Biologists Create Self-Healing Concrete 94
Mr.Intel writes: A team of microbiologists from the Delft University of Technology claims to have invented "bioconcrete" — concrete that heals cracks and breaks using bacteria. The goal was to find a type of bacteria that could live inside concrete and also produce small amount of limestone that could re-seal cracks. This is a difficult prospect because concrete is quite dry and strongly alkaline. The bacteria needed to be able to stay alive for years in those conditions before being activated by water. The bacteria also need a food source — simply adding sugar to concrete will make it weak. The scientists used calcium lactate instead, adding biodegradable capsules of it to the concrete mix. "When cracks eventually begin to form in the concrete, water enters and open the capsules. The bacteria then germinate, multiply and feed on the lactate, and in doing so they combine the calcium with carbonate ions to form calcite, or limestone, which closes up the cracks."
Amazing! (Score:3)
I'm all for it, as long as nothing could possibly go wrong!
Those pour [sic] souls (Score:5, Funny)
>The goal was to find a type of bacteria that could live inside concrete
If you can call that "living." Think of the bacteria!
Re:Those pour [sic] souls (Score:5, Funny)
Humans have been living in concrete in NYC for over 100 years. They seem to enjoy it.
Then again -- maybe that's why New Yorkers are so mean and rude...
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The Romans lived in concrete too, but they died
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http://corrosion-doctors.org/Elements-Toxic/Lead-history.htm [corrosion-doctors.org]
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Making lead the likely reason for the collapse of the Roman empire, strange that it should repeat again for the US empire, except this time via car exhausts.
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I think that had more to do with their use of Lead for piping and the aqueduct.
Lead piping and such is not that much of a danger. If it was we would all show lead levels in our blood, and we don't.
The Romans discovered this really neat artificial sweetner, though. It was a lead compound and they used it in many their wines.
-That- is what caused the problems!!
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They also have an abundance of people who wear funny hats.
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Maybe that's why *THEY* were mean and rude!
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Humans have been living in concrete in NYC for over 100 years. They seem to enjoy it.
And they're quite good at sealing up cracks in concrete to! No bacteria needed, and no need for complicated feeding schemes. Just send the sealers to the next supermarket. (They even pay for the food themselves!)
Re:Those pour [sic] souls (Score:5, Funny)
interesting theory, could vegans use buildings made of this material? Or does their highfalutin standards only apply to multicellular creatures?
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Vegans must be in a quandary in general. To live, they must consume resources that one way or another kill animals (ecological destruction, oil use - spills, etc) but if they kill themselves, they take all their gut bacteria and other such human ecological systems with them.
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yet they die. so what would be most useful... ideologically at least, is to sterilize themselves as to not propagate the continued abuse.
I wonder what vegan parents think of this?
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Straw vegans (Score:1)
Vegans aren't unwilling to do anything that could feasibly kill animals, they're unwilling to eat animal products. Gut bacteria are not animals and probably don't suffer (or even think for that matter). I'm not a vegan myself, but I'd imagine they're trying to minimize their contribution to suffering and don't pretend to eliminate it entirely.
You strike me as someone who says "atheists don't believe in anything" and "vaccine supporters think the government owns you".
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Bacteria are no more animals than a rock or baseball bat. They're Prokaryotes, which is an entire different kingdom than Eukaryotes which include plants and animals.
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You need to read some biology text that's younger than 30 or 40 years old.
Life hasn't been divided into just plants and animals in a long time. There's also fungi, bacteria, archaea, ... See here [wikipedia.org] for example.
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It's a good thing that cows don't eat.
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It's a good thing that cows don't eat.
mod points,please!
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Far opposite from the truth. I'm no vegan myself -- but growing meat animals requires vastly more inputs (grain, water, etc) than would be needed if skipping the (delicious) intermediate step. Humans consume less grains in sum when consuming them directly, rather than via an intermediate layer.
Re:Those pour [sic] souls (Score:4, Funny)
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"I use electricity, and electricity has killed people, so I'm a murderer, and even if I kill myself others will use electricity at my funeral, which is more murder, so I might as well go around shooting people".
You can always tell when somebody starts with a conclusion and works backwards.
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Vegans aim to minimise their use of animals as far as is practical and possible.
