Preparation of greener geopolymer binder based fly ash: An effective strategy toward carbon neutrality.

Decarbonizing the building sector to achieve sustainable development goals (SDGs) is a complex issue that poses significant challenges to the scientific community. In this context, the current paper aims to assess the viability of employing incinerated by-products as a sustainable mineral resource to produce sustainable geopolymers. To this end, the study focuses on the formulation of geopolymer binders using fly ash with various proportions (ranging from 0 % to 50 %) of metakaolin (MK), investigating their physico-mechanical, microstructural analysis as well as their sealing capacity. The results indicate that incorporating 30 % MK not only preserves good workability but also significantly improves mechanical strength, ensuring long-term durability by increasing bulk density and concurrently reducing water absorption and harmful porosity. Moreover, the results of the Toxicity Characteristic Leaching Procedure (TCLP) demonstrated that the released contaminants remained within the regulatory limits established by the USEPA. The geopolymer binder developed exhibited a significant reduction of 77.23 % and 57.92 % in terms of carbon dioxide equivalent (CO 2 -e) emissions and energy demand compared to conventional cement. This study introduces a novel approach to promoting a circular economy within the building sector. [Display omitted] [ABSTRACT FROM AUTHOR]