Combined effect of silica nanoparticles and carbonation process for the elaboration of mortars with recycled fine aggregates

Natural aggregates (NA) are essential materials in mortar manufacturing; however, these raw materials are becoming increasingly scarce, leading to the necessity of finding alternative sources. In this study, mortars were produced using fine recycled aggregates (FRA), which were subsequently treated with SiO 2 nanoparticles (Si-NPs; 0,5%, 1,0% and 2% w/w) and a combination of Si-NPs and CO 2 carbonation process. The physical (water absorption, bulk density, porosity, capillarity, and thermal conductivity) and mechanical (compressive and flexural strength) properties of the different mortars were evaluated. The results showed that the combined use of Si-NPs and CO 2 improved the mortar properties by decreasing absorption and porosity, increasing density, thermal conductivity, and mechanical strength. The optimal dosage was determined to be 1% Si-NPs combined with CO 2 , suggesting a synergistic effect. This study demonstrated that FRAs can be effectively reused in mortar production, contributing to waste recovery and global sustainability. • Mortars with Si-NPs and accelerated carbonation were produced. • Physical and mechanical properties of treated mortars were evaluated. • Si-NPs and carbonation contribute to pore sealing and improving microstructure. • Optimal dosage for a synergistic effect of 1% Si-NPs combined with CO 2 .