Micro computed tomography images of capillary actions in natural sand

The present work investigates the effect of both surface roughness and particle morphology on the retention behaviour of granular materials. To study this, X-ray micro-computed tomography tests were performed on two types of spherical glass beads (i.e. smooth and rough) and two different sands (i.e. natural and roughened). Each sample was subjected to either drainage or soaking paths consisting in a multiphase ‘static’ flow of potassium iodine (KI) brine (wetting phase) and dry air (non-wetting phase). Tomograms were taken at different saturation states ranging from fully brine saturated to air dry conditions