The term "CBR test" typically refers to the California Bearing Ratio test, which is a laboratory test used to evaluate the strength and bearing capacity of subgrade soils and base materials. The objective of the CBR test is to determine the potential load-bearing capacity of the soil or material in relation to pavement design and construction.
During the CBR test, a soil sample or compacted material is prepared in a standardized mold and subjected to a compressive load. The load is applied at a specific rate and the resistance or penetration of the soil is measured. The test provides a numerical value known as the CBR value, which represents the ratio of the material's resistance to penetration to that of a standard crushed stone material.
The CBR test helps engineers and pavement designers assess the suitability of soils and materials for road construction, especially in terms of their load-bearing capacity and potential for deformation or failure under traffic loads. The test results are used in the design and evaluation of pavement structures, such as determining the required thickness of pavement layers and assessing the need for soil stabilization or improvement.
In summary, the objective of the CBR test is to provide engineers with valuable information about the strength and bearing capacity of soils and materials to make informed decisions regarding pavement design and construction.