The aim of this paper is to study the performance of infused nanoSiO2 gel (NSG) on the developed alkaline activated binary blending of ground blast furnace slag (GBFS) and ultrafine palm oil fuel ash (UPOFA) based mortar (AAGU) using the constant mass of combined activators (10 M NaOHaq+Na2SiO3aq (Ms = SiO2/Na2O=3.3)). The methods include using the 3-day compressive strength results and microstructural characterization (SEM+EDX and FTIR). The finding revealed that the compressive strength of the mortar increased with NSG and the maximum strength achieved was 57.3 MPa signifying 21% strength gain compared to NSG-free sample. The NSG also played the role of microcracks and pore fillings, increased the product homogeneity and reduced its amorphousity due to silicate re-organization but has no effects on Si-Al substitution.