Evaluating the permeability of an organically modified bentonite to natural seawater

The hydraulic performance of a modified bentonite (MSB) in the presence of natural seawater is evaluated in view of waterproofing applications in coastal areas. Permeability tests were performed with and without prehydration in freshwater. The hydraulic conductivity of MSB hydrated with seawater was low (4÷510-9 cm/s); therefore, MSB can represent a suitable component of hydraulic barriers (e.g. GCLs) in the presence of saltwater. Contrarily to untreated bentonite, prehydration with freshwater prior to exposure to saltwater resulted in higher permeability than direct exposure to saltwater, suggesting that modified bentonites may not necessarily behave like untreated bentonites.