Shear Strength Improvement of Lateritic Soil Stabilized by Biopolymer Based Stabilizer

Abstract

Chemical stabilization is extensively employed to enhance the physical and mechanical properties of problematic soils. For instance, there are various types of chemical additives in liquid and powder forms. One of the potential bio-polymer stabilizer is Xanthan Gum which has widely been employed due to the environmental issues and the effect of land desertification. This research is devoted to studying the effect of Xanthan Gum on the strength improvement of lateritic soil. The lateritic soil sample is provided from the hilly area at Universiti Teknologi Malaysia. The physical and engineering tests on untreated and treated samples were conducted according to BS1377:1990. The Maximum Dry Density (MDD) and Optimum Moisture Content (OMC) were determined using the compaction test results. Then, MDD and OMC are used for the Unconfined Compressive Strength (UCS), and direct shear tests sample preparation. The lateritic soil was mixed with different percentages of Xanthan Gum including 0.5%, 1.0% and 1.5% of the soil mass and cure for 3, 7 and 14 days. It was found that the UCS and direct shear strength parameters of cohesion and internal friction angle improve with the curing duration. The Field Emission Scanning Electron Microscopy (FESEM) shows the generation of new cementitious products as a result of the reaction between Xanthan Gum and lateritic soil. New generated products fill the porous areas within the soil particles, leading to a continuous soil structure. Therefore, stronger and denser soils are provided as the pore space is reduced.