Rheological properties and microstructure of binary waste red brick powder/metakaolin geopolymer

The findings showed that the yield stress of all mixtures was very low, but it increased with time as the geopolymerization reaction proceeded. The more MK was used in the mixture, the faster the yield stress developed. On the other hand, the plastic viscosity strongly depended on the composition of the mixtures and dropped with increasing WRB/MK ratio. The mixtures containing more than 50% MK exhibited a decrease in viscosity with time due to higher reactivity and the faster dissolution of the MK particles.