TxDOT Research Library - TxDOT Research Project

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Compaction of Soils and Base Materials using Superpave Gyratory Compactors

What Was the Need?

TxDOT utilizes impact hammer compaction in test procedures Tex-113-E (Laboratory Compaction Characteristics and Moisture-Density Relationship of Base Materials) and Tex-114-E (Laboratory Compaction Characteristics and Moisture Density Relationship of Subgrade, Embankment Soils, and Backfill Material) to develop moisture-density relationships and fabricate specimens for strength testing. Although recent modifications to the test procedure enabled improvements in the precision of specimen molded moisture content and density, the precision of compressive strength remains a problem. This poor precision of compressive strength results in conflicting test results regarding whether a material meets specification requirements. The conflicting test results cause project delays and increase the dollar value of a material source.

What's the Solution?

The research team analyzed whether the use of the Superpave Gyratory Compactor (SGC) to compact test specimens would improve the precision of compressive strength results for base and soil materials. Researchers found more consistency in the SGC test results as compared to results of the Impact Hammer tests.

Project Number

0-6883

Status

Completed

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