Pondcrete

Pondcrete is a mixture of cement and sludge. Its role is to immobilize hazardous waste and in some cases lower-level radioactive waste in the form of solid material. Its name originates from the evaporation ponds where the sludge is being concentrated. It is a form of mixed waste.

Pondcrete should be solid, however if improperly manufactured, it will not solidify, remaining in pudding-like consistence unsuitable for storage.

Pondcrete was used in 1980's by United States Department of Energy in an attempt to handle the radioactive waste from contaminated ponds in Rocky Flats Plant for burial in Nevada desert, however the resulting material tended to not cure properly due to too low cement content, crumbled, and leaked.

See also saltcrete.