![]() The calibration procedure only needs to be performed once unless the mass of the pycnometer deviates from the calibrated value by 0.06g or more.Įach step for calibration is described in the test method, but here are the main points: The process is time-consuming but can be performed for up to six pycnometers at a time. Test Sieve: this test method requires samples with particle sizes passing the ASTM E11 No.4 (4.75mm) mesh sieve.Ĭalibration of the pycnometers is the first phase for the ASTM/AASHTO method.Drying Oven: moisture determinations and final drying of the test solution are performed in a standard laboratory oven capable of maintaining a uniform temperature of 110 ±5☌.Balance: a laboratory balance meeting ASTM D4753 requirements, with a capacity of at least 1,000g and readability to 0.01g, is sufficient for this test. ![]() A dispersion cup with no baffles is available for use with the mixer, contact our customer service department to order. We suggest the soil dispersion mixer, typically used to prepare soil specimens for hydrometer analysis. Blender: mixing the soil with water in a blender or “other suitable device” disperse the sample into a slurry.clear tubing added to a wash bottle will have the same effect. A purpose-built pycnometer filling apparatus can be fashioned following the description in the test method, or a length of 1/4in I.D. Pycnometer Filling Tube: when adding deaired water to the pycnometer during calibration or testing, it is essential to avoid turbulence or the introduction of air into the fluid.A plastic or Styrofoam container with room for three to six pycnometers plus a container of deaired water is usually sufficient. Insulated Container: the pycnometers must be stored in an insulated container for temperature equilibration during calibration and testing.Desiccator: a desiccator equipped with a desiccator plate and desiccant is required to cool the sample to room temperature after drying in an oven.A digital residual pressure manometer is optional to monitor vacuum levels. A vacuum pump or water aspirator that produces a vacuum of at least 100mm of mercury (approximately 26in) absolute pressure is needed for deairing. Using a heating plate or other apparatus can be used to heat the pycnometer. Entrapped Air Removal: deairing of the water and soil slurry may be accomplished by boiling, application of a partial vacuum, or both.Full-immersion thermometers are not permitted. Thermometric Device: the thermometer must have readability to 0.1☌ with an accuracy of ☐.5☌ and be standardized to a NIST traceable device.Group image of 250ml, 500ml, and (unnamed) stoppered flasks. A minimum capacity of 250ml is specified, and a 500ml capacity flask is sometimes required. The stopper physically controls the water volume of stoppered flasks. Volumetric flasks are typically used but require careful adjustment of water to the calibration mark. Pycnometers: the test method permits the use of a volumetric flask or iodine flasks with a stopper.Table Resource: Specific Gravity Lab Equipment and Apparatus This blog post will focus on the equipment and procedures used to perform the ASTM/AASHTO method. Reliable test results depend on strict adherence to the practices and techniques outlined. Practitioners should be aware of the significant differences between the test methods. While the equipment required is not sophisticated, the procedures are extensive and meticulous, and performing the test by the book can be a challenge. As with any laboratory test, these methods require attention to detail but are easy to perform correctly and do not require much in the way of specialized techniques or equipment.ĪSTM D854, and the identical AASHTO T 100, Standard Test Methods for Specific Gravity of Soil Solids by Water Pycnometer, focus on producing measurements with a high degree of precision. Army Corps of Engineers laboratory soils testing manual, and some state DOTs are often considered adequate for basic applications. Standard test methods described in the U.S. Traditional methods for determining specific gravity are straightforward. Applications include the foundation design for structures, calculations for the stability of soil embankments, and estimations of settlement for engineered soil fills. This dimensionless unit is the ratio of material density to the density of water and is used to calculate soil density, void ratio, saturation, and other soil properties. ![]() Specific gravity is a fundamental property of soils and other construction materials. Importance of Specific Gravity of Soil Solids
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