68    OVERVIEW OF COAL ASH USE IN CONSTRUCTION AND
RELATED APPLICATIONS
Samuel S. Tyson, Executive Director
Thomas H. Blackstock, Jr., Director of Technical Services
American Coal Ash Association
Washington, DC 20006
INTRODUCTION
An annual survey of electric utilities is conducted by American Coal Ash Association (ACAA) to
determine the quantities of coal ash produced and used in the United States.1 In 1992 approximately
82 million short tons of coal ash were produced in the U.S. in the form of fly ash, bottom ash, boiler
slag and a by-product from flue gas desulfurization (FGD). Approximately 25% of the combined
production of these by-products was used, while the remaining three-quarters went to disposal areas.
Production and use quantities for these by-products are summarized in Table I.
It is clear from survey data gathered by ACAA over the years that the annual use of 20 million tons
of coal combustion by-products represents a major continuing effort by a number of parties, including the electric utility producers of ash and their marketers. It is equally clear, however, that significant amounts of coal ash are not used each year. Therefore it is essential for ACAA to promote the
use of coal combustion by-products in numerous applications that are technically sound, commercially effective and environmentally safe.
Coal ash is an engineering material and its use is similar to the use of competing virgin, processed
and manufactured materials in that it is affected by local and regional factors. These factors include
production rates, processing and handling costs, transportation costs, availability of competing materials, seasonal adjustments, and the experience of materials specifiers, design engineers, purchasing
agents, contractors, and other construction professionals.
FLY ASH APPLICATIONS
It is instructive to consider the total amounts of coal fly ash that are used in the five leading markets
for coal fly ash based on ACAA's 1992 survey results. This information is presented in Table II. The
top three fly ash uses, cement and concrete, structural fills, and road base, accounted for 57, 17, and
10%, respectively, of the total amount of fly ash used.
BLASTING GRIT AND ROOFING GRANULES
Blasting grit and roofing granule applications, with an annual usage of 2.1 million short tons in
1992 represents 10% of the total coal ash used in that year. This market is extremely important to the
coal ash industry as high-quality blasting grit and roofing are in fairly constant demand.
The use of blasting grit and roofing granules are for the most part specialty applications of boiler
slag with demand being typically regional in character. For example, the largest users of blasting grit
are the large shipyards that perform contract maintenance for the U.S. Navy and for commercial
shipping lines.
Table I.    Production and Use of Coal Ash [1992 data; million short tons]
Fly Ash
Bottom Ash
Boiler Slag
FGD By-product
Production                     48
Use                                 13.1
% Use                            27%
13.9
3.4
28%
4.1
3.1
75%
15.9
0.3
2%
49th Purdue Industrial Waste Conference Proceedings, 1994 Lewis Publishers, Chelsea, Michigan 48118. Printed in
U.S.A.
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