Indexed on: 05 May '16Published on: 05 May '16Published in: Environmental Geology
Biogeotechnology is a recently established branch of geotechnical engineering, associated with the practical uses of microbiological techniques to improve the engineering properties of geomaterials. This study explores the utility of xanthan gum, an eco-friendly biopolymer obtained from microbial sources, for stabilization of tropical organic peat, using a series of macroscale and microscale test approaches. At the macroscale, the shear strength characteristics of both untreated and stabilized peat were evaluated using unconfined compression strength (UCS) and standard direct shear tests. Microscopic techniques, including field emission scanning electron microscopy (FESEM), Brunauer, Emmett, and Teller (N2-BET) surface area analysis, and particle size analysis, were also utilized to examine changes in the microstructural characteristics of stabilized peat that are caused by the chemical reaction that occurs between the xanthan gum and peat particles. UCS test results showed that the xanthan gum stabilization significantly improved the shear strength of the peat in its natural condition, with the 28-day strength of the stabilized peat being six times higher than the strength of the untreated peat. Microstructural analysis showed that the morphological characteristics of the peat are changed due to the chemical reaction that occurs during the curing process, as indicated by the FESEM results. Over time, formation of cementitious products was clearly observed, which welded peat particles and filled the pores in the soil structure, yielding a denser soil fabric with less pore volume and stronger attractive forces. From the testing that was performed, xanthan gum stabilization is recommended for peat as an eco-friendly and sustainable alternative to traditional soil stabilization additives such as cement or lime.