The study focuses on the analysis of the effects of swell-shrinkage potentials on the microstructure of bentonite-sand mixtures, to gain insights on changes with varying hydration state, performed by field emission scanning electron microscopy (FESEM) and Nuclear Magnetic Resonance (NMR). Also, permeability experiments on similar artificial soils have been undertaken in oedometric conditions, by means of a constant head permeameter, to validate the suitability of the soil for the construction of liner in landfills, with the purpose of aquifer protection. FESEM observations indicate microstructural changes with dehydration that involve reorientation of the tactoids and closure of micropores. As for permeability test on the mixtures, the results showed that the addition of very small percentages of clay induces variations of more than 3 orders of magnitude. Following the results, a final discussion will highlight the suitability of Revil and Cathles (1999) model, using NMR and permeability test.
Aquifer protection: a combined study of microstructure and transport properties in clay-sand mixtures
MACINI, PAOLO;MESINI, EZIO;
2006
Abstract
The study focuses on the analysis of the effects of swell-shrinkage potentials on the microstructure of bentonite-sand mixtures, to gain insights on changes with varying hydration state, performed by field emission scanning electron microscopy (FESEM) and Nuclear Magnetic Resonance (NMR). Also, permeability experiments on similar artificial soils have been undertaken in oedometric conditions, by means of a constant head permeameter, to validate the suitability of the soil for the construction of liner in landfills, with the purpose of aquifer protection. FESEM observations indicate microstructural changes with dehydration that involve reorientation of the tactoids and closure of micropores. As for permeability test on the mixtures, the results showed that the addition of very small percentages of clay induces variations of more than 3 orders of magnitude. Following the results, a final discussion will highlight the suitability of Revil and Cathles (1999) model, using NMR and permeability test.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
