ASTM Hydrometer Soils: 151H, Range 0.995 to 1.038 (SG)
The ASTM Soils Hydrometer 151H,Range 0.995 to 1.038 (SG) has a one piece stem and bulb that does not vary in particle diameter. One piece ballast is attached to the bottom of the body. Guaranteed calibration eliminates errors due to variable dilution.
Total length: 11" (280mm).
Meets Test Methods:
AASHTO T88
ASTM C 775
ASTM D 422
What is Hydrometer Analysis?
Hydrometer analysis is a laboratory test used to determine the particle size distribution gradation of fine grained soils, such as clay and silt. This test is based on the principle of sedimentation, where the rate at which soil particles settle out of suspension in a liquid is measured. By measuring the rate of sedimentation, the test provides a complete particle size distribution for soils finer than the No. 200 (75µm) sieve. Hydrometer is a key tool in geotechnical labs as it helps evaluate the engineering behavior of soils, to get accurate and reliable data for various applications.
Test Method
The method for analysis involves mixing a soil sample with water and a dispersing agent, such as sodium hexametaphosphate, to prevent clay particles from flocculating. This mixture is then poured into a sedimentation cylinder and a hydrometer is used to measure the density of the suspension at intervals. The hydrometer readings are used to calculate the particle size distribution of the soil. This is based on Stokes’ law which relates the settling velocity of a particle to its size and density, to get a detailed analysis of the soil.
ASTM D7928 and Hydrometer 151H for Soils
ASTM D7928 is a standard test for analysis of soils. This test covers various parameters such as sample preparation, hydrometer type and hydrometer offset. The Hydrometer 151H is designed for this test, to measure the density of the suspension with high accuracy. The combination of ASTM D7928 and Hydrometer 151H is a reliable and precise method to analyze the particle distribution of fine grained soils, that’s why it is the preferred choice in geotechnical testing.
Soil Particle Size Analysis of for Specific Gravity
Particle size analysis is a key aspect of soil characterization, it affects the engineering behavior of soils. Hydrometer method is one of the several techniques used to determine the size distribution of soils along with sieve analysis and other sedimentation methods. Hydrometer method is particularly useful for fine grained soils, can measure particle size down to 0.001 mm. The results of particle size analysis is used to classify soils, assess their engineering properties and design geotechnical structures, to ensure the stability and safety of the project.
Applications and Limitations for Specific Gravity
Hydrometer analysis has many applications in geotechnical engineering such as soil classification, soil stabilization and foundation design. However the standard test method has some limitations. It is not suitable for soils with fibrous peat, less than 5% fine grained material or extraneous matter. Also the hydrometer test may not give consistent results for fine grained soils that flocculate during sedimentation or do not disperse readily. So it is important to evaluate the suitability of analysis for the specific soil being tested and consider these limitations when interpreting the results.
Related Blogs for Soils Hydrometers for Specific Gravity
ASTM D 422: Sieve Analysis and Particle Size
The ASTM Soils Hydrometer 151H is a precision instrument to measure the density of soil within a range of 0.995 to 1.038 specific gravity (SG). This hydrometer has a seamless, symmetrical stem and bulb with the same diameter throughout, to give consistent results every time. The one piece ballast at the bottom of the body helps to stabilize the hydrometer during testing, to reduce the errors caused by dilution fluctuations.
11 inches (280mm) long, this ASTM hydrometer is suitable for various soil testing applications. It meets the standards of hydrometer test methods AASHTO T88, ASTM C 775 and ASTM D 422 to be compatible with existing testing procedures and guidelines.
For more information on soil analysis methods and particle distribution check out our related blogs Understanding ASTM D 422: Sieve Analysis and Particle Size.
Buy the ASTM Soils Hydrometer 151H for precise and accurate soil density measurement in your lab or field testing. Guaranteed calibration for consistent and reliable results for geotechnical, construction and environmental professionals.