Ballast, a mixture primarily composed of sand and gravel, serves a crucial role in construction by providing a stable and reliable foundation.
According to the provided reference, ballast is generally used when building foundations for specific jobs such as houses and roadways as well as railways.
Key Uses of Ballast in Construction
The core function of ballast is to create a robust base layer for various structures. This material is vital in foundational work for several types of projects:
- Houses: Providing a solid ground base for residential structures to prevent settling and movement.
- Roadways: Forming the underlying layer that supports asphalt or concrete, distributing vehicle weight and preventing roadbed deformation.
- Railways: Creating the bed beneath the tracks, supporting the sleepers (ties) and rails, absorbing vibration, and allowing for drainage.
Why is Ballast Used for Foundations?
Ballast is specifically chosen for these applications due to a combination of essential properties:
- Stability: It is heavy enough to provide a stable base, preventing the overlying structure from shifting or moving over time.
- Drainage: Crucially, while heavy, its granular nature allows water to drain through it. This prevents water buildup under the foundation, which could otherwise lead to instability, erosion, or frost heave.
In summary, ballast provides a heavy, stable, and well-draining foundation layer essential for the longevity and safety of various construction projects, particularly houses, roads, and railways.
