I'm always curious, in this case not the Roman cement hardening (well discussed in Logos resources), but rather, the chemistry and lower temperatures that Roman engineers worked with. Portland cement does chew up some serious heat.
http://azdailysun.com/news/local/flagstaff-geoscientist-unlocks-secrets-of-indestructible-roman-concrete/article_0b9f3bd9-506f-55ce-8e73-3d6bad382706.html
Absolutely fascinating![:)]
[Y]
That is very interesting.
