Concrete itself can be made of reused materials. One of the most-common recycled components used in concrete is fly ash, a residue created in the combustion of coal. Fly ash is a pollutant when released into the environment, but when captured in chimneys at power-generation facilities, it can be used as part of cement mixtures.
While concrete can be an important part of durable, sustainable buildings, it can also contribute to wastefulness through energy-intensive production and carelessness in the way waste is managed. That's why it is important for concrete contractors, just like any other professional seeking to be part of the greening of the building industry, to educate themselves on green building best practices and to work as part of a dedicated LEED team.