When the required thickness of Item 200 exceeds 150 mm, how should the aggregate sub-base be compacted?

When the required thickness of an aggregate sub-base exceeds 150 mm, it is essential to compact the material in two or more layers to ensure uniform density and proper stability of the sub-base. Compaction in multiple layers allows for more effective and thorough consolidation of the aggregate, preventing issues such as settling or uneven support beneath any pavement or structure placed on top.

Compacting in a single layer for thicker sections can lead to inadequate compaction, as the equipment may not be able to sufficiently penetrate the entire thickness of the layer. This can result in air voids and weak areas within the sub-base, undermining the integrity of the surface above.

By opting for two or more layers, each layer can be effectively compacted to achieve the desired density. This layered approach minimizes the risk of structural failure and enhances longevity, thereby promoting a stable foundation for subsequent construction activities.