IRC recommended camber for thin bituminous surface in a light rainfall area is
- A1 in 60
- B1 in 50Correct
- C1 in 40
- D1 in 33
Solution
Concept
IRC standard camber for thin bituminous pavements
Formula
Camber = 1 / N
Step-by-step solution
1. Refer to IRC standards for roadway camber based on surface type and rainfall intensity. 2. For thin bituminous surfacing: - Heavy rainfall area: Camber = 1 in 40 (2.5%) - Light rainfall area: Camber = 1 in 50 (2.0%) 3. The question asks for thin bituminous surface in a light rainfall area. 4. Therefore, the required camber is 1 in 50 (option B). Answer: B
Explanation
According to IRC specifications, for a thin bituminous surface (such as surface dressing or thin premix carpet), the recommended camber is 1 in 50 (2.0%) in areas of light rainfall, and 1 in 40 (2.5%) in areas of heavy rainfall.
Why the other options are wrong
A) 1 in 60 (1.7%) is recommended for cement concrete and high-type bituminous surfaces in light rainfall areas. C) 1 in 40 (2.5%) is for thin bituminous in heavy rainfall or WBM in light rainfall. D) 1 in 33 (3.0%) is for WBM/gravel roads in heavy rainfall areas.
Shortcut
Thin Bituminous: Heavy rain = 1 in 40 (2.5%); Light rain = 1 in 50 (2.0%).
Common mistake
Confusing thin bituminous surface with cement concrete / heavy bituminous surfacing, which requires 1 in 60 in light rainfall areas.
Correct answer: B) 1 in 50