Every tonne of fly ash, a fine grey powder, or bottom ash, a coarser substance, produced when coal is burned for power generation needs to be disposed of. Georgia conducted one of the first field tests, and road builders, who require large quantities of inexpensive material, have been a clear customer for decades. In 1985, the Georgia Department of Transportation built a 2.6-kilometre relocation of State Route 22 west of Crawfordville, including a 1,000-foot cement-stabilized pond-ash base section and an 800-foot cement-stabilized fly-ash base section. Pond ash was used in one portion, which was about 305 metres (1,000 feet) long, while fly ash was used in another, which was about 244 metres (800 feet) long. Each layer was around 215 mm thick, and the strength results from the experiment indicate that it held up well.
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