How much relative density is required for sandy materials in pavement reconstruction?

In pavement reconstruction, the required relative density for sandy materials is crucial for ensuring adequate stability and load-bearing capacity. A relative density of 70% is typically sufficient for sandy materials because it strikes a balance between compaction and void space. This level of compaction helps achieve the necessary strength for traffic loads while maintaining some degree of permeability, which is essential for drainage and preventing issues like water pooling or erosion.

A density lower than 70% may not provide the necessary support for pavement layers, leading to potential settlement and deformation under traffic loads. On the other hand, opting for a significantly higher relative density, like 90%, might not be advisable for all sandy materials, as this may lead to over-compaction, reducing drainage capacity and potentially leading to other structural issues down the line. Thus, the choice of 70% is rooted in engineering best practices for trailering balance between compaction, stability, and drainage requirements in pavement construction.