Compaction

Summary

Compaction - is the reduction of air voids in fresh concrete after it has been placed.

Technical Information

Methods of compaction include:

Internal vibration – Pokers are inserted into the concrete element at a regular distance from each other. As they vibrate, air bubbles rise from within the slab depth and leave the concrete at the surface.
External vibration – Certain screeding equipment can vibrate to compact the concrete at the same time as screeding it.
Hand compaction (Rodding, ramming and tamping) – The concrete is hit by hand using various methods and types of stick. Generally only used in small-scale projects where it’s not economical to compact by vibration.

Proper compaction is essential because unwanted air in the concrete could lead to relatively large voids which, in turn, could lead to lower strength and durability of the concrete.