Rheology of an alkali-activated Fe-rich slag suspension: Identifying the impact of the activator chemistry and slag particle interactions

Iron-silicate slags, originating from metallurgical industry, are upon alkali-activation precursors for synthesis of inorganic polymer binders, which can be used in construction. The slag?s rheology is important for certain construction applications, which is for alkali-activated Fe-rich slag suspensions (AAS) still largely unmapped. To identify the contribution of the activator and of an early formed binder to the rheology, the activator SiO2/Na2O molar ratio and H2O content was modified. The flow behaviour of AAS was compared with an activator alone, and a quartz suspension to reveal the effect of the slag particles on the rheology and its degree of activation. Raising SiO2/Na2O molar ratio resulted in a higher yield stress and elasticity, explained by the increase of silicate complexes, while decreasing SiO2/Na2O molar ratio resulted in more monomers. AAS exhibited a yield stress fluid-like behaviour conform to the Herschel-Bulkley model and driven by the strong physical interaction between the slag particles.

Automated summary

The flow behavior of alkali-activated Fe-rich slag suspensions was studied, with modifications to the activator SiO2/Na2O molar ratio and H2O content to determine their impact on rheology. Changes in these parameters led to variations in yield stress and elasticity, with higher ratios resulting in more complex silicate structures and lower ratios leading to increased monomers. The AAS exhibited a yield stress fluid-like behavior driven by strong physical interactions between slag particles.