Slag–cement mortar made with cement and slag vitrified from MSWI fly-ash/scrubber-ash and glass frit

Properties were studied of cement mortars made with replacing 20% of ordinary Portland cement by a slag powder vitrified from an ash mixture (composed of fly-ash and scrubber-ash from a municipal solid waste incinerator, MSWI) and a glass frit with the aim of tackling the difficult problems of being not able to vitrify scrubber-ash by melting. The ash mixture was found fusible to become slag when the basicity (CaO/SiO2 weight ratio) was adjusted from 0.8 to 1.2 by the addition with suitable amount of a glass frit obtained from waste glass bottles. Toxicity characteristics leaching procedure (TCLP) tests on the slag and the cured mortar revealed that the concentrations of leached heavy metals were far below the regulation values. The 28-day compressive strength was similar to that of ordinary cement mortar while after 60 days and 90 days, the compressive strength were 2–11% higher, revealing the beneficial effect of Pozzolanic reaction. The results of this work demonstrate the feasibility of simultaneously recycling by melting the fly-ash and scrubber-ash, as well as waste glass bottles to become useful resources.