This test method presents a direct, qualitative measurement of the dispersibility and consequent colloidal erodibility of clay soils by causing water to flow through a small hole punched in a specimen. This test method is complemented by Test Method D4221. This test method and the criteria for evaluating test data are based upon results of several hundred tests on samples collected from embankments, channels, and other areas where clay soils have eroded or resisted erosion in nature. This test method is not applicable to soils with less than 12% fraction finer than 5mm and with a plasticity index less than or equal to 4.
2.87 in diameter x 1.5 in height
Clay, colloidal erodibility, dispersibility, dispersion, dispersive clays, erosion, pinhole