N. Passas et al., ROCK POROSITY DETERMINATIONS USING PARTICLE DENSITIES MEASURED IN DIFFERENT FLUIDS, ASTM geotechnical testing journal, 19(3), 1996, pp. 310-315
Rock porosity, when calculated from measurements of bulk and particle
rock density, is found to depend on the method used to determine these
densities. The particle density, which is found experimentally, varie
s with the immersion fluid used; hence, the porosity determined depend
s on it, too. Organic fluids are recommended in standards for describi
ng particle density for special applications; however water is general
ly considered to be virtually inert when in contact with inorganic par
ticles, particularly if the particles are composed of silicates. Thus,
the results of measurements made using water as the immersion liquid
are not considered to have been measurably affected by water. This pap
er shows that water does, in fact, alter measurably the value of silic
ate particle density obtained compared with measurements made using an
organic fluid, viz., n-heptane. Explanations for this finding are und
er further consideration.