Fly ash

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fly ash

[′flī ‚ash]
(engineering)
Fine particulate, essentially noncombustible refuse, carried in a gas stream from a furnace.
Coal combustion residue.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

Fly ash

A fine glass powder recovered from the gases of burning coal during the production of electricity. It is an ash residue from high-temperature combustion processes. Electric motor plants using western coal produce a nontoxic fly ash that because of its very high calcium content can be a substitute for Portland cement, the common bonding material in concrete, and these micron-sized Earth elements consist primarily of silica, alumina, and iron. When mixed with lime and water, fly ash forms a cementitious compound with properties very similar to that of Portland cement. Because of this similarity, fly ash can be used to replace a portion of cement in the concrete, providing some distinct quality advantages. The concrete is denser, resulting in a tighter, smoother surface with less bleeding. Fly ash concrete offers a distinct architectural benefit with improved textural consistency and sharper detail. Regulations vary from state to state; however, ASTM International suggests that fly ash must not contain more than 6 percent unburned carbon to be used for its cementitious qualities. Substitution of fly ash for Portland cement in concrete is considered a sustainable building strategy, as it reduces the amount of energy-intensive (and CO2-producing) cement in the mix.
Illustrated Dictionary of Architecture Copyright © 2012, 2002, 1998 by The McGraw-Hill Companies, Inc. All rights reserved

fly ash

The finely divided residue resulting from the combustion of ground or powdered coal, transported from the firebox through the boiler by flue gases.

fly ash

as the aggregate.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
References in periodicals archive ?
There is an influence of sawdust on the compressive strength of the alkali-activated material based on fly-ash.
ALKALI-ACTIVATED MATERIALS BASED ON FLY-ASH WITH A SAWDUST ADDITION
(1988) Boron release and sorption by fly-ash as affected by pH and particle-size.
Kukier U, Sumner ME, Miller WP (1994) Boron release from fly-ash and its uptake by com.
Engineering studies indicate that in designing HMA pavements, the structural coefficient for pulverized, fly-ash stabilized base course, increases from 0.14 to 0.30 in the American Association of State Highway and Transportation Officials formula, accounting for the savings in HMA thickness.
"The predicted cement shortage presents a perfect opportunity for the concrete industry to utilize more mineral admixtures, such as fly-ash and slag, both produced from waste by-products of manufacturing," said Parnes.
[19, 20] used fly-ash to produce a suitable controlled low strength material as a backfill for bridge abutment.
In Hungary, the biggest pipelines transport coal power plant fly-ashes, and this is our primary interest.
ARTBA has been actively engaged in the regulatory and legislative debate in Washington over fly-ash since 2007 and applauded the decision as a "win-win" for both the taxpayer and the environment.
Funamoto, "Study on compressive strength development of concrete with type-II fly-ash in standard curing," AIJ Journal of Technology and Design, vol.