Low plasticity clays are commonly present in compacted soils such road embankments: in this context, prolonged spillage from storage tanks (e.g., refueling stations) containing conventional and alternative fuels (biofuels) may trigger changes in the hydrogeological and geotechnical properties of the soil structure, influencing its overall stability. Moreover, these changes may facilitate migration of pollutants into the environment. This article examines the effect of bioethanol-based fluids on the coefficient of permeability of kaolinitic clay, experimentally investigated by means of an oedometer set up for a falling-head permebilty test. Test results indicate that the addition of high fractions of ethanol in gasoline substantially increases the permeability up to two orders of magnitude with respect to water: changes are produced by the formation of clusters (flocculation) and the development of cracks and pores identifiable at both a macro and micro scale using a high-resolution scanning electron microscope. Although the intrinsic permeability increases with increasing fractions of ethanol in water, no appreciable changes were observed when pure ethanol or a mixture of ethanol/water up to 50 % were used as pore fluids. This work is to be considered as a starting point for further studies, to be extended to other clayey soils with low plasticity used in road engineering: results may be also useful in designing remediation techniques in areas potentially affected by ethanol spillage from refineries or pipelines.
Permeability of remoulded low-plasticity clay contaminated by bioethanol-based fluids
DI MATTEO, Lucio
Writing – Original Draft Preparation
;VINTI, Giuseppe
2016
Abstract
Low plasticity clays are commonly present in compacted soils such road embankments: in this context, prolonged spillage from storage tanks (e.g., refueling stations) containing conventional and alternative fuels (biofuels) may trigger changes in the hydrogeological and geotechnical properties of the soil structure, influencing its overall stability. Moreover, these changes may facilitate migration of pollutants into the environment. This article examines the effect of bioethanol-based fluids on the coefficient of permeability of kaolinitic clay, experimentally investigated by means of an oedometer set up for a falling-head permebilty test. Test results indicate that the addition of high fractions of ethanol in gasoline substantially increases the permeability up to two orders of magnitude with respect to water: changes are produced by the formation of clusters (flocculation) and the development of cracks and pores identifiable at both a macro and micro scale using a high-resolution scanning electron microscope. Although the intrinsic permeability increases with increasing fractions of ethanol in water, no appreciable changes were observed when pure ethanol or a mixture of ethanol/water up to 50 % were used as pore fluids. This work is to be considered as a starting point for further studies, to be extended to other clayey soils with low plasticity used in road engineering: results may be also useful in designing remediation techniques in areas potentially affected by ethanol spillage from refineries or pipelines.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.