Effect of AEA-SP dosage sequence on air content and air void structure in fresh and hardened fly ash mortar

Abstract

Laboratory measurements show that varying the dosage sequence of air-entraining agent and copolymer in the mix (SP added before, after or together with AEA) greatly affects air entrainment in fresh and hardened fly ash mortar. Image analysis shows a good correlation between total air content and the air void spacing factor, though with a somewhat lower specific surface when SP is added together with AEA. Foaming measurements on the same materials and dosage sequences were therefore found less useful for studying the effect of admixture combinations. More work, including AVA measurements, is in progress to learn how to combine AEA, SP and fly ash in concrete.