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.
Specifications : 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. The handle is graduated in MM. Penetration can be recorded to the nearest 0.5mm.