Opus caementicium uncovered in the characteristic Roman arch. In contrast to contemporary concrete constructions, the concrete used in Roman properties was typically covered with brick or stone. The Romans applied concrete thoroughly from three hundred BC to AD 476.[18] In the course of the Roman Empire, Roman concrete (or opus https://spencer79e45.livebloggs.com/42243236/5-simple-statements-about-concrete-reinforced-stone-explained