Structure of 'concrete disease' solved

When bridges, dam walls and other structures made of concrete are streaked with dark cracks after a few decades, the culprit is AAR: the alkali-aggregate reaction. AAR damages concrete structures all over the world and makes complex renovations or reconstructions necessary. Researchers from the Paul Scherrer Institute and Empa have now solved the structure of the material produced in the course of AAR at atomic Level.