Determining the Liquid Limit of Soil - Soil Properties: Testing, Measurement, and Evaluation - page 82

numbers of blows to close the groove. One of the trials shall be for
a closure requiring 25 to 35 blows, one for closure between 20 and
30 blows, and one trial for a closure requiring 15 to 25 blows.

(8) Determine the water content of the soil specimen from each
trial in accordance with ASTM Method D 2216 (Chapter 4).

(8.1) Determination of initial masses (container plus moist soil)
should be performed immediately after completion of the test. If the
test is to be interrupted for more than about 15 minutes, determine
the mass of the water content specimens already obtained at the
time of the interruption.

If using One-Point Liquid Limit—Method B, prepare the specimen
in accordance with procedures described previously (page 75), except
that at mixing, adjust the water content to a consistency requiring 20 to
30 drops of the liquid limit cup to close the groove. The step-by-step pro-
cedure is as follows (ASTM D 4318-95a [5]):

(1) Proceed as described in (1) through (5) for Method A except that
the number of blows required to close the groove shall be 20 to 30.
If less than 20 or more than 30 blows are required, adjust the water
content of the soil and repeat the procedure.

(2) Immediately after removing a water content specimen as
described in (5) for Method A, re-form the soil in the cup, adding a
small amount of soil to make up for that lost in the grooving and
water content sampling orientations. Repeat (2) through (5) for
Method A, and, if the second closing of the groove requires the same
number of drops or no more than two drops difference, secure
another water content specimen. Otherwise, remix the entire spec-
imen and repeat.

Note 2 —Excessive drying or inadequate mixing will cause the
number of blows to vary.

(3) Determine water contents of specimens in accordance with (8)
for Method A.

The data to be collected for each trial are the number of drops required
to close the groove and the water content of the soil at that number of
drops. Recall from Chapter 4 that, in order to determine water content,
the mass of the container, mass of container plus wet soil, and mass of
container plus oven-dried soil must be obtained. Because more than one
water content must be determined, each container identification num-
ber should be recorded also. To summarize, the data collected for each
trial in this test should include the following:

DATA

Number of drops, N
Container identification number