settled on pretty pedestrian epoxy and fiberglass cloth due to it's reasonable cost, strength, and overall characteristics. I built my first boat and found it more than rewarding.
Learning about composites and their characteristics was far more interesting and rewarding that I would have ever imagined. How and why they do what they do is just cool - and trying to understand what the best composite for the best application is can sometimes involve a lot of research (and even then you will here different opinions from different experts - who are all naturally trying to sell you something).
Fero-cement boats are actually kind of common and have been in use for many years. While heavier than a comparible fiberglass or steel boat, they have some advantages (easier to make complex curves than steel for instance). Over years a "concrete" boat (and all cement based products are in their own right composites) wear out and require more and more maintenence to keep them seaworthy. One of the hardest things to engineer is the fact that you have to deal with expansion and contraction (this is why roadways and sidewalks have seams in them).
Flexible concrete that only contains a small percentage of interlinking fibers could revolutionize concrete for boat building purposes. While I am allowing myself to dream here a little bit, I think it is possible that in time concrete could become the matterial of choice to build large ships!
In larger ships the added weight of concrete would not add so much mass that it would really reduce the effiency of the ship much at all and construction could be a whole lost faster (especially if mass produced in molds).
reinforced cement has been re-invented - woohoo...
Oh well, what the hell...
Reminds me of an old "Beetle Bailey" cartoon:
Sgt. Snorkel: Zero, go get me some rubber cement.
Zero: Rubber cement? [long thoughtful pause] Sure would make walking more fun.
I figure by 2030 or so my 6-digit UID will be something to brag about.
towers out of this, then the airplanes would have just bounced off, right? Boingy boingy, but no fallee!
Okay, "scientists" eh? All anyone had to do was mix a 2 lb. block of Pillsbury Baker's Yeast with warm water, some sugar, & bigbottleof Metamucil. Wait 20 minutes and dump it into the concrete batch. Geez. hehehehe
> No, but because of it's bendability, it can actually dodge incomming plains.
/ plate-tectonics.html
But how fast can these incomming plains, that you mention, move? . . and is this all due totectonic plate creap?
http://www.seismo.unr.edu/ftp/pub/louie/class/100
.
(David Bowman, EVA near HUGE Monolithic Win-PC in orbit around Jupiter) "My God - its full of Malware!"
I work for the company that makes the fibers mentioned in this story. This mix is called PVA-ECC and our site is www.kuraray-am.com/pvaf/ . The third party site with all the research is www.engineered composites.com The way it works is that the fibers have low stretch and a free hydrogen molecule that creates a chemical bond with the cement during hydration. So what you get, as concrete shrinks over time, is millions of microcracks generally too small for water to penetrate. Those cracks can heal by themselves from the free, unhydrated lime in the mix. But using a crystal-generating product like Xypex, Kryton or Tegraproof will certainly assist in the healing of the microcracks. These cracks are so small that usually--even without control joints--you have to wet the surface to see them. Because of the molecular bond between the fibers and the cement, and because at 40 microns, 8mm long, you have many millions of fibers at 40lbs/yard dosage, this material is also highly fatigue resistant. Hence the bridge angle. Yeah, that's a lot of fiber, but you can cut your concrete cover way down, cancelling out fiber costs. For many applications you can eliminate most or all of the steel reinforcement. But because of these features, plus chemical, alkali, UV and abrasion resistance, there are a myriad of uses for PVA fibers. Even just a pound per yard cuts long term cracks by 50% in regular old ready mix. Just toss it in the truck. Rick McCabe
There is a natural fibery texture to PVA-ECC because we use 40 lbs/yard of 40 micron fibers. You can pour it in a mold and have it come out glass smooth, but generally we use texture rollers to move it around. (The standard recipe is nearly self-levelling.) A good finisher can make it very smooth (no hairs, 1.3 density) but you would probably then want to go back and put a brush finish on it for driveways and sidewalks. I don't know how they are texturing the road work, if at all. Over time the concrete will probably break down and not the fibers. (But with a very high fly ash content, the pozzlanic characteristics will help with aging.) The fibers are enormously abrasion resistant. Where a client had a one inch bump for his heavy forklifts to go over, I put down some PVA-ECC and feathered it down to paper thickness. After months, there were no cracks or damage in the main section. At the paper thin area, the mortar was gone but the fibers were still intact in their molecularly bonded grid. Strange stuff but it works. Rick McCabe
(no text)
and I for one can see where he's coming from.
When I see how inefficient the road construction around my town is I suspect the city council members must be getting kickbacks from the construction companies. The street I live on, which gets quite a bit of traffic, was resurfaced and repainted. It took the construction crew only a day or so, and the job was adequate. But (I think it's because the contract and kickback scheme must go by the hour) they came back and spent over a week standing around, putting another layer on top of what they had just done without removing anything, and then drilling through this second layer to reach the manholes they had idiotically cemented over. When they left and reopened my street, there was a dropoff of about an inch from the edge of the road surface to the gutters. I didn't complain to the city because I thought it might prompt another weeklong street closure.
Even beyond suspicions of graft, it seems a lot of cities are perfectly willing to tear up and redo a street because somebody suggested the street wasn't aesthetically pleasing enough but completely unwilling to spend another cent on education.
See the website for the research group that works on this.
"Sometimes I lie awake at night, and I ask, 'Where have I gone wrong?' Then a voice says to me, 'This is going to take
Brick roads make a perfect ice rink in freezing weather i.e. very dangerous, I cursed naive estate designers for this when cycling in icy weather!