9 ms·

Using bacteria to make self-healing cement

156 points by vinnyglennon 7y ago

samgtx 7y ago
>Being mixed with concrete and distributed evenly throughout it, they can lay there in a dormant state for up to 200 years; only when the concrete cracks, air and moisture awaken the bacteria which use the calcium lactate as a food source and start to produce limestone, sealing off the cracks in 3 weeks’ time. The technology, currently able to seal cracks of any length but only up to 0.8 mm wide, was a finalist for the European Inventor Award 2015, an initiative of the European Patent Office (EPO). That's brilliant. I wonder what the cost increase would be for including this solution v. the cost of traditional repairs.
- justinmchase 7y ago
  The article says it costs about twice as much. > Currently the cost of this new technology is still considered prohibitive, as it is twice the cost of regular concrete manufacture (70-80 € / m3), making it only viable for projects where leakage and corrosion are particularly problematic, such as underground and underwater structures. What's funny to me though is that they consider this cost prohibitive despite the expected theoretically longer life without replacement or maintenance.
  - LegitShady 7y ago
    How often do you think most concrete structures (with only minor cracking like in the article) undergo serious rehab? Maybe once in their service life. Also, when planners are choosing between alternatives, net present value (NPV) is calculated which takes into account predictable maintenance, so the cost of future repairs is already considered in these decisions. Civil engineering is also not computer engineering. There is no agile development and you have to get it right the first time. The industry as a whole is not quick to adopt new technologies without seeing them proven in the field relatively thoroughly.
    - vbezhenar 7y ago
      May be it's true for Europe, but in my country they're re-building roads every few years. Not sure if they are agile or just corrupt...
      - munk-a 7y ago
        Qualification: I can't really confirm this fiscal responsibility of this. Vermont is of the opinion that resurfacing roads frequently (like every two years) is cheaper than investing in anti-frost heavy road beds and cement... The reasoning behind this is that intense ground freezing can end up upsetting the best bedding techniques and causing frost heaves anyway - that coupled with frequent ploughing to deal with heavy snow fall makes long term road investments fiscally irresponsible. Also the state has frequent flooding issues which can upset road bedding in more different and fun manners.
        LegitShady 7y ago
        depending on how plastic the soil, replacing it with the road base doesn't stop deformation just slows it down. If the base material is heavier than the native material it will speed the whole thing up. Then you get into the territory of lightweight fills and it gets really expensive very quickly even beyond basic roadbuilding.
      - LegitShady 7y ago
        the complexities of road construction depend on all sorts of factors from weather, subgrade composition, labour and material costs, traffic weight, total traffic, availability of capital, willingness to take risks, etc etc. Most likely the roads are not being "rebuilt" but rather getting microsurfacing, and occasionally a mill and inlay of just top layers of the road surface. Fully rebuilding roads is more time consuming.
        hermitdev 7y ago
        Ive been enduring a rebuild of I-294 around Chicago. It's around a 40 mile rebuild (ripping everything out down to dirt), IIRC. They're widening the highway in stretches, completely redesigning interchanges as well to remove sharp turns so that semis can keep speed and better merge. Lots of overpasses and other bridges being rebuilt to accommodate the extra lane each way. They completed the stretch around Ohare airport pretty quickly, in about a year, but seeing the materials used, I doubt it will hold up over time. I expect it will need maintenance on the first completed stretch before the 10 year project is complete. They went from concrete to an all asphalt layering from what I saw. Doubt it will hold up. Edit: designing -> redesigning.
  - dragonwriter 7y ago
