Fly ash and eggshell powder based geopolymer on silty soil: Unconsolidated undrained triaxial test.

Silt can behave like sand when most silt particles are in the more extensive range of the silt particle-size band. Silt frequently exhibits more clay-like behaviors, and silt and clay are frequently combined, which causes severe geotechnical challenges in the building involving silt soil. Silts can pose serious difficulties in the construction stage and retain moisture; their dilatancy makes improving them more challenging. The geopolymer approach, which substitutes environmentally friendly waste fly ash (FA) and eggshell powder (ESP) for cement and lime, can stabilize and improve the soil. Sodium silicate (Na₂SiO₃) and sodium hydroxide (NaOH) are used as alkaline activators (Na₂SiO₃: NaOH) with a ratio of 1:1 and molarity of five molars and ten molars for NaOH concentration. For this investigation, triaxial unconsolidated undrained (UU) testing was conducted. This study investigates the effects of FA and ESP content, alkaline activator molarity, and curing period on stress-strain behavior and soil shear strength. The replacement of 5% FA with ESP contributed to an increase in early-period strength. The internal friction angle tended to be slightly greater in soil stabilized with a 15% FA+5% ESP precursor-based geopolymer. However, the cohesiveness of the 20% FA-based geopolymer dramatically increased. The increase in molarity and curing time caused the increase in strength. [ABSTRACT FROM AUTHOR]