Unifying granular and suspension rheology

Using an original pressure-imposed shear cell, we study the rheology of very dense suspensions. We show that they dexhibit a visco-plastic behavior similarly to granular media successfully described by a frictional rheology and fully characterized by the evolution of the friction coefficient $\mu$ and the volume fraction $\phi$ with a dimensionless viscous number $I_v$. Dense suspension and granular media are thus unified under a common framework. These results are shown to be compatible with classical empirical models of suspension rheology and provide a clear determination of constitutive laws close to the jamming transition.