What is the minimum layer thickness for S 12.5C as per design standards?

The minimum layer thickness for S 12.5C according to design standards is determined by the need to ensure proper compaction and stability of the pavement structure. The correct choice indicates that the minimum thickness should be three times the nominal maximum aggregate size. This guideline is essential because it helps achieve adequate density and strength within the pavement layer, allowing for proper load distribution and reducing the risk of deformation or failure over time.

When the thickness is set to three times the nominal maximum aggregate size, it ensures that there is sufficient material for effective compaction, which improves the durability and longevity of the roadway. Choosing a thickness that is less than this can lead to insufficient support and could result in structural issues such as cracking or settling, as the aggregates may not bond properly when they are too sparse.

Other choices suggest varying minimum thicknesses, but they do not provide the same level of structural integrity that three times the nominal maximum aggregate size offers. Thus, adhering to this standard helps in achieving a more resilient and reliable pavement design.