Evaluating water and gas permeability of fiber-modified landfill clay-base liner

Abstract

Due to the progressive use of landfills and the challenges about their effect on their surrounding environment, the hydraulic and gas permeability of the landfill liners have always been a great concern for geotechnicians. Clay-based materials are usually used as the main material for landfill liners. Various additives are implemented to control the hydraulic and gas permeability of these clay liners under different climate conditions. The attempt of this research was to investigate the effect of using four types of geo-fibers, including ordinary and web polyester, polypropylene, and polyvinyl alcohol fibers, on reducing the hydraulic and gas permeability under wet and dry conditions. In this regard, two sets of water and gas permeability tests were performed for clay-fiber mixtures with 0.2, 0.4, and 0.6 weight percentages of fiber additives. The results show an initial decrease and then a growth in the permeability coefficients by increasing the fiber dosages, resulting in an optimum percentage for each fiber type. Among the fibers used in this study, polyvinyl alcohol fiber with 0.2 weight percent performed best by reducing the permeability coefficient by approximately 65% and 75% for hydraulic and gas permeability coefficients under wet and dry conditions.