ASTM D7115-20 PDF Download

ASTM D7115-20 is a standard test method that describes the measurement of the Superpave Gyratory Compactor (SGC) internal angle of gyration using simulated loading conditions. The purpose of this test method is to assess the volumetric properties and predict the performance of asphalt mixture specimens in the laboratory.

The test method involves placing loose asphalt mixture inside a metal mold, which is then placed into the SGC. A constant consolidation pressure is applied to the sample while the mold gyrates at a constant internal angle of gyration and rate. Consistency in the density of the asphalt specimens is crucial for accurate test results, and this is achieved when the SGC maintains a constant pressure and a known constant internal angle of gyration during the compaction process.

There are various manufacturers and models of SGC, each employing a unique method of setting and maintaining the internal angle of gyration. The existing calibration systems cannot be universally used on all SGC models, leading to inconsistencies in the produced asphalt specimens. This method aims to provide instruments and processes that can independently measure the internal angle of gyration of any SGC model under simulated loading conditions.

The test method specifies the application of a tilting moment of 466.5 N-m to the SGC during this measurement. The quality of the results obtained from this test method is dependent on the competence of the personnel performing the procedure and the calibration and maintenance of the equipment used. User compliance with Specification D3666, or similar guidelines, is essential for reliable results.