Scabbling

Scabbling is a process of removing a thin layer of concrete from a structure, this can be achieved by air powered chipping machines.A typical Air-Powered machine uses several heads, each with several carbide tips that peck at the concrete. It takes several passes with the machine to achieve the required depth.
The machine known as a Scabbler operates by pounding a number of rods, tipped with steel or carbide, down on the concrete surface in rapid succession
The process is used to remove road marking, surface contamination (used in the nuclear industry) or to add a decorative or textured pattern to the concrete.

Also known as scappling, in building, it is the process of reducing a stone to a rough square by the axe or hammer. In Kent the rag-stone masons call this knobbling.

References

*1911