Determining the Density and Unit Weight of Soil in Place by the Rubber-Balloon Method - Soil Properties: Testing, Measurement, and Evaluation - page 220

A field test was conducted according to the previous procedure. The
following field data were obtained:

NUMERICAL
EXAMPLE

Initial reading of volume indicator on rubber-balloon apparatus

51 mL
Final reading of volume indicator on rubber-balloon apparatus

1,317 mL
Mass of pan 815 g

Mass of pan plus all moist soil from test hole 3,172 g

Data for moisture content determination:
Mass of container 45.2 g

Mass of container plus moist weight of moisture sample

293.8 g
Mass of container plus dry weight of moisture sample

258.8 g

With these data known, calculations proceed as follows:

M wet
V h

(15-2)

wet

M wet 3,172 815 2,357 g

V h = 1,317 - 51 = 1,266 mL

2,357
1,266

wet 1.862 g cm 3

(62.427)(1.862) 116.2 lb ft 3

wet

293.8 258.8

w

45.2

100 16.4%

258.8

wet

d

100

100 (15-3)

w

116.2
16.4

d

100

100 99.8 lb ft 3

All data—both given and calculated—are presented on the form
shown on page 222. (At the end of the chapter, two blank copies of this
form are included for the reader's use.) Careful study of this form should
facilitate understanding of the calculations required to determine
in-place dry density/unit weight by the rubber-balloon method.