CBR (California Bearing Ratio) Test: Apparatus, Procedure & Advantages
IMPORTANT LINKS
CBR Test – Correction for Curve Concavity
CBR Test FAQs
Why is the CBR test important?
The CBR test is important as it helps in evaluating the strength of the subgrade soil, subbase, and base course material for use in roads and pavements.
How to calculate load intensity in the CBR test?
C.B.R. = (LT/LS) X 100 where LT = Corrected test load corresponding to the specified penetration, and LS = Standard load for the same penetration.
At what penetration is the CBR value obtained?
The C.B.R. values are usually calculated for penetration of 2.5 mm and 5 mm and the C.B.R. value at 2.5 mm will be greater than at 5 mm.
What is a good CBR value for the subgrade?
More the strength of the surface, the greater the CBR value. Typically, a CBR value of 2% is obtained for clay, while sands have a CBR value of around 10%. Sub-base of very high quality can have a CBR value between 80 to 100%.
What is the CBR test formula?
The CBR test formula is: CBR = (LT/LS) X 100 where LT = Corrected test load corresponding to the penetration. LS = Standard load for the same penetration.