Roller Compacted Concrete (RCC) is a special concrete mixture with low cement content, frequently used for concrete gravity dams. To reduce the thermal cracking, RCC dams are usually cut by transverse contraction joints into monoliths. The number and position of the joints should be determined based on the thermal-stress computations. The numerical model should consist of: (a) definition of the thermal and mechanical RCC properties, (b) computation of the temporal evolution of the thermal field, and (c) thermal-stress computation. Up to date models do not simulate accurately the long-term RCC behaviour (, ), due to simplifications. This research presents one of the first attempts to faithfully predict the RCC dams contraction joint distance, and to estimate it’s influence on the thermal stress field. The developed model takes into account: the actual shape of the dam, different types of concrete, actual initial and boundary conditions, thermal and mechanical properties of RCC and construction technology, . Calibration and verification of the thermal model are based on the in-situ temperature measurements of the Platanovryssi dam, .