A comparative study of wet-mix vs. dry-mix to prepare geopolymer artificial aggregates utilizing municipal solid waste incineration bottom ash (IBA) via crushing technique

The demand for sustainable alternatives to utilize incinerator bottom ash (IBA) alongside the current scarcity of natural aggregates drives the construction industry to seek innovative solutions, among which cold bonding geopolymer artificial aggregates (GPA) have tremendous leverage. This study suggests combining dry-mix and crushing techniques for producing IBA-GPA, aiming to overcome the challenges of volume instability related to metallic aluminum. The materials used as precursors include IBA, CFA, and GGBS, with anhydrous sodium metasilicate as the activator. The mixing method, water content, and IBA content are key parameters examined in this research, using characterization techniques such as XCT, TCLP, XRD, FTIR, and SEM. The results show that a proper balance between water and IBA contents is crucial for producing high-quality IBA-GPA cubes, at which the proposed technologies successfully mitigate volume instability and enhance the reliability of IBA-GPA. The dry-mix samples were less porous and more compact, with irregularly shaped pores, while the wet-mix samples had a foam-like structure with more uniformly spherical pores. Adding IBA increased pore sizes in both samples, with a more pronounced effect in the wet-mix samples. The findings provide insights into the impact of mixing methods on the properties of IBA-GPA. © 2024 Elsevier Ltd.