A rheological model is used to describe the long-term behaviour of masonry. Special attention is paid to the evolution of damage and the description of the damage parameters, based on the continuum damage theory. The parameters of the model are derived from a test program, including three types of mortar compositions and three kinds of tests: monotonic compressive, short-term and long-term creep tests. Furthermore, a range of stress evolutions is simulated to evaluate the model and the results are compared with experimental test datastatus: publishe