'Absolute miracle' breakthrough provides recipe for zero-carbon cement
newatlas.com
Concrete and steel production are major sources of CO2 emissions, but a new solution from Cambridge could recycle both at the same time. Throwing old concrete into steel-processing furnaces not only purifies iron but produces “reactivated cement” as a byproduct. If done using renewable energy, the…
  • tyler@programming.dev
    2·
    7 months ago

    Unfortunately it’s not easy to recycle back into a form that can be used to make new concrete structures

    Wait what? I am pretty sure I’ve seen videos explaining that concrete is the most recycled substance in the world …

    • jarfil@beehaw.org
      7·
      7 months ago

      Depends on your definition of “recycled” (spoiler: you’ve been lied to).

      Concrete = cement + sand + aggregate (rubble) + water

      • Cement: requires a lot of energy to product
      • Sand: riverbed sand, no desert sand
      • Aggregate: some crushed rock-like stuff (of varying sizes)

      “Recycling” concrete, is done by crushing it and using as either road filler, or aggregate for new concrete with worse properties than the original. It doesn’t turn concrete back into “cement + sand + aggregate”.

      For an example, check this funny definition of “recycling” (*with just some waste) from Sika:

      https://www.sika.com/en/knowledge-hub/can-concrete-be-recycled.html

      • tyler@programming.dev
        3·
        7 months ago

        “Recycling” concrete, is done by crushing it and using as either road filler, or aggregate for new concrete with worse properties than the original. It doesn’t turn concrete back into “cement + sand + aggregate”.

        I mean… That’s recycling. You literally just said “you’ve been lied to” and then immediately followed it up with an explanation of how it’s recycled. And then you literally linked an article that explains that concrete is recycled…

        However, within a recycling economy, old concrete may be recycled and reused within new concrete production. This is already being done in the concrete industry. Ultimately, we strive for a circular economy, where there is no waste at all in the concrete production and recycling process.

        • jarfil@beehaw.org
          1·
          7 months ago

          If you think “recycling” a thing means throwing part of it away, then adding some fundamental non-renewable component in order to make the same thing again, or that “recycling” is not the same as “circular production”… maybe you’ve not only been lied to, but also brainwashed?

          • tyler@programming.dev
            2·
            7 months ago

            Also, yeah that’s literally how recycling works… do you think they recycle the labels on glass bottles? no they burn them off to get the glass. Then they make a new bottle, then they put new labels on it. literally doing exactly what you’re saying “isn’t recycling”.

            Still, that’s not at all what happens when recycling concrete.

            • jarfil@beehaw.org
              1·
              7 months ago

              Did you read what you just wrote? If they don’t recycle the labels, then… yeah, that’s not recycling.

              Cherry-picking which part gets recycled and which not, then calling it all “recycling”, is where the brainwashing comes into play.

              You may notice that in action on the web I linked, where they call “Recycling” whatever they want, but come up with a different name of “Circular economy” for… let’s see, “re-cycling”… where does that word come from, again?

              With concrete it’s even more egregious.

          • tyler@programming.dev
            1·
            7 months ago

            That’s literally not what’s happening. Did you even read the article you posted? Or did you just google, find something that you thought supported your position, then cherry picked that bit out not realizing that the entire article completely disagrees with you?