Dynamic evolution of multiscale pore structures and hydration behaviors of cement mixtures involving municipal solid waste incineration bottom ash (MSWIBA) through physicochemical activation

The properties of municipal solid waste incineration bottom ash (MSWIBA) relevant to its role as a potential cement replacement are not fully well understood. This study explores the efficacy of diverse physical and chemical pre-treatments in enhancing the physical properties and microstructural integrity of MSWIBA within mortar mixtures. Through extensive microscopic analysis, the obtained results revealed the effectiveness of ball milling MSWIBA for 0.5 h in optimizing the hydration response, evidenced by reduced porosity, increased hydration product formation, and improved crystallinity. Moreover, the addition of an alkaline chemical (Ca(OH)2, NaOH, and Na2CO3) accelerated early hydration, albeit resulting in an irregular structure that impaired strength development. Notably, Ca(OH)2 alkali solution facilitated a greater production of hydration products via the provision of additional nucleation sites. These findings established a foundation towards advancing the performance and broader utilization of MSWIBA in cement-based formulations.