Abstract: The California bearing ratio CBR is an indicator for evaluating the strength of soil materials. The CBR test has a very important application in pavement engineering. The “dry density-CBR” curve obtained from the test is combined with the compaction index required for subgrade construction to determine if the soil is appropriate to be used as desired subgrade material with given strength; It can also be determined whether the CBR strength of the in-situ subgrade soil of the zero-fill and cut zones meets the code requirements. In the practical projects, although some test inspectors are familiar with the procedures of the CBR test, and can obtain the dry density of three groups of test pieces and the corresponding CBR value through the test data, they do not know how to use these test results in combination with the pavement construction technical specifications to analyze the mechanical properties of soil. Based on this, a case history was presented to elaborate this issue with the graphical method and the analytical method, respectively, and then the pavement performance of the material was determined to provide a reference for the test inspectors and construction technicians.

Key words: California Bearing Ratio, CBR Tests, Compaction, Subgrade Engineering