Twice the Kelly ball reading approximately equals the slump.
The Kelly ball test is considered to be simple and much faster than the slump test.
The apparatus is used to determine the work ability of Portland cement & concrete.
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
Kelley Ball Penetration Apparatus Operation Manual, Lab Instructor Guide and Student Workbook. Kelley Ball Penetration Apparatus for Educational Vocational, Didactic Technical Training Equipment Labs.