Quicklime (CaO) or reactive magnesia (MgO) could be utilized as a novel activator of ground granulated blast-furnace slag (GGBS) to produce the geopolymer. The geopolymer was used to solidify soft soil, showing a significant environmental benefit over conventional Portland cement. In this study, the geopolymers were made according to the weight ratio of CaO/MgO to GGBS of 1:9 and 2:8 and were further used to solidify silty clay. The engineering and microstructural characteristics of the solidified silty clay were investigated through various physicochemical, mechanical, and microscopic tests. ...