A concrete slump is a concrete test designed to measure the consistency of fresh concrete. The test determines how far concrete slumps before it flows, enabling concrete mix designs to be adjusted for concrete that has settled or “slumped” in forms.
The slump cone is often used as a means of testing concrete concentrations for construction companies. This concrete slump test is a simple and economical procedure that gives concrete mix designs the needed flexibility for workability.
How Concrete Slump is Measured?
The concrete slump test is done by filling a cone with fresh concrete and then gently turning it upside down within 90 seconds. The distance the concrete flows before it starts to break off from the sides of the cone is the concrete slump.
The concrete slump test is done by filling a concrete slump cone with concrete. After filling, the concrete slump cone is inverted to allow concrete to flow towards the base of the concrete slump cone. The distance that concrete flows before it starts breaking off from the sides of the concrete slump cone is the concrete slump.
The concrete slump test generally indicates the consistency of concrete mixtures used in construction. The procedure is not sensitive to variations in water content, but it does detect changes in concrete mix proportions or aggregate gradation that might affect workability. This concrete slump test is used during concrete casting, particularly for large-dimensioned concrete.
Concrete Slump Test Procedure
1) Place concrete in a cone (a 6-inch diameter cone is most commonly used, but other sizes are available) and fill it with concrete to about four inches from the top of the cone. A narrower concrete slump cone can be utilized when testing small concrete samples or making local mix adjustments.
2) Use a concrete slump cone that is free of defects. Record the concrete slump test results on the production record for concrete mixtures made with that concrete. Manufacturers often print result tables on their concrete containers to simplify slump testing and concrete mix design calculations.
3) After filling, gently invert the concrete slump cone and note the concrete slump in inches. The concrete slump test should be conducted within 90 seconds of concrete placement to ensure accurate concrete slump readings.
4) If concrete is placed in the cone and allowed to stand without being moved, it will settle or slump further before breaking away from the sides of the concrete slump cone. This settling can cause inaccurate concrete slump measurements to be taken.
5) Clean concrete slump cone after concrete slump testing before moving it or placing concrete in it for other tests. Do not reuse concrete slump cones when concrete is used more than once.
What is the Concrete Slump Test?
A concrete slump is one of the most common tests to determine how fluid fresh concrete is, meaning how much work concrete can do when it’s in concrete forms. The concrete slump test is typically carried out by filling a concrete slump cone with concrete and then overturning it gently to allow concrete to flow towards the base of the concrete slump cone. The distance the concrete flows before it starts breaking off from the sides of the concrete slump cone (typically within 90 seconds) is the concrete slump.
A concrete slump is an important test for concrete workability that helps concrete mix designs to be adjusted for concrete that has settled or “slumped” in forms. The results of concrete slump tests are also often printed on the concrete product containers, which may make concrete slump testing even easier.
Why Concrete Slump Test is Important?
Concrete slump tests provide concrete mix designers with concrete workability for concrete placed in forms. The concrete slump also starts to show how concrete will settle or “slump” within the concrete form before it hardens, which can affect concrete strength and other concrete properties such as durability and frost resistance.
Finally, concrete slump test results are often available on concrete product containers for easy concrete slump testing.
How Concrete Slumps can be Measured?
There are concrete slump measuring devices, the most common being a simple concrete slump cone. Concrete slump cones come in a variety of sizes and shapes, but typically measure from 6 to 12 inches wide at the top and from 5 to 8 inches high. Other concrete slump testing devices include straight concrete slump cones and concrete slump tubes.
What Concrete Slump Test can Measure?
With concrete slump cone devices, concrete slumps are measured in inches, the typical concrete slump range being 3 to 6 inches. A concrete slump is typically more important when concrete is placed within concrete forms compared with concrete that is spread on an unreinforced soil surface.
What Concrete Slump Test can be Used for?
Concrete slumps are typically measured when concrete is being placed in concrete forms, which means concrete workability plays an important role compared to concrete slumps when concrete is spread on an unreinforced soil surface. This results in the importance of concrete slump tests increasing when concrete slabs or concrete columns are being poured.
What is the Concrete Slump Test Procedure?
The concrete slump test procedure involves filling a concrete slump cone with concrete and then inverting the concrete slump cone to allow concrete to flow towards the base of the concrete slump cone while taking concrete dimensions. When concrete dimensions are taken, concrete slumps range from 3to 6 inches
Concrete slump test results are often printed on concrete product containers, which may make concrete slump testing even easier
Why is a Concrete Slump Important?
