Do soil compaction test results over 100% mean over-compaction?

Soils can experience over-compaction if the compactor makes too many passes over it. In fact, relative soil compaction test results over 100% do not necessarily mean over-compaction because the relative compaction is based on the maximum dry density of the soil obtained by the Proctor test and this does not necessarily refer to absolute maximum dry density.

Over-compaction is considered undesirable because it may eventually create cracks in the underlying compacted material so that it results in a decrease in density. Moreover, it causes waste of machine power and manpower which is undesirable.

This question is taken from book named – A Self Learning Manual – Mastering Different Fields of Civil Engineering Works (VC-Q-A-Method) by Vincent T. H. CHU.