CBR Test Equipment (California Bearing Ratio)

The California Bearing Ratio (CBR) test yields relative strength of laboratory-compacted or in–situ soils and base course materials. This laboratory test is based on penetration resistance of a soil to a standard-sized piston.


In the lab, soils at specific moisture contents are compacted into molds. Sample preparation prior to testing may include soaking and addition of surcharge weights to the molded specimens. The penetration test is carried out in a load frame outfitted with CBR test components.

CBR Field Tests measure strength of in–situ soils and some base course materials, providing valuable information to pavement designers. Field tests are run by forcing a piston into the soil at the test site and comparing the load on the piston to the depth of penetration. Typically, the reaction load used for testing is a heavy piece of equipment such as a loaded dump truck.

The Florida Limerock Bearing Ratio (LBR) FM 5-515 test was developed to evaluate limerock and soil materials typically found in Florida, and uses similar equipment and methods compared to the laboratory CBR test.

Gilson offers a complete line of equipment for performing the California Bearing Ratio (CBR) test in laboratory and field conditions and lab equipment for the Florida Limerock Bearing Ratio (LBR) test.

  • CBR Load Frames are customizable Load Frames fitted with components to perform the CBR or LBR Tests. Frames can also be outfitted with a variety of components for other soil testing applications.
  • CBR Test Equipment/Lab includes molds, Spacer Discs, Swell Plates Surcharge Weights, and other accessories to test laboratory-prepared soil samples.
  • CBR Test Equipment/Field consists of CBR Field JacksLoad Rings, Surcharge Plates and Penetration Pistons to provide useful information to pavement designers from in-situ field tests. These tests are run by forcing a piston into the test site soil and comparing the load vs piston penetration.
  • Limerock Bearing Ratio (LBR) Test Equipment is used to determine the LBR values of limerock and typical Florida soils compacted in the laboratory.