When concrete is placed in concrete forms, concrete mix designs must be adjusted to account for concrete that has settled or “slumped” within the concrete form. In concrete slabs and concrete columns, concrete slumps can affect concrete strength and other concrete properties such as durability and frost resistance.
Concrete Slump is the Test Concrete Undergoes to Determine Its Quality
Concrete slump tests involve tamping concrete down into a cone cradle with tamping rods, tamping at different depths for each rod, and testing the final plug. The final plug is tested by pulling out the plugs consecutively with increasing force until it fails. This test is used to determine concrete slump, concrete density, concrete cylinder compressive strength and concrete volume.
To create concrete slump test samples, concrete is placed in a cylindrical mould, which is then filled to approximately two-thirds of its volume. This concrete plug is then removed from the mould and compressed with increasing force until it fails, creating a concrete slump test sample.
When concrete is tested for slump flow it has a value that will affect the concrete used in the construction of a building for example, if the concrete has to be pumped from one place to another because it isn’t possible to use other methods. The concrete’s slump flow can also affect how well concrete adheres to reinforcement bars.
The concrete slump test is used to determine the concrete’s ability to flow. The value of the concrete slump is also related to concrete strength, as a stronger concrete mixture will have a higher slump number.
A concrete slump is one of the most important tests that are performed on concrete which helps in determining whether it can be ready for concrete pavement or concrete bridge.
There are three slump test methods that are used for concrete slump testing. These include the rapid slump method, the Arizona concrete slump test and also a modified version of the rapid slump method. With both of these tests, concrete is placed in a cone cradle using a tamper to create a concrete plug that will be tested.
The concrete slump test is one of a number of concrete tests performed to determine the quality and capability of concrete. Determining concrete slumps, along with concrete density and compressive strength, is an important part of many concrete projects.
Concrete slump test samples are created by placing concrete into a cylindrical mould to create concrete cylinders. These concrete cylinders are then compressed until failure occurs to determine the concrete slump value.
The concrete slump test is used to determine concrete’s ability to flow, its strength and the strength of concrete with reinforcing bars. The concrete slump test is one of many concrete tests performed.
Usage of Freshly Mixed Concrete and Excess Concrete
Freshly mixed concrete and excess concrete from concrete forms and concrete trucks should not be used for concrete slump testing due to the high probability of obtaining a failed result.
How to Get Zero Slump Concrete?
If concrete is not mixed correctly, it can develop a concrete slump. A concrete slump is a concrete that has too much or too little water. This means the concrete will not flow smoothly and may collapse slightly after it hardens. To ensure concrete does not slump, you must mix concrete properly.
Neither under- nor over-watering concrete will cause a concrete slump. Concrete that is either too wet or too dry will cause a concrete slump. The concrete needs a certain amount of water to be mixed properly and this water must be distributed evenly through the concrete mixture.
When concrete is not properly mixed, it does not have the right cement-to-sand ratio and loses its ability to drain water and bond together. This concrete will slump and form a weak concrete mixture
Over-watering concrete can make it too thin, decreasing the concrete’s ability to hold itself together and forming a concrete slump. Concrete should be thick enough to hold its shape without breaking or cracking when lifted off the ground, but not so thick that it cannot flow into the concrete forms
Concrete slump can be measured by concrete slump flow test. The concrete slump flow test measures the concrete slump in per cent of water added. If the concrete slump is above 10 per cent, mix concrete again to see if the concrete slump can be reduced or removed.
Shear Slump Concrete
Shear slump concrete is concrete with concrete slumps due to poor mixing techniques. Shear slump concrete can be remedied by removing the concrete slump and pouring fresh concrete.
Over-watering concrete will make it too thin, causing a concrete slump. While under-watering concrete may cause a concrete slump as well, over-watering concrete is much more common.
Not mixing concrete thoroughly will cause concrete slumps. This is because the concrete does not have the right amount of cement to sand ratio and loses its ability to drain water and bond together. Concrete should be thick enough so it can hold its shape but thin enough so it flows into concrete forms
Concrete Slump Explained
A concrete slump is best described as when concrete has lost most of its fluidity, leaving the mixture gooey and sticky. This can best be achieved in a short amount of time by adding water to it or applying pressure to the mixture itself.
When this happens, you then test out how well your concrete is flowing (referred to as flow table). Concrete slump testing measures the consistency of freshly mixed concrete before it sets up completely.
Types of Concrete Slump
Concrete slump test measurements are based on the height of a conical slump cone. There are three types of concrete slumps – low, medium and high.
