ASTM International

Standard Test Method for Water Content and Density of Soil In situ by Time Domain Reflectometry (TDR)
 N D6780/D6780M

Annotation

This test method may be used to determine the water content of soils and the in situ density of soils using a TDR apparatus.

This test method applies to soils that have 30 % or less by weight of their particles retained on the 19.0-mm [ -in.] sieve.

This test method is suitable for use as a means of acceptance for compacted fill or embankments.

This test method may not be suitable for organic and highly plastic soils.

All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.

The method used to specify how data are collected, calculated, or recorded in this standard is not directly related to the accuracy to which the data can be applied in design or other uses, or both. How one applies the results obtained using this standard is beyond its scope.

Two alternative procedures are provided.

Procedure A involves two tests in the field, an in situ test and a test in a mold containing material excavated from the in situ test location. The apparent dielectric constant is determined in both tests.

Procedure B involves only an in situ test by incorporating the first voltage drop and long term voltage (V1 and Vf) in addition to the apparent dielectric constant. While the bulk electrical conductivity can be determined from these measurements, it is not needed for the determination of water content and density.