Screening Untreated Municipal Solid Waste Incineration Fly Ash for Use in Cement-Based Materials – Chemical and Physical Properties

Concrete manufacturing impacts the environment and construction industry sustainability. The impact is reducible by either using less cement or replacing it with secondary cementitious materials (SCMs). Limited potential for further reduction has been identified, due to low SCM availability. Fly ash from municipal solid waste incineration (MSWI) is an unused material, that could be used as an SCM to further reduce the environmental impact. Before implementing MSWI fly ash for use in cement-based materials, its chemical and physical properties should be evaluated. The present study aims to evaluate the potential of using untreated MSWI fly ash in cement-based materials and its quality, by comparing the chemical properties of MSWI fly ash samples with the chemical requirements of coal fly ash specified in EN 450-1 2012, as well as analysing their potential as filler materials. The screened ash in the present study was sourced from different types of combustion units, in different locations, and from the same location at varying times. MSWI fly ash samples were acquired from three different combustion units, located in Denmark, Sweden and Greenland respectively. Two fly ash samples were acquired from both the units in Denmark and Greenland, sourced several months apart and one from the unit in Sweden. The screening showed that the five fly ash samples, based on their chemical properties, were unsuited for use in cement-based materials. The samples potential as filler materials were found to be limited for all but one sample that had a slightly finer particle size distribution than CEM I cement.