Mechanical and Durability Properties of GGBS- Based Geopolymer Stabilized Earth

The use of geopolymer binders has attracted increasing interest in the construction industry, especially due to the promising results it has provided as a substitution for cement in the production of concrete. Recently, the use of geopolymers for soil stabilization started emerging, allowing the enhancement of the mechanical properties of clayey or sandy soils for geotechnical applications. However, very few research studies exist addressing the use of geopolymers to stabilize compressed earth bricks for construction purposes. This paper aims to investigate the use of a geopolymer binder, manufactured using ground granulated blast furnace slag as a precursor and a solution of sodium hydroxide as an activator, for the stabilization of a clayey silty soil for use as earthen materials in construction applications. The mechanical properties of the stabilized earth are assessed in terms of unconfined compressive strength on compacted cylindrical samples (7.2x3.6 cm) cured under wrapped and unwrapped conditions for 7 and 28 days. In addition, the durability against water is assessed using immersion, drip, and contact tests on compacted unwrapped bricks (4x4x16 cm) cured for 7 and 28 days. The findings suggest a noticeable improvement in the stabilized earth's strength and durability, though exposure to air has a negative influence on the strength caused possibly by carbonation.