A similar method, which does not include pore volume, is to suspend a known mass of particles in molten wax of known density, allow any bubbles to escape, allow the wax to solidify, and then measure the volume and mass of the wax/particulate brick.
An alternative approach that doesn't involve calculating pore volume entails suspending a set amount of particles in melted wax with a known density, permitting air bubbles to dissipate, letting the wax harden, and subsequently determining the volume and mass of the wax/particle block.