Manufacturing and durability of alkali activated mortars containing different types of glass waste as aggregates valorisation

Mortars containing glass waste as a partial substitution for natural sand have been formulated. Alkali activated fly ashes have been used as a binder. The selected cullets are those deriving either from the discarded lamps collection or the fraction of the selective urban glass collection (about 10 wt% on the whole amount) that, because of its highly heterogeneous composition, cannot be used in the production of new glass items. Mechanical properties of the obtained mortars have been investigated as well as their durability. In details, the reactivity towards alkali silica reactions and sulphates diffusion, as well as the stability to freeze–thaw cycles have been compared to the ones of unmodified mortars. Both types of waste do not lead to a decrease in the durability of the obtained materials. The inertness of these cullets towards alkali silica reaction is quite remarkable since both wastes are highly reactive in Portland cement matrix. This introduces a possible reuse in the formulation of low-impact renders for these fractions that presently have no alternatives to landfilling.