Definition of CBR: It is the ratio of force per unit area required to penetrate a soil mass with standard circular piston at the rate of 1.25 mm/min. Draw the graphs between the penetration (in) and penetration load (in) and find the value of CBR. Tests are carried out on natural or compacted soils in water soaked or un-soaked conditions and the results so obtained are compared with the curves of standard test to have an idea of the soil strength of the subgrade soil. CBR Test PROCEDURE: Normally 3 specimens each of about 7 kg must be compacted so that their compacted densities range from 95% to 100% generally with 10, 30 and 65 blows. USES AND SIGNIFICANCE of California Bearing Ratio Test: The CBR test is one of the most commonly used methods to evaluate the strength of a sub grade soil, sub base, and base course material for design of thickness for highways and airfield pavement. Back to top . Site Map Civil Engineering Training Contact Us 2014 WebTechTix..
Take sample for determination of moisture content. Weight of mould + compacted specimen. Test Data Observations & Calculations 5. Place the mold in the soaking tank for four days (ignore this step in case of unsoaked CBR. C B R Apparatus Used 3. to that required for the corresponding penetration of a standard material. Weigh of empty mould Add water to the first specimen (compact it in five layer by giving 10 blows per layer) After compaction, remove the collar and level the surface. Subjects Professional Ethics Soil Mechanics I Engineering Economics Technical Report Skills Surveying & Leveling II Differential Equations Strength of materials Engineering Geology Building Construction Steel Structures Hydraulics Reinforced Concrete Hydrology Past Papers Project Planning Hydraulics Structures Civil Engineering Ebooks Video Training Tutorial AutoCAD Videos VICO Constructor SAP2000 Training MS Project Tutorials Civil Related Links Jobs Engineering Projects Suggest us, What to Add Some Concrete Q/A What is Durable Concrete? Why are admixtures used? Why conventional concrete is not Green? Concrete Sustainibility Enhancement Deterioration of Concrete Occur? .