Technical Questions

ACI Committees, Membership, and Staff have answered common questions on a variety of concrete related topics.



What is fly ash?

Q. What is fly ash?

 

A. Fly ash is the finely divided residue that results from the combustion of ground or powdered coal and that is transported by flue gasses from the combustion zone to the particle removal system. ASTM C618 provides classification for Class F and Class C.

 

References: SP-1(02); ACI CT-18; SP-242; ACI 232.2R-03; ASTM C618; ACI PRC-232.4-20

Topics in Concrete: Fly Ash; Concrete Fundamentals; Materials in Concrete; Pozzolan

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