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

Benjamin A.R Ebert,Mette R Geiker,Wolfgang Kunther,Gunvor M Kirkelund

doi:10.1016/j.conbuildmat.2021.125193

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.

Highlights

Portland cement clinker production has been estimated to account for approximately 8% of the global anthropogenic CO2 emissions, rep resenting a significant environmental issue [1]
Municipal solid waste incineration (MSWI) residues such as fly ash and air pollution control (APC) residues may serve as new supplementary cementitious materials (SCM)
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 MSWI residues

Summary

Introduction

Portland cement clinker production has been estimated to account for approximately 8% of the global anthropogenic CO2 emissions, rep resenting a significant environmental issue [1]. Research into replacing Portland cement with other cement types, e.g. belite cement, and magnesium-based cement, is ongoing [2]. Concrete based on Portland cement clinker is estimated to dominate in the foreseeable future [2]. A well-established strategy for reducing Portland cement clinker use is to partially replace it with supplementary cementitious materials (SCMs). Limited potential for reducing CO2 emission further with commonly used SCMs such as ground granulated blast furnace slag or fly ash from coal incineration has been identified because of limited supplies of these SCMs [2]. The introduction of new sources of SCMs is needed

Methods

Results

Conclusion