Effects of spodumene flotation tailings as aggregates on mechanical properties of cement mortar.

This work explored the use of spodumene flotation tailings (SFT) as an aggregate used in cement mortar to mitigate their environmental impact. The principal phase compositions of SFT were quartz (Qtz), feldspar (Fsp) and muscovite (Ms). So, the effects of variations in the particle size of Qtz, and mineral additives, Ms and Fsp, on the compressive strength and hydration products were examined. Ms additives imparted the lowest compressive strength. Finer Qtz aggregates (4000–106 µm) reduced the nano-pore volume, and Ms increased the nano-pore width of cement mortar. In addition, fewer hydration products, and poor crystallinity of both ettringite (Aft) and portlandite resulted in a decrease in the compressive strength of the cement mortar, eventually. Therefore, increasing the particle size or optimisation of the mineral composition of SFT could provide a facile route to improving the mechanical properties of cement mortars. [Display omitted] • SFT results fewer hydration products, and poor crystallisation. • A reduction in the Qtz particle size (4000–106 µm) reduced the compressive strength. • Ms additives imparted the lowest compressive strength because of its properties. • Finer Qtz aggregates (4000–106 µm) resulted in a reduced pore volume. [ABSTRACT FROM AUTHOR]