Concrete is a composite construction material made primarily with aggregate, cement, and water. There are many formulations of concrete, which provide varied properties, and concrete is the most used man-made product in the world.
Concrete is widely used for making architectural structures, foundations, brick/block walls, pavements, bridges/overpasses, motorways/roads, runways, parking structures, dams, pools/reservoirs, pipes, footings for gates, fences and poles and even boats.
Famous concrete structures include the Burj Khalifa (world’s tallest building), Hoover Dam, the Panama Canal and the Roman Pantheon.
Concrete technology was known by the Ancient Romans and was widely used within the Roman Empire—the Colosseum is largely built of concrete. After the Empire passed, use of concrete became scarce until the technology was re-pioneered in the mid-18th century.
The environmental impact of concrete is a complex mixture of not entirely negative effects; while concrete is a major contributor to greenhouse gas emissions, recycling of concrete is increasingly common. Structures made of concrete can have a long service life. As concrete has a high thermal mass and very low permeability, it can be used for energy efficient housing.