Highway engineering — recommended camber for cement concrete (CC) pavements in heavy rainfall regions What is the recommended camber (cross fall) for cement concrete roads where rainfall intensity is high, to ensure rapid surface drainage while maintaining ride quality?

Introduction / Context:
Camber (cross fall) is the transverse slope provided on road surfaces to quickly drain rainwater and prevent water film formation, skidding, and premature surface distress. Recommended values depend on surface type and exposure. Cement concrete (CC) pavements are relatively impervious and stable; hence they typically require a moderate but consistent camber, even in areas with heavy rainfall.

Given Data / Assumptions:

• Surface type: cement concrete pavement.
• Climatic exposure: heavy rainfall region.
• Objective: ensure efficient drainage without discomfort or excessive slope.

Concept / Approach:
Standard practice adopts smaller cambers for dense, impervious surfaces and larger cambers for pervious/loose surfaces (e.g., gravel or earthen roads). For CC pavements, commonly adopted values cluster around 1 in 50 (≈ 2%). This achieves a balance: rapid runoff yet minimal lateral force on vehicles and minimal crossfall-induced discomfort. Even with heavy rainfall, CC does not need as steep a camber as earthen or gravel surfaces, because its smooth, impermeable finish sheds water readily.

Step-by-Step Solution:
Identify the surface: CC pavement → lower camber than loose surfaces.Match to recommended range: ~1 in 50 for CC, while bituminous ranges around 1 in 50–1 in 60 and gravel/earthen are steeper (1 in 33 to 1 in 25).Select the appropriate value for heavy rainfall without oversteepening: 1 in 50.

Verification / Alternative check:
Design manuals show tabulated cambers by surface type; CC is typically specified at about 2% (1 in 50). Field experience confirms that this value provides adequate drainage on straight sections and standard crown profiles.

Why Other Options Are Wrong:
1 in 25 and 1 in 33: Excessive for CC; more suited to earthen/gravel roads.
1 in 40: Steeper than common CC practice; may be used in special cases but not the standard recommendation.
1 in 60: Flatter than ideal for heavy rainfall, risking water film.

Common Pitfalls:

• Applying steep cambers meant for earthen roads to CC pavements, causing discomfort and drainage concentration at edges.
• Ignoring camber continuity across intersections and transitions, which can trap water.

Final Answer:
1 in 50