Compressive strength of fly ash magnesium oxychloride cement containing granite wastes

► Granite waste and fly ash are incorporated into magnesium oxychloride cement (MOC). ► The water absorption of granite waste from the slurry results in increased hydration product of 5 Mg(OH)2⋅MgCl2⋅8H2O. ► The excess water absorption of granite waste from low-concentration brine leads to compact microstructure of GFMOC, whereas from the high concentration of brine leads to porous microstructure. ► The sound composition and compact microstructure of the hydration product lead to high compressive strength of GFMOC. ► Incorporated granite waste can increase the compressive strength of fly ash MOC.