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.
Roman cement
James Frost is reported to have erected a manufactory for making of an artificial cement in 1826. In 1843, Aspdin's son William improved their cement, which was initially called "Patent Portland cement," although he had no patent. In 1848, William Aspdin further improved his cement and in 1853, he moved to Germany where he was involved in cement making. William Aspdin made what could be called meso-Portland cement (a mix of Portland cement and hydraulic lime).
Artificial cement: Development in the 1860s of rotating horizontal kiln technology brought dramatic changes in properties, arguably resulting in modern cement. Certainly it is difficult to define whether an old render was a natural cement (single source marl) or an artificial one, but there is no doubt as whether the cement was fired in a vertical or horizontal kiln. The names Natural cement or Roman cement then defines a cement coming from a single source rock. Early or Proto Portland cement could be used for early cement that comes from a number of sourced and mixed materials. There is no widely used terminology for these 19th-century cements. There had been, in order to rediscover this technology, two projects carried out by the European Union ROCEM and subsequently ROCARE (an ongoing project). Both these only deal with Natural cement - referred to as Roman cement without reference to the early artificial cements.