Because fly ash use displaces cement use, it also reduces the need for cement production – a major energy user and source of “greenhouse gas” emissions.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 percent 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.
Conserving landfill space is also an important consideration. Every ton of coal combustion products that is used to improve our nation’s highways and buildings is a ton that is not deposited in a landfill, saving the same amount of space that the average American uses over 455 days.
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.
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