Re:Roman Ruins Found in France Are Called ‘Exceptional’
by DoubleCribble on Friday August 04, 2017 @01:02PM
(#14930078)
Indeed. One need only look at a few DIY sidewalk repair jobs to see what happens to unreinforced concrete in relatively short order.
This article doesn't mention what the usable cure time is, but the magic of Roman cement is that it continues to get harder over centuries.[1]
[1]http://www.sciencemag.org/news/2017/07/why-modern-mortar-cru...
Re:Roman Ruins Found in France Are Called ‘Exceptional’
by lostlogin on Friday August 04, 2017 @04:27PM
(#14931941)
Pour it thicker and it lasts one hell of a lot longer. Cheaping out on the volume is a huge part of paths breaking up.
Re:Roman Ruins Found in France Are Called ‘Exceptional’
by sgc on Friday August 04, 2017 @01:54PM
(#14930536)
We do for niche uses. Runways, bunkers, etc can have even 2 year curing times to make "hardened concrete", which is up to 7x stronger than the same formulation allowed to dry out instead of keeping it wet for extended curing.
Re:Roman Ruins Found in France Are Called ‘Exceptional’
by wlesieutre on Friday August 04, 2017 @01:12PM
(#14930151)
Recent research on Roman concrete, particularly in constructions exposed to seawater: https://phys.org/news/2017-07-ancient-concrete-romans.html
Not as long as you would think. Non-reinforced concrete only lasts a few generations, whereas there are Roman concrete roads still in (mild, rural) use today.
We actually know why too. Recent science shows that Roman concrete used a slightly different formula that took much longer to set -- weeks or maybe months rather than days. They didn't know how to make fast-setting concrete like we have today. But the length of time also made the structure stronger. We could build that way, if we wanted. But we don't.