The Kelly ball test is a commonly used method for measuring the workability of freshly mixed concrete. It is also known as the ball penetration test, and is often used as an alternative to the slump test. This test is performed in the field and is relatively quick and simple to carry out. In this article, we will provide an overview of the test procedure for the Kelly ball test, as well as its advantages and drawbacks.
The Kelly ball test is designed to measure the consistency and workability of fresh concrete. It involves the use of a metal ball, which is dropped onto the surface of the concrete from a specific height. The depth of penetration of the ball into the concrete is then measured, and this measurement is used to determine the workability of the concrete.
One of the main advantages of the Kelly ball test is its simplicity and ease of use. It can be performed quickly in the field, and requires only a small amount of equipment. Additionally, the test does not require any special preparation of the concrete sample, which can be an advantage in certain situations.
However, there are also some drawbacks to the Kelly ball test. For example, the results can be affected by the skill and experience of the person carrying out the test. Additionally, the test may not be as accurate as other methods for measuring workability, such as the slump test. Finally, the test may not be suitable for all types of concrete mixes, and may need to be supplemented with other tests in some cases.
In conclusion, the Kelly ball test is a useful method for measuring the workability of freshly mixed concrete. It has several advantages over other methods, including its simplicity and ease of use. However, it also has some drawbacks, and may not be suitable for all types of concrete mixes. Overall, the Kelly ball test can be a valuable tool for concrete contractors and others involved in the construction industry.
wKelly Ball Test Apparatus
The Kelly ball apparatus is a device that comprises of a metal ball in a hemispherical shape, which weighs approximately 13.6 kilograms (30 pounds) and has a diameter of about 15 cm (6 inches). The flat end of the metal ball is connected to a graduated stem that has a handle for easy handling. In between the ball and the stem, a frame is placed, which enables the stem to slide vertically when the ball moves. Typically, the frame of the device rests on a concrete surface during testing.
Test Procedure of Kelly Ball Test
The Kelly ball workability test involves pouring a significant amount of freshly mixed concrete into a container that is wider than the Kelly ball apparatus. The depth of the poured concrete should be at least 20 cm, and the surface should be leveled using suitable equipment. The Kelly ball apparatus is then placed on the leveled concrete surface using the handle provided, ensuring that the frame rests on the concrete surface and the center of the metal ball is at least 23 cm away from any container edge.
Once the apparatus is in position, the handle is released, and the ball penetrates through the concrete. The penetration value is noted by observing the reading on the graduated stem, which should be taken to the nearest 0.6 cm (1/4 inch). This procedure is repeated four more times, placing the apparatus at different points on the same test sample.
The workability of the concrete is determined by calculating the average value of all the readings obtained from the test.
Result for Kelly Ball Test
The workability of concrete is determined by measuring its ball penetration value, which is calculated as the average of all the readings obtained during testing. This testing process involves using a standard ball to penetrate the concrete and recording the depth of penetration. The ball penetration value is an important factor in determining the strength and durability of the concrete, as it can affect its ability to resist wear and tear over time. By taking multiple readings and averaging them, a more accurate representation of the concrete’s workability can be obtained. This information is crucial in ensuring that the concrete is suitable for its intended use and will be able to withstand the stresses it will be subjected to in its lifetime.
Advantages of Kelly Ball Test
The Kelly Ball workability test has several advantages. One of the key benefits is that it can be conducted in the field, which means it can be performed on-site rather than in a laboratory. This can save time and resources as there is no need to transport samples to a lab for testing.
Another advantage of the Kelly Ball test is its speed and precision. Compared to the slump test, the Kelly Ball test is faster and more accurate. This means that results can be obtained quickly and with a higher level of accuracy, which is important when making decisions about the suitability of a particular concrete mix for a construction project.
Overall, the Kelly Ball workability test is a useful tool for assessing the workability of concrete mixes in the field. Its ability to provide quick and accurate results makes it an attractive option for engineers and contractors who need to make informed decisions about the suitability of concrete mixes for specific construction projects.
Drawbacks of Kelly Ball Test
The kelly ball workability test has some limitations that should be considered. Firstly, a significant amount of test sample is necessary to carry out the test, which may be challenging for small-scale projects. Additionally, the test sample of concrete must be levelled before performing the test, which can be time-consuming and require additional resources.
Moreover, the accuracy of the results obtained through this test may be affected when large size coarse aggregates are used in the concrete mix. Due to this limitation, the kelly ball workability test is not widely used in many countries as a reliable method for assessing the workability of concrete mixes. Therefore, it is essential to be aware of these drawbacks while considering the use of this test in concrete construction projects.