Significance of using a Superpave Gyratory Compactor to Simulate Field Compaction of Fine Grained Soil

Abstract

Field compaction equipment used for fine grained soil usually applies a kneading action or vibration that produces shear forces which also reshape soil particles arrangement. A state that might not be completely simulated by laboratory Proctor tests. This study aims at investigating the significance of using the newer modified Texas superpave gyratory compactor (SGC) to simulate field compaction of fine grained soil due to its
ability to apply loads in different angles
generating shear forces on the compacted soil
specimens. Two types of soil (A-4) and (A-7-6)
were compacted using standard Proctor,
modified Proctor and (SGC). The results were
compared to dry field densities of the same soil
in order to evaluate the most representative test.
It was found that maximum dry densities of soil
type (A-4) obtained using (SGC) under (200
kPa) and (600 kPa) were lower by (2.07%) and
higher by (1.35%) than the maximum dry
densities obtained using standard and modified
Proctor tests respectively. It was also found that
maximum dry densities of soil type (A-7-6)
obtained using (SGC) under (300 kPa) and (600
kPa) were lower by (1.02%) and higher by
(1.23%) than the maximum dry densities
obtained using standard and modified Proctor
tests respectively. The aforementioned
confinement pressure values were applied in
order to achieve dry densities similar to that
obtained by Proctor tests. When comparing
laboratory results to dry filed densities, it was
found that (SGC) test results were slightly closer
to them than Proctor tests results. Nevertheless,
the difference between (SGC) and Proctor tests
results seems to be insignificant for these types
of soil compared to the higher effort needed to
perform (SGC) tests.