Resistance of Alkali-activated Slag Cement Against Sodium Sulfate

This work evaluates the resistance of alkali-activated slag (AAS) mortar against sodium sulfate attack. The effects of immersion in ۵% sodium sulfate solution under room temperature and wetting-drying cycles on the compressive strength of mortar specimens were considered for evaluating the extent of degradation. Mortar specimens prepared from type II and V Portland cements (PC۲ and PC۵) in accordance with ASTM standard were also used as reference. To characterize the chemical products of the degradation process due to sodium sulfate attack, the specimens were also studied by X-ray diffractometry, scanning electron microscopy, and the elemental analysis by energy dispersive X-ray spectroscopy. After ۳۶۰ days of exposure to the sodium sulfate solution, PC۲, PC۵ and AAS cements showed ۷۱, ۵۲ and ۴۵% reduction in compressive strength, respectively. According to the obtained results, AAS cement exhibits a higher sulfate resistance compared to PC۲ and PC۵.

کلیدواژه ها:

Sulfate resistance ، Compressive strength ، Slag ، Alkali-activation