Geopolymer Aircrete?

  • Portland cement production creates a great deal of atmospheric carbon waste, which I'd like to avoid as much as possible. Does anyone have any experience making aircrete from a geopolymer cement base?

  • Little Dragon Tamer

    I don't have any experience using geopolymer cement. Where would I get it?

  • Sounds like a lot of dangerous work, 14 mole caustic is very strong solution, I'll stick with my Portland, thank you.

  • There are other ways to make it. I just tossed up a link I found in a thirty-second google search. If you're interested in the concept, look around; you may well find a recipe that better suits your needs.

  • @moonrise said in Geopolymer Aircrete?:

    Portland cement production creates a great deal of atmospheric carbon waste

    While this is true, nearly every building material carries a carbon footprint:
    Compare wood, steel and concrete

    Following the Domegaia recipe yields an airecrete building material that, for a given volume, uses just a fraction of the portland cement of traditional concrete. This significantly reduces its carbon footprint, so that it becomes comparable to many other common construction methods.

  • Little Dragon Tamer

    My understanding is that the classic domegaia aircrete recipe is 1 cubic foot of cement per 6 cubic feet of aircrete. My basic understanding of standard concrete is that 1 cubic foot of cement would yield about 3 cubic feet of concrete. If those figures are realistic, then aircrete uses about half the amount of cement per volume, suggesting a fraction of 1 over 2.

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  • @zander that may well be, and it ain't nothin' -- but arsenic is less immediately deadly than strychnine, but that doesn't mean I recommend it as a cooking ingredient.

  • Major Contributor

    @zander said in Geopolymer Aircrete?:

    1 cubic foot of cement would yield about 3 cubic feet of concrete.

    I thought the "standard" mix for concrete was 1 part cement, 6 parts other -
    A concrete mixture ratio of 1 part cement, 3 parts sand, and 3 parts aggregate will produce a concrete mix of approximately 3000 psi.
    from link text

  • Little Dragon Tamer

    1 cement, 2 sand, and 3 gravel is also popular. But either way, the sand, water, and cement mostly fill in the voids between the gravel. So the volume we end up with is little more than the volume of the gravel only. This article states that it takes 800 pounds (8.5 x 94 pound bags*) of cement to get 27 cubic feet of concrete, which supports the notion that 1 cubic foot of dry cement powder yields 3 cubic feet of concrete.

    *94 pounds of dry cement powder is one cubic foot of dry cement powder

  • @Moonrise you bring up a very good point about the Portland cement and CO2 emitted in production. Its about a 1 to 1 ratio of 1 ton CO2 emitted per 1 ton produced due to the heating process and the amount of fossil fuel burned to do so.
    Check that link for information on a recipe (pg 4) that uses a less corrosive solution (Potassium Silicate solution) and cures at room temperature vs the alkali activated that needs some heat to cure if I'm not mistaken. Interesting to note that the compressive strength of the geopolymer cement in the paper is listed to be up to 95 kpa (much higher than traditional concrete). It also utilizes fly ash and slag which are waste products rather than the mostly mined raw materials Portland production uses.

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