    > What's funny to me though is that they consider this cost prohibitive despite the expected theoretically longer life without replacement or maintenance. Unless almost all maintenance and replacement needs are due to cracks that don't rapidly become more than 0.8mm wide, this reduces maintenance costs but doesn't let it go an extended time without normal maintenance and replacement. At double manufacturing cost, that could well be a losing trade-off for most applications.
  - ThrustVectoring 7y ago
    >What's funny to me though is that they consider this cost prohibitive despite the expected theoretically longer life without replacement or maintenance. Time value of money plays a big part here. The extra cost is now, the maintenance costs are paid later. Costs paid immediately are significantly more expensive than costs paid a long time from now.
    - daniel-cussen 7y ago
      With current low interest rates, I'd say this effect is sharply reduced. The twenties will produce infrastructure that will last a really, really long time because those maintenance costs will be incorporated almost without discount.
      - asdff 7y ago
        A lot of public budgets don't have room for a big upfront cost, but a longer pay period can be incorporated more smoothly and disturb fewer other parts of the budget, even if it ends up costing more in the long run. Sometimes there are federal grants to provide quick windfall for public works.
  - asdff 7y ago
    To be honest I really don't want concrete repaired. It's not like a steel girder that get exposed to rust but can otherwise be swapped out with a new piece. If concrete is cracked there is a reason why: something shifted. Raze and rebuild because the earth will never stop settling and/or shaking. Don't they bust up old concrete into new gravel and concrete as well? Probably cuts down on how much land needs to be quarried.
  - ako 7y ago
    The cost of replacement or repair is not something the current buyer will have to deal with, so the cost saving are also not his cost savings...
  - rkagerer 7y ago
    I interpret that as twice the cost of a traditional initial pour, but I think the question was how much that premium is offset by savings on repairs and maintenance over the life of the structure. The article implies it's currently only viable where where leakage and corrosion are particularly problematic, but mentions they're working on an alternative strain of bacteria grown from a sugar-based nutrient rather than more costly calcium lactate.
inflatableDodo 7y ago
Sounds like a great material for floating arcologies.
UI_at_80x24 7y ago
Wasn't it discovered that these bacteria are what make "Roman Cement" so much better then modern 'Portland Cement'? (or was I supposed the RTFA?)
- ThrustVectoring 7y ago
  The primary difference between Roman and modern cement is that Roman cement does not have reinforcing steel in it and cannot support loads that put it under tension stress. This reinforcing steel is what fails with age - cracks develop, let in air, and corrode the steel. No steel, and what you have is basically a shaped rock, and that can last a really long time. The downside, of course, is that not being able to resist tensile loads severely limits the designs you can make with concrete. Reinforced concrete is significantly more useful than unreinforced concrete.
  - LegitShady 7y ago
    and to add to this, all reinforced concrete cracks. Otherwise it doesnt need to be reinforced.
  - dustfinger 7y ago
    I wonder if it would be feasible to replace the steel reinforcement rods with ceramic? No iron no rust. I also wonder if concrete might bond better with ceramic. My understanding is that concrete does not bond well with steel.
    - dustfinger 7y ago
      It looks like some effort was made in 2010 to coat the reinforcing steel with a porcelain enamel [1]. I believe the enamel's primary function was to provide a bond with the encasing concrete. Naturally, it would also help to protect the steel from water and oxygen. There must be a reason why ceramic cannot fully replace steel. Cost perhaps. Maybe these technologies would be better combined. [1] https://www.ceramicindustry.com/articles/90943-improving-steel-reinforced-concrete-structures https://www.ceramicindustry.com/articles/90943-improving-ste...
nsb1 7y ago
<puts down Cat's Cradle> "Are you double-dog sure this stuff can never get out in the wild?"
- anonymfus 7y ago
  I think that Belyaev's "Eternal Bread" (1928) is much more relevant because it's about actual biotechnology and the scientist had good intentions.
- Gibbon1 7y ago
  I think a) the bacteria aren't novel. b) Calcium Lactate is what enables this.
- glloydell 7y ago
  There is absolutely no way this could possibly go wrong.
