Opus caementicium exposed inside of a characteristic Roman arch. In distinction to contemporary concrete structures, the concrete used in Roman structures was generally lined with brick or stone. The Romans made use of concrete extensively from 300 BC to Advert 476.[eighteen] Throughout the Roman Empire, Roman concrete (or opus caementicium) https://martintuson.mybuzzblog.com/15595272/the-best-side-of-concrete-reinforced-beam