Digital foam index for evaluating fly ash air entrainer interactions

Abstract

Real-time evaluation of fly ash and air-entrainer (AEA) interaction was performed by acquiring and analyzing videos of the evolving foam layer in cement-fly ash-water mixtures using the foam index test. This modified foam index test or digital foam index, defines two fundamental parameters linked to foam generation and stability, and thus can be used to improve concrete air-entrainment for freeze-thaw durability. The AEA dosage required to produce a metastable foam is defined as foam stability dosage, whereas the incremental AEA dosage beyond the foam stability dosage to achieve a foam layer covering the entire container surface is termed foam efficiency dosage, and the summation of these dosages is the traditional foam index. The foam stability and efficiency dosages are independent parameters as a vinsol resin-based AEA had a higher foam efficiency dosage but a lower foam stability dosage than a sulfonate–based AEA.