  - smrq 7y ago
    While I'm sure I agree with you, this comment reads like some famous last words!
epiphanitus 7y ago
Fun Fact: Much of the Great Wall is still in very good condition thanks to its amazingly resilient mortar. The secret ingredient: sticky rice. https://www.telegraph.co.uk/news/worldnews/asia/china/7785842/Great-Wall-of-Chinas-strength-comes-from-sticky-rice.html https://www.telegraph.co.uk/news/worldnews/asia/china/778584...
- dmos62 7y ago
  I love hearing about possibly competitive low-tech solutions.
mrfusion 7y ago
What’s cool about this is could it save the cost of making expansion joints? Edit. What I mean is you could do really big pours instead of sections. Think a mile long sidewalk with no sections.
- jacobush 7y ago
  But you would need a long queue of cement trucks :)
- munk-a 7y ago
  I don't believe so - those expansion joints exist IIRC to account for the fact that cement is quite temperature volume stable... but it isn't temperature inert. The seasonal temperature swings cause expansion and shrinking of cement and, especially on the scale of a bridge, those slight volume changes add up. I imagine this tech would allow shrinkage during the winter to be automatically repaired if it manifested as hairline gaps - but when summer rolled around you'd get a severe amount of buckling the cement expanded... then those buckles might partially repair - be reinforced when gaping occurred in winter - then buckle even more come next summer.
- jessriedel 7y ago
  I don't think so. It takes weeks for this cement to heal itself, whereas the sort of temperature swings that would cause very long pieces to crack happen in hours. You'd have frequent cracking and re-cracking without enough time to heal. I think this is better suited for damage from infrequent events (earthquakes, temperature swings from 10-year storms, human accident, etc.).
blacksqr 7y ago
"I'm beginning to think I can cure a rainy day!"
ninju 7y ago
please apply date [2017] to title as the article is old >Friday, 12 May 2017 01:00cat
ddxxdd 7y ago
I would like to understand the science behind how bacteria can live under the 50 gigapascals of pressure that one would find in the base of a skyscraper. My intuitions currently tell me that finding life underneath such mechanical stress is comparable to finding life inside the lava of a volcano or on the surface of the sun.
- YayamiOmate 7y ago
  Well, there are bateria living on chemical energy deep down in the oceans near volcanoes, that's not far from your example.
  - Gibbon1 7y ago
    There are actually bacteria living in rocks thousands of feet below the surface.
- jaclaz 7y ago
  >the 50 gigapascals of pressure that one would find in the base of a skyscraper. I guess you will need to rethink about the order or magnitude of the pressure you cited: https://en.wikipedia.org/wiki/Orders_of_magnitude_(pressure) https://en.wikipedia.org/wiki/Orders_of_magnitude_(pressure) Easy comparison terms are pressure to create artificial diamonds 18 GPa, pressure at the bottom of the Mariana Trench 110 MPa. Compression resistance of concrete is between 20 and 80 MPa: https://en.wikipedia.org/wiki/Compressive_strength https://en.wikipedia.org/wiki/Compressive_strength Where 20 is "common" concrete, 30-50 is typical reinforced concrete, anything above is specisl, high strength concrete.
- traverseda 7y ago
  Check out pascalization, an alternative to pasteurization that uses extreme pressure. https://en.wikipedia.org/wiki/Pascalization https://en.wikipedia.org/wiki/Pascalization
JadeNB 7y ago
The materials scientist Mark Miodownik discusses this and other miracles of modern, well, materials science in his marvellous book "Stuff matters" (https://books.google.com/books/about/Stuff_Matters.html?id=_5yUAwAAQBAJ https://books.google.com/books/about/Stuff_Matters.html?id=_...). I found it fascinating—though, fair warning, the material on cement was by far the most fascinating to me.
- JadeNB 7y ago
  By the way, I just discovered he's got a new (to me) book, my copy of which is titled "Liquid rules" (apparently a later printing of a book originally just called "Liquid") (https://books.google.com/books?id=7p_FwQEACAAJ https://books.google.com/books?id=7p_FwQEACAAJ ).
Hitton 7y ago
Ancient Romans had kinda similar technology, although chemically not bacteria based. https://www.nature.com/news/seawater-is-the-secret-to-long-lasting-roman-concrete-1.22231 https://www.nature.com/news/seawater-is-the-secret-to-long-l...

