Environmental Engineering Reference
In-Depth Information
For earthfill in dams, the maximum dry density should be obtained using the standard
compaction method (also known as standard Proctor) using the standard applied in the
country, e.g.
- AS1289 E1.1 - Australia;
- ASTM D698-78 - USA;
- BS1377 4.1 Test 12 - United Kingdom.
The in-situ density should be determined using the sand replacement, rubber balloon or
core cutter method
- AS1289 E3.1, E3.2 and E3.3;
- ASTM D1556-32, D2167-66 and D2937-71;
- BS1377 4.1 Tests 5, 15.
For cohesionless soil (sand, silt, sand/gravel) the degree of compaction is determined by
density index, (or relative density), where
e
e
max
density index
100%
(14.2)
e
e
max
min
where
e
void ratio in place
e max
void ratio in loosest state
e min
void ratio in most compact state
(
)
dmax
d
dmin
also density index
100%
(14.3)
(
d min )
ddm
ax
where
d
dry density in place
dmax
dry density in most compact state
dmin
dry density in loosest state
The maximum and minimum dry densities are determined in the laboratory using the
standard applying to the country, e.g.:
-
AS1289 E5.1;
-
ASTM D2049-69;
-
BS1377 4.3 Test 14.
These methods all require the water content to be determined using an oven. As this
usually takes about 24 hours at 110°C it may be unacceptably long for the construction
condition.
For this reason it is common to specify that routine quality control will be carried out
using the Hilf method which is described in detail in USBR (1985) and is a standard test
(AS1289 E7.1). The method allows approximate determination of the density ratio within
1 hour of the density in place test, and accurate determination the next day when the
 
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