Natural and Engineered Clay Barriers, 1st edition. Chapter 5. Stability of clay barriers under chemical perturbations. Olivier Bildstein, Francis Claret (France).
Natural and Engineered Clay Barriers, 1st edition Chapter 5. Stability of clay barriers under chemical perturbations Olivier Bildstein, Francis Claret (France)
Abstract The efficiency of deep geological storage systems relies on the confinement properties of the natural or engineered clay-rich material: low permeability and diffusivity, high retention and swelling capacity. The reactivity of clay barriers (CB) is intimately linked to the nature and properties of their constitutive minerals. The CB react due to changes in the initial physicochemical conditions (pH and redox potential, aqueous species concentrations) and/or the introduction of “foreign” materials (iron, steel, concrete, glass, bitumen, etc.). This chapter describes the impact on CB, for different storage systems, as a result of the dissolution of primary minerals and precipitation of secondary minerals, as well as modifications of mineral properties (especially related to the exchange capacity, the interlayer cation content, and the swelling ability of clay minerals) and transport properties through modifications in porosity, permeability and tortuosity.
Keywords clay mineral dissolution; claystone; bentonite; iron corrosion; CO2 sequestration; reactive transport modeling; laboratory experiments; in situ experiments; archaeological analogs
