Abstract
The normal stress and its distribution for several kinds of solid powders with various amonnts of water in the vicinity of the shearing plain have been measured both by a constant volume shear tester and a constant vertical load tester. The yield loci have been calculated from the measured actual normal stress data. The tensile test of wet powders has been also made.
The distribution of normal stresses in the vicinity of the shearing plane is the narromest for dry powders and becomes wider with change from the funicular and capillary to the mixed zone. The internal friction factor decreases with increase in the water contest of the powders in the pendular zone, while it is almost constant for funicular, capillary and the mixed zones, The internal friction factor calculated from the actal normal stress measured by the constant vertical load tester is agrees well with that obtained by the constant volume tester. Cohesion in the pendular zone increases remarkably with increasing water contest in the powders, gradually increases in the funicular zone, and is almost constant in the funicular-and-capillary mixed zone. It is also found that the cohesion coincides well with the tensile strength. Flowability of wet powders is less enhanced as the cohesion or tensile strength becomes larger.
