Fly ash


Also found in: Dictionary, Thesaurus, Acronyms, Wikipedia.
Related to Fly ash: fly ash concrete, Silica fume

fly ash

[′flī ‚ash]
(engineering)
Fine particulate, essentially noncombustible refuse, carried in a gas stream from a furnace.
Coal combustion residue.

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.

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.
References in periodicals archive ?
offer further STAR III insight, describing the technology as "Specifically designed and operated to reduce the heterogeneity of fly ash by eliminating or lowering the amount of unburned carbon and other contaminants, including unburned organics from alternative fuels.
Portland cement, fly ash and fine aggregates were initially dry mixed at low mixing speed for 5 minutes to achieve the desired homogeneity.
According to the Secretary General of the Centre for Fly Ash Research and Management Dr.
1-4 shows the workability of concrete containing different mineral admixtures such as fly ash, copper slag and silica fume with steel and polypropylene fibres.
Research at the TFC demonstrated that the current ASTM C-618 classification of fly ash into Class F and Class C is insufficient to predict its potential as a geopolymer precursor.
Initially, the strength of the green concrete mixtures after 28 days slightly lagged that of concrete without any fly ash.
Pastes P2 and P3 which contain the highest amount of fly ash in the FA-G blend (100% and 95%, respectively) record the highest TPV.
Particle size distribution (PSD) and aging of the aerosols of fly ash formed by PF and CFB were studied in chamber experiments in the USA and Estonia.
The homogeneity of the bottom ash + fly ash slurry in it is ensured by a mixing agitator with a vertical axis.
3] in ferrochromium fly ash (28-33 percent) is lower compared to chrome oxide with technical purity (99 percent) and it includes components such as [Fe.
Accumulation of ash-derived B by plants depends on properties of the fly ash and the soil to which the ash is applied, rate of application, and the crop type.