ABSTRACT In order to meet sustainability criteria and reduce carbon emissions associated with the production of cement and its related composites, it is necessary to completely replace Ordinary Portland Cement (OPC) with a new binding substance. This study focuses on a novel method of manufacturing geopolymer concrete by utilizing a single activator instead of the traditional two activators. An analysis was conducted on the mechanical properties and microstructure of geopolymer concrete made from several source materials, including Fly ash (FA), granulated blast furnace slag (GGBS), and nano silica (NS). The findings indicated that the mechanical characteristics of GPC, generated by combining 80% GGBS and 20% FA, using a single source alkali activation method under ambient curing conditions for 28 days, had superior performance compared to other mixtures. Additionally, there was a decrease in carbon emissions. composites OPC (OPC substance activators materials FA , (FA) GGBS, (GGBS) NS. NS . (NS) GPC 80 20 2 days mixtures Additionally (FA (GGBS (NS 8