ABSTRACT
In this study, expansive soil (ES) was treated with a non-traditional binder, alkali-activated slag (AAS). Compaction characteristics, uniaxial compressive strength (UCS), free swell index (FSI), and mineralogy were assessed at different slag contents (0–20%) and alkali concentrations (0–8 M). The incorporation of chemical additives enhanced the maximum dry unit weight of ES-AAS mixes with reduced optimum moisture contents. After stabilizing with AAS (20% slag and 8 M NaOH) and allowing for 30 days of curing, the UCS of specimens improved to 5.43 MPa, and FSI was significantly reduced to 18%. The environmental impacts (embodied energy and embodied CO2 emission) of AAS were assessed per unit strength gain. Based on the mechanical strength and environmental impacts, the geopolymer binder with 20% slag and 6 M NaOH is considered as an effective material for sustainable chemical stabilization.
