Humboldt H-4262 Plastic Limit Device - Manual (Page 2)

Introduction
Easily repeatable mechanical technique produces consistent test results and
saves time. Includes integral top plate/handle, one pad of 50 sheets of special
adhesive backed paper to cover contact surfaces (paper will not introduce
fibers into soil samples), and instructions. Rigid acrylic 8 x 4-1/2 x 1-1/4"
(203 x 114 x 32mm).
Meets ASTM D4318; AASHTO T90, TX DOT 105-E.
Preparation of the Plastic limit Device for Testing
Place one sheet of adhesive-backed Plastic Limit paper on the bottom plate
and one on the top plate of the Plastic Limit Device.
Procedure
1. Reduce the water content of the soil to approximately the Plastic Limit
(i .e. where the soil is non-sticky).
2. Select four to five 1.5 to 2g portions of soil.
3. Roll each portion of soil into an ellipsoidal mass.
4. Place each ellipsoidal mass about 1 to 1-1/2" apart on the bottom plate.
See Figure 1.
6. When the top plate comes into contact with the 1/8" rail, check to see
if the soil is at the Plastic Limit. For an example of the Plastic Limit, see
Figure 2. (Be sure to checkall Plastic Limit definitions with the procedure.)
Positions of Soil Portions on the Bottom Plate.
7. If the soil is not at the Plastic Limit, collect the threads and knead them
together. Repeat Steps 2-6.
8. When the soil is atthe Plastic Limit, push the threads to one side of the
bottom plate and dump them into a tared container. Weigh immediately.