Dynamic CBR Test with Light Weight Deflectometer (LWD) Overview

Using extensions to the Light Weight Deflectometer, dynamic CBR (California Bearing Ratio) is measured in-situ and also laboratory CBR in a cylinder can be simulated at the construction site. The equipment provides immediate repeatable results so that on-site decisions can be made straight away. It can be used in confined spaces and difficult to access locations, with no support equipment required. Two CBR test options are available:

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Portable Laboratory CBR Extension

In-situ CBR Extension

Portable Laboratory CBR Extension


California Bearing Ratio (CBR) is a simple penetration test developed to measuring the load-bearing capacity of soils for road subgrade and base courses used for building roads, airport runways or railway track beds. The dynamic CBR test, in particular the in-situ field test, is a material test on undisturbed samples, with which one can judge what level of compaction can be achieved on the tested soil.

The Dynamic CBR Extensions together with the ZFG 3000 Light Weight Deflectometer can be used instead of the static CBR test and is used primarily because of the ability of get immediate results on site. To find out more, Contact Us.

Advantages of the CBR field extension include:

  • Adherence to TP BF – StB Part B 7.1, removing the need for a load frame and the static load device (compression test). In its place, a loading device according to TP BF – StB Part B 8.3 is used.
  • All readings and analysis can be done in the field and the results are immediately available at the construction site
  • The measurement takes only three minutes per test point
  • No necessity of a loaded truck (required counterbalance of the static plate bearing test)
  • Measurements are also possible in narrow conditions including ditches and foundation trenches, back fill, core holes or other areas that are difficult to reach
  • Only a little space is needed and the test equipment is light weight

Staibilor Stabilisation LWD in-situ CBR