• fullsquare@awful.systems
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    14 hours ago

    concrete is calcium carbonate and silicate, both are basic. it’s also slightly porous but mostly waterproof by itself, doesn’t matter that hard in this application since there will be AC removing water from the inside 24/7 anyway

    • FiniteBanjo@feddit.online
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      7 hours ago

      Carbonation causes acidity and the traditional methods of creating concrete involves furnaces which introduce various forms of carbonation. The Calcium Carbonate once dissolved in water will start to form the Calcium Hydroxide layer on the surface, thats the alkaline layer, and deeper in the carbonation creates acidity.

      • fullsquare@awful.systems
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        6 hours ago

        calcium carbonate is still basic and even hydrogen carbonate is basic enough to be protective against steel corrosion

        The Calcium Carbonate once dissolved in water will start to form the Calcium Hydroxide layer on the surface, thats the alkaline layer, and deeper in the carbonation creates acidity.

        100% wrong, how come there’s more carbon dioxide inside than outside, you’re starting from calcium hydroxide and silicate. on the surface there’s some carbonate formation from carbon dioxide, but when it can’t get there calcium silicate forms instead. either way both are basic

        • FiniteBanjo@feddit.online
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          2 hours ago

          Well, now you’re contradicting yourself from earlier when you stated we were discussing Calcium Carbonate and Silicate.

          The Calcium Carbonate degrades into Calcium Oxide. Calcium Oxide will form Calcium Hydroxide on the cured surface.

          The only reliable way to seperate the Calcium from the oxidation afaik would be the introduction of Chlorine, so you’re definitely not seeing the reverse happening regardless of how much carbon dioxide there is.