Thermal expansion of the Paintbrush tuff recovered from borehole USW SD-12 at pressures 30 MPa: Data report
- New England Research, Inc., White River Junction, VT (United States)
- Sandia National Labs., Albuquerque, NM (United States). YMP Performance Assessment Applications Dept.
Experimental results are presented for 24 thermal expansion experiments performed on 5 welded specimens of the Paintbrush tuff recovered from borehole USW SD-12 at Yucca Mountain, Nevada. The thermal expansion experiments were performed at constant confining pressures between 1 and 30 MPa. On three specimens, the highest confining pressure measurements were performed first to inhibit thermally induced damage which might occur at lower confining pressures. At each confining pressure two complete thermal cycles were performed. The specimens were heated (to a nominal temperature of 250 C) and cooled at the nominal rate of 0.319 C per minute. The change in specimen length as a function of temperature was measured with two linear variable displacement transducers mounted on endcaps secured to the specimen. The strain increases with increasing temperature and the strain vs temperature curves are concave upward. On cooling, there is hysteresis at the higher temperatures at all confining pressures. The first heating/cooling cycle is anomalous; hysteresis is pronounced, and a permanent shortening of the specimen is observed at the termination of the cycle. The magnitude of the effect was similar for all five specimens regardless of whether the first cycle was carried out at the highest or lowest confining pressure. For subsequent cycles at all confining pressures, no permanent strain develops, and the strain versus temperature curves re very similar. The mean coefficients of thermal expansion ({alpha}) range from 7.9 to 10.8{sup {minus}6} C{sup {minus}1} at temperatures below 100 C, to 14.2 to 20.6 x 10{sup {minus}6} C{sup {minus}1} at temperatures approaching 250 C. The effect of confining pressure on thermal expansion is small. For temperatures above 175 C, the mean coefficients of thermal expansion decreases by 10--12% as the pressure increases from 1 to 30 MPa.
- Research Organization:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE Office of Civilian Radioactive Waste Management, Washington, DC (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 537269
- Report Number(s):
- SAND-95-1904; ON: DE98000430; TRN: 98:000084
- Resource Relation:
- Other Information: PBD: Sep 1997
- Country of Publication:
- United States
- Language:
- English
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