The Equation of State and Strength Properties of Copper Mountain Sandstone

SiO₂ in its various forms are of interest, due to their relative abundance in nature and application in defense, industry, construction, and geophysics. While many studies examining SiO₂ have been conducted, there was an opportunity to examine this material at high strain rate. Therefore, a series of experiments utilizing 0.5 mm to 3.0 mm thick samples of Copper Mountain Sandstone (CMS), a 98.94 wt. % alpha quartz material, with a grain diameter of 0.153±0.059 mm and 9.48±2.01 % porosity, from low to high strain rate have been performed. Low strain rate yield surfaces, taken between 10^-1 and 10^-5 1/s and equations of state for CMS between 3 m/s to 720 m/s, compare favorably with generalized mesoscale fits, as determined from porosity and grain size. The results of elastic and uniaxial strain experiments demonstrate the consequences of high feature size to sample thickness ratios. Finally, the results of Pressure Shear Plate Impact (PSPI), taken at high strain rates between 10⁴ and 10⁵ 1/s, are used to augment existing data at higher porosity.