Flyash is a waste product from coal fired power plants. It replaces cement but requires cement to react so the amount of cement needed is reduced. The reducing of cement usage reduces carbon dioxide emissions and ozone depletion. The Federal government requires the use of this mix component. Basically, flyash is less expensive than cement and makes better concrete.

Cement is mixed with water to create the “glue” that holds strong aggregates together. Fly ash works in tandem with cement in the production of concrete products. Concrete containing fly ash is easier to work with because the tiny, glassy beads create a lubricating effect that causes concrete to flow and pump better, to fill forms more completely, and to do it all using up to 10% less water. Because the tiny fly ash particles fill microscopic spaces in the concrete, and

because less water is required, concrete using fly ash is denser and more durable. And fly ash reacts chemically with lime that is given off by cement hydration, creating more of the glue that holds concrete together. That makes concrete containing fly ash stronger over time than concrete made only with cement.

Fly ash is also a cost-effective resource. When fly ash is added to concrete, the amount of cement that is necessary can be reduced. Because fly ash use displaces cement use, it also reduces the need for cement production. For every ton of cement manufactured, about 6.5 million BTUs of energy are consumed. For every ton of cement manufactured, about one ton of carbon dioxide is released. Replacing that ton of cement with fly ash would save enough electricity to power the average American home for 24 days, and reduce carbon dioxide emissions equal to two months use of an automobile.

Experts estimate that cement production contributes to about 7% of carbon dioxide emissions from human sources. If all the fly ash generated each year were used in producing concrete, the reduction of carbon dioxide released because of decreased cement production would be equivalent to eliminating 25 percent of the world's vehicles.

Concrete itself is an environmentally sound building material. Roads and structures built from concrete last longer and require less maintenance than other materials. When used in freeways, concrete can result in less vehicle fuel consumption. Because concrete reflects light, less energy is needed to illuminate the roadway. Concrete is recyclable, with 45 to 80 percent of crushed concrete usable as aggregate in new construction.

Additionally, recent studies conducted by the Environmental Council of Concrete Organizations have determined certain metropolitan areas experience higher overall temperatures than surrounding less-developed areas. Using lighter colored concrete products instead of asphalt pavement can help reduce excessive temperature, further conserving energy.