Determining the Specific Gravity of Soil - Soil Properties: Testing, Measurement, and Evaluation - page 63

(7) If heat has been used, allow the specimen to cool to approxi-
mately room temperature.
(8) Thermal Equilibrium —Put the pycnometer(s) into a covered
insulated container along with the thermometer, a beaker (or
bottle) of deaired water, stopper(s) (if a stoppered pyncnometer is
being used), and either an eyedropper or pipette. Keep these items
in the closed container overmight to achieve thermal equilibrium.
(9) Pycnometer Mass Determination —If the insulated container is
not positioned near a balance, move the insulated container near the
balance or vice versa. Open the container and remove the pycnome-
ter. Only touch the rim of the pycnometer because the heat from
hands can change the thermal equilibrium. Place the pycnometer on
an insulated block (Styrofoam or equivalent).
(9.1) If using a volumetric flask, adjust the water to the calibration
mark as follows: If using a volumetric flask as a pycnometer, adjust
the water to the calibration mark, with the bottom of the meniscus
level with the mark. If water has to be added, use the thermally
equilibrated water from the insulated container. If water has to be
removed, use a small suction tube or paper towel. Check for and re-
move any water beads on the pycnometer stem or on the exterior of
the flask. Measure and record the mass of pycnometer and water to
the nearest 0.01 g.
(9.2) If a stoppered flask is used, adjust the water to prevent en-
trapment of any air bubbles below the stopper during its place-
ment. If water has to be added, use the thermally equilibrated
water from the insulated container. Then, place the stopper in the
bottle. If water has to be removed, before or after inserting the stop-
per, use an eyedropper. Dry the rim using a paper towel. Be sure the
entire exterior of the flask is dry.
(10) Measure and record the mass of pycnometer, soil, and water
to the nearest 0.01 g using the same balance used for pycnometer
calibration.
(11) Pycnometer Temperature Determination —Measure and record
the temperature of the slurry/soil-water mixture to the nearest
0.1°C using the thermometer and method used during calibration.
This is the test temperature, T t .
(12) Mass of Dry Soil —Determine the mass of a tare or pan to the
nearest 0.01 g. Transfer the soil slurry to the tare or pan. It is im-
perative that all of the soil be transferred. Water can be added. Dry
the specimen to a constant mass in an oven maintained at 110 ±
5°C and cool it in a desiccator. If the tare can be sealed so that the
soil cannot absorb moisture during cooling, a desiccator is not re-
quired. Measure the dry mass of soil solids plus tare to the nearest
0.01 g using the designated balance. Calculate and record the mass
of dry soil solids to the nearest 0.01 g.