March 27, 2013

Clays can expand under pressure

It was always believed that water is “squeezed” out of the clay structure under pressure but physicists at Umeå University together with German colleagues show that this appear to be not always true if excess of liquid water is available around. The new findings are published in Angewandte Chemie.

Clay minerals are among most common on the Earth and some of the most important materials in the construction and building industry. Layered structure of clays can easily be expanded if water is added. This phenomenon is called swelling and it is explained by the insertion of water into the inter-layer space of clays structures. Swelling affects all possible applications of these materials and is important for example in sealing of natural oil reservoirs as the hydrated clays are not permeable for oil.