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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?
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?
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!
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?
Concrete roads are far more resiliant to wear than asphalt/tar roads, this means (generally) less repair work. This is a major factor when you're dealing with a massive arterial system.
Overall concrete roads and asphalt tend to work out the same in terms of costs (over a period of years), concrete being more expensive to lay but lower repairs and vice-versa for asphalt.
I forgot to note that the "noise" that you're suffering is from the grooving they put into the concrete road. Without this grooving people would be crashing everywhere when it starts raining from aquaplaning (even the smoothest asphalt road will not be as slippery as a wet smooth concrete one).
Paul.
No, the only reason asbestos is damaging to lungs is that it
tends to form particles 0.5 to 1.4 microns in diameter, which is the range in which any paticulate matter is lung damaging and carcinogenic in nature. Asbestos is not mutagenic; any particles that form mainly in that size will cause lung cancer. It is a strange twist of fate that asbestos fibers disintigrate to particles that size, but it has nothing to do with fibers in general or their chemistry.
Fiber reinforced materials have been around for years. Carbon and glass fiber reinforced polymers are used in many everyday applications without harm. The problem with asbestos was its crystal structure and cleavage planes, which enabled it to break down into very small (micrometer scale) fibers that were easily inhaled.
The above comment is about as insightful as saying "Cotton fiber? That seems eerily reminiscent of asbestos, better not wear clothes!" or "AIDS medicine? Wasn't thalidomide also orally available in pill form? Better not give it to pregnant women..."
Making the moon less necessary since 1998.
The architects, contractors, and construction workers of the Petronas towers in Kuala Lumpur simultaneously shout, "D'oh!"
From what I remember of watching a documentary on the construction of the Petronas towers, the primary concern of the engineers was the compressibility of the concrete -- each floor has to withstand the weight of the numerous floors above it. Flexibility was the least of their worries.
Furthermore, the two towers are located on a relatively 'soft' foundation -- they essentially 'float' on sea of soft land. The towers aren't anchored to the bedrock. Additionally, the bridge that connects the two towers is designed to allow the towers to move towards and away from each other. 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.
I'm Trappped at Berkeley.
There's an alternative they're trying out in certain areas of Wisconsin. It's basically asphalt, but with a very high rubber content. They grind old tires into the asphalt. The net result is that it costs about the same to lay, and it can "heal" itself to some degree. The main concern is how safe it is when completely frozen, which is why it's only being tested in certain sections of freeway.
If it does prove to be a viable material to replace basic asphalt, it'll be great for Wisconsin drivers... we deal with slippery roads all winter then road construction in the spring, summer, and fall. If this can at least eliminate pothole patching, it'll pay for itself many times over.
You have enemies? Good. That means you've stood up for something, sometime in your life. --Winston Churchill
"Tiny fibers that comprise about 2 percent of the mixture's volume partly account for its performance."
The fibers are only one part of the improvement. The article also mentions replacing other major components in the concrete, including the bulk aggregate. Presumably the new components are also lighter and would account for the 40% reduction.
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
The increased strength makes it possible to use less of it to build structures of similar strength. You need 40% less of the fiber concrete to get the same strength as the traditional concrete.
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.
Concrete was the first material that was used in the construction of mass use roadways back in the early days of the automobile as asphalt hadn't been discovered yet. Theres a very good chance that the concrete roads you drive on today were laid back in the 40s and early 50s. But concrete was always expensive to use, and required extensive preperation of the ground in order to pour it. So it was a slow and tedious proces, and not many cities could not afford to have more than one crew going at a time.
When it was discovered that Asphalt, a by-product of oil refining, could be mixed with a small sized aggregate *gravel* and basically smooshed ontop of any roughly prepared surface to create a roadway, well that was the end of using concrete. Most concrete projects were abandoned overnight and roads started being laid at a fraction of the price and at triple the speed.
The one caveat is that in Northern Areas it was discovered that asphalt roadways were not holding up as long as their concrete breathern. Many asphalt roads were having to be torn up and replaced every other year due to extensive freeze damage. Many cities went back to using concrete for their roads, until better techniques of preparing the roadbeds were discovered. Which were to compress and smooth the roadbed as much as possible, then lay a barrier layer of aggregate *gravel* on top of that to help with drainage and settling, then to finally slope the finished road from the middle to the edges for increased water run-off.
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.
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.
...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...
I don't quite understand.
Improved roads reduce fuel consumption, and also pollution. Maintaining bad roads is also costly, removing funds that can be used for other purposes, and can be itself polluting. In the long term, everyone gains, and cost is reduced. It's almost a free lunch.
So long as we are talking about upgrading existing roads, not building a massive new network of roads, I don't see how anyone can be displeased by this.