<p>The incorporation of chemical admixtures into geopolymers modifies their performance in harsh environmental conditions, e.g., cold climates. This study investigates how calcium chloride (CaCl₂) and borax affect the setting time, mechanical properties, and microstructure of waste-based geopolymers containing fly ash and glass-waste powder. We tested the effect of admixtures on various geopolymer properties to determine setting time, compressive strength, mass loss over 100 freeze–thaw cycles, chemical alterations, and micromorphological changes. We found a markedly lower mass loss after 100 freeze–thaw cycles: from 10.1% in the control geopolymer to 2.7% with 2% CaCl₂ and 1.6% with 5% borax. This enhanced durability likely resulted from the formation of zeolite-X, which contributes to the controlled microporosity that mitigates damage from freeze–thaw expansion. Our results highlight the importance of customized mix designs in geopolymers to achieve high performance and long-term durability in cold climates.</p> Graphical Abstract <p></p>