How will fly ash affect entrained air in concrete?
Fly ash is a very fine material. As with any fine material, its addition to concrete will, for a given air entrainment, cause an increase in the required air entraining admixture dosage. Further, a commonly accepted theory states that the residual carbon found in many fly ashes also drives up the air entrainment requirement of fly ash concrete. Field experience shows that fly ashes are very easy to work with from an air entrainment dosage standpoint. Typically with fly ash, once the air entrainment dosage for a given mix has been determined, it varies very little from fly ash load to fly ash load although seasonal and other causes of dosage requirement variation still exist.
