History 135: World Civilization
Dr. Ian Wendt
August 17, 2011
Roman Pozzolanic Concrete
The Roman Empire has contributed a wide variety of knowledge, ideas and technology to the world. These include novel concepts regarding the legal system, Roman numerals, architecture and the Roman calendar. However, the development of concrete as a building material is not the first thing that comes to mind when considering the Roman contributions to civilization. While the use of concrete predates the Roman era, the Romans discovered important improvements to the way that concrete is produced and used. Being that concrete is strong, inexpensive and easy to work with, this discovery has had a lasting impact on civilizations and how they construct buildings and infrastructure.
Concrete is a mixture made up of an aggregate, a binding agent and water. Typically the aggregate is gravel, sand or small stones. This is the filler that gives the final product its mass. The binding agent is what causes the mixture to set and harden. When the aggregate and binding agent are combined with water a thick mixture is created that can be poured into a form which then solidifies. In early civilization the binding agent was typically limestone powder or gypsum. The Romans discovered the use of pozzolana as a binding agent (Yegeul, n.d.). Pozzolana is a fine, sandy, volcanic ash which when used as a binding agent creates a strong durable concrete (Wikipedia, 2011, Pozzolana).
For the Romans, concrete was the perfect building material. Its great strength made it possible to erect enduring structures such as amphitheaters, aqueducts, dams and bridges. Because it could be poured, it was easily formed into nearly any shape that was desired. The Romans developed domed roofs and arches known for their strength which became common types of architecture during this time period (Bulliet, 147). Concrete did not require particularly skilled craftsman to work with...