Nuclear Densometer Test

A Nuclear Densometer Test is a field test used in geotechnical engineering. The test is performed on a compacted base to establish its percentage of compaction. Before field tests are performed, the technician performs a calibration on the gauge which records the 'standard count' of the machine. Standard counts are the amount of radiation released by the two nuclear sources inside the machine, with no loss or leakage. The allows the machine to compare the amount of radiation released to the amount of radiation received. With the use of a 3/4" diameter rod a hole is created in the compacted base by hammering the rod into the base to produce a hole that the densometer's probe can be inserted into. The densometer is placed on top of the hole, and then the probe is inserted into the hole by unlocking the handle at the top of the probe. One source produces radiation that interacts with the atoms in the soil, and is then compared to the standard count, to calculate the density. The other source interacts with hydrogen atoms to calculate the percentage of water in the soil.

References

• ASTM D2922-05 Standard Test Methods for Density of Soil and Soil-Aggregate in Place by Nuclear Methods (Shallow Depth), doi:10.1520/D2922-05  (Standard withdrawn 2007)
• ASTM D6938 - 08a Standard Test Method for In-Place Density and Water Content of Soil and Soil-Aggregate by Nuclear Methods (Shallow Depth), doi:10.1520/D6938-08A 

See also

Nuclear densometer