effort. Compaction testing is not included in this
TRAMAN but will be discussed at the EA2 level.
6. Field control testing is used to determine
(1) the field moisture content (with an eye to
reducing or increasing it to the optimum, if
feasible) and (2) the point at which the specified
density has been obtained by compaction. Field
control testing is not included in this TRAMAN
but will be discussed at the EA2 level.
DETERMINING MOISTURE
CONTENT
Several methods of determining moisture con-
tent of soil are in existence. The most accurate
is the ovendrying method, in which an electric or
portable gasoline oven is used to dry the samples.
A more expedient method is the calcium carbide
gas pressure method. This method, however, is
less accurate and should always be approved by
your supervisor. A third method uses the
NUCLEAR MOISTURE-DENSITY METER.
Since specialized training and operator certifica-
tion are required, use of the nuclear moisture-
density meter will not be discussed in this
training manual.
Ovendrying Method
As noted above, this is the most accurate
method used to determine moisture content. The
apparatus and procedures used are discussed
below.
APPARATUS.— Laboratory apparatus for
moisture content determination includes the
following items:
l A balance (fig.
15-26) for weighing
material in grams. There are 453.6 g in a pound.
. Several small circular moisture boxes
(called cans) (fig. 15-26) for placing samples in
to weigh and dry.
. An electric oven or a portable gasoline
oven to dry samples.
l Crucible tongs.
In the absence of an electric oven or gasoline
oven, you may dry the materials in a frying pan
held over an ordinary stove or hot plate. The
Figure 15-26.-Apparatus for determining moisture content.
15-18