- Low Concrete Slump: 3-inches or less
- Medium Concrete Slump: 4-inches to 6-inches
- High Concrete Slump: 7 inches or more
There are three different types of slump tests: drop test, thumb test, and flow table test which all measure various levels of consistency for freshly mixed cement.
What is a True Slump Concrete?
A good slump test is one that is best done when the cement has just been mixed up. If it has already started to set, then you will get a different result.
Slump tests are best done when fresh concrete comes off the ready-mix truck and before it sets in the form or in the mould. It should be between 1/2 inches to 2 inches thick in the form or in the bucket. Testing concrete slumps can help you determine whether your cement was mixed properly by doing slump tests for concrete.
What are Some Projects that Use Concrete Slumps?
Some projects that use concrete slumps are
- Hard standing slab gutters
- Garage floorings
- Basement floors
- House slabs and even retaining walls etc.
What is the Price Range for Concrete Slump Installation?
It’s best to check with your supplier Concrete slumps can vary from job to job. We can have a difference in materials properties, other differences can be fluid i.e (water-cement ratio), workability, the concrete mix used, wet or dry mix choice etc. will all affect the cost of concrete installation.
Concrete slumps do not have a specific value that you should aim for as they can change based on the project and weather conditions.
There’s a lot of information to take in when it comes to having concrete slumps installed. Making sure you’re hiring the right professional for your project is crucial, so that means making sure that you do some research and find out what others have had done before. If you have any concerns or questions about how this process works, make sure to talk to a Concrete professional if needed!
Your location can influence some concrete slump decisions. For example, if you stay in Europe, the European standard will be applied during your construction. If you are installing in a low-temperature region or a hot region, a sample slump layer can be constructed first to prevent collapse slump occurrence.
What’s the Best Way to Learn How to Reach Your Concrete Slump Goals?
There are a few things you can do:
- Find out if your state or municipality has regulations that deal with concrete slumps.
- Do an internet search on “slump testing guidelines” and choose one that works for you.
And finally, talk to a specialist such as yourself! Ask them questions about what needs to be done; questions such as will your concrete slump affect existing pipework bedding
How To Perform a Concrete Slump Test?
Concrete slump testing is also very helpful in assessing the quality of the concrete mix itself. When you are building a structure, it’s important that everything lines up correctly with your plans and specifications. A concrete slump test will determine if your concrete is ready to use or not, the test is also conducted to prevent collapse slump.
How to Perform a Concrete Slump Test to Avoid Improperly Mixed Batch Concrete?
Note: The information below is for entertainment purposes only and should not be used as a guide for testing.
For concrete slump testing, you may need is a small slope or ramp, an empty bucket or some kind of container to mix the concrete in, and then test by filling it with your mixture.
The Steps on How to Perform a Concrete Slump Test are the Following:
1. Draw out a line on the ground where you want your slumps measured from. Use this line as the starting point as an indication of the entire process so that you’ll have something to compare your slumped area to after making changes. This will be used as one measurement for comparison during slump testing for concrete.
2. Use mould-form on each corner of your newly drawn line on the ground, being careful not to pull them out when removing them later on in the slump test.
3. Fill a clean, empty bucket with the concrete mixture that you intend to use for your slumps. The best professional for Concrete Slump? You’ll then want to place this filled bucket of concrete on top of the stakes that you’ve already placed down in order to keep it from tipping over while performing your slump test.
4. Next, you’ll need a straightedge or slump cone leaning against the front edge of the bucket so that you can measure how far over the side of your new slump is going. Note; be careful so the weight for the layer of concrete does not create air pockets. This will be used as one measurement for comparison during slump testing for concrete.
5. Remove the mould and straightedge, and carefully spin around to see how much space there is between where it was and your line. This is what will be used for the other measurement during slump testing for concrete
6. Repeat steps 3 through 5 until you have two measurements on each side of your bucket, all while keeping in mind that the two measurements on each side must not vary by more than 1/2 inch to keep your concrete mixture at its best quality.
The most common slump values that are recommended are 1-inch to 2-inches for most jobs, but it really depends on the industry and location of where you’re getting your job done.
NOTE: Be careful to avoid Zero Slump.
Zero slumps occur as a result of dry mixes of concrete. Trench filled foundations are sometimes prone to this error because excess concrete might be mixed with small water or too much water is added to the concrete.
A high water-cement ratio, i.e. concrete mix is too wet or it is a high workability mix, is not appropriate for the slump test.
Types of Concrete Slump Tests
- Standard Test
- Elapsed Time Test
- Automatic & Pneumatic
- Transit Time
- Slip Form Vibrator
- The Pressuremeter Test.