How much recycled industrial byproducts are used in concrete production?
A. Concrete contains recycled materials and therefore helps reduce industrial byproducts that would otherwise clog landfills. For example, 11,400,000 metric tons of fly-ash a byproduct of coal combustion at electric utilities were used in concrete in 2001. Concrete production uses about 3 million metric tons of recycled slag, a byproduct of steel production.