How are the results of CBR test obtained and interpreted?
Based on the result of CBR value was obtained from of the rapid impact compaction, indicating that the effect of the number of blows will be dominant to the achievement of CBR values, especially for CBR which has value greater than 80% of the maximum value, in case for all energy levels that is given although the mass …
What CBR value is good for soil?
CBR values for common soil subgrades can be estimated according to the USC soil types, for example: clay around 2%, sand from 7% (poorly graded) to 10% (well graded), well graded sandy gravel 15%, clayey sand 5-20%, silty gravel 20-60%, gravel from 30-60% poorly-graded to 40-80% if well-graded.
What is the minimum CBR value for subgrade?
CBR value for subgrade in road construction in India : CBR value is taken at 2.5mm & 5 mm penitration. in subgrade material CBR value should be nearly 15-19% .
What is a good CBR value for subgrade?
To understand the impact of CBR (subgrade strength) on the pavement, let’s look at some typical CBR values. A clayey soil generally has a low CBR value (less than 8). Sands are more granular and drain better and will generally have CBR values between 15 and 35. Gravel will have the best CBR values, generally 25 and up.
What is the size of GSB?
Granular Sub Base (GSB) Road Material, Packaging Size: 50 kg
| Usage/Application | For Construction |
|---|---|
| Packaging Size | 50 Kg |
| Density | 2.1 g/cc |
What is CBR test PDF?
The laboratory CBR test consists essentially of preparing a sample of soil in a cylindrical steel mould and then forcing a cylindrical steel plunger, of nominal diameter 50 mm, into the sample at a controlled rate, whilst measuring the force required to penetrate the sample.
What is the California Bearing Ratio ( CBR ) test?
CALIFORNIA BEARING RATIO TEST 1.Objective CBR is the ratio expressed in percentage of force per unit area required to penetrate a soil mass with a standard circular plunger of 50 mm diameter at the rate of 1.25 mm/min to that required for corresponding penetration in a standard material.
What are the results of the CBR test?
From the calculation done for CBR, CBR was found to be 60.2%, 26.7% and 8.1% for MD1, MD3 and MD7 samples respectively. By looking at the results for CBR at 2.54 mm, 5.08 mm and 7.62 mm for all the 3 samples the CBR tends to decrease as the penetration increases.
How is the CBR test used in civil engineering?
The CBR test is fully described in BS 1377: Soils for civil engineering purposes – Part 4, Compaction related tests. The CBR rating is used for measuring the load-bearing capacity of soils used for building roads and to determine the material properties for pavement design.
What is the correlation between CBR and E?
CBR with E as, E = 17.6 CBR 0.64 (MPa) (2) Thus, the correlation between E and CBR developed by NAASRA (1950) has been divided into two parts. For CBR less than 5, E = 16.2 CBR 0.7 (MPa) (3) Then, for CBR more than 5, E = 22.4 CBR 0.5 (MPa) (4)