Upcycling Incineration Ash in Reactive Magnesium Oxide Cement: Effects of Carbonation

Over the past decade, increased economic activity and population growth have led to a rise in global waste generation. Current waste management strategies focus on enhancing waste collection, recycling, and converting waste into energy through incineration. While waste incineration effectively reduces both mass and volume, it generates substantial residuals, including fly ash and bottom ash, which pose significant management challenges. Despite the potential of incineration ash, large-scale utilization remains limited, typically confined to applications such as road sub-base materials, landfill stabilizers, and cement additives. The construction industry’s reliance on concrete has spurred research into using incineration ash, but challenges such as low density, high heterogeneity, and the presence of toxic contaminants hinder its effectiveness. Reactive magnesium oxide cement (RMC) has attracted attention due to its ability to sequester carbon dioxide (CO2). This study investigates the potential of replacing RMC with 10% and 20% by mass of incineration ash in mortar. Six types of fly ash were analyzed for chemical composition and particle size, and the behavior of RMC-ash pastes was studied. Results indicate that limited ash replacement remains beneficial, offering environmental advantages like waste reduction and the production of value-added materials from byproducts.