The recycling of municipal solid waste incineration (MSWI) bottom ash as a supplementary cementitious material (SCM) has attracted global attention, driven by the increasing availability of this by-product and the demand for sustainable SCMs to lower CO₂ emissions from cement production. Currently, the widespread use of MSWI bottom ash in the cement industry is hindered by the lack of guidelines to regulate material composition, optimize pretreatment processes, and specify mix design requirements. This review compiles and analyzes literature data on mix design, microstructural evolution, fresh properties, mechanical properties, durability, leaching risks, and environmental impacts of MSWI bottom ash-blended cement pastes, mortars, and concretes. The analysis aims to assess the influence of the pretreatment and physicochemical properties of bottom ash¹ on the microstructure and performance of blended cementitious materials.² The Ash Impact Strength Index (AISI) is introduced to quantify the effects of various factors on compressive strength, enabling direct comparison across different studies. Based on the statistical analysis of the 28-day AISI, the key quality requirements for MSWI bottom ash as an SCM are proposed, along with the optimal mix design. This work provides valuable insights and practical guidance to support the integration of bottom ash into the cement industry.

Alkali-activated foams are ceramic-like materials prepared at near-ambient temperature. This study investigates them for point-of-use water disinfection, thus providing an alternative to ceramic filters fired at a high temperature. Alkali-activated foams with different compositions were characterized for the porosity, mechanical strength, shrinkage, and microstructure. The optimized foam, employing metakaolin as the raw material, was coated with a colloidal Ag solution. The disinfection performance and leaching behavior of the foams was followed in a continuous 10 week experiment, where clean water with a weekly pulse of contaminated water was distributed through the foam. The average inactivation of Escherichia coli with the Ag-coated foam was 2.84 log₁₀, which was 1.27 units higher compared to foam without Ag. A quantitative polymerase chain reaction analysis and metagenomic sequencing verified that foams with and without Ag were both capable of reducing the microbial load. Furthermore, the changes induced by the foam with Ag on the microbial community composition, antibiotic resistome, and metal and biocide resistomes were significant. The leached concentrations of Ag, Na, Si, and Al were in accordance with the drinking water guidelines. Finally, a life cycle assessment indicated the possibility of reducing the global warming potential and the total embodied energy in comparison with a conventional ceramic filter.

In recent years, the widespread application of waste incineration technology has led to an increased generation of municipal solid waste incineration (MSWI) bottom ash. There is growing interest in the use of MSWI bottom ash as a mineral resource to produce construction materials. The utilization potential of MSWI bottom ash is determined by its chemical and mineralogical compositions, which can vary from incineration plant to incineration plant, and even from batch to batch within a single incineration plant. The quality of MSWI bottom ash often needs to be improved before it can be used as supplementary cementitious material (SCM) and precursor for alkali-activated materials (AAM). This review summarizes the composition of MSWI bottom ash sourced from different regions and the proposed treatments for quality upgrades of MSWI bottom ash. The reactivity of MSWI bottom ash as SCM and AAM precursor is discussed. Finally, the challenges regarding the use of MSWI bottom ash as a mineral resource for the production of construction materials are examined and possible solutions are provided.