This set of Pavement Design Multiple Choice Questions & Answers (MCQs) focuses on “Highway Maintenance – Rehabilitation of Flexible Pavement”.
1. The in-plane recycling can be of how many types?
Explanation: There are two types of in-plane recycling options available. They are hot in-plane recycling and cold in-plane recycling. The hot in-plane recycling is used for asphalt concrete surface distress and the cold in-plane recycling is for bituminous surface layers.
2. Which of the below is not a process in the hot in-place recycling (HIR) method?
Explanation: There is no process of reheating in the HIR technique of rehabilitation. There are three processes – recycling, remixing and repaving. The heating of materials is done in the remixing stage, the materials have to be heated for mixing.
3. To what temperature is the pavement surface heated in the hot in-place recycling process?
a) 95 – 100°C
b) 95 – 180 °C
c) 85 – 130 °C
d) 85 – 150 °C
Explanation: There is a special machine to heat the surface of the pavement to a temperature ranging from 95 to 180°C. This is done to make the scarifying, rejuvenation and remixing of the top surface materials easy.
4. What component does not belong to the special train used for cold in-place recycling?
a) Milling machine
b) Screen unit
c) Mixing unit
d) Heating unit
Explanation: In the cold in-place recycling method, there is no need to heat the surface. Cold milling is carried out on the existing pavement surface. Then the screen or crushing unit is used to crush the milled surface, then it is mixed thoroughly. Virgin mix is added to the reclaimed crushed materials.
5. While using geosynthetics for the rehabilitation of flexible pavements, what should be taken into consideration?
a) Future rehabilitation
b) Cost of maintenance
c) Thickness of pavement
d) Transportation of geosynthetics
Explanation: The future rehabilitation is an important factor to be taken into consideration while using geosynthetics for the rehabilitation works. It is because of the fact that it might cause the fouling of the milling equipment when milling is done in future.
6. Which step comes after the pulverization step in the FDR method?
a) Moisture conditioning
Explanation: FDR stands for full depth reclamation and it is the last resort for rehabilitation. There are eight steps in the process. The first step is the pulverization, then moisture conditioning, breakdown roller, shaping, intermediate roller, finish roller, sealant and the last step is the surface treatment.
7. The sealant used in the FDR method is the ______ seal.
Explanation: The fog seal is used as the sealant for the FDR method. It is a light application of asphalt emulsion. These are slow-setting, low cost and are applied over aged pavements.
8. Which of the below rehabilitation strategies is called pavement preservation?
b) Structural overlays
c) Surface treatments
d) Non-structural overlays
Explanation: Non-structural overlays are used primarily for improving ride quality, surface texture, cross-slope drainage and waterproofing. It is due to this that this method of rehabilitation has been termed as pavement preservative.
9. In which type of surface treatment is the bitumen emulsion applied on the pavement using brooms?
a) Scrub seal
b) Fog seal
c) Seal coat
d) Tack coat
Explanation: As the name suggests, a series of brooms placed at varying angles are used to spread the emulsion over the pavement surface. Along with this, it also has crushed stones spread along the pavement surface.
10. Underseals are used to provide bonding between the existing surface and the new surface.
Explanation: Underseals are provided on top of the existing pavements for two main reasons. One is to cover the existing cracks and seal it for preparing a new layer. The second reason is to form a bonding between the existing layer and the new one.
11. ______ HIR technique uses the processes of heating, scarifying and adding a recycling agent.
Explanation: The Cutler HIR process is an alternative to the real HIR process. In this technique, a recycling agent is added. The recycled material is placed and then the new hot mix is poured over it. In the Dustrol HIR technique, the recycling agent is mixed and placed together.
12. Which method can be used to increase the structural capacity of the low to moderate volume highways?
a) Flexible base overlay
b) Flexible base thickening
c) Flexible subgrade thickening
d) Flexible sub-base thickening
Explanation: Flexible base thickening is a measure to strengthen the pavement by increasing its structural capacity. It is used for low to moderate volume highways having a low level of existing structural damages, good subgrade support and uniform base.
13. The application of a new bituminous surface course is called ______
Explanation: Resheeting involves laying a new bituminous surface over the existing pavement surface. This is usually machine laid and it improves the skid resistance and surface shape. Resealing is another method that uses a spray seal.
14. Which of the below is not a method to extract the rigid pavement for reusing as the base in flexible pavements?
a) Break and seat
b) Crack and seat
c) Multi-head breaker
d) Smash and seat
Explanation: The existing rigid pavement that is low performing can be extracted and used to strengthen the base in the flexible pavement rehabilitation process. This can be done using one of the methods – break and seat, crack and seta, multi-head breaker or rubblizing. Smash and seat is not a method.
15. The flexible base overlay is provided as a new top surface for rehabilitation.
Explanation: The flexible base overlay is not a new top surface provided for rehabilitation. It is an intermediate layer provided on top of the existing pavement in order to receive a new layer. It helps in resisting the propagation of reflective cracks present on the existing surface.
Sanfoundry Global Education & Learning Series – Pavement Design.
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