The impact of granulation on the mineralogy of a modified-BOF slag and the effect on kinetics and compressive strength after alkali activation

This work explored the effect of mineralogical changes of a modified basic-oxygen furnace slag (BOFS) on the properties of alkali-activated binders. The study quantified the amorphous-crystalline proportions of particles from three different size ranges. These size fractions were finely milled and activated with NaOH solutions. The effects on the reaction kinetics and the mechanical strength of the produced binders were established. The early-stage reaction kinetics were tracked, and the significance of the precursor fraction, the addition of admixtures (gypsum and plasticizer), and the liquid-to-solid ratio (L/S) on the reaction kinetics were identified. The relative variation in the amorphous content between fine and coarse fractions was 45%. These mineralogical differences interacted with the presence of admixtures and the L/S, which impacted the kinetics of the cementitious reactions and the rate of strength development of the binder. Nevertheless, the 30-day strength was similar for all specimens (58 MPa).

Automated summary

This study investigated the influence of mineralogical changes in modified BOFS on the properties of alkali-activated binders. The amorphous-crystalline proportions of particles from different size ranges were quantified and activated with NaOH solutions. The results showed that these reactions affected the reaction kinetics and mechanical strength of the produced binders. The differences in amorphous content between fine and coarse fractions were found to interact with admixtures and liquid-to-solid ratio, impacting the kinetics of cementitious reactions and the rate of strength development.