Apparatus and test procedure for measuring the cohesive, adhesive, and frictional properties of bulk granular solids

Abstract

A test apparatus for measuring the cohesive, adhesive and frictional properties of bulk solids has a bulk solid sample confined between two essentially parallel plates with a single load applied that produces both shear and normal stress and strain to the bulk solid in a manner that nearly uniformly distributes stress throughout the granular solid test region. The apparatus has a close proximity of the plates compared with the length of the plates in the direction of shear, the design of a load hanger to produce a resultant load near the shear plane, the roughening of any surface in contact with the solid that is not intended to have shear on it and involves one-directional movement of the parallel plates with respect to each other and the control of both the direction and magnitude of the applied load relative to the parallel plates. A test method uses the apparatus to measure the unconfined yield strength angle of internal friction and steady state deformation effective angle of internal friction with a single test. A test method uses replacement of the lower part of the test sample with a plate of material that the bulk solid may be required to slip on and measures the friction angle and adhesion of the bulk solid on the plate of material.