11 ms·

Low-carbon concrete stays strong with polymer lattice reinforcements

67 points by panabee 6y ago

01100011 6y ago
> The team found success using acrylonitrile butadiene styrene (ABS) polymers to produce the lattice So, don't spill acetone on it or your building will collapse? I realize this is just research and the final product will likely be more robust. As someone who just had a bottle of acetone leak in the freezer(home chemistry gone wrong I guess), I am acutely aware of the destructive power of simple acetone. Did I mention freezers are apparently made of ABS?
- raverbashing 6y ago
  Yeah, don't use acetone or instant glue on Styrofoam (unless you want a gooey mess)
  - TeMPOraL 6y ago
    Isn't the goo also highly flammable? As kids, my friends and I used to refer to a mix of polystyrene and gasoline as "DIY napalm".
    - jabl 6y ago
      > As kids, my friends and I used to refer to a mix of polystyrene and gasoline as "DIY napalm". Yeah, I experimented with this once as a teenager. It's sort of fascinating how much polystyrene you can dissolve into gasoline (makes sense, as EPS is mostly air). Burns with thick black smoke and an acrid smell.. I didn't have any WP to blend into it, though. In retrospect, that was good.
    - fogihujy 6y ago
      It's not too different from the real thing. It's one of those "don't try this at home" things. :D
spiderfarmer 6y ago
Instead of polymers you can also use elephant grass: https://marketplace.chemsec.org/Alternative/High-performing-concrete-made-from-Elephant-Grass-153 https://marketplace.chemsec.org/Alternative/High-performing-... That seems even more environmentally friendly. It's all being tested though. You don't want to rush things when it comes to concrete.
- datavirtue 6y ago
  I'm wanting to try hemp fibers. Straight fiberglass, which is a common additive, increases strength significantly. Dried hemp is impervious to moisture and was the main material used in maritime rope for centuries. It can be made into fibers of various length or mesh.
iasmseanyoung 6y ago
Concrete has a high compressive strength without steel rebars. Steel rebars are added to concrete to increase its tensile and sheer strength. The article alludes that these polymer reinforcements can replace steel but then only talks about increasing the concretes compressive strength, which exactly not why they're used.
- jcims 6y ago
  The article did kind of circle around the objective of the work without digging into it. The picture and some of the text (strain test) indicates they are evaluating tensile loads, but it didn't really say if this was intended to increase mechanical performance, reduce weight, reduce concrete used, etc. I think the point, given the title, is to reduce the volume of concrete that is cured for a given pour by replacing some of it with polymers.
  - mjevans 6y ago
    Using even less material seems likely to lead to most buildings trying to do only that and failing to include any other mechanism for acoustic isolation and privacy. I am almost equally worried about other previously assumed goals that traditional construction methods happen to fulfill but which could be overlooked due to under-specification. What things? I don't know, and my worry is that experts in those fields might not either until that data is gleaned the hard way.
    - jcims 6y ago
      Great points. Any major change in 'concrete' is likely to yield a few surprises when folks try to drop it in as a replacement for the standard.
londons_explore 6y ago
ABS and other plastics inside concrete doesn't sound great for the environment... Concrete is already pretty bad for the environment - a chunk of it lasts thousands of years, with a pretty alkaline surface meaning many plants don't want to be nearby, but otherwise at least is mostly inert like rock. By adding polymers, we're probably going to have plasticisers oozing out of these things for thousands of years, turning all the fish into all three genders at once, together with lots of as-yet-unidentified effects of polymer breakdown products.
- gonzo41 6y ago
  Really what we want is concrete to absorb co2 over time. I know that's not how the chemistry works but it'd be a great way to solve the diffuse carbon problem.
- FooHentai 6y ago
  Yeah that doesn’t sound great. If it effectively encapsulates waste plastics in a steady state across thousand-year timeframes then it could be a net positive, but otherwise does sound like a big liability/disaster in slowmo.
nabla9 6y ago
Even better: carbon-cured concrete. The process binds carbon dioxide, and it is even possible to make the final product carbon negative if ordinary cement is replaced with alternative binders with a low carbon footprint. Carbon neutrality is achieved using blast-furnace slag and carbon negativity using a mix of slag, green liquor dregs and bark ashes. https://www.vttresearch.com/en/news-and-ideas/turning-cons-concrete-pros https://www.vttresearch.com/en/news-and-ideas/turning-cons-c...
Gravityloss 6y ago
If carbon emissions become really expensive, other materials than concrete become more viable. Steel can be quite carbon intensive as well though. Timber and mud could become great again. Also hydro cut stone.
- noir_lord 6y ago
  Engineered timber is surprisingly strong and fire resistant - the problem is in what the word "engineered" means in terms of environmental impact.
- dwiel 6y ago
  What are you referring to when you mention hydro cut stone? A quick google shows gemstone cutting, small subtractive milling of gargoyles and cutting/etching of thin decorative stone. Are you talking about a quarrying process? I've got a little bit of knowledge about quarrying as there are many active limestone quarries in my area, but always interested to learn more.
  - tonyarkles 6y ago
    My guess would be water-jet cut stone blocks. At the quarry you often cut stuff off in big slabs; once you’ve got the slabs at the water-jet, you could cut standard dimension blocks out of the slab and have a pretty modular building material.
    - Gravityloss 6y ago
      Yeah that's what I meant. Why would one prefer concrete over that?
      - rch 6y ago
        Imagine the scale of the gaping maw left behind after a century of quarrying for high quality stone to support modern city construction.
black6 6y ago
The concrete-strengthening carbon-sequestering solution I'm interested in is adding graphene to concrete to increase compressive and tensile strength[0]. A team at Rice University has developed a simple means of producing "turbostratic" graphene from just about any carbon-containing waste[1]. 0: https://onlinelibrary.wiley.com/doi/epdf/10.1002/adfm.201705183 https://onlinelibrary.wiley.com/doi/epdf/10.1002/adfm.201705... 1: https://www.nature.com/articles/s41586-020-1938-0 https://www.nature.com/articles/s41586-020-1938-0
- ctack 6y ago
  I wonder what the environmental impact of graphene is from an end of life waste management point of view.
jaclaz 6y ago
Fibre reinforced concrete is not really "news", we were using the one or the other forms more than 30 years ago, exactly to prevent cracks, the issue in real life applications is to distribute the fibres (be them metallic or plastic). But this, see the actual picture of the lattice on the article: https://www.sciencedirect.com/science/article/pii/S026412752030719X https://www.sciencedirect.com/science/article/pii/S026412752... look more like traditional reinforced or mesh reinforced concrete. ABS is not such a great material for construction due to its sensibility to UV rays, surely there are "better" plastics for this use even if maybe not suited to 3D printing.
- 0xffff2 6y ago
  Why is UV sensitivity a problem for something that's going to be embedded inside the concrete?
  - jaclaz 6y ago
    >Why is UV sensitivity a problem for something that's going to be embedded inside the concrete? IF it will ever become an actual mass product, the lattice will be manufactured in "bulk" (not 3D printed on spot) and it will become a "building material" like rebar or steel mesh, etc. Normally building materials are stored in the open for months either at the factory, at the store or on site before being actually put in the concrete formwork. You simply don't want something that needs to be stored in a dark, cool place. Very early versions of polyethilene pipes (think of 30+ years ago) were not UV resistant/stabilized and of course they were put in digged trenches and covered, but it came out that after a few years they started leaking, you don't want to have something structural that may loose its properties in a few years.
m0llusk 6y ago
Longevity is turning out to be a major issue with steel reinforced concrete. This might solve some of that by using reinforcements that do not react chemically with the concrete. Lifetime usage issues including durability and recycling loom large in this context.

