Ancient Roman architecture
Although concrete had been used on a minor scale in Mesopotamia, Roman architects perfected Roman concrete and used it in buildings where it could stand on its own and support a great deal of weight. The first use of concrete by the Romans was in the town of Cosa sometime after 273 BC. Ancient Roman concrete was a mixture of lime mortar, aggregate, pozzolana, water, and stones, and was stronger than previously-used concretes. The ancient builders placed these ingredients in wooden frames where they hardened and bonded to a facing of stones or (more frequently) bricks. The aggregates used were often much larger than in modern concrete, amounting to rubble.
Opus signinum
Opus signinum ('cocciopesto' in modern Italian) is a building material used in ancient Rome. It is made of tiles broken up into very small pieces, mixed with mortar, and then beaten down with a rammer. Pliny in his Natural History describes its manufacture: "Even broken pottery has been utilized; it being found that, beaten to powder, and tempered with lime, it becomes more solid and durable than other substances of a similar nature; forming the cement known as the "Signine" composition, so extensively employed for even making the pavements of houses." Pliny's use of the term "Signine" references "Signia (modern Segni), the name of a town in Latium which was famous for its tiles."