Engineering Properties of Soils Based on Laboratory Testing
Prof. Krishna Reddy, UIC
20
EXPERIMENT 3
DENSITY (UNIT WEIGHT) DETERMINATIOM
Purpose:
This lab is performed to determine the in-place density of undisturbed soil
obtained by pushing or drilling a thin-walled cylinder. The bulk density is the ratio
of mass of moist soil to the volume of the soil sample, and the dry density is the
ratio of the mass of the dry soil to the volume the soil sample.
Standard Reference:
ASTM D 2937-00 – Standard Test for Density of Soil in Place by the Drive-
Cylinder Method
Significance:
This test is used to determine the in-place density of soils. This test can
also be used to determine density of compacted soils used in the construction of
structural fills, highway embankments, or earth dams. This method is not
recommended for organic or friable soils.
Equipment:
Straightedge, Balance, Moisture can, Drying oven, Vernier caliper
Engineering Properties of Soils Based on Laboratory Testing
Prof. Krishna Reddy, UIC
21
Test Procedure:
(1) Extrude the soil sample from the cylinder using the extruder.
(2) Cut a representative soil specimen from the extruded sample.
(3) Determine and record the length (L), diameter (D) and mass (Mt) of
the soil specimen.
(4) Determine and record the moisture content of the soil (w).
(See Experiment 1)
Engineering Properties of Soils Based on Laboratory Testing
Prof. Krishna Reddy, UIC
22
(Note: If the soil is sandy or loose, weigh the cylinder and soil sample
together. Measure dimensions of the soil sample within the cylinder. Extrude and
weigh the soil sample and determine moisture content)
Data Analysis:
(1)
Determine the moisture content as in Experiment 1
(2)
Determine the volume of the soil sample
3
m
4
L
2
πD
V
c
=
(3)
Calculate bulk density (ρt) of soil
3
cm
g
V
tM
tρ =
or unit weight
g
t
t ρ
γ =
(4)
Calculate dry density (ρd) of soil
3
t
d
cm
g
w
1
ρ
ρ
+
=