Performance and interaction of sodium silicate activated slag with lignosulfonate superplasticiser added at different mixing stages

This paper investigated the effect of adding lignosulfonate (LS) superplasticiser at different stages mixing on workability and rheological behaviour sodium silicate activated slag (SSAS) in order to find a practically feasible approach tackling incompatibility issue between alkaline activator. In addition rheology minislump tests, adsorption, zeta potential environmental scanning electron microscopy tests were also undertaken understand interactions fresh SSAS reveal mechanisms behind observation. The results show that LS activator separately can significantly improve both initial 60-min retention due increased adsorption improved dispersion particles, with prior better than delayed addition. However, nonlinear was observed LS-superplasticised under separate and, consequently, modified Bingham model found be more suitable for describing this kind behaviour.