What are the effects of fly ash on air entrainment?
The impact of fly ash on air entraining admixture (AEA) is primarily due to the carbon, represented as loss-on-ignition (LOI), remaining in the fly ash after combustion of the coal fuel. Due to the high rate of absorption of surfactants such as air entrainment into carbon, the loss-on-ignition generally has a positive correlation with AEA dosage demand. When using fly ash with a relatively high LOI, care should be taken to dose the concrete for the desired air content, and perform quality control checks using volumetric/pressure air testing and/or unit weight testing.
