21.2.4. California Bearing Ratio Test

Try these first

1. 1.

   What is the purpose of a CBR test?

   Hint

   Think about the role of soil in supporting structures.

2. 2.

   What tool is used to apply pressure in the CBR test?

   Hint

   Consider the instrument that penetrates the soil.

3. 3.

   What is the main purpose of the CBR test?

   • To assess moisture
   • To evaluate soil strength
   • To measure temperature

   Hint

   Consider the role of the test in the context of pavement design.

4. 4.

   True or False: The CBR test can only be done on undisturbed soil samples.

   • True
   • False

   Hint

   Think about the flexibility of soil testing methodologies.

5. 5.

   A contractor is using soil with a CBR value of 15% for road construction. What implications does this have for the thickness of pavement required?

   Hint

   Think about how the strength of the soil impacts design choices.

6. 6.

   During a CBR test, the 2.5 mm penetration ratio was found to be 45%, and the 5 mm ratio was higher than that. If repeated testing confirms this, what CBR value should be reported?

   Hint

   Refer to how we handle differing CBR values from test results.