A concrete slump test is a commonly used test. Its purpose is to show the consistency of the fresh concrete mix. The concrete slump test gives immediate results and can also tell if the concrete mix has been blended accurately or not. This is a cheap and easy way to test concrete. The slump test is used on site to directly help determine the quality of the concrete.
When doing a concrete slump test, you take a metal cone, place it on a surface that is hard, stable and doesn't absorb anything, and then fill it up with concrete in different steps. We will explain the process further below.
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The characteristics determine how the consistency of the mix will be.
If there is too much water, the mix will be loose, and if it is too little water the mix will be difficult to work with.
The temperature of the mix will decide how slow or fast the concrete will harden.
To be able to perform a concrete slump test in a proper way, you need the following equipment:
- A metallic mould in the shape of a cone. The measurements should be 20 cm (8 in) in diameter measured at the bottom, 10 cm (4 in) in top diameter and a height of 30 cm (12in).
- Tamping rod in steel. This shall be 16 mm (approx. 0,63 in) in diameter and have a length of 60 cm (approx. 24 in) with one of the ends rounded.
The procedure for the concrete slump test is:
Read more: Curious to know more about different tests of concrete? Learn more of the concrete cube test here!
There are four different types of results you can get from a slump test. These are:
- Zero Slump.
If you get the result of zero slump, the concrete retains its shape completely after the cone is removed. A dry kind of mix is holding this shape.
- Shear Slump.
The shear slump indicates that the test should be retaken.
- True Slump.
The mix retains its shape to a large degree.
- Collapsed Slump.
A collapsed slump means that the amount of water in the mix is too high, and the concrete is too “loose”.
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To be able to execute a slump test for concrete, you’ll need a metal mould shaped as a cone, a steel tamping rod, and a trowel.
By doing a slump test, you can determine the quality and the workability of a concrete mix. You will also be able to see if the ingredients were proportioned wrong and if the ratio between water and cement is correct.
Yes! Since you only need 3 tools and the concrete mix, it is a very cheap and easy test if you want to measure the quality and workability of your concrete mix.
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