Originally published at: Concrete gets tougher with graphene | Boing Boing
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Another great approach to concrete is this…
“The major key to DomeGaia’s AirCrete is the foaming agent that works by suspending tiny air bubbles in the cement mixture. A continuous foam generator disperses a mix of the foaming agent (like all-natural “high foaming” dish detergent) into the cement mixture and continues to mix it. It eliminates the need for aggregates, gravel, sand, or rock which are costly, take up space on-site, require heavy equipment to deliver, and hard labor to work with.”
The cool part is that they figured out how to produce it in mass on the cheap. Throw in some graphene…
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The aggregate isn’t just taking up space, though. It’s where the strength comes from. The cement is just holding the rocks together. How does “air concrete” do this?
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Not debating you as I’m sure you know more about it than I do, but I thought that the strength of concrete came from the crystalline structures that form over time. Or maybe that’s just hydraulic cement? I’m very curious to hear some informed discussion because I have been interested in alternative building materials all of my life and if Mrs Peas and I can ever afford to buy land and build, our home would look and function very similarly to these domes. Not that it couldn’t be done with traditional materials, but there’s a big appeal in being able to DIY something this strong, weather impervious and energy efficient.
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While new approaches to concrete are definitely required. Right now reusing our concrete built environment and adapting it to contemporary needs is a much more urgent requirement for the future of the world. I’m serious, this is essential. Concrete is so terrible for the environment that we need to stop breaking up buildings and remaking them.
This seems hopeful for a change in attitude, but I’m just a complete amateur here.
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I gotta go dig a hole, and put a fence post in with concrete. Just wanted everyone to know what I’m up to.
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Make sure when the post has rotted away that you bury the concrete instead of excavating it. +1 if you use welded wire fencing and allow vegetation to grow over it until it’s impossible to remove. +5 for barbed wire.
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By then I’ll be well into my dirt nap. It’ll be an issue for another meat popsicle mutant…
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I’ve been reading about improved concrete since 80s & all these roads are still tearing up cars.
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(from https://www.domegaia.com/aircrete.html)
By comparison, concrete seems to handle pressures more like 3000-5000 psi. Those numbers (160 vs. 3000) seem different enough that I worry I’m misreading something.
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They invent a super duper new concrete, and the first thing they use it for is a fire pit? WTF?
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Oh, and boy do I love “Joey.” Makes me cry every time.
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How tough is it?
Thanks, Kurtis.
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And so the great circle of life continues.
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I had to do this for our little free library.
Between ground dwelling termites and clay moisture retaining soil, we had to use treated wood with a absolutely delightful plastic sheath over the part above concrete, but in contact with soil. Seemed like a remarkably toxic solution, but even cedar etc… gets rotted and eaten in our weird “used to be ocean bottom” soil.
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I think the company behind it is happy for any users ATM. This stuff is a little less CO2ey than some other concrete alternatives, apparently, but may be a little pricey comparatively. There are apparently some concrete options that are carbon negative, so this, which appears to be a simple additive to ordinary concrete may not be the long haul winner. The company’s patent apparently just specifies an amount of graphene to ad to an ordinary mix and the greater strength allows the use of less conventional concrete . Concrene is said to be good at excluding water, so might be why a firepit was considered an appropriate application. (and my basement please 
)
EDIT: Apparently I am much too attached to the use of the word apparently and it’s derivatives. Sorry about that. In my defense when I’ve looked into these concrete alternatives it is usually a company website. You see the claims and you say “Un huh…we’ll see”
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As a drunken loser who isn’t nearly as good looking as that guy.
I’ve always loved that song.
I think that you see where I’m going with this…
Next up is a Mary on the Half-Shell garden shrine. You can offer sacrifices in your firepit if you want.
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aka
(it’s been a standard building material in the EU for 50+ years)
We have some AAC blocks, stockpiled, to start a project with.
The blocks are roughly the size of a two-cell cinderblock, and weigh very little comparatively.
The material is soft-ish, can easily be cut with a handsaw used for woodworking. It is also easy to dent, chip, crack, and really benefits from a more durable finish like cement stucco, to take some of the beating on the surface of the AAC substrate.
I don’t know if adding graphene would allow the chemical reaction (that causes bubbling) in the materials’ manufacture phase, or if they’d have to find a different chemical way to entrain air bubbles in AAC if graphene were in the mix. My high school chemistry classes were very long ago.
No doubt Hebel and their competitors are all tracking the graphene issue though.
ETA: grammar
and
thinking about this more, I realize that if one were to add graphene to AAC block, it may be far more difficult to cut and tool; part of the appeal of AAC block is how easy it is for ordinary people to cut, shape, and custom fit to their purposes, with a minimum of tools…
see also
folks, please always wear a breathing filter when cutting cement block and mixing powdered mortar! aaaaaaaarrrgh! 
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That definitely helps, but the aggregate is part of that. The cement is just the “glue” essentially, so this “air concrete” seems like the equivalent of epoxy foam. Maybe it’s strong enough for some applications, but honestly cutting out the aggregate doesn’t buy you much anyway, IMHO. The environmental cost of concrete (the harmful lime strip mining and CO2 emissions of curing, which are substantial) all come from the cement. The aggregate is just rocks, and you can use whatever is around, for the most part.
I’m not a materials engineer, though, so I’m open to this idea. I need to understand more about it though, because the broad strokes don’t seem to add up. It’s an interesting idea, but I think they are overstating the problem they are solving for. Concrete’s big big problem is CO2, and this doesn’t do much to address that. You’d have to get rid of the cement to do that, and then you’re just digging holes and piling rocks. 
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