CBR testing can be used to analyse existing ground conditions, this allows you to plan and fine-tune your project to any formation encountered during construction.
CBR Testing (California Bearing Ratio)
The CBR test is fully described in BS1377: Part 9: 1990: Soils for civil engineering purposes. It was first developed by the California State Highway Department and is used in the field as an arbitrary strength test which is considered to stress soils and replicate wheel loads.
What Is CBR Testing
CBR testing is performed by measuring the pressure required to penetrate a soil sample with a plunger of standard area. The measured pressure is then divided by the pressure required to achieve an equal penetration on a standard crushed rock material.
The harder the surface, the higher the CBR value. Typically, a value of 2% equates to clay, while some sands may have a CBR value of 10%. High quality sub-base will have a value of between 80-100% (maximum). For more information and contact us.