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 5% sodium sulfate solution under room temperature and wetting-drying cycles on the compressive strength of mortar specimens were considered to evaluate the extent of degradation. mortar specimens prepared from type ii and v portland cements (pc2 and pc5) in accordance with astm standard were also used as a 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 360 days of exposure to the sodium sulfate solution, pc2, pc5 and aas cements showed 71, 52 and 45% reduction in compressive strength, respectively. according to the obtained results, aas cement exhibits a higher sulfate resistance compared to pc2 and pc5.