California Bearing Ratio (CBR)

California Bearing Ratio (CBR)

California Bearing Ratio (CBR) – the CBR value of a soil is a measure of it’s mechanical strength when compared to that of a standard crushed rock material. As well as being determined using in-situ tests, the CBR value of a soil may be determined in the laboratory on tests carried out on either undisturbed or disturbed samples.  Only materials with particle sizes less than 20mm are suitable for test, although materials with up to 30% oversize can be tested by removing coarse particles and replacing with finer ones.  Samples are commonly tested in their ‘as received’ condition, but if required can be soaked prior to test in accordance with guidelines given in the British Standard.