1. Soil compacted at optimum moisture content reduces swelling of the soil.
a) true
b) false
Explanation: When the soil is compacted, the soil particles come closer and the density increase. The water deficiency of the soil hence increases and due to this, the swelling of soil mass decreases.
2. Which of the below sieve sets for gravel has been arranged in sequential order?
a) 2, 1 mm, 600, 425, 212, 150, 75 microns
b) 600, 425, 212, 150, 75 microns
c) 80, 40, 20, 10, 4.75 mm
d) 40, 20, 10, 5, 4.75 mm
Explanation: The gravel fractions are larger in size and hence the sieve sets are those in mm. The largest sieve size used is 80 mm, then 40, 20, 10 and 4.75 mm are used in decreasing order of particle size. For sand fractions, the size ranges from 4.75 mm to 75 microns. The sieve sets used are 2, 1 mm, 600, 425, 212, 150 and 75 microns.
3. In the vane shear test, the difference between the initial and final reading gives the ______
a) Angle of failure
b) Angle of repose
c) Angle of internal friction
d) Angle of torque
Explanation: The vane shear test consists of equipment with four steel blades and it is inserted in the sample and rotated at 0.1° per second using torque. The reading before rotating is the initial reading and final reading is taken when the sample fails. The difference between these gives the angle of torque.
4. Find the angle of shearing resistance of sand subjected to drained triaxial test for the following data:
Deviator stress, σd = 475 kN/m2
Cell pressure, σ3 = 200 kN/m2
a) 23.88°
b) 32.88°
c) 33°
d) 32°
Explanation: The equation for normal stress, σ1 is given by:
σ1=σ3+σd=200+475=675 kN/m2
The formula for the drained triaxial test is given by:
σ1=σ3NΦ + 2c\(\sqrt{N_{\phi}}\) Where \({N_{\phi}}\) is \((tan(45+\frac{\phi }{2}))^2\) Substituting values from the question and taking c = 0 (sand has no cohesion),
675 = 200× \((tan(45+\frac{\phi }{2}))^2\)+0
Φ=32.88°
5. The sub-base course is also called as ______ sub-base.
a) Layered
b) Graded
c) Granular
d) Bituminous
Explanation: The sub-base course also called granular sub-base because the materials used for its construction include gravel and crushed stones. These are essentially made of stones to allow the drainage of water.
6. Which of the below base course types is the most preferred one because of its quality?.
a) Open-graded premix carpet
b) Bituminous macadam
c) Built-up spray grout
d) Bituminous penetration macadam
Explanation: In the bituminous macadam, the aggregates and the bitumen are mixed in a hot mix plant and then transported to the sites to be laid. The aggregates are hence completely coated with bitumen and have better wear-resistant. In bituminous penetration macadam and built-up spray grout, the aggregates are partially coated with bitumen and hence are not as wear-resistant as bituminous macadam. Open-graded premix carpet is a surface course.
7. Under which situation is cutback bitumen used as a stabilizing agent?
a) Low density
b) High density
c) High natural moisture content
d) Low natural moisture content
Explanation: In case the natural moisture content of the material is low, cutback bitumen or emulsified bitumen can be used as stabilizing agents. For high moisture content, viscous cutback bitumen can be used.
8. Bituminous penetration macadam can be used as a ______ course in flexible pavement
a) Base
b) Sub-base
c) Surface
d) Binder
Explanation: Bituminous penetration macadam consists of coarse aggregates, bitumen spray and key aggregates. It can be used as the base course in the pavement for certain stretch or in small projects where hot mix plant facility is not available.
9. It is very necessary to provide a sub-base course in the pavement.
a) true
b) false
Explanation: Sub-base course is not a compulsory component of pavement, but it is usually provided in most cases. It is an additional layer that is provided when the subgrade is of poor quality.
10. In a rigid pavement, what type of traffic requires dry lean concrete as a base course?
a) Very heavy
b) Light
c) Moderate
d) No
Explanation: Granular base course is sufficient to be provided in low volume roads and moderate traffic roads. For heavy traffic loads, high quality materials are required to be used as a base course. Lean cement concrete or dry lean concrete can be used in the heavy traffic roads.