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.
Charles Pasley
In 1826, as lecturer in architecture and engineering at the Royal School of Military Engineering at Chatham, he began research and experiments on artificial hydraulic cement, attempting to match or make an improvement over natural or "Roman" cement, invented by James Parker in 1796. In 1830, he succeeded and with chalk and Medway clay, produced a hydraulic lime equal to the natural "Roman" cement and similar to that produced by Joseph Aspdin in Wakefield.