Self-healing concrete eats CO2 to fill its own cracks in 24 hours:
Concrete has a massive carbon footprint, so technologies that boost its performance and enable it to last longer could have profound benefits for the environment. This has led to the development of self-healing concrete that can repair its own cracks, and scientists have now demonstrated an exciting new form of this that makes use of an enzyme found in human blood.
Tiny cracks that form in concrete mightn't pose an immediate problem to the structural integrity of a construction, but as water gets in and the rupture spreads it can greatly compromise its strength. The idea with self-healing concrete is to intervene in this process while the cracks are still tiny, sealing up the material to prevent not just a catastrophic collapse, but expensive maintenance or a complete replacement of the structure.
[...] Through their testing, the scientists demonstrated their doped concrete can repair its own millimeter-scale cracks within 24 hours. The team says this is a marked improvement on some previous technologies that have used bacteria to self-heal, which are more expensive and can take up to a month to heal even far smaller cracks.
While the amount of CO2 the concrete gobbles up is likely to be negligible in the grand scheme of things, the real environmental potential of the material lies in its potential longevity. Rahbar predicts that this type of self-healing technology could extend the life of a structure from 20 years to 80 years, which reduces the need to produce replacement concrete in what is a notoriously carbon-intensive process.
There is a related 44-second video on YouTube.
Previously:
Biologists Create Self-Healing Concrete
Fungi Can Help Concrete Heal Its Own Cracks
Related Stories
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."
One thing that is left out of the articles mentioned above is the amount of time needed for a given crack to "heal" closed.
[researchers] have found an unusual candidate to help concrete heal itself: a fungus called Trichoderma reesei.
We initially screened about 20 different species of fungi in order to find one that could withstand the harsh conditions in concrete. Some we isolated from the roots of plants that grew in nutrient-poor soils, including from the New Jersey Pine Barrens and the Canadian Rocky Mountains in Alberta.
We found that as calcium hydroxide from concrete dissolved in water, the pH of our fungal growth medium increased from a close-to-neutral original value of 6.5 all the way to a very alkaline 13.0. Of all the fungi we tested, only T. reesei could survive this environment. Despite the drastic pH increase, its spores germinated into threadlike hyphal mycelium and grew equally well with or without concrete.
We propose including fungal spores, together with nutrients, during the initial mixing process when building a new concrete structure. When the inevitable cracking occurs and water finds its way in, the dormant fungal spores will germinate.
As they grow, they'll work as a catalyst within the calcium-rich conditions of the concrete to promote precipitation of calcium carbonate crystals. These mineral deposits can fill in the cracks. When the cracks are completely caulked and no more water can enter, the fungi will again form spores. If cracks form again and environmental conditions become favorable, the spores could wake up and repeat the process.
The spores wake up when cracks form in concrete and admit moisture.
(Score: -1, Flamebait) by Anonymous Coward on Monday June 21 2021, @08:58PM (1 child)
end your life
(Score: 2) by FatPhil on Wednesday June 23 2021, @09:42AM
One of the almost definitional properties that "modal" (sometimes called "auxiliary") verbs have is that they can form the -n't negation. "Might" is as much a modal verb as "can", "do", "have", etc. and certainly would be expected to have such a form. As the article proves, it indeed does.
And now for a bonus trivium: A lot of people overlook the fact that "dare" can be considered a modal verb; however, the fact that "daren't" is so unexceptional, and the fact that it forms all the other constructs that modals should, support the fact that it is indeed a modal.
Another unusual gramattical property that modals have is their ability to form questions by reversing subject-verb order. "You can ..." -> "Can you ...?", but not "I eat ..." -> *"Eat I ...?", say. Dare anyone doubt me on this matter?
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: -1, Redundant) by Anonymous Coward on Monday June 21 2021, @09:04PM (6 children)
"Self-healing concrete is the only concrete I endorse, and I glare at anyone who disagrees with my position" - St Greta
(Score: -1, Redundant) by Anonymous Coward on Monday June 21 2021, @09:07PM (2 children)
Watch out, the Greta fan club is going to polish off their witty comments questioning your manhood.
(Score: 5, Insightful) by Tork on Monday June 21 2021, @09:49PM (1 child)
Heh. It's not a "Greta Fan Club" (does that actually exist?) that won't stop bringing her up. Oh and it's not like anybody's successfully disputed anything she's said.... which actually explains why the attacks on her are disproportionately frequent and lack sophistication.
🏳️🌈 Proud Ally 🏳️🌈
(Score: 0) by Anonymous Coward on Tuesday June 22 2021, @09:26PM
Sophistry is more commonly associated with the woke left and the global warming crowd.
(Score: 5, Insightful) by Anonymous Coward on Monday June 21 2021, @09:10PM (1 child)
You must be very insecure in your masculinity to make fun of an autistic 16 year old high school dropout.