67 points by panabee 6y ago

> The team found success using acrylonitrile butadiene styrene (ABS) polymers to produce the lattice So, don't spill acetone on it or your building will collapse? I realize this is just research and the final product will likely be more robust. As someone who just had a bottle of acetone leak in the freezer(home chemistry gone wrong I guess), I am acutely aware of the destructive power of simple acetone. Did I mention freezers are apparently made of ABS?

raverbashing 6y ago
Yeah, don't use acetone or instant glue on Styrofoam (unless you want a gooey mess)
- TeMPOraL 6y ago
  Isn't the goo also highly flammable? As kids, my friends and I used to refer to a mix of polystyrene and gasoline as "DIY napalm".
  - jabl 6y ago
    > As kids, my friends and I used to refer to a mix of polystyrene and gasoline as "DIY napalm". Yeah, I experimented with this once as a teenager. It's sort of fascinating how much polystyrene you can dissolve into gasoline (makes sense, as EPS is mostly air). Burns with thick black smoke and an acrid smell.. I didn't have any WP to blend into it, though. In retrospect, that was good.
  - fogihujy 6y ago
    It's not too different from the real thing. It's one of those "don't try this at home" things. :D

spiderfarmer 6y ago

Instead of polymers you can also use elephant grass: https://marketplace.chemsec.org/Alternative/High-performing-concrete-made-from-Elephant-Grass-153 https://marketplace.chemsec.org/Alternative/High-performing-... That seems even more environmentally friendly. It's all being tested though. You don't want to rush things when it comes to concrete.

datavirtue 6y ago
I'm wanting to try hemp fibers. Straight fiberglass, which is a common additive, increases strength significantly. Dried hemp is impervious to moisture and was the main material used in maritime rope for centuries. It can be made into fibers of various length or mesh.

iasmseanyoung 6y ago

Concrete has a high compressive strength without steel rebars. Steel rebars are added to concrete to increase its tensile and sheer strength. The article alludes that these polymer reinforcements can replace steel but then only talks about increasing the concretes compressive strength, which exactly not why they're used.

