Stabilization of Expansive Soil Using Agar Biopolymer

Expansive soil causes severe damage to geotechnical structures due to its excessive swelling-shrinkage behavior. In addition to that, they have low shear strength at higher degree of saturation. The conventional admixture materials that are used to improve the engineering properties of expansive soils have detrimental effect on the environment and ecosystem. Hence, in the current research, a new environment-friendly agar biopolymeric admixture material has been used to stabilize the Nagpur expansive soil. A series of swell pressure tests and unconfined compression tests were performed on the treated specimens of Nagpur expansive soil by adding agar biopolymer in different concentrations (0.5%, 1%, 2%, and 3%) at different curing periods (4 h, 8 h, 1, 3, and 7 days). X-ray diffraction (XRD) and scanning electron microscope (SEM) tests were also performed to understand the microstructural modification of agar treated Nagpur soil. The swell pressure was found to decrease by 85%, and shear strength was increased by 100% with the addition of agar biopolymer up to 3% at 7 days of curing period.