Shrinkage Limit Set

The shrinkage Limit Test is one of the Atterberg Limits methods of defining characteristics of cohesive soils. The shrinkage limit of cohesive soils is defined as the water content at which further loss of moisture will not cause a decrease in volume. The shrinkage limit apparatus includes components necessary to run the test.

ASTM recommends this new method as an alternative to the original D427 test method, which was withdrawn due to its use of mercury for volume determinations. This procedure uses similar apparatus for the preparation of a soil pat but requires coating the pat in melted wax prior to immersion in water for mass determination.

Soil samples for shrinkage limit tests are usually taken from a larger sample prepared for liquid and plastic limit tests. A soil specimen with moisture content above the liquid limit is placed in the shrinkage dish and struck off with the straightedge. The sample is then oven-dried. After coating in wax, the volume of the soil pat is computed by weighing in water and noting the difference from its weight in the air.

The SA-56 Shrinkage Limit Set includes a special Monel shrinkage dish, a 4x0.75in spatula used as a straightedge, fine thread to suspend the soil pat, a glass calibration plate, and a tube of petroleum jelly used when calibrating the dish. The SA-19 Wax Melting Pot is purchased separately. SAA-15 microcrystalline wax is available in 5lb (2.3kg) quantities. The Melting Pot has a 2qt (1.9L) capacity and a thermostat to control temperatures between 50°–250°F (10°–120°C). The electrical requirements are 600 Watts at 115V/60Hz. Other available accessories are the HMA-10 Spatula for mixing and handling and the SC-74 1.3qt Pan for use as a water bath for immersion weighing.

Features:

• Determines Atterberg shrinkage limits of cohesive soils
• Requires immersion of soil pat in melted wax
• Aligns with ASTM D4943

Included Items:

• Shrinkage Limit Set
  • 15mL Monel Shrinkage Dish
  • Spatula with 4x0.75in Blade
  • Glass Calibration Plate
  • Fine Thread to suspend the soil pat
  • Tube of Petroleum Jelly for coating the shrinkage dish

Accessories:

• Liquid Limit Machines, motor-driven or manually operated
• Mortar and Pestles for particle size reduction
• SA-19 Wax Melting Pot for Shrinkage Limit Tests for melting microcrystalline wax needed in shrinkage limit determinations
• SC-74 1.3qt Stainless Steel Pan used as a water bath for immersion weighing of soil pats
• HMA-10 Spatula with 4x0.75in Blade for mixing of soils in Atterberg Limit tests
• SAA-16 Fine Thread is used for suspending weighing of the specimen
• SAA-15 Microcrystalline Wax is melted for coating soil pats before water immersion in soil Shrinkage Limit Tests
• SA-55A Monel Shrinkage Dish used to form soil pats for shrinkage limit determinations
• SAA-17 Shrinkage Limit Glass Plate for calibration of the dish
• SAA-18 Petroleum Jelly is used to coat the Shrinkage Dish

Related blogs:

• Atterberg Limits: A Quick Reference Guide