Question

If the CBR value obtained at 5 mm penetration is higher than that at 2.5 mm, then the test is repeated for checking; and if the check test reveals a similar trend, then the CBR value is to be reported as the

• A. mean of the values for 5 mm and 2.5 mm penetration
• B. higher value minus the lower value
• C. lower value corresponding to 2.5 mm penetration
• D. higher value obtained at 5 mm penetration

Answer 1

The correct option is D higher value obtained at 5 mm penetration

The average CBR value of three test specimens is reported to the first decimal place, as the CBR value of the test specimen. If the maximum variation in the CBR values of these specimens exceeds specified limits (3% for CBR up to 10%; 5% for CBR upto 30% and 10% for CBR 30-60%), then the design CBR should be the average of at least six specimens.