Durability of alkali-activated Fe-rich fayalite slag-based mortars subjected to different environmental conditions

Fe-rich alkali activated materials (AAMs) require detailed understanding of their durability prior to their real-life application in the construction industry. Three mixes were formulated with fayalite slag (FS) as the main precursor. The effect of incorporation of ladle slag (LS) or blast furnace slag (BFS) on the shrinkage and exposure to physical and chemical attacks representing environmental conditions in cold and tropical regions (acidic solution at room temperature and in freeze-thaw, combined sodium sulfate and sodium chloride solution at room temperature and in freeze-thaw, freeze-thaw in water and dry-wet cycles) was investigated via visual observation, mass loss, compressive strength, X-ray diffraction (XRD), mercury intrusion porosimetry (MIP), and scanning electron microscope coupled with energy dispersive X-ray spectroscopy (SEM-EDS). Experimental results show the considerable role of incorporated LS and BFS in modifying the gels formed and controlling material degradation of blended AAMs after exposure. In contrast, sole FS-based samples were completely degraded particularly those exposed to freeze-thaw in water, acid, and combined sodium sulfate and sodium chloride solution, indicating their vulnerability to frost and chemical attacks.