Sabkha Soil Improvement by the Use of Chemical Additions

Iraq is located within the arid and semi-arid region which include large areas of Sabkha soil particularly in the southern regions. Stabilization of properties of Sabkha soils in terms of strength, durability, and cost is required from engineering point of view. In this study the synthesis of a new chelating Schiff's base of Furfural with Metal ions (SFM) was used for stabilization Sabkha soil. The present study investigates the possibility of using the SFM to enhance Sabkha soil properties in the southern regions in Iraq. In this study, experimental approach was employed to investigate the properties of treated and untreated Sabkha soil. In laboratory tests, Sabkha soil samples have been mixed with 2%, 4%, and 6% of SFM for mineralogical tests whereas other samples tested in order to identify the physical and mechanical properties of the treated samples. The stabilization mechanisms of treated sabkha soil have been investigated using modern approaches, such as Scanning Electron Microscope (SEM), Energy Dispersive X-ray analysis (EDX) and X-Ray Diffraction analysis (XRD). Sabkha soil, when mixed with 4% and 6% SFM, has been observed to transform into a solid material potentially suitable for use in the sub-base layer of rigid pavements. The study revealed that the compressive strength of the treated Sabkha samples was increased from 51 kPa to 402 kPa. Compared to untreated Sabkha soil the improvement ratio of treated sabkha soil increased from 119% to 443%. However, results of triaxial test showed that the cohesion increased by133.6 kPa without affecting the angle of internal friction. While the results of direct shear test showed that the angle of internal friction increased from 35 to 41 degrees. The soaked CBR values showed an increase with the addition of SFM at concentrations of 0%, 2%, 4%, and 6%, rising from 11% to 21%, 32%, and 58%, respectively. Added SFM values were increases this showed Sabkha soil is suitable material for to be a pavement foundation course. Based on the wetting and drying testing results, stabilized Sabkha soil with 6% SFM lost roughly 8.4% of its weight over time. In contrast, soil stabilized with 4% SFM and 2% SFM lost approximately 10.5%, and 15.4% of its weight respectively.