Which layer comes directly under the base in ICPS?

Which layer comes directly under the base in ICPS?

• A. Sub-base (compacted)
• B. Base (compacted aggregate)
• C. Bedding (sand)
• D. Edge restraint

Answer: (A)

In an ICPI/ICPS pavement system, the layers from bottom to top typically are subgrade, sub-base, base, bedding sand, and pavers. The layer that sits directly beneath the base is the sub-base. It’s a compacted granular layer that provides drainage, frost protection, and a stable foundation so the base can effectively distribute loads to the subgrade. The base sits on top of the sub-base and then bedding sand goes above the base to create a smooth bed for the pavers. Edge restraints are perimeter components, not a foundational layer under the base. Therefore, sub-base is the layer directly under the base.

In an ICPI/ICPS pavement system, the layers from bottom to top typically are subgrade, sub-base, base, bedding sand, and pavers. The layer that sits directly beneath the base is the sub-base. It’s a compacted granular layer that provides drainage, frost protection, and a stable foundation so the base can effectively distribute loads to the subgrade. The base sits on top of the sub-base and then bedding sand goes above the base to create a smooth bed for the pavers. Edge restraints are perimeter components, not a foundational layer under the base. Therefore, sub-base is the layer directly under the base.