ASTM D7263 Outlines Procedures for Soil Density Testing
June 10, 2009 // Published as a news service by IHS
ASTM International Subcommittee D18.03 on Texture, Plasticity and Density Characteristics of Soils developed ASTM D7263 - Test Methods for Laboratory Determination of Density (Unit Weight) of Soil Specimens.
Wet and dry density of soils are important values for geotechnical engineers in determining over-burden stresses, void ratios, maximum compaction and percent compaction of soils, according to ASTM. Density value can also aid in the evaluation of soil strength and sensitivity.
While reporting on soil density has been part of routine laboratory testing for years, there were no standards that outlined procedures for density testing until now, experts said.
"The applications of ASTM D7263 span many soil tests, including much more sophisticated testing," said Bill Quinn, chair of Subcommittee D18.03.
Quinn listed the following areas in which soil density testing plays a role including:
- Soil density is routinely determined and reported when thin-walled tube samples, which are used to obtain an intact soil specimen with limited disturbance, are taken.
- Strength testing, such as unconfined compression, direct shear and triaxial tests, almost always report soil density.
- Soil void ratio, which is important in strength testing, soil porosity and ground water studies, requires the density determination in its calculations.
- Consolidation tests report soil density both before and after the test as a function of the measured soil settlement.
- Hydraulic conductivity tests (flow of water through a soil matrix) are influenced by void ratio and soil density.
- Density of remolded or reconstituted specimens can serve to evaluate field conditions of back-filling operations, embankments and landfill clay liners.
"This particular standard will require an interlaboratory testing program to enable a precision and bias statement to be developed," said Quinn. "An adequate test program will be established, testing protocols will be outlined, laboratories need to be contacted for participation and the data obtained will need to be summarized."
Subcommittee D18.03, which developed the standard, is part of ASTM Committee D18 on Soil and Rock.
Source: ASTM International.