Evaluation of the Performance of the ISRM Suggested Methods for Measuring Density and Porosity when Applied to Low-Porosity Rocks

Abstract Recent studies conducted in the context of geological disposal spent nuclear fuel low-porosity crystalline bedrock have found density and porosity values obtained following ISRM Suggested Method (ISRM 1977) to occasionally be sporadic. To investigate this behaviour, 137 core specimens 5 different rock types (granite, granitic pegmatoid, veined gneiss, mica gneiss sandstone) were submerged water under NTP conditions measured repeatedly until observed saturated mass was constant within accuracy measurement system. These then fully dried subsequently again, time (1 hour at <800 Pa vacuum) again for porosity. Density systematically lower than using immersion saturation. Specimens reached on average 40 – 60 % level saturation with method. This resulted significant differences when compared after Performance method proposed should thus studied more detail possibly re-evaluated.