Which of the following is not a functional characteristic of kerbs used in road construction?
- AProtects the pavement edge
- BPresents a more finished appearance
- CProvides cross slope to the pavement so that immediate drainage of water takes placeCorrect
- DActs as a boundary between the pavement and the footpath
Solution
Concept
A kerb marks the edge of the pavement, protects that edge and separates the pavement from the footpath. Cross slope for drainage comes from the camber, not from the kerb.
Step-by-step solution
1. Recall the functions of kerbs: they mark the boundary between the pavement and the footpath or shoulder, protect the pavement edge, guide traffic, and give a neat finished look. 2. Cross slope (camber) is given to the pavement surface itself for quick drainage of rain water. 3. A kerb does not create cross slope. It only forms the edge, and water flows along the kerb into the drains. 4. So option (C) is not a function of kerbs.
Explanation
Kerbs are raised edges along the pavement that protect the edge, act as a boundary and give a finished appearance. The cross slope for draining water is provided by the camber of the pavement surface. Therefore providing cross slope is not a function of the kerb.
Why the other options are wrong
A: Protecting the pavement edge is a main function of kerbs. B: Kerbs give the road a neat, finished appearance. D: Kerbs act as the boundary between the pavement and the footpath.
Shortcut
Cross slope = camber, not kerb.
Common mistake
Confusing the kerb (edge element) with the camber (surface cross slope) because both are related to drainage.
Correct answer: C) Provides cross slope to the pavement so that immediate drainage of water takes place