Significance of using a superpave gyratory compactor to simulate field compaction of fine grained soil

Abstract EN

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.