title: Experimental compaction of anisotropic granular media.
abstract: We report on experiments to measure the temporal and spatial evolution of packing arrangements of anisotropic and weakly confined granular material, using high-resolution gamma-ray adsorption. In these experiments, the particle configurations start from an initially disordered, low-packing-fraction state and under vertical solicitations evolve to a dense state. We find that the packing fraction evolution is slowed by the grain anisotropy but, as for spherically shaped grains, can be well fitted by a stretched exponential. For a given type of grains, the characteristic times of relaxation and of convection are found to be of the same order of magnitude. On the contrary, compaction mechanisms in the media strongly depend on the grain anisotropy.
authors.affiliation: Groupe Matière Condensée et Matériaux, UMR CNRS 6626, Université de Rennes 1, Campus de Beaulieu, F-35042 Rennes cedex, France.
authors.forename: P
authors.initials: P
authors.lastname: Ribière
authors.forename: P
authors.initials: P
authors.lastname: Richard
authors.forename: D
authors.initials: D
authors.lastname: Bideau
authors.forename: R
authors.initials: R
authors.lastname: Delannay