Dispersive soils are considered as unstable, as these are easily erodible by wind and water. Structures, such as embankments, channels and foundations are vulnerable to severe erosion when this type of soil is used. Dispersive soil exhibits no strength resistance against environmental factors like air and water forces and fails rapidly during soaking as per crumb test and double hydrometer test. In the present study two biopolymers; xanthan gum in 1.0%, 2.0%, 3.0% and guar gum in of 0.5%, 1.0% and 2.0% are used for stabilization of the dispersive soil. The effects of biopolymer stabilizing agents are studied through crumb test and cylinder dispersion test for erosion control and other geotechnical properties like compaction and unconfined compression test (UCS). The optimum moisture content (OMC) of the bio treated samples increased and maximum dry density (MDD) decreased with increase in percentage of biopolymer. The bio treated samples cured in sun light for a period of 3 days shows higher unconfined compressive strength (UCS) value compared to as compacted sample and cured under ambient condition. Microstructural studies like scanning electron microscope (SEM), x-ray diffraction (XRD) and energy dispersive x-ray (EDX) tests were also conducted. The SEM analysis showed that the particles of biopolymer modified dispersive soil are bonded together by gum layer. This may be the cause of decreases in the dispersivity of the soil. Guar gum was found to be more effective than xanthan gum.
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