Studying Ancient Roman concrete may help slow climate change

[glatt]

Yeah. I wasn't sure where to put this article, but I thought it was very fascinating. I don't pretend to understand it all.

I had heard this before, but it bears repeating that a huge portion of carbon dioxide released into the atmosphere comes from making concrete. We apparently use 19 Billion tons of concrete a year, and making it accounts for 7% of the greenhouse gases humans emit. You have to burn a lot of coal or oil to heat up limestone to like 2,500 degrees F in order to make portland cement today, which you mix with sand and gravel to make modern concrete. And then that modern concrete only lasts for 50-100 years or so before it starts to crumble.

The ancient Romans made concrete that is still perfectly solid today, 2000 years later. And by examining its microscopic structure, scientists see that it uses about half of the limestone, and substitutes volcanic ash for much of the rest. And the limestone was only heated up to about 1,500 degrees F, instead of the 2500 degrees F we use today.

All this is to say that if we change our practices to use the Roman recipe (even substituting fly ash for volcanic ash) it looks like we can make stronger, longer lasting concrete with less pollution.

Anyway, that's my take on the article. You can read the article to get much deeper into the chemistry and numbers if you want. But this could be a real game changer.