Developing Low pH concrete for tunnel plugging structures in nuclear waste containment

This presentation describes research done within an EU FP7 Euratom project, to develop and validate the performance of low-pH concretes used in high level radioactive nuclear waste containment structures. The unique type of concrete is used for deposition tunnel end plugs that are approximately 400 metres underground within repository conditions. The research has focused on producing highly workability mixtures with local materials, where rheology and heat of hydration have been optimized simultaneously with long-term durability and watertightness targets. The results are being implemented with full-scale construction of the 6 metre long tunnel plug in the 15 m2 tunnel cross section.