Recommended Camber for Water Bound Macadam Roads
(A) 1 in 24 to 1 in 30
(B) 1 in 30 to 1 in 48
(C) 1 in 60 to 1 in 80
(D) 1 in 80 to 1 in 120
Explanation
Camber is the transverse slope provided to the road surface to facilitate the drainage of rainwater, preventing water stagnation and surface damage. For a Water Bound Macadam (WBM) road, which has a relatively rough and permeable surface, a higher camber is required compared to smoother or less permeable surfaces like bituminous or cement concrete roads. This ensures quick drainage and maintains road integrity.
According to the Indian Roads Congress (IRC) guidelines, the recommended camber for WBM roads is 1 in 24 to 1 in 30, which corresponds to a slope of approximately 4.17% to 3.33%.
Camber Values for Different Road Types
The following table summarizes the recommended camber values for various types of road surfaces, as per IRC guidelines:
| Type of Road Surface | Recommended Camber | Remarks |
|---|---|---|
| Water Bound Macadam (WBM) or Gravel Road | 1 in 33(3%) to 1 in 40(2.5%) | Higher camber due to rough surface and poor drainage. |
| Bituminous Surfaced Roads | 1 in 40(2.5%) to 1 in 50(2%) | Moderate camber, smoother surface. |
| Cement Concrete Roads | 1 in 50(2%) to 1 in 60(1.7%) | Smooth, impermeable surface; low camber needed. |
| Earthen Roads | 1 in 25(4%) to 1 in 33(3%) | Very high camber required due to poor drainage and high permeability. |
Key Notes
- The higher camber for WBM roads ensures effective drainage, as their rough and permeable surface is prone to water retention.
- Bituminous and cement concrete roads require less camber due to their smoother and less permeable surfaces.
- Earthen roads need the highest camber because of their high permeability and poor drainage properties.
- Proper camber design is critical for road longevity and safety, especially in areas with heavy rainfall.
Note: Accurate camber design for WBM roads, following IRC guidelines, is essential for effective drainage and maintaining road durability in highway and civil engineering projects.
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