The Nuclear Density Meter or NDM is an important field assessment tool used by civil or geotechnical technicians/engineers to evaluate different types of density, moisture content, air voids etc both directly and indirectly.
The Nuclear Density Meter emits radiation through the soil and detects how much is reflected back to the machine. This helps us calculate degree of saturation, degree of compaction, and air void percentage.
A good test regime including NDM testing can provide the client with real time assurance that their project works are achieving target compaction requirements or immediate identification that the need for further compaction/rework of a failed area is required.
Failing to test and identify sub optimal compaction creates the potential for future issues (i.e. settlement, subsidence, rutting etc) requiring rework and unforeseen costs.
Typical Scenarios where NDM testing is recommended and/or required include,
- Public and in some cases private road pavement testing
- Earthfill outside the scope of NZS3604:2011.
- Earthworks and Land Development (i.e. subdivisions) that requires site monitoring in compliance with NZS4431:2022 (Engineered fill construction for lightweight structures) and NZS4404:2010 (Land Development and Subdivision Infrastructure) including Geotechnical Completion Reporting with a Schedule 2a Statement of Professional Opinion on Suitability of Land for Building Construction.
- To supplement other compaction field assessment tools i.e. Scala penetrometer, Clegg Hammer, Shear Vane etc.
