Characterization and properties of geopolymer nanocomposites with different contents of nano-CaCO3

•The mechanical properties of geopolymers were improved after the addition of 1–2 wt% CaCO3.•Nanocomposites was found to be denser as compared to the control sample.•Mechanical properties decrease when the contents of CaCO3 particles increases higher than 2.0 wt%. This study investigated the impact of calcium carbonate nanoparticles (nano-CaCO3) on the mechanical properties of geopolymer composites. To that end, varying contents of nano-CaCO3 were mixed with geopolymer paste. On the other hand, mechanical properties were investigated based on three aspects: flexural and compressive strengths, impact strength, and hardness. According to the findings of this study, nano-CaCO3 could be efficacious in improving all the mechanical properties of geopolymer. Microstructures of the geopolymer mixed with nano-CaCO3 were also evaluated by scanning electron microscopy (SEM). According to the findings, nanoparticles could potentially enhance the mechanical performance of the geopolymer nanocomposites. In addition, the SEM micrographs of fractured surfaces were found to exhibit a greater packed structure with a reduced number of pores of the geopolymer that contained nano-CaCO3; this, in turn, enhanced the strength of geopolymer nanocomposite specimens.