156 points by vinnyglennon 7y ago

>Being mixed with concrete and distributed evenly throughout it, they can lay there in a dormant state for up to 200 years; only when the concrete cracks, air and moisture awaken the bacteria which use the calcium lactate as a food source and start to produce limestone, sealing off the cracks in 3 weeks’ time. The technology, currently able to seal cracks of any length but only up to 0.8 mm wide, was a finalist for the European Inventor Award 2015, an initiative of the European Patent Office (EPO). That's brilliant. I wonder what the cost increase would be for including this solution v. the cost of traditional repairs.

justinmchase 7y ago
The article says it costs about twice as much. > Currently the cost of this new technology is still considered prohibitive, as it is twice the cost of regular concrete manufacture (70-80 € / m3), making it only viable for projects where leakage and corrosion are particularly problematic, such as underground and underwater structures. What's funny to me though is that they consider this cost prohibitive despite the expected theoretically longer life without replacement or maintenance.
- LegitShady 7y ago
  How often do you think most concrete structures (with only minor cracking like in the article) undergo serious rehab? Maybe once in their service life. Also, when planners are choosing between alternatives, net present value (NPV) is calculated which takes into account predictable maintenance, so the cost of future repairs is already considered in these decisions. Civil engineering is also not computer engineering. There is no agile development and you have to get it right the first time. The industry as a whole is not quick to adopt new technologies without seeing them proven in the field relatively thoroughly.
  - vbezhenar 7y ago
    May be it's true for Europe, but in my country they're re-building roads every few years. Not sure if they are agile or just corrupt...
    - munk-a 7y ago
      Qualification: I can't really confirm this fiscal responsibility of this. Vermont is of the opinion that resurfacing roads frequently (like every two years) is cheaper than investing in anti-frost heavy road beds and cement... The reasoning behind this is that intense ground freezing can end up upsetting the best bedding techniques and causing frost heaves anyway - that coupled with frequent ploughing to deal with heavy snow fall makes long term road investments fiscally irresponsible. Also the state has frequent flooding issues which can upset road bedding in more different and fun manners.
      - LegitShady 7y ago
        depending on how plastic the soil, replacing it with the road base doesn't stop deformation just slows it down. If the base material is heavier than the native material it will speed the whole thing up. Then you get into the territory of lightweight fills and it gets really expensive very quickly even beyond basic roadbuilding.
    - LegitShady 7y ago
      the complexities of road construction depend on all sorts of factors from weather, subgrade composition, labour and material costs, traffic weight, total traffic, availability of capital, willingness to take risks, etc etc. Most likely the roads are not being "rebuilt" but rather getting microsurfacing, and occasionally a mill and inlay of just top layers of the road surface. Fully rebuilding roads is more time consuming.
      - hermitdev 7y ago
        Ive been enduring a rebuild of I-294 around Chicago. It's around a 40 mile rebuild (ripping everything out down to dirt), IIRC. They're widening the highway in stretches, completely redesigning interchanges as well to remove sharp turns so that semis can keep speed and better merge. Lots of overpasses and other bridges being rebuilt to accommodate the extra lane each way. They completed the stretch around Ohare airport pretty quickly, in about a year, but seeing the materials used, I doubt it will hold up over time. I expect it will need maintenance on the first completed stretch before the 10 year project is complete. They went from concrete to an all asphalt layering from what I saw. Doubt it will hold up. Edit: designing -> redesigning.
- dragonwriter 7y ago
  > What's funny to me though is that they consider this cost prohibitive despite the expected theoretically longer life without replacement or maintenance. Unless almost all maintenance and replacement needs are due to cracks that don't rapidly become more than 0.8mm wide, this reduces maintenance costs but doesn't let it go an extended time without normal maintenance and replacement. At double manufacturing cost, that could well be a losing trade-off for most applications.
- ThrustVectoring 7y ago
  >What's funny to me though is that they consider this cost prohibitive despite the expected theoretically longer life without replacement or maintenance. Time value of money plays a big part here. The extra cost is now, the maintenance costs are paid later. Costs paid immediately are significantly more expensive than costs paid a long time from now.
  - daniel-cussen 7y ago
    With current low interest rates, I'd say this effect is sharply reduced. The twenties will produce infrastructure that will last a really, really long time because those maintenance costs will be incorporated almost without discount.
    - asdff 7y ago
      A lot of public budgets don't have room for a big upfront cost, but a longer pay period can be incorporated more smoothly and disturb fewer other parts of the budget, even if it ends up costing more in the long run. Sometimes there are federal grants to provide quick windfall for public works.
- asdff 7y ago
  To be honest I really don't want concrete repaired. It's not like a steel girder that get exposed to rust but can otherwise be swapped out with a new piece. If concrete is cracked there is a reason why: something shifted. Raze and rebuild because the earth will never stop settling and/or shaking. Don't they bust up old concrete into new gravel and concrete as well? Probably cuts down on how much land needs to be quarried.
- ako 7y ago
  The cost of replacement or repair is not something the current buyer will have to deal with, so the cost saving are also not his cost savings...
- rkagerer 7y ago
  I interpret that as twice the cost of a traditional initial pour, but I think the question was how much that premium is offset by savings on repairs and maintenance over the life of the structure. The article implies it's currently only viable where where leakage and corrosion are particularly problematic, but mentions they're working on an alternative strain of bacteria grown from a sugar-based nutrient rather than more costly calcium lactate.

