The factors which affect compaction are:
- Water content
- Amount of compaction
- Types of soil
- Method of compaction and
Water content:- As it evident from laboratory compaction tests, the dry density increases with water content, attains a maximum at O.M.C. and thereafter decreases with further increase in water content.
Amount of compaction:- The amount of compaction affects both maximum dry density and optimum water content. An increase of compactive effort, for a given soil, causes an increase in dry density and decrease in optimum water content.
Types of soil:- For a given compaction effort, the maximum dry density achieved depends to a large extent upon the soil type. In general, well-graded coarse-grained soils attain much higher maximum density at lower maximum content when compared with fine-grained soils.
Method of compaction:- The dry density achieved depends not only upon the amount of compactive effort but also on the method of compaction. For the same amount of compactive effort, the dry density will depend upon whether the method of compaction utilizes kneading action or rolling action, dynamic action, or static action.
Admixtures:- The addition of certain admixtures to soils results in modification of their compaction properties. Calcium chlorid3e has been a widely used chemical additive.