It's not about being perfect, it's about trying to be less abusive by cutting out as many products which cause suffering as possible.
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interesting theory, could vegans use buildings made of this material? Or does their highfalutin standards only apply to multicellular creatures?
Aww I was going to answer your question, but found it too highfalutin. So you'll have to do your own googling now.
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If you can call that "living." Think of the bacteria!
I believe you may have stumbled upon a new cause for PETA.
Practical use (Score:5, Informative)
Bacterial concrete is ideal for constructing underground retainers for hazardous waste, as no humans would have to go near it to repair any occurring cracks. For residential buildings, however, it does seem the traditional repairing of cracks will remain the most economically attractive solution for now.
Currently, our research focuses on creating the right conditions for the bacteria to produce as much calcite as possible and on optimizing the distribution of food for the bacteria.
Re:Practical use (Score:4)
Re:Practical use (Score:5, Funny)
Okay, so the bacteria are going to be in the walls, exposed to mutagens and/or radiation, and unobserved by humans for years at a time. I want movie rights!
Re:Practical use (Score:5, Insightful)
Okay, so the bacteria are going to be in the walls, exposed to mutagens and/or radiation, and unobserved by humans for years at a time. I want movie rights!
That basically describes how your walls are right now.
is this kinda/sorta like coral reefs? (Score:2)
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i think you are thinking of land sharks
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I'm guessing that you: A) dictated this post, and B) have imbibed several alcoholic beverages.
This is a ridiculous way to make concrete. (Score:1)
We already have a plethora of contractors, engineers and manufacturers intent on bypassing the critical stoichiometry required to produce defect free, indestructible concrete. Of course, this is all caused by cost. Which means, due to greed and stupidity, people will accept inferior products if it is cheaper. Even dirt. Most people will tell you that ALL concrete will eventually develop cracks. They are incompetant morons.
Not sure if anyone is working on 3d printing concrete, I just assume someone i
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If I can't stop concrete sidewalks from being cracked by tree roots over the years, something is wrong with me? Obviously, I should just chop down all nearby trees.
If I can't stop idiots with trucks that surpass expected weight limits or heavy objects falling onto the concrete, something is wrong with me? I'm not Superman.
This has nothing to do with concrete when it being formed. The worst that happens at that time are paw prints and graffiti.
My concern is, if this stuff works, how much will it work? Will i
Re:This is a ridiculous way to make concrete. (Score:5, Informative)
Concrete longevity has a LOT to do with preparation and maintenance.
For example tree roots - proper subsurface preparation, which isn't normally done for sidewalks, will result in roots not extending far under the concrete, and even if they do penetrate somewhat, not growing large enough to crack the concrete. Failing that, routine maintenance with certain products will kill the roots before they get too large, but leave the rest of the tree unaffected.
As for your questions -
1. It will probably only fix any given crack spot once.
2. 99% of the fixes will be practically microscopic in nature.
3. At the depths we're looking at, restoring a barrier is a bigger deal than being structural.
4. Most of the time the very cracking releases the stress that caused the crack, then water gets in and freezes, widening it. This keeps the water out(after the bacteria do their job).
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My concern is, if this stuff works, how much will it work? Will it repair itself in the same area more than once? What is to stop the bacteria from forming a big lump on the surface after they bridge the crack's gap. Is the replacement material even nearly as strong as the original concrete or will it just break again under less stress? If the intended use of this for building construction or surfaces to walk on? I can see it being used in 1-3 story buildings as material, but any where solid concrete has to be used instead of those hollow cinder blocks, I can't see it being possible, much less if water is needed to activate it.
Being able to repair small cracks to keep water out would go a long way to minimize the freeze/thaw damage that makes small cracks into big cracks. Even without the same strength as uncracked concrete, concrete with some small filled cracks will perform much better and last much longer than concrete with growing numbers of growing sized cracks.
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If you can't produce crack free concrete, there is something wrong with you.
Concrete is often deliberately cracked to allow for thermal expansion and contraction. That's why we have lines on the sidewalks and joints in the roads. These bacteria would fill those in and cause heaving.
