Grouts and Concretes for the Waste Isolation Pilot Project (WIPP)

Abstract

ABSTRACTThe Structures Laboratory of the U.S. Army Engineer Waterways Experiment Station has conducted research on cement-based composites for the Waste Isolation Pilot Project (WIPP) since 1977, in cooperation with Sandia National Laboratories. Field testing requirements guided initial development of grouts. Concurrent and later laboratory studies explored the chemical stability and probable durability of these mixtures. Beginning in 1985, a series of small-scale seal performance tests at the WIPP prompted development of an expansive salt-saturated concrete. Important lessons learned from this ongoing work include: (1) carefully tailored mixtures can tolerate phase changes involving Ca, Al, and S04, without loss of structural integrity; (2) handling and placement properties are probably more crucial to the mixtures than is exact phase composition; and (3) for the environment of a geologic repository, demonstrated chemical durability will be the best indicator of long-term performance.