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.

[xoxoxoBruce]

Everyone uses various recipes of Portland Cement because it's been tested to death, and all the engineering tables use it. In order to use something else in anything but your backyard Bar-B-Que, you'd have to have a shitload of testing and paperwork.
Ain't nobody got time for that.

[wanderer]

There does seem to be some research going into the field "green concrete/building materials". I came across this not so long ago:

http://www.time.com/time/specials/pa...021669,00.html

[Undertoad]

Originally Posted by glatt

All this is to say that if we change our practices to use the Roman recipe (even substituting fly ash for volcanic ash).

That all sounds great but where are we gonna get all those flies. Think, man.

[Perry Winkle]

What about reinforced concrete? I understand the pollution is probably the same, but does it crumble in the same timeframe? When does it become structurally unsound? How is this mitigated on skyscrapers?

[glatt]

If you can protect it from the elements, it will do better than if it's being exposed to regular freeze/thaw cycles and road salt.
1920s bridge in GA:

[Lamplighter]

... a smattering of Georgia mud will fix that up fine.

[piercehawkeye45]

Interesting. Keep in mind that lime stabilized Roman roads have lasted 2,000 years as well. We have the technology to stabilize our roads to that degree, however, the cost would be considered much too high.

Hopefully this Roman style concrete is looked further into but it may just end up being that this particular Volcano Ash had optimal chemical properties (pozzolan...alumina especially) which cannot be reproduced on a mass scale. That is the main issues with fly ash; the properties are very inconsistent since they are purely naturally variable products and not manufactured.

[zippyt]

fly ash comes from coal fired power plants , Ultra fine , nasty shit it gets every where