Plastic Limit Testing Tools
Plastic Limit Set
Perform plastic limit tests in accordance with specifications.
Plastic Limit Plate
Glass plate with ground finish on one side and seamed edges.
Plastic Limit Roller
Easily repeatable mechanical technique produces consistent test results and saves time.
Pad of 50 sheets of special adhesive backed paper for Plastic Limit.
Plastic Limit Testing Tools, continued
If the soil is at a moisture content where its behavior is plastic, this thread will retain its shape down to a very narrow diameter. The sample can then be remolded and the test repeated. As the moisture content falls due to evaporation, the thread will begin to break apart at larger diameters. The plastic limit is defined as the moisture content where the thread breaks apart at a diameter of 3.2 mm (about 1/8 inch). A soil is considered non-plastic if a thread cannot be rolled out down to 3.2 mm at any moisture possible.