Question

The camber prescribed by the I.R.C. for cement concrete or high type bituminous roads in percentage is

• A. \( 3.0 - 4.0 \)
• B. \( 1.7 - 2.0 \)
• C. \( 2.5 - 3.0 \)
• D. \( 2.0 - 2.5 \)

Hint:

Camber ensures efficient drainage of surface water, which is crucial for pavement longevity and safety. The steeper the camber, the faster the drainage, but excessively steep camber can be uncomfortable for drivers and may lead to stability issues. Therefore, the choice of camber is a balance, depending on rainfall intensity and pavement material. Impermeable and smooth surfaces require less camber.

Answer 1

The Correct Option is B

Step 1: Understand Camber.
Camber (or cross slope) is the transverse slope provided to the road surface to drain off rainwater from the road surface to the side drains. It helps in preventing water accumulation, which can cause damage to the pavement and reduce skid resistance. The amount of camber depends on the type of road surface and the amount of rainfall.
Step 2: Recall IRC recommendations for Camber.
The Indian Road Congress (IRC) provides guidelines for different types of road surfaces and rainfall conditions. Common IRC recommended camber values:

• For Heavy Rainfall areas:
  • WBM \& Gravel: 3.0% to 4.0% (1 in 25 to 1 in 33)
  • Bituminous surfaces (thin): 2.5% to 3.0% (1 in 33 to 1 in 40)
  • Cement Concrete / High type Bituminous: 2.0% (1 in 50)
• For Light Rainfall areas:
  • WBM \& Gravel: 2.5% to 3.0% (1 in 33 to 1 in 40)
  • Bituminous surfaces (thin): 2.0% to 2.5% (1 in 40 to 1 in 50)
  • Cement Concrete / High type Bituminous: 1.7% (1 in 60)

The question asks for the camber for "cement concrete or high type bituminous roads". This refers to highly impermeable and smooth surfaces.
Step 3: Identify the relevant range from the options.
For cement concrete or high type bituminous roads, the camber values typically range from 1.7% (for light rainfall) to 2.0% (for heavy rainfall). Looking at the options:

• (1) \( 3.0 - 4.0 \): This range is for WBM \& Gravel roads.
• (2) \( 1.7 - 2.0 \): This range accurately covers the IRC prescribed values for cement concrete or high type bituminous roads.
• (3) \( 2.5 - 3.0 \): This range is typically for thin bituminous surfaces or WBM/Gravel in light rainfall.
• (4) \( 2.0 - 2.5 \): This range is typically for thin bituminous surfaces.

Step 4: Select the correct option.
The camber prescribed by the I.R.C. for cement concrete or high type bituminous roads is 1.7% to 2.0%. $$\boxed{1.7 - 2.0}$$