Compaction by Pressure and Jolting:

This is one of the effective methods of compacting very dry concrete. This method is used for compacting hollow blocks, solid concrete blocks and cavity blocks. The stiff concrete is pressed, vibrated, and also given jolts and due to this the stiff concrete gets compacted to dense form to give good strength. By applying great pressure, a concrete of very low water cement ratio could be compacted to yield very high strength. Generally this method is used in the laboratory.

Compaction by Spinning

Spinning is one of the recent methods of compaction of concrete and is used for the fabrication of concrete pipes. The plastic concrete while spun at an extremely high speed, gets well compacted through centrifugal force.