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Those "cracks" (technically they are expansion joints) are not made by mechanically cracking hardened concrete. They are made before pouring, by placing spacers that are poured in. Therefore the process should not crack the outer shell of the "healing agent" capsules. Thus the bacteria will not fix the expansion joints.
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That is not how it's done here it the Netherlands.
I imagine that tool will be outdated for rubber spacers with this type of concrete.
Interesting implications for subterranean homes (Score:2)
Foundation Repair (injection) (Score:5, Interesting)
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You're kidding, right? They fix cracks in concrete now by injecting hydraulic cement. Exactly the same delivery process, except the crack is then sealed as soon as the cement dries, and it uses an existing, inexpensive substance.
I don't think anyone is complaining that injected hydraulic cement is not strong enough, or doesn't fill all of the gaps.
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You're kidding, right? They fix cracks in concrete now by injecting hydraulic cement. Exactly the same delivery process, except the crack is then sealed as soon as the cement dries, and it uses an existing, inexpensive substance.
I don't think anyone is complaining that injected hydraulic cement is not strong enough, or doesn't fill all of the gaps.
But can reopen.
Think plaster walls and ceilings. You can repair cracks, but just get new ones.
Concrete (Score:4, Funny)
heal thyself!
Theoretical? (Score:5, Funny)
Is this a theoretical development or does it have concrete uses?
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Is this a theoretical development or does it have concrete uses?
These are scientists. It's all theoretical until the civil engineers get their hands on the stuff.
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In theory, there are no concrete applications for this, but concretely, there are.
I hope it's a fast process... (Score:2)
It will have to repair fast enough to beat the dirt and weeds from staking a claim to those cracks.
Biocrete? (Score:1)
As a trade representative from Janus VI, my Horta constituents are very interested!
What about Geopolymer Concrete? (Score:2)
Why not just make self healing limestone instead?
Antifragility? (Score:1)
Not mentioned in the article.... (Score:4, Interesting)
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Isn't limestone relatively easy washed out by water? (Which is major cave building mechanism)
Good question. But that process in caves is not so easy and happens very slowly. If our buildings last ten thousand years, that is probably enough... 8-)
Growing at the surface (Score:5, Interesting)
What keeps the surface of the concrete from "growing"?
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The lack of exposed broken bacteria capsules and food.
So this is how the T-1000 started out (Score:2)
Cementinator
Reservations (Score:2)
Crack Filling = Hiding Critical Flaws? (Score:4, Insightful)
If the concrete fills it's own cracks automagically, two questions spring to mind: 1) Will the crack-filling material have the same load bearing properties or (as I suspect) it will be much weaker at those spots, and 2) will the filled cracks disguise the facts that the object may be under a load that was not anticipated by the designer (tensile or bending loads vs. compressive loads)?
Reinforced concrete is often used in bending and tensile load applications in architecture, and if the reinforcing is not stiff enough cracks often will appear on the surface. They are unsightly, but if the reinforcing is taking the load (as it should) these are not structural deficiencies. But for complex architectural domes and shells, the presence and size of these cracks is something that needs to be monitored.
If the concrete is used in a container and it cracks, we may actually want to see the crack as that is a warning that something is being loaded in an unanticipated way. Hiding it with a self-filling mechanism may not be desirable.
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TFA has pictures. The cracks are very visible, they have a different color.
Open cracks are almost always structural weak points as water, dirt and plants get in them, further cracking the concrete and rusting the reinforcement (which, incidentally, cracks the concrete). If cracks form to make the reinforcing take a normal load then there should have been (more) pre-tension on the reinforcing. It is a clear cut case of bad building practice.
If the and all similar bad building practices have been removed then
Dear Peter F. Hamilton, (Score:2)
You can now stop calling futuristic concrete 'enzyme bonded concrete'.
Thank you,
Reader
Mortar Forker (Score:1)
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one thing to note (Score:1)
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Usually parts break off from concrete when there was a small crack to begin, then either one of the next cases happens:
1. water enters the hole-> freezes (expands) -> crack gets bigger -> more water enters -> freezes-> crack gets bigger -> etc -> part breaks off.
2. Dirt and water enters the crack -> plant grows in crack -> roots crack the concrete further -> part breaks off.
This self healing concrete prevents both scenarios as it heals the initial small crack, preventing water