How much compaction is required for materials used for sand bedding in asphalt pavement reconstruction?

The requirement for 70% relative density for materials used in sand bedding during asphalt pavement reconstruction is important for ensuring the stability and durability of the pavement structure. Achieving this level of compaction helps to minimize voids in the bedding material, which supports the asphalt layer above and provides a solid foundation.

By reaching 70% relative density, the bedding material is compacted enough to resist deformation under load while also allowing for some drainage, which is crucial in preventing water accumulation that could lead to weakening over time. Insufficient compaction, such as the lower percentages, may lead to settlement or instability, which can negatively impact the performance and lifespan of the pavement. Therefore, 70% relative density strikes a good balance between structural support and drainage, making it the ideal specification for this application.