Report on laboratory tests of drying and re-wetting of intact rocks

This report is an update on progress made during FY1995 on hydrological property measurements performed in the laboratory. The report contains descriptions of experimental designs and procedures, data, observations, preliminary analyses, and future work. The primary focus of this report is the measurement of moisture retention curves of tuff as a function of temperature for both drying and re-wetting conditions. This work is a continuation of work described in MOL80 (UCRL-ID-119033), Hydrological Property Measurements of Topopah Spring Tuff (Roberts and Lin, 1995). Knowledge of unsaturated transport properties is critical for understanding the movement of water through the unsaturated zone. Evaluation of the performance of a potential nuclear waste repository also depends on these properties. Moisture retention data are important input for models of moisture movement in unsaturated porous media. Also important is the effect of sample history on the moisture retention curves, whether or not a complete saturation cycle at elevated temperature affects the moisture retention curve at subsequent lower temperature cycles. This report addresses initial observations regarding this aspect of the research