Residual design strength of cement-based materials for nuclear waste storage systems

摘要

Calcium leaching of concrete may be critical for the mechanical integrity of hazardous waste storage systems, in which cement-based materials are employed as construction material or grouting material. Results from a recent triaxial strength test campaign on calcium depleted cementitious materials highlight that these materials exhibit decohesion and frictional softening and become increasingly pressure sensitive. But the overall emerging picture is one of a material with a residual, finite accountable strength, which is well above either the particulate or the matrix strength. This allows us to propose a 'safe' lower bound for calcium depleted cement-based composites, which may serve for the durability performance design of concrete structures subjected to calcium leaching-one critical design scenario of e.g. nuclear waste storage systems.