Concrete and cement-based materials must operate in increasingly aggressive aqueous environments, whichmay be either natural or industrial. These materials may suffer degradation in which ion addition and/or ion exchange reactions occur, leading to a breakdown of the matrix microstructure and consequent weakening. Sometimes this degradation can be extremely rapid and serious such as in acidic environments, while in other cases degradation occurs over long periods. Consequences of material failure are usually severe - adversely affecting the health and well-being of human communities and...