This set of Pavement Design Multiple Choice Questions & Answers (MCQs) focuses on “Highway Maintenance – Destructive Structural Evaluation”.
1. How can we evaluate the data using destructive testing of pavement materials?
a) Visual inspection
b) Laboratory tests
c) Laboratory tests and visual inspection
d) Laboratory tests and
Explanation: There are two ways to evaluate the data using destructive testing of pavement materials. Extracted pavement portion can be tested for physical, chemical and mechanical properties in the laboratory. The sample of pavement can be extracted as such and the visual inspection of the same can also be carried out.
2. ______ is used to extract the undisturbed sample from the pavement.
a) Shelly tubes
b) Shebby tubes
c) Shebly tubes
d) Shelby tubes
Explanation: Shelby tube is a sharpened pipe that is driven into the pavement layers using hydraulic rams. These tubes are driven and taken out in the same manner, thereby getting undisturbed samples every time it is extracted.
3. Which of the below is not a method to extract the pavement materials?
Explanation: The pavement materials can be extracted by using any of the following methods – trenching, augering and coring. Shelling is not a method used for the extraction of samples. It is not a term related to the evaluation of the pavements.
4. In the coring process, at what speed is the barrel spun at?
a) 50 rpm
b) 500 rpm
c) 100 rpm
d) 250 rpm
Explanation: The coring process consists of a barrel that is driven into the pavement layers to extract the sample. The barrel spins with a speed of 500 rpm. It is gradually lowered into the pavement.
5. Augering is very useful in determining the ______ of the pavement.
a) Existing layer thickness
b) Layer thickness
c) Existing layer defects
d) Layer defects
Explanation: Augering is done to evaluate the structural properties of the pavement. But it is very useful in determining the existing layer thickness, not the layer thickness. The thickness of the existing layer can give an idea of the deterioration of the pavement.
6. Shelby tube samples can be used to determine the PVR value of materials. What does PVR mean?
a) Potential Volume Rise
b) Present Vertical Ratio
c) Potential Vertical Rise
d) Present Volume Ratio
Explanation: The samples obtained from the Shelby tubes are undisturbed and therefore the evaluation of a wide variety of properties can be done. One such property is PVR or potential vertical rise. It is a measure of soil to swell in the vertical direction and it is expressed in inches.
7. What is the size of the trench that is made for extracting samples?
a) 3 ft X 12 ft
b) 6 ft X 12 ft
c) 9 ft X 12 ft
d) 12 ft X 12 ft
Explanation: Trenching is done by first making saw marks on the pavement surface to demarcate the trench. The size of the trench is generally taken as 3 ft X 12 ft. There can be any number of such trenches depending on the need of the project.
8. Which test is done to find the amount of bitumen in the pavement?
a) Bitumen content test
b) Bitumen volume test
c) Bitumen fraction test
d) Bitumen extraction test
Explanation: The destructive testing of flexible pavements involves conducting the bitumen extraction test. It is done to determine the amount of bitumen. The main apparatus required for this test is the centrifuge extractor.
9. ______ sampling technique can be used for acquiring materials to determine the type and quantity of stabilizers for full-depth reclamation.
Explanation: Augering is done to extract a disturbed sample of the pavement materials. This is particularly useful in finding the type and quantity of stabilizers required for the full-depth reclamation projects. This is because the consistency of the retrieved sample is similar to that processed through pavement reclaimer.
10. In the bitumen extraction test, the test is performed until the colour of the extract is not darker than ______
a) Pale yellow
b) Light straw
c) Dull yellow
d) Light brown
Explanation: In order to stop the testing and obtain correct results, the extract must be clear and not darker than light straw. The procedure is repeated at least three times to ensure this. The extract is then dried in the oven to obtain the weight of the extracted sample.
11. The Shelby tubes can only be driven through unbound fine-grained soil layer.
Explanation: The Shelby tubes are sharpened pipes and not very strong enough to be driven through the hard bituminous and granular layers of the pavement. The fragile nature of it makes it necessary to remove the upper layers in order to extract the undisturbed soil sample.
12. ______ is used in to cool the barrel in coring if sample at in-situ moisture content is desired.
b) Dry ice
c) Liquid nitrogen
Explanation: Usually cold water is used to cool the barrels in the coring process. But where the samples at in-situ moisture content are required, it is advised to use dry ice. This is done so as to avoid damages to stripping-susceptible pavements.
13. A six-inch slot is cut in the trenching process to ______
a) Mark the boundary of trench
b) Take the samples for lab testing
c) Pour water to ease the digging
d) Allow backhoe to dig further
Explanation: It is not easy for a backhoe to lift the trench marked on the pavement surface. To make it possible, a six-inch slot is cut using hand tools. Otherwise, the backhoe would end up damaging or cracking the trench surrounding areas.
14. The Shelby tube can be pushed further into the same hole to extract more sample.
Explanation: In case if deeper samples are required, then the tube can be pushed further into the same hole to extract more sample. This allows the person to get data on the complete soil profile up to the desired depth. The sample is joined and kept in the same order to get the same profile as in the field.
15. Which type of auger is used for extracting the samples using the augering method?
a) Wood auger
b) Earth auger
c) Continuous flight auger
d) Continuous screw auger
Explanation: Continuous flight auger is used for extracting sample using the technique of augering. It is a type of drilling that is done into the pavement surface. Wood and earth augers are the different types of augers that are used for different purposes.
Sanfoundry Global Education & Learning Series – Pavement Design.
To practice all areas of Pavement Design, here is complete set of 1000+ Multiple Choice Questions and Answers.