Laboratory California Bearing Ratio Test Apparatus

The California Bearing Ratio test, (usually called CBR test) is an empirical test developed in California, USA for determining the Relative Bearing Ratio and expansion characteristics under known surcharge weight of base, sub-base and sub grade soils for the design of roads, pavements and runways. The CSR test is used extensively in selection of materials and control of subgrades. The test can be performed in the laboratory on prepared samples or in-situ on location. It is important to appreciate that this test, being of an empirical in nature, is valid only for the application for which it was developed i.e., the design of highway base thickness.