inflatableDodo 7y ago

Sounds like a great material for floating arcologies.

UI_at_80x24 7y ago

Wasn't it discovered that these bacteria are what make "Roman Cement" so much better then modern 'Portland Cement'? (or was I supposed the RTFA?)

ThrustVectoring 7y ago
The primary difference between Roman and modern cement is that Roman cement does not have reinforcing steel in it and cannot support loads that put it under tension stress. This reinforcing steel is what fails with age - cracks develop, let in air, and corrode the steel. No steel, and what you have is basically a shaped rock, and that can last a really long time. The downside, of course, is that not being able to resist tensile loads severely limits the designs you can make with concrete. Reinforced concrete is significantly more useful than unreinforced concrete.
- LegitShady 7y ago
  and to add to this, all reinforced concrete cracks. Otherwise it doesnt need to be reinforced.
- dustfinger 7y ago
  I wonder if it would be feasible to replace the steel reinforcement rods with ceramic? No iron no rust. I also wonder if concrete might bond better with ceramic. My understanding is that concrete does not bond well with steel.
  - dustfinger 7y ago
    It looks like some effort was made in 2010 to coat the reinforcing steel with a porcelain enamel [1]. I believe the enamel's primary function was to provide a bond with the encasing concrete. Naturally, it would also help to protect the steel from water and oxygen. There must be a reason why ceramic cannot fully replace steel. Cost perhaps. Maybe these technologies would be better combined. [1] https://www.ceramicindustry.com/articles/90943-improving-steel-reinforced-concrete-structures https://www.ceramicindustry.com/articles/90943-improving-ste...

nsb1 7y ago

<puts down Cat's Cradle> "Are you double-dog sure this stuff can never get out in the wild?"

anonymfus 7y ago
I think that Belyaev's "Eternal Bread" (1928) is much more relevant because it's about actual biotechnology and the scientist had good intentions.
Gibbon1 7y ago
I think a) the bacteria aren't novel. b) Calcium Lactate is what enables this.
glloydell 7y ago
There is absolutely no way this could possibly go wrong.
- smrq 7y ago
  While I'm sure I agree with you, this comment reads like some famous last words!

epiphanitus 7y ago

Fun Fact: Much of the Great Wall is still in very good condition thanks to its amazingly resilient mortar. The secret ingredient: sticky rice. https://www.telegraph.co.uk/news/worldnews/asia/china/7785842/Great-Wall-of-Chinas-strength-comes-from-sticky-rice.html https://www.telegraph.co.uk/news/worldnews/asia/china/778584...

