This report presents results of the Bambus II project (Backfill and material behaviour in underground salt reporsitories), a joint project between FZK (DE, coordinator), BGR (DE), DBE, (DE), G.3S (FR), GRS (DE), IfG (DE), NRG (NL), UPC (ES) and US DoE/CBFO (US), carried out between August 2000 and April 2003. The project was funded by the European Commission and the national governments and authorities. The project extends the basis for optimising repository design and construction and for predicting long-term performance of barriers in a salt repository for radioactive waste. The research includes in-situ investigations, laboratory experiments, forensic examinations, computational simutations and desk studies. In-situ investigations were conducted in the Asse salt mine subsequent to completion of the large-scale experiment 'TSDE' (Thermal simulation of drift emplacement) in wich six disposal cask mock-ups were heated for over eight years.