jcims 6y ago
The article did kind of circle around the objective of the work without digging into it. The picture and some of the text (strain test) indicates they are evaluating tensile loads, but it didn't really say if this was intended to increase mechanical performance, reduce weight, reduce concrete used, etc. I think the point, given the title, is to reduce the volume of concrete that is cured for a given pour by replacing some of it with polymers.
- mjevans 6y ago
  Using even less material seems likely to lead to most buildings trying to do only that and failing to include any other mechanism for acoustic isolation and privacy. I am almost equally worried about other previously assumed goals that traditional construction methods happen to fulfill but which could be overlooked due to under-specification. What things? I don't know, and my worry is that experts in those fields might not either until that data is gleaned the hard way.
  - jcims 6y ago
    Great points. Any major change in 'concrete' is likely to yield a few surprises when folks try to drop it in as a replacement for the standard.

londons_explore 6y ago

ABS and other plastics inside concrete doesn't sound great for the environment... Concrete is already pretty bad for the environment - a chunk of it lasts thousands of years, with a pretty alkaline surface meaning many plants don't want to be nearby, but otherwise at least is mostly inert like rock. By adding polymers, we're probably going to have plasticisers oozing out of these things for thousands of years, turning all the fish into all three genders at once, together with lots of as-yet-unidentified effects of polymer breakdown products.

gonzo41 6y ago
Really what we want is concrete to absorb co2 over time. I know that's not how the chemistry works but it'd be a great way to solve the diffuse carbon problem.
FooHentai 6y ago
Yeah that doesn’t sound great. If it effectively encapsulates waste plastics in a steady state across thousand-year timeframes then it could be a net positive, but otherwise does sound like a big liability/disaster in slowmo.

nabla9 6y ago

Even better: carbon-cured concrete. The process binds carbon dioxide, and it is even possible to make the final product carbon negative if ordinary cement is replaced with alternative binders with a low carbon footprint. Carbon neutrality is achieved using blast-furnace slag and carbon negativity using a mix of slag, green liquor dregs and bark ashes. https://www.vttresearch.com/en/news-and-ideas/turning-cons-concrete-pros https://www.vttresearch.com/en/news-and-ideas/turning-cons-c...

Gravityloss 6y ago

If carbon emissions become really expensive, other materials than concrete become more viable. Steel can be quite carbon intensive as well though. Timber and mud could become great again. Also hydro cut stone.

noir_lord 6y ago
Engineered timber is surprisingly strong and fire resistant - the problem is in what the word "engineered" means in terms of environmental impact.
dwiel 6y ago
What are you referring to when you mention hydro cut stone? A quick google shows gemstone cutting, small subtractive milling of gargoyles and cutting/etching of thin decorative stone. Are you talking about a quarrying process? I've got a little bit of knowledge about quarrying as there are many active limestone quarries in my area, but always interested to learn more.
- tonyarkles 6y ago
  My guess would be water-jet cut stone blocks. At the quarry you often cut stuff off in big slabs; once you’ve got the slabs at the water-jet, you could cut standard dimension blocks out of the slab and have a pretty modular building material.
  - Gravityloss 6y ago
    Yeah that's what I meant. Why would one prefer concrete over that?
    - rch 6y ago
      Imagine the scale of the gaping maw left behind after a century of quarrying for high quality stone to support modern city construction.

black6 6y ago

The concrete-strengthening carbon-sequestering solution I'm interested in is adding graphene to concrete to increase compressive and tensile strength[0]. A team at Rice University has developed a simple means of producing "turbostratic" graphene from just about any carbon-containing waste[1]. 0: https://onlinelibrary.wiley.com/doi/epdf/10.1002/adfm.201705183 https://onlinelibrary.wiley.com/doi/epdf/10.1002/adfm.201705... 1: https://www.nature.com/articles/s41586-020-1938-0 https://www.nature.com/articles/s41586-020-1938-0

ctack 6y ago
I wonder what the environmental impact of graphene is from an end of life waste management point of view.

jaclaz 6y ago

Fibre reinforced concrete is not really "news", we were using the one or the other forms more than 30 years ago, exactly to prevent cracks, the issue in real life applications is to distribute the fibres (be them metallic or plastic). But this, see the actual picture of the lattice on the article: https://www.sciencedirect.com/science/article/pii/S026412752030719X https://www.sciencedirect.com/science/article/pii/S026412752... look more like traditional reinforced or mesh reinforced concrete. ABS is not such a great material for construction due to its sensibility to UV rays, surely there are "better" plastics for this use even if maybe not suited to 3D printing.

0xffff2 6y ago
Why is UV sensitivity a problem for something that's going to be embedded inside the concrete?
- jaclaz 6y ago
  >Why is UV sensitivity a problem for something that's going to be embedded inside the concrete? IF it will ever become an actual mass product, the lattice will be manufactured in "bulk" (not 3D printed on spot) and it will become a "building material" like rebar or steel mesh, etc. Normally building materials are stored in the open for months either at the factory, at the store or on site before being actually put in the concrete formwork. You simply don't want something that needs to be stored in a dark, cool place. Very early versions of polyethilene pipes (think of 30+ years ago) were not UV resistant/stabilized and of course they were put in digged trenches and covered, but it came out that after a few years they started leaking, you don't want to have something structural that may loose its properties in a few years.

m0llusk 6y ago

Longevity is turning out to be a major issue with steel reinforced concrete. This might solve some of that by using reinforcements that do not react chemically with the concrete. Lifetime usage issues including durability and recycling loom large in this context.