(Score: -1, Flamebait) by Anonymous Coward on Monday June 21 2021, @10:20PM
Indeed, if only her parents hadn't whored her out to Globohomo like the parents of child Hollywood stars whore them out to Jewish casting directors.
Assuming she's actually a real person, she'll end up in another few years like Macaulay Culkin, River Phoenix, or the 2 Coreys: Pimped out by greasy fat Jews, to greasy fat Jews, in exchange for low-grade heroin. The lucky ones won't choke on their own vomit after doing the Fentanyl Floyd* banana-dance.
* People have literally made a saint out of an ugly criminal dope-addict. People are putting up statues of that dead dope-addict all over the place. Fentanyl Floyd is heralded as a saint because Jewish money-launderers profiting from the corporate BLM scheme made it so. I wouldn't be so stupid as to worship an ugly dead criminal dope-addict, but you might be.
(Score: 0) by Anonymous Coward on Monday June 21 2021, @10:30PM
Greta or no Greta, I'm now waiting for "concrete healer" to become available at my local home store. The concrete driveway put in ~10 years ago still looks pretty good. It was sealed by the contractor after it cured, but may be due for some preventative maintenance about now(??)
(Score: 3, Interesting) by bzipitidoo on Monday June 21 2021, @09:07PM (6 children)
Only 20 years? So how is it that for many highways that were first paved in the 1930s, that original concrete was still in use in the 1980s? There was a real easy way to tell if it was the original. The first paved roads were 18 feet wide, and while it served, it's stressful driving on such a narrow road. Iowa soon widened all the roads to 20 feet by adding a 1 foot strip on each edge, with a line of tar. If you saw that line, you knew you were on pavement that was laid in the 30s.
(Score: 0) by Anonymous Coward on Monday June 21 2021, @09:20PM
It lasts more than 20 years, but you know how AGW advocates like to stretch the truth for dramatic effect.
(Score: 0) by Anonymous Coward on Monday June 21 2021, @10:18PM (4 children)
Maintenance.
(Score: 0) by Anonymous Coward on Monday June 21 2021, @10:25PM (1 child)
>> Only 20 years? So how is it that for many highways that were first paved in the 1930s, that original concrete was still in use in the 1980s?
> Maintenance.
And not a lot of heavy truck traffic is my guess. Road damage increases with the 4th or 5th power of the load.
(Score: 2) by bzipitidoo on Tuesday June 22 2021, @12:25PM
> And not a lot of heavy truck traffic is my guess.
Yes. The busier highways had to be rebuilt sooner. The state highways that lead only to a few small towns had the original pavement longer than the busy US and state highways that connected cities. Those less busy roads were also the last to be paved.
(Score: 0, Troll) by TheMightyChickadee on Monday June 21 2021, @10:28PM (1 child)
In other words, American highways have been regularly slathered with human blood, given American driving habits, which as allowed concrete highways to self-heal their micro-fractures.
(Score: 0) by Anonymous Coward on Monday June 21 2021, @11:27PM
"This is infrastructure!" [politicususa.com]
(Score: 2, Offtopic) by Runaway1956 on Monday June 21 2021, @10:34PM (3 children)
That lends some credibility to the oft-repeated story about Roman concrete requiring blood in the mix. Maybe they really did sacrifice a slave before mixing concrete? Maybe it wasn't the volcanic ash after all that gave their concrete such strength and durability.
Can't help wondering if cow's blood, or sheep's blood might work just as well.
(Score: 0) by Anonymous Coward on Monday June 21 2021, @11:25PM
The Romans did use small amounts of animal blood, it adds air pockets (like today's admixtures) which help protect against damage due to thermal expansion and contraction. Perhaps the blood does help explain why roman structures are still standing but I've never heard of them using human blood.
(Score: 2) by captain normal on Tuesday June 22 2021, @12:04AM
I can see it now, next fall's scary Halloween movie. "The Vampire Highway" a story about teenage kids that can't stay away from the favorite make-out spot located next to the creepy cement plant.
Stephen King if you use this, you owe me big time.
Everyone is entitled to his own opinion, but not to his own facts"- --Daniel Patrick Moynihan--
(Score: 2) by c0lo on Tuesday June 22 2021, @10:19AM
Eggses
https://www.atlasobscura.com/articles/filipino-desserts [atlasobscura.com]
https://patents.google.com/patent/DE4017623A1/en [google.com]
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by PiMuNu on Tuesday June 22 2021, @10:52AM (2 children)
> When a small crack forms in the concrete, the enzyme interacts with CO2 in the air to produce calcium carbonate crystals
How does this conserve energy? Where does the calcium come from? The reaction they are trying to do is
CaO + CO2 -> CaCO3
but I believe this is a net energy sink; and calcium is needed from somewhere.
(Score: 4, Interesting) by sjames on Tuesday June 22 2021, @08:33PM (1 child)
The CaO is likely left over from the incomplete curing of concrete. CaO -> CaCO3 is exothermic.
(Score: 2) by PiMuNu on Wednesday June 23 2021, @07:03AM
Thanks