Abstract
Soil is a nature made material which inherently does not exhibit the properties desired for construction. Enhancement the soil properties by means of compaction is a classical and widely used improvement method. Selection of an appropriated soil from a borrow pit and field compaction control can be achieved by laboratory compaction test results conducted under standard testing manuals, e.g. American Society for Testing and Materials. A change of a compaction mold size is one important regulation specified in the standard testing manuals. This report presents an influence of confining states, i.e. compaction mold sizes, on compaction test results. It is found that the compaction mold size affects laboratory compaction test results if a compacted specimen contains more than 20% of gravel. The results are accordance to those specified in the standard testing manuals.