PBR is performed at the foundation level, but at times, it can be done on the surface that is slightly below the ground. The method involves the application of pressure on the surface that is under testing.
When it comes to CBR, penetration is the primary action required whereby, the machines cylindrical plunger is driven into the ground at a constant rate. Usually, a four-wheel drive vehicle is used to provide reaction weight for the purposes of force production. That because the test has to be done with real weighs that are available.
PBR requires a total of six tests mostly to be able to come up with a conclusion on a ground that would influence plans. However, the CBR requires at least eight tests for analysis as well as determination to be derived. The differences in testing are due to surface areas. It is easier to ascertain results for plate bearing than in the case of CBR that tests smaller areas regarding surface penetrated. For PBR, a large surface area is involved.
When it comes to PBR, tests can be done on the ground or testing of a sample in a lab setup. Both can be effective and reliable. For CBR, both site ground, and sample tests can also be done. It is more recommendable for CBR conduction on the site ground where you can test with real carriage vehicles to come up with results that are more reliable.