Effect of Guar Gum Biopolymer on Shear Strength and Liquefaction Response of Coal Ash

Improvement in geotechnical properties of coal ash is required for its better utilization in large infrastructure projects. Lime and cement are the most commonly used material to stabilize coal ash for railway and highway embankment construction. However, these admixtures have negative impact on the environment. This experimental study explores the viability of commercially available guar gum biopolymer, as an eco-friendly and cost-effective additive for coal ash stabilization. Guar gum biopolymer is chosen because of its pH stability, cold water dissolving characteristics and formation of hydrogen bonds along with being inexpensive. Different concentrations (1–5%) of guar gum biopolymer were used to treat the coal ash collected from Gandhinagar thermal power plant. A series of shear strength tests were conducted on coal ash before and after its treatment with guar gum biopolymer at different concentrations and curing time/conditions. Scanning electron microscopy (SEM) images of guar gum-treated coal ash specimens were also obtained to evaluate the morphological characteristics of stabilized coal ash. Stress–strain and pore pressure response of guar gum treated coal ash were studied by conducting Consolidated Undrained (CU) triaxial tests. Effect of gaur gum on liquefaction response of coal ash was also evaluated by conducting cyclic triaxial tests with pore pressure evolution.