Determining the air-entraining admixture dosage in concrete with non-traditional coal ash

Due to the shortages in traditional fly ash, there is increased interest in using non-traditional coal ash (NTCA) in concrete mixtures. NTCA shows great promise for use in concrete, but there are concerns with the consistency of the material. One area of concern is the impact of the NTCA and traditional fly ash on the air entrainment agent (AEA) demand in concrete. This work aims to investigate the correlation of the foam index [FI], loss on ignition (LOI), and nitrogen surface area (BET), with the AEA dosage required to produce 6% air in a concrete mixture for 12 different coal ash sources. The results show that the foam index has the best correlation with the AEA dosage in concrete. When the LOI is less than 6%, there is a correlation to AEA dosage in concrete, but this same relationship does not hold for fly ash with LOIs greater than this. The LOI and BET show a direct relation to the materials investigated in this study.