Degree Of Compaction
Degree of compaction = Field dry density / maximum dry density determined in the laboratory.
For non-cohesive soil, it is some times called density index.
Optimum Moisture Content
The moisture content of the soil sample is at which a certain amount of compaction gives maximum dry density is known as optimum moisture content.
Maximum Dry Density
It is the dry density of soil sample at optimum moisture content.
In the compaction process, the energy applied per unit of soil is called compacting effort.
The compacting effort to the soil in the field is imparted by mechanical rollers. The magnitude of compacting effort plays an important role in the compaction process.
An increase in compacting effort result in an increase in the maximum dry density and a corresponding decrease in the optimum moisture content.