Automated Soil Particle Specific Gravity Analysis Using Bulk Flow and Helium Pycnometry
SourceDetermining the apparent and bulk specific gravity of soil and aggregate has widespread applications in civil engineering. Current ASTM standards for attaining these values are available, but several drawbacks exists such as the time involved in testing and inconsistency between laboratory technicians. Automated specific gravity measurements for both soil and aggregate can be economically determined using a helium pycnometer, while automated bulk specific gravity can be found using an envelope density analyzer. An evaluation of these instruments resulted in the following observations. Very good agreement was found for apparent specific gravity measurements between the helium pycnometer and measurements made following ASTM standards. For bulk specific gravity measurements, good agreement was found between measurements made with an envelope density analyzer and ASTM standards for coarse aggregate particles larger than 2.38 mm. However, for particles smaller than 2.38 mm the agreement decreases with decreasing particle size.