This work was performed in the framework of workpackage WP6 of the TIMODAZ project (Thermal Impact on the Damaged Zone around a Radioactive Waste Disposal in Clay Host Rocks). All of the experimental works performed in TIMODAZ contribute to a better understanding of the processes occurring within the clay around a disposal system for heat-emitting waste in clay during the thermal transient phase. As this transient spans over several centuries, the development and testing of sound, phenomenology-based models becomes an essential step towards meeting the Safety Case requirement of adequate understanding of the long-term evolution. The results of the TIMODAZ project have been situated in the context of the long term performance of a repository. The knowledge gained within the TIMODAZ project allows assessing the significance of the Thermal Damaged Zone (TDZ) in the safety case for disposal in clay host rocks and provides direct feedback to repository design teams.