How many equal layers is a modified effort sample compacted in?

When compacting a modified effort sample, the standard practice requires that the sample be compacted into five equal layers. This method is specified to ensure uniformity and consistency in the compaction process, which is essential for accurate testing and evaluation of the sample's properties. Each layer is subjected to a specified number of blows or strokes from the compaction equipment to achieve the desired density and structural integrity.

Compacting in five layers allows for more controlled and homogeneous distribution of the material, as well as better representation of the full depth of the sample. This systematic approach helps to avoid issues such as segregation or inadequate compaction that could arise from using fewer layers. The indentation and shape of the compacted sample can also be crucial in assessing the material's performance in practical applications, making adherence to this layering protocol vital in aggregate base testing.