Fat

Summary

Fat - is a term used to describe the excess concrete paste found on top of a concrete slab after it has been placed and compacted.

Technical Information

A layer of fat is usually found on top of a freshly placed concrete slab after vibration. This layer is required for floating and trowelling, as it ensures that there is no exposed aggregate.

When installing a slab with armoured joints, it is important to ensure that the joint armour is clear of fat at all times. Failure to do so will result in part of the slab protruding upwards when it has hardened which, if caught by a Materials Handling Equipment (MHE) wheel, can cause damage. This makes that area of the slab more vulnerable to further impacts from MHE wheels.