Table of Contents
What should be the CBR value for subbase?
in subgrade material CBR value should be nearly 15-19% .
What is the CBR of base course?
The California Bearing Ratio (CBR) test is the most widely used method of evaluating subgrade, sub-base, and basecourse materials in pavements, but has many limitations, primarily because it is arbitrary. In 1982, a Modified Bearing Ratio (MBR) test was proposed for base/sub-base aggregates of larger size.
What is the minimum CBR value?
1 Answer. Min. CBR Value is 6. If the value for subgrade is less than 4, 300mm thick bolder solling is required (Base Corse).
How do I know my CBR value?
C.B.R. = (PT/PS) X 100 The C.B.R. values are usually calculated for penetration of 2.5 mm and 5 mm. Generally the C.B.R. value at 2.5 mm will be greater than at 5 mm and in such a case/the former shall be taken as C.B.R. for design purpose.
Is code for CBR value?
CBR (CALIFORNIA BEARING RATIO) TEST OF SOIL(IS-2720-PART-16-1979)
What should the CBR value of a sub base be?
The harder the material, the higher the CBR value. A CBR value of 2% is usually found for clay, high-quality sub-base will have CBR values between 80% and 100%, and some sands may have values around 10%. The CBR testing can be applied to soils with a maximum particle size of 20 mm.
What is the minimum CBR values for a subbase layer of a road pavement?
In India IRC: 37–2012 is used for design of flexible pavements. It gives design charts for pavement on the basis of CBR value for subgrade material ranging from 3% to 15%. However for subbase layer, MR (modulus of resilience) value is now considered.
What are the typical CBR values for gravelly soil?
California bearing ratio typical values. In the gravelly soils, more than 50% of the coarse fraction has a particle size larger than 4.75 mm. The CBR values of gravelly soils range from 20% to 80%. In the sandy soils, more than 50% of the coarse fraction has a particle size smaller than 4.75 mm.
What’s the minimum CBR for sub grade cement?
Many type of pavement need different %CBR of sub-grade. For soil-cement, the MEPDG (Part 2, Chapter 2) suggests a MINIMUM value of Resilient Modulus of 25,000. Using the “magic” formula Mr = 1,500 CBR, this implies a minimum CBR of about 17. Therefore your CBR = 12 appears quite low.