This Standard sets out a method for determining the California Bearing Ratio (CBR) of a soil when compacted and tested in the laboratory. The CBR value is measured on the fraction of material passing the 19 mm sieve. This Standard is not applicable to materials with more than 20% retained on the 19 mm sieve.NOTES: 1 Where there is a significant amount of material retained on the 19 mm sieve, the strength of the soil may be much greater than indicated by the results of this test and this may need to be taken into account in design or in selection of suitable materials for construction.2 Guidance on improving the reproducibility of the test is provided in Appendix B.