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Fly Ash Facts for Highway Engineers


Coal fly ash is a coal combustion product that has numerous applications in highway construction. Since the first edition of Fly Ash Facts for Highway Engineers in 1986, the use of fly ash in highway construction has increased and new applications have been developed. This document provides basic technical information about the various uses of fly ash in highway construction.

Fly ash has been used in roadways and interstate highways since the early 1950s. In 1974, the Federal Highway Administration encouraged the use of fly ash in concrete pavement with Notice N 5080.4, which urged states to allow partial substitution of fly ash for cement whenever feasible. In addition, in January 1983, the Environmental Protection Agency published federal comprehensive procurement guidelines for cement and concrete containing fly ash to encourage the utilization of fly ash and establish compliance deadlines.

This document is sponsored by the U.S. Department of Transportation, through the Federal Highway Administration, in cooperation with the American Coal Ash Association and the United States Environmental Protection Agency. The United States Government assumes no liability for its contents or use. The Federal Highway Administration endorses no products or manufacturers. This publication does not constitute a standard, specification, or regulation.

The United States Environmental Protection Agency supports the beneficial use of coal combustion products as an important priority and endorses efforts by the Federal Highway Administration as described in this document.

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Mike Rafalowski
Office of Asset Management, Pavements, and Construction
E-mail Mike

Updated: 02/20/2015

United States Department of Transportation - Federal Highway Administration