On Mon, 07 Jun 2021 17:44:13 -0500, AMuzi wrote:

Concrete can be durable if it's done right:
https://www.historicmysteries.com/roman-concrete/
Couple thousand years anyway, maybe longer.

Yep. However, hydraulic cement isn't the current problem. The Romans
didn't have rebar. The problem is that concrete is 15 to 20% water.
You can convince yourself that there's water in concrete with a
oxy-acetylene torch and watch concrete chunks fly from the steam
explosions. When rebar rusts, it expands, which causes the concrete
to crack. Once it cracks, more water, chlorides, acidic liquids, etc
get in and cause some more rust. If the Romans had rebar, they would
have had the same problems we're having:
"Concrete degradation"
https://en.wikipedia.org/wiki/Concrete_degradation




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Jeff Liebermann
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
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