Examination of ERDA-10 Grout Specimens at Different Ages: Fid-Bau Portal

Examination of ERDA-10 Grout Specimens at Different Ages

A. D. Buck / J. P. Burkes / J. E. Rhoderick

A borehole in Eddy Co., N. Mex. designated ERDA-10 was filled with portland cement base grout in October 1977. The hole was filled with grout of four compositions, three of which were similar and made with salt water as mixing water; the upper portion of the hole was filled with a grout made using fresh water as mixing water. Tests and examinations were made after 23 +- 8 days, 1 year, and 3 years. This report presents results of petrographic examination. The grouts made with salt water formed tetracalcium aluminate dichloride-10-hydrate (C sub 3 A(CaCl sub 2 )H sub 10 ) at the expense of ettringite during continued hydration. The C sub 3 A(CaCl sub 2 )H sub 10 was already present when the grouts were examined at the early ages (23 +- 8 days). The amount of calcium hydroxide in both the saltwater and the freshwater grouts decreased with age. The microstructures of the grouts showed progressive densification with age. This microstructure was always fairly open due to the high water-to-solids ratios; these were 0.64 to 0.74 by mass for the three saltwater grouts and 0.49 for the freshwater grouts. Phase composition and microstructure were considered normal for these materials. It was found that carbonation had taken place during 3 years of immersion in salt water or fresh water. Carbonation was largely confined to surfaces of specimens. Some cracking of specimens took place. (ERA citation 06:034373)