Advances in using municipal solid waste incineration (MSWI) bottom ash as precursor for alkali-activated materials: A critical review

Abstract

The pursuit of low-carbon binders as alternatives to Portland cement has sparked interest in developing alkali-activated materials (AAM).11Alkali activated materials (AAM) can be categorized into alkali-activated pastes, alkali-activated mortars, and alkali-activated concretes. These three are differentiated by the aggregates. Alkali-activated pastes have no aggregates. Alkali-activated mortars contain only fine aggregates, typically sand. Alkali-activated concretes incorporate both fine aggregates and coarse aggregates (like gravel and crushed stone). Using municipal solid waste incineration (MSWI) bottom ash as precursor for AAM has attracted increasing attention as it offers a sustainable, resource-efficient solution to mitigate the environmental impacts associated with the landfill of MSWI bottom ash. However, the varying properties of MSWI bottom ash present challenges in its wide application as AAM precursor. This review provides a comprehensive overview of advances in MSWI bottom ash-based AAM,22In this text, the term “MSWI bottom ash-based AAM” describes the alkali-activated materials prepared using MSWI bottom ash as a significant component in the precursor. with a particular focus on the relationship between the physicochemical properties of MSWI bottom ash and the engineering properties of MSWI bottom ash-based AAM. This work consolidates the most up-to-date understanding of the reaction mechanism and reaction products of MSWI bottom ash, along with the existing knowledge about mix design and microstructure formation of MSWI bottom ash-based AAM. The factors influencing the engineering properties of MSWI bottom ash-based AAM are detailed, and the environmental impacts of MSWI bottom ash-based AAM are reviewed. Ultimately, this review provides recommendations for the standardized and effective use of MSWI bottom ash as AAM precursor.