Impact of electrodialytic remediation of MSWI fly ash on hydration and mechanical properties of blends with Portland cement

Abstract

Municipal solid waste incineration (MSWI) residues such as fly ash and air pollution control (APC) residues may serve as new supplementary cementitious materials (SCM). These SCMs may, however, require a pre-treatment to improve material properties. This study investigates the impact of electrodialytically remediated (EDR) MSWI residues to remove heavy metals and salts, on the phase development, setting, and compressive strength development of composite cements with 10 wt% cement replacement, compared to inert quartz or untreated (raw) MSWI residues. All treated MSWI residues showed reactivity in mortar, resulting in higher compressive strength than inert quartz, attributed to additional ettringite and monocarbonate formation. The results indicate that electrodialytical remediation improves the performance of MSWI fly ash in blends with Portland cement, while MSWI APC residues might be used without pre-treatment.