A borehole designated ERDA-10 was filled with portland cement based grout in October 1977. The borehole is located in Eddy Co., N. Mex. 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. During the filling operation, test specimens were cast using these grouts. The deepest plug (plug 1) was cored 48 hours after placement. During the filling operation, test specimens were cast using all four grout compositions. The core from plug 1 and the test specimens were sent to the Structures Laboratory of the U.S. Army Engineer Waterways Experiment Station for physical tests and petrographic examination. They were stored in the laboratory at temperatures ranging from about 23 C to 54 C. Tests and examinations were made at three ages: (a) 23 + or - 8 days, (b) approximately 1 year, and (c) approximately 3 years. This report presents the results of the petrographic examination which included use of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The grouts made with salt water formed tetracalcium aluminate dichloride-10-hydrate (C3A(CaCl2)H10) at the expense of ettringite during continued hydration. The C3A(CaCl2)H10 was already present when the grouts were examined at the early ages (23 + or - 8 days).

Forty one years ago, the International Society for Rock Mechanics (ISRM) held its 1st International Congress in Lisbon, Portugal. In July 2007, the 11th ISRM Congress returned to Lisbon, where the Portuguese Geotechnical Society (SPG), the Portuguese National Group of the ISRM, hosted the meeting. The Second Half Century of Rock Mechanics comprises

Portland cement grout identified as BCT-1-FF (Bell Canyon Test 1-FF) was used in borehole plugging experiments in the Bell Canyon Tests in Hole AEC-7 at the Waste Isolation Pilot Plant site in New Mexico during September 1979 and February 1980. This grout was made with fresh water. A study of this grout was begun in August 1979 in the laboratory to evaluate the possible effects of temperature, pressure, and storage in fresh water or simulated groundwater (brine) on its phase composition and compressive strength at early ages. Phase composition was determined by X-ray diffraction. Temperatures ranged up to about 150 F and included elevation at a few hours age after mixing; pressure was as high as 1500 psi; specimens were stored in simulated groundwater (brine) or in fresh water. Data from 1 to 90 days showed: Higher temperature accelerated early strength gain. These differences essentially vanished by 90 days age. Hydration products as identified by X-ray diffraction were normal; this indicated that a temperature range of 78 to 153 F was not significant. Pressure did not affect composition. Storage in simulated groundwater (brine) or fresh water had no detectable effect. Since the BCT-1-FF grout mixture contained added sulfate, it formed more ettringite as judged by X-ray diffraction than comparable portland cement mixtures without added sulfate. (Author).