Accession Number:

ADA254019

Title:

Deteriorated Concrete from Liner of WIPP Waste Shaft

Descriptive Note:

Final rept.

Corporate Author:

ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS STRUCTURES LAB

Report Date:

1992-06-01

Pagination or Media Count:

92.0

Abstract:

Samples of a fly-ash concrete were studied after 6 years in service underground. The cores studied represented a construction joint and other areas of exposure to local groundwater. Observed evidence of deterioration, relative to companion cores of nondeteriorated concrete, included softening of the paste fraction, discoloration, an extensive network of microfractures cutting through both paste and aggregates, and crystalline deposits along fractures. In laboratory studies, we sought to determine the causes of these features, by studies of phase composition, chemical composition, and microstructure. X-ray diffraction analyses revealed magnesium chloride hydroxide hydrate, gypsum, and brucite in subsamples that should have been cement paste and along fractures. We attribute the condition of the concrete to chemical alteration by interaction with magnesium-bearing groundwater, which occurs naturally in the service environment.

Subject Categories:

  • Physical Chemistry
  • Ceramics, Refractories and Glass
  • Radiation Pollution and Control

Distribution Statement:

APPROVED FOR PUBLIC RELEASE