Ball penetration test for concrete
Ball penetration test or kelly ball test used to measure concrete workability. The ball penetration test is easier and quicker to perform when compared to the slump test. The test conducted by measuring the penetration of a hemisphere of 152 mm(6 in) diameter and weight of 14 kg (30 lb) under it self-weight into the concrete. The figure no:1 showing the kelly ball.
The use of this test declined in recent years. However, it is simpler and quicker to perform. Also, it can be used to test the concrete while it is in forms. To avoid boundary effects, the depth of concrete should be more than 200 mm (8 in), and the least lateral dimension should be more than 460 mm (18 in).
The test will be conducted by placing the ball penetration test apparatus above the concrete surface. The frame of the apparatus should rest on the concrete surface, as shown in figure no:2. Then the ball will allow to fall, and the penetration depth will be recorded. The reading of penetration should be taken to the nearest 0.60 cm (0.25 in). The test should be repeated four times by placing the apparatus on different locations for the same concrete sample. The workability is the average of test results.