On its own, fly ash doesn’t have any real benefits.
It’s now collected and stored at coal power plants or sent to landfills.
Similarly, mixing fly ash with lime and water can create a substance similar to Portland cement.
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Find out more about fly ash and how it is used in concrete with this thorough guide.
What Is Fly Ash?
Fly ash is also a filler in paints, adhesives, and metal and plastic composites.
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Fly ash contains mercury, cadmium, and arsenic.
This concrete mix also requires less water and has a tendency to resist shrinking.
However, using fly ash in concrete does come with potential problems.
Substituting fly ash for Portland cement in a concrete mixture leads to longer drying and curing times.
Though, air-entraining admixtures can be used to minimize the damage from freeze-thaw cycles.
The exact components of fly ash can vary depending on the source and composition of the coal being burned.
However, all fly ash includes significant amounts of calcium oxide, aluminum oxide, and silicon dioxide.
Fly ash is not environmentally friendly.
It is a waste byproduct of combusted coal, and it’s generally considered an environmental hazard.
US EPA, O.
(2014, December 11).
Disposal of coal combustion residuals from electric utilities rulemakings [Other Policies and Guidance].
https://www.epa.gov/coalash/coal-ash-rule
US EPA, O.
(2014, December 11).
Coal ash reuse [Other Policies and Guidance].
https://www.epa.gov/coalash/coal-ash-reuse
US EPA, O. https://www.epa.gov/coalash/coal-ash-rule
US EPA, O.
(2014, December 11).Coal ash basics[Overviews and Factsheets].
