Cementitious matrices are being used worldwide as a containment medium for radioactive and non-radioactive waste in order to retard the mobility of contaminants. The present thrust of research is to further the understanding of contaminant binding in the cementitious matrix in order to predict the long-term behaviour and the potential impact of the waste on the environment.
The workshop “Mechanisms and Modelling of Waste/Cement Interactions”, held in Meiringen, Switzerland, between May 8 and 12, 2005, focused on the chemical understanding and thermodynamic modelling of the processes responsible for the retention of radioactive and non-radioactive species in cementitious systems. The objectives of the workshop were to bring together scientists from different disciplines, i.e. cement chemistry, radioactive and non-radioactive hazardous waste disposal, to stimulate discussions on current developments and to identify future needs in this field of research. The topics treated in the workshop were chosen to maximize the benefit to the different fields of research. Cement chemists reported on developments in the understanding of cement mineralogy and thermodynamic modelling of cement systems. The hazardous and radioactive waste management communities presented their ideas on the mechanisms of contaminant binding to cement minerals as well as field, laboratory and modelling results from practical applications. In this paper important areas of research on waste/cement interactions presented in the workshop will be outlined and briefly discussed. The following overview reflects a subjective perception of the workshop and does not lay claim to deal comprehensively with all the papers that were presented in the workshop.