Round Two—Confined Compression: Young's Modulus, Poisson's Ratio, and Ultimate Strength
The Institute for Standards Research interlaboratory study of rock properties has provided precision statements for two additional ASTM rock-property test methods, D 5407 (Young´s modulus and Poisson´s ratio) and D 2664 (ultimate strength), both in confined compression. Three types of intact rock, Barre Granite, Berea Sandstone, and Tennessee Marble, were used in this study. Data were collected for both test methods at confining pressures of 10, 25, and 40 MPa, with four replications per rock type. The rock testing was preceded by pilot testing for Young´s modulus and Poisson´s ratio on aluminum alloy 2024 T351, with three replications. Young´s modulus and Poisson´s ratio were evaluated, for both aluminum and rock, from stress-strain data for the intervals from 25–50% and 40–60% of the maximum differential stress. Seven laboratories produced pilot data, and six of these laboratories produced data on rock for this report. Both the aluminum and rock specimens were prepared at central locations and were furnished ready for testing to the participating laboratories. For both elastic moduli, the overall normalized repeatability limit (“within laboratory”) for rock is about twice that for aluminum; the overall normalized reproducibility limit (“between laboratory”) for rock is about the same as that for aluminum.