This article presents the different steps of a research process initiated in the field of dam engineering, through collaboration between EDF and ENS Cachan, following Jacky Mazars' pioneering work on the application of the damage concept to concrete structure modelling. Considering the importance of concrete swelling phenomena for the long-term behaviour of concrete dams, special efforts have been devoted to the development of a rheologic model in this field. This paper explains how the research performed contributed to the elaboration and the justification of the main equations included. An application to the Temple-sur-Lot dam is presented.