Posted: Jul 16, 2017 2:13 am
by LucidFlight
DavidMcC wrote:
Alan C wrote:Their concretes in general seem to last a bloody long time.

What makes you think that modern concretes are any different from that (except, of course, badly made ones, with a poor composition).

The article mentions volcanic ash. Could that be something to do with it? :ask: