研究期間：10101~10112;Engineered barrier and high integrity container for the final disposal of low-level radioactive wastes serve to isolate the wastes from human biosphere for a very long design life. Concrete has been widely accepted as engineering barrier material due to its longevity, which provides good structural integrity for prolonged service life. Recently, reactive powder concrete (RPC) has been proposed as barrier materials for the construction of engineered barrier and high integrity container. However, the durability properties of RPC remain unanswered and there is very limited information available in the literature. On the other hand, the adverse environmental conditions at the disposal site could attack concrete barrier material and results in degradation of the material. The proposed study is the second part of a 2-year study, focused on the durability properties and degradation behavior of reactive powder concrete as an engineered barrier subjected to adverse environmental and geochemical conditions at the final disposal site. Potential RPC mixes has been evaluated for various factors such as replacement of cement by pozolanic materials, heat curing, and addition of steel fiber. Laboratory tests were conducted on RPC with various compositions to investigate the physical and durability properties of RPC. These include mechanical strength, pulse velocity, dynamic modulus, and sulfate attack, chloride ion ingress, carbonization, and leaching of reactive powder concrete, respectively. The degradation process of concrete material under simple adverse environment has been studied by many researches so far, this study aims to develop a model for the safety evaluation of reactive powder concrete barrier material for applications to final disposal of low-level radioactive wastes. In addition, the evaluation model developed will be used in the review processes of barrier design for the low-level radioactive wastes disposal site.
