Shrinkage-Reducing Admixture Efficiency in Alkali-Activated Slag across the Different Doses of Activator
One of the largest obstacles for the wider use of alkali-activated slag (AAS) in a building industry is its severe drying shrinkage. According to some studies shrinkage-reducing admixtures (SRAs) could be a solution of this problem, but they were also reported to have a fatal impact on AAS hydration resulting in a serious strength development slowdown. The aim of this paper was to investigate this phenomenon in a wide range of the waterglass doses (4–12% Na2O of the slag mass). Mortars without and with 2% of SRA based on hexylene glycol were prepared and their shrinkage and compressive strength development was tested. By far the highest shrinkage reduction was observed for the lowest doses of waterglass, but these were also the cases of the highest compressive strength decrease. However, it is possible to suppress the negative effect of SRA on AAS strength development through the activator dose increase with certainly decreased shrinkage reducing ability of SRA.
Šárka Nenadálová, Vlastimil Bílek, Zbyněk Keršner, Stanislav Seitl and Dr. Hana Šimonová
V. Bílek Jr. et al., "Shrinkage-Reducing Admixture Efficiency in Alkali-Activated Slag across the Different Doses of Activator", Key Engineering Materials, Vol. 761, pp. 19-22, 2018