dmos62 7y ago
I love hearing about possibly competitive low-tech solutions.

mrfusion 7y ago

What’s cool about this is could it save the cost of making expansion joints? Edit. What I mean is you could do really big pours instead of sections. Think a mile long sidewalk with no sections.

jacobush 7y ago
But you would need a long queue of cement trucks :)
munk-a 7y ago
I don't believe so - those expansion joints exist IIRC to account for the fact that cement is quite temperature volume stable... but it isn't temperature inert. The seasonal temperature swings cause expansion and shrinking of cement and, especially on the scale of a bridge, those slight volume changes add up. I imagine this tech would allow shrinkage during the winter to be automatically repaired if it manifested as hairline gaps - but when summer rolled around you'd get a severe amount of buckling the cement expanded... then those buckles might partially repair - be reinforced when gaping occurred in winter - then buckle even more come next summer.
jessriedel 7y ago
I don't think so. It takes weeks for this cement to heal itself, whereas the sort of temperature swings that would cause very long pieces to crack happen in hours. You'd have frequent cracking and re-cracking without enough time to heal. I think this is better suited for damage from infrequent events (earthquakes, temperature swings from 10-year storms, human accident, etc.).

blacksqr 7y ago

"I'm beginning to think I can cure a rainy day!"

ninju 7y ago

please apply date [2017] to title as the article is old >Friday, 12 May 2017 01:00cat

ddxxdd 7y ago

I would like to understand the science behind how bacteria can live under the 50 gigapascals of pressure that one would find in the base of a skyscraper. My intuitions currently tell me that finding life underneath such mechanical stress is comparable to finding life inside the lava of a volcano or on the surface of the sun.

YayamiOmate 7y ago
Well, there are bateria living on chemical energy deep down in the oceans near volcanoes, that's not far from your example.
- Gibbon1 7y ago
  There are actually bacteria living in rocks thousands of feet below the surface.
jaclaz 7y ago
>the 50 gigapascals of pressure that one would find in the base of a skyscraper. I guess you will need to rethink about the order or magnitude of the pressure you cited: https://en.wikipedia.org/wiki/Orders_of_magnitude_(pressure) https://en.wikipedia.org/wiki/Orders_of_magnitude_(pressure) Easy comparison terms are pressure to create artificial diamonds 18 GPa, pressure at the bottom of the Mariana Trench 110 MPa. Compression resistance of concrete is between 20 and 80 MPa: https://en.wikipedia.org/wiki/Compressive_strength https://en.wikipedia.org/wiki/Compressive_strength Where 20 is "common" concrete, 30-50 is typical reinforced concrete, anything above is specisl, high strength concrete.
traverseda 7y ago
Check out pascalization, an alternative to pasteurization that uses extreme pressure. https://en.wikipedia.org/wiki/Pascalization https://en.wikipedia.org/wiki/Pascalization

JadeNB 7y ago

The materials scientist Mark Miodownik discusses this and other miracles of modern, well, materials science in his marvellous book "Stuff matters" (https://books.google.com/books/about/Stuff_Matters.html?id=_5yUAwAAQBAJ https://books.google.com/books/about/Stuff_Matters.html?id=_...). I found it fascinating—though, fair warning, the material on cement was by far the most fascinating to me.

JadeNB 7y ago
By the way, I just discovered he's got a new (to me) book, my copy of which is titled "Liquid rules" (apparently a later printing of a book originally just called "Liquid") (https://books.google.com/books?id=7p_FwQEACAAJ https://books.google.com/books?id=7p_FwQEACAAJ ).

Hitton 7y ago

Ancient Romans had kinda similar technology, although chemically not bacteria based. https://www.nature.com/news/seawater-is-the-secret-to-long-lasting-roman-concrete-1.22231 https://www.nature.com/news/seawater-is-the-secret-to-long-l...