Kelly ball test also known as a ball penetration test is done on freshly mixed concrete to check its workability. It is a fast simple field test and is taken as a choice to the slump test.
1. Kelly Ball Test Apparatus
The Kelly ball apparatus consists of a metal ball that is hemispherical and weighs about 13.6 kilograms (30 pounds). The radius of the metal ball is about 7.5 cm (3 inches).
The flat end of the metal ball is connected to a graduated stem with a handle. A frame is managed between the ball and the stem in a way that the stem can move through it when the ball slides vertically. The frame majorly lies on the concrete surface during testing.
2. Kelly Ball Test Procedure
The procedure of the Kelly ball workability test is as follows.
a. A huge quantity of freshly mixed concrete is considered and is flowed into a container.
b. The container should be more than large sufficient to keep the Kelly ball apparatus in it.
c. The depth of flowed concrete should be a minimum of 20 cm.
d. The level of the concrete surface utilizing the best equipment.
e. Keep the Kelly ball apparatus on the leveled concrete surface utilizing the handle given.
f. The apparatus should be kept that way the frame should lie on the concrete surface and also the center of the metal ball should be a minimum of 23 cm away from any end of the container.
g. Now remove the handle and permit the ball to penetrate through the concrete. Write down the penetration value by looking at the reading on the graduated stem. The observation should be considered to the nearest 0.6 cm (1/4 inch).
h. Repeat the previous procedure more than 4 times by keeping the apparatus at various points on the same test sample.
i. The workability of concrete is the mean value of all the readings taken.
4. Result
The workability of concrete = Ball penetration value = average of all the readings obtained.
5. Advantages of the Kelly Ball Test
The advantages of the kelly ball workability test are as follows:
a. This test can be performed in the field.
b. It is a quicker and more precise test compared to the slump test.
6. Disadvantages of Kelly Ball Test
The drawbacks of the kelly ball workability test are as follows.
a. A huge quantity of test samples is needed to do the test.
b. The test sample of concrete must be leveled to do the test.
c. This test may not result accurately when huge-size coarse aggregates are utilized in the concrete. Hence, it is not commonly utilized.
7. References1. Content Filter & Authenticity Checking Team, The Civil Engineering (Our team checks every content & detail to maintain quality.) |
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