Scabbling

In masonry, it refers to shaping a stone to a rough square by use of an axe or hammer.

In modern construction, scabbling is a mechanical process of removing a thin layer of concrete from a structure, typically achieved by compressed air powered machines.

A typical scabbling machine uses several heads, each with several carbide or steel tips that peck at the concrete.

It operates by pounding a number of tipped rods down onto the concrete surface in rapid succession.

[2] Scarifying machines with flails attached to a drum cage are sometimes referred to as rotary scabblers.

Example of a compact scabbler machine. Video.
A worker beginning to scabble a concrete foundation prior to installing grout for an equipment skid.
Closeup of scabbled concrete during the process of preparing a foundation for grouting under a new equipment skid.