The apparatus is used to determine the workability of Portland cement & concrete.
The Kelly ball test is considered to be simple and much faster than the slump test.
Twice the Kelly ball reading approximately equals the slump.
It consists of a cylinder with a ball shaped bottom and handle, together weighing 15 kg.
A strip frame, guides the handle and serves as a reference for measuring the depth of penetration.
Penetration can be recorded to the nearest 0.5 mm.
The handle is graduated in mm.