PROPERTIES OF GRANULATED BENTONITE MIXTURES FOR RADIOACTIVE WASTE DISPOSAL: A REVIEW
Keywords:Granulated bentonite mixtures (GBM), Radioactive waste disposal, Buffer/backfill material, Dry density,, Thermo-hydro-mechanical (THM) properties
Bentonite has long been considered as a potential sealing material in engineered barrier systems (EBS) for the geological disposal of radioactive waste due to its favorable physical and chemical properties. In some disposal concepts, the research evolution has led to the adaption of granulated bentonite mixtures (GBM) as a candidate buffer/backfill material owing to its high compaction properties, operational advantages, and ability to close gaps between the seal and host rock. A thorough understanding of the behavior of GBM is essential for proper design and construction of an efficient repository. As compared to compacted bentonite blocks, studies on GBM are somewhat limited. Thus, a review of former experimental studies conducted on GBM over the past two decades was performed. The topics included compaction properties, thermo-hydro-mechanical properties, gas transport, and microstructure. This work comprises a summary table listing material properties, sample scale, methodology, test conditions, and graphical representation of results. Based on the review, prospects for further investigations/studies have also been recommended to understand the behavior of GBM.