Flexible Pavement Design - IES Previous Year Questions

1.  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 _____ .

[IES 1997]

  1. Higher value minus the lower value.
  2. Lower value corresponding to 2.5 mm penetration.
  3. Higher value obtained at 5 mm penetration
  4. Mean of the values for 5 mm and 2.5 mm penetration.
Answer: Option C
Explanation:
  • Normally, CBR value at 2.5 mm penetration will be higher than the CBR value at 5 mm penetration. In such cases, the higher value observed at 2.5 mm penetration is reported as the CBR value of the specimen.
  • But, if the CBR value at 5 mm penetration is more than the CBR value at 2.5 mm penetration, then repeat the test for the purpose of checking. On re-testing, if the results are similar, then the higher value at 5 mm penetration is reported as the CBR value of the specimen.

2.  As per latest IRC guidelines for designing flexible pavement of CBR method, the load parameter required is _____ .

[IES 1999]

  1. Cumulative standard axles in msa.
  2. Equivalent single axle load.
  3. Number of vehicles (all types) during design life.
  4. Number of commercial vehicles per day.
Answer: Option A
Explanation:
As per IRC 37:1984, the design of flexible pavement depends on the cumulative number of standard axles (in Million Standard Axles) to be carried during the design period of the road.
Note: IRC 37:1984 is the latest code in 1999. Check for the latest versions.

3.  California Bearing Ratio (CBR) is a _____ .

[IES 2005]

  1. Method of soil identification. 
  2. Measure to indicate the relative strengths of paving materials.
  3. Measure of shear strength under lateral confinement.
  4. Measure of soil strength.
Answer: Option B
Explanation:
California Bearing Ratio (CBR) test is a measure of evaluating the strength of soil subgrade and other flexible pavement materials with respect to the strength of standard aggregates.

4.  Match List-I (Method of design for flexible pavement) with List-II (Principle) and select the correct answer using the codes given below the lists: 

List-I 

  1. Group Index Method
  2. CBR method
  3. US Navy Method
  4. Asphalt Institute Method

List-II

  1. Semi-theoretical
  2. Quasi-rational
  3. Empirical method using soil classification test
  4. Empirical method using soil strength test

[IES 1999]

Codes: A B C D
  1.  2  4  1  3
  2.  3  4  1  2
  3.  2  1  4  3
  4.  3  1  4  2
Answer: Option B
Explanation:
Empirical methods of design of flexible pavement:
  • Group Index method
  • CBR method
  • California R value method or Stabilometer method
  • McLeod method
Semi-empirical or semi-theoretical methods of design of flexible pavement:
  • Triaxial test method
Theoretical methods of design of flexible pavement:
  • Burmister method

5.  What are the maximum value of CBR and minimum value of GI of any material, respectively ?

[IES 2007]

  1. 100, 20
  2. 50, 5
  3. 10,0
  4. 100,0
Answer: Option D
Explanation:
  • The CBR value of soil subgrade varies from 0% to 100%.
  • The Group Index value of soil subgrade varies from 0 to 20.

6.  IRC code No. 37-1985 deals with which one of the following ?

[IES 2008]

  1. Design of rigid pavements, taking axle load and CBR into account.
  2. Design of flexible pavement, taking ESWL and CBR into account. 
  3. Design of flexible pavement taking cumulative axle loads and CBR into account.
  4. Design of rigid pavements, taking ESWL and CBR into account.
Answer: Option C
Explanation:
IRC 37 deals with the “Guidelines for the Design of Flexible Pavements”.The design of flexible pavement is based upon the cumulative number of standard axles (in Million Standard Axles) to be carried during the design period of the road and the CBR value.

7.  Assertion (A): California Bearing Ratio Test is carried out to evaluate the stability of soil subgrade and other flexible pavement materials.

Reason (R): It is essential that at no time are the soil subgrade as well as other flexible pavement materials over stressed.

[IES 2008]

  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true but R is not a correct explanation of A.
  3. A is true but R is false.
  4. A is false but R is true.
Answer: Option C
Explanation:

8.  Which of the following correspond to the recommendations of IRC for pavement thickness determination by CBR method ?

  1. CBR tests are to be conducted in-situ.
  2. Static compression is best adopted.
  3. The top 50 cm of subgrade should be compacted to as near the proctor density as possible.

[IES 2011]

  1. 1 and 2 only
  2. 2 and 3 only
  3. 1 and 3 only
  4. 1, 2 and 3
Answer: Option B
Explanation:
CBR tests are carried out on remoulded soil in the laboratory. In-situ field tests are not recommended for design purposes.

9.  In a flexible pavement,

[IES 2014]

  1. The vertical compressive stress is the maximum at the lowest layer.
  2. Tensile stresses get developed.
  3. Maximum stress induced by a given traffic load is dependent on the location of the load on the pavement surface. 
  4. Vertical compressive stresses decrease with depth of the layer.
Answer: Option D
Explanation:
The vertical compressive stress decreases with the depth of the pavement layer.

10.  What will be the initial traffic after construction, in the commercial vehicles per day (CVD) for the following data ?

Annual average daily traffic at last count = 400 CVD

Rate of traffic growth per annum = 7%

The road is proposed to be completed in 3 years.

[IES 2015]

  1. 421
  2. 490
  3. 449
  4. 500
Answer: Option B
Explanation:
Initial traffic after construction, A = P(1 + r)n
⇒ A = 400 (1 + 0.07)3
⇒ A = 490 CVD
PYQs of Competitive Exams :
Join Us On:
Scroll to Top