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

Study of portland-cement based grouts made with salt water and stored in salt water and of a similar grout made with fresh water and stored in fresh water at temperatures between about 23 exp 0 C to 54 exp 0 C over a 38-month period showed: (a) Salt water grouts form tetracalcium aluminate dichloride-10-hydrate (C sub 3 A(CaCl sub 2 )H sub 10 ) at the expense of ettringite during hydration. (b) The amount of calcium hydroxide in both types of grout decreased with time, presumably due to its combination with fly ash in the mixture to form calcium silicate hydrate. (c) While the microstructure of the grouts tended to be open due to the fairly high water to solids ratios as mixed, it did become denser with time. (d) Phase composition and microstructure were considered normal for these mixtures and were generally unaffected by the conditions of storage. (e) Carbonation of the grouts made with salt water and stored in salt water was pronounced at specimen surfaces but not in their interiors. This is an effect of storage environment on the specimens. (f) The cracks that were observed in many specimens were considered normal for these materials under the storage and testing conditions. Since the storage and treatment of these specimens is not a simulation of conditions in a borehole, it is not believed that similar cracking would take place in this grout in such use. (g) Available data indicate the properties of the specimens are satisfactory for their intended use. (ERA citation 08:010350)