21.2.4.1. Test Procedure

Try these first

1. 1.

   What does CBR stand for?

   Hint

   Think about the test's full name.

2. 2.

   What is the diameter of the standard plunger used in the CBR test?

   Hint

   Recall the measurement of the test equipment.

3. 3.

   What is the primary purpose of the CBR test?

   • To measure soil moisture
   • To evaluate strength of subgrade soil
   • To classify soil type

   Hint

   Think about how soil impacts pavement.

4. 4.

   True or False: The CBR value increases with deeper penetration.

   • True
   • False

   Hint

   Focus on the expected behavior of soil during testing.

5. 5.

   If a soil has a CBR value of 50% at 2.5 mm and a CBR value of 70% at 5 mm, should this soil be considered robust enough for roadway support? Discuss the implications if the values were reversed.

   Hint

   Consider the characteristics of soil strength and implications for road durability.

6. 6.

   Describe a scenario where the CBR value might dramatically change. What environmental or physical factors could influence this result?

   Hint

   Reflect on the effects of weather or mistreatment of the soil during the CBR test.