3. Experimental demonstration

The frictional transition model offers a coherent theoretical framework to explain the rheo-thickening of concentrated suspensions. However, it is difficult to test experimentally on real suspensions. Indeed, conventional rheology tools provide access to suspension viscosity, but not to inter-particle friction, which is the key parameter in the mechanism. In this chapter, we present two experimental approaches that have provided access to this property. These studies provide direct validation of the frictional transition model for rheo-thickening suspensions.