Enhancing thixotropy and structural build-up of alkali-activated slag/fly ash pastes with nano clay

Abstract

This study investigates the influence of nano clay on the rheological properties of alkali-activated cement pastes having different GGBFS/FA ratios. The thixotropic index, structural build-up, dynamic yield stress and heat evolution of fresh AAC pastes with addition of nano clay are studied. Test results showed that nano clay had a strong influence on the thixotropy/structural build-up and dynamic yield stress of AAC pastes depending on the GGBFS/FA ratio of the mixture. It was found that the pastes with lower GGBFS/FA ratio exhibited higher thixotropic index, but lower dynamic yield stress in the presence of nano clay. This study reveals the importance of GGBFS/FA ratio in the presence of nano clay for obtaining AAC mixtures with low dynamic yield stress for a better flowability and high thixotropy/structural build-up for stability.