Experimental Study on Improving the Bearing Capacity of Sabkha Soil Using Geopolymer

Sabkha soil is a saline soil that covers large areas in arid and semi-arid regions. It has a low bearing capacity and experiences significant settlement when moistened, making it a challenging soil type for foundation engineering. Hence, there is a demand to develop innovative and eco-friendly methods to enhance the characteristics of sabkha soil. Geopolymer is a novel material, that can be applied to treat sabkha soil by blending it using waste materials, such as fly ash and mine tailings, and compacting it. Geopolymer treatment can augment the load-bearing capacity of sabkha soil by modifying its physical and chemical properties. This study conducts a thorough investigation of the behavior of circular foundations subjected to axial loads on untreated and geopolymer-treated sabkha soil. The effects of various factors, such as geopolymer precursor type and content and thickness of treated soil layer to foundation diameter ratio (Hm/Df, where Hm is the thickness of the treated soil layer and Df is the foundation diameter), were examined using physical models. The results revealed that the geopolymer-treated sabkha soil displayed superior load-displacement behavior to untreated sabkha soil, indicating significant improvements in ultimate bearing capacity for different values of Hm/Df. The ultimate bearing capacity increased from 11.56 kPa for untreated sabkha soil to 49.1 kPa, 275.6 kPa, and 404.50 kPa for treated soil with geopolymer at layer thicknesses of 10 mm, 30 mm, and 50 mm, respectively, representing improvements of 325%, 2284%, and 3399%, respectively. The failure mechanisms of the geopolymer-treated soil were also evaluated and discussed. This study offers valuable insights for researchers and geotechnical engineers aiming to design effective soil stabilization strategies, optimize the application of geopolymer treatments, and precisely predict the behavior of treated soil under various conditions.