What does mean by CBR in sub base compaction test?

CBR stands for California Bearing Ratio, which is a test used to evaluate the strength of subgrade soil and sub-base materials in road construction. The test measures the resistance of a material to penetration by a standard-sized plunger, comparing it to the resistance of a standard crushed stone material. A higher CBR value indicates better load-bearing capacity, which is crucial for ensuring the durability and stability of the pavement structure. It is commonly used in the design of flexible pavements and in assessing the quality of sub-base materials.