What Is Slump Cone Test | Principle of Slump Test | Types of Concrete Slump
Important Point
What Is Slump Cone Test?
A Slump cone test or concrete Slump test is to determine the workability or consistency of the concrete mixture prepared in the laboratory or at the construction site during the course of work.
A concrete Slump test is performed from batch to batch to check the uniform quality of the concrete during construction.
The Slump test is the simplest test of workability for concrete, involves low cost, and provides immediate results. Due to this fact, it has been widely used for workability tests since 1922.
The Slump is performed according to the procedures mentioned in the ASTM C143 standard in the United States, IS 1199 – 1959 in India, and EN 12350-2 in Europe.
Generally, the value of the concrete loss is used to find workability, which indicates the water-cement ratio, but there are several factors, including material properties, mixing methods, dosing, additives, etc. also affect the amount of concrete loss.
Also, read: M30 Grade of Concrete Mix Design Procedure with OPC 53 Cement
Principle of Slump Test
The result of the Slump test is a measure of the behavior of a compacted inverted concrete cone under the action of gravity.
It measures the consistency or moisture of the concrete, which gives an idea of the workability of the concrete mixture.
Slump Test Apparatus
- Slump Cone
- Scale for Measurement
- Temping Rod (steel)
Temping Rod (steel)
The Concrete Slump Test Procedure:
- The mold for the concrete Slump test is a 300 mm high cone-shaped trunk. The base is 200 mm (8 in) in diameter and has a smaller opening at the top of 100 mm (4 in).
- The base is placed on a smooth surface, and the container is filled with concrete in three layers, whose workability must be tested.
- Each layer is tempered 25 times with a standard 16 mm (5/8 in) diameter steel rod, rounded at the end.
- When the mold is completely filled with concrete, the upper surface is reached (flush with the upper opening of the mold) through the sieving and rolling motion of the quenching rod.
- The mold must be held firmly against its base during the entire operation so that it cannot move due to concrete leakage, and this can be done through handles or footrests welded to the mold.
- Immediately after completing the filling and leveling the concrete, the cone is slowly and carefully lifted vertically. An unsupported concrete will now Slump.
- The decrease in the height of the center of the Slumped concrete is called a Slump.
- The Slump is measured by placing the cone just beside the Slumped concrete, and the quenching rod is placed over the cone so that it also exceeds the area of the Slumped
- The decrease in the height of the concrete in relation to that of the mold is observed in (usually measured up to the nearest 5 mm (1/4 inch).
Also, read: What Is Honeycomb In Concrete | Cause | Cure | Type of Grouting
Precautions in the Slump Test
Concrete Slump Test To reduce the influence of Slumping variation in surface friction, the interior of the mold and its base must be moistened at the beginning of each test and, before lifting the mold, the area immediately around the base The cone must be cleaned of concrete that may have Slumped accidentally.
Types of Concrete Slump
Slumped concrete takes various forms and, according to the profile of Slump concrete, the Slump is termed as;
- True Slump
- Shear Slump
- Collapse Slump
1. True Slump:
In a real Slump, the concrete simply disappears, maintaining more or less the shape. This is the only Slump that is used in several tests.
Mixtures of rigid consistency show a Zero Slump, so that, in the very dry range, no variation can be detected between mixtures of different workability.
However, in a lean mixture with a tendency to roughness, a real Slump can easily change to the type of shear Slump or even collapse, and widely different Slump values can be obtained from different samples of the same mixture; therefore, the Slump test is not reliable for lean mixtures.
Also, read: What Is Cover in Concrete | Clear Cover in Beams, Slab, Column, Footing
2. Collapse Slump:
In a collapse Slump, the concrete Slumps completely. A collapse Slump generally means that the mixture is too moist or is a highly workable mixture, for which the Slump test is not appropriate.
This means that the water-cement ratio is very high, that is, the concrete mixture is very wet or is a highly workable mixture, for which a Slump test is not appropriate.
3. Shear Slump:
In a sheer Slump, the top of the concrete cuts and slides to the side. Or
If half of the cone slides downward on an inclined plane, the Slump is considered a sheer Slump.
The sheer Slump indicates that the result is incomplete, and the concrete needs to be tested again to obtain valid results. If a shear Slump or collapse is achieved, a new sample must be collected, and the test is repeated.
If the shear Slump persists, as can happen with aggressive mixtures, this is an indication of a lack of cohesion of the mix.
Also, read: Quality Testing of Sand for Concrete | Quality Testing of Sand for Construction | Type of Sand Test
Applications of Slump Test:
The Slump test is used to ensure uniformity for different batches of similar concrete under field conditions and to verify the effects of plasticizers on their introduction.
This test is very useful on the spot, as checking the variation from day to day or hourly in the materials being fed into the mixer. An increase in a Slump may mean, for example, that the moisture content of the aggregate has increased unexpectedly.
Another cause would be a change in the classification of the aggregate, such as a sand deficiency. A very high or very low Slump gives an immediate warning and allows the mixer operator to resolve the situation.
This application of Slump tests, as well as its simplicity, is responsible for its widespread use.
Slump Test
The Slump Test is a neural tension test used to detect altered neurodynamics or neural tissue sensitivity.
Slump Test of Concrete
Concrete slump testing is a quick and easy procedure that can be performed in real-time and on-site that is used to determine the workability as well as the consistency of fresh concrete. Concrete with slump values that are too low or too high can be identified and corrected prior to use.
Slump Value
In case of a shear slump, the slump value is measured as the difference in height between the height of the mould and the average value of the subsidence.
Slump Cone Size
The American standards explicitly state that the slump cone should have a height of 12-in (300 mm), a bottom diameter of 8-in (200 mm) and an upper diameter of 4-in (100 mm).
Slump Test Apparatus
The Slump Cone apparatus for conducting the slump test essentially consists of a metallic mould in the form of a frustum of a cone having the internal dimensions as Bottom diameter: 20 cm, Top diameter: 10 cm, Height: 30 cm and the thickness of the metallic sheet for the mould should not be thinner than 1.6 mm.
Slump Value for Different Grades of Concrete
Slump test procedure is performed to check the workability of concrete. A good workable concrete has good strength.
Slump test values for Different Concrete Mixes:
| Sr.No. | Concrete Mixes | Slump Range in mm |
|---|---|---|
| 1 | Beams & Slabs | 50-100mm |
| 2 | Columns, Retaining walls | 75-150mm |
| 3 | CC Pavements | 20-30mm |
| 4 | Decks of bridge | 30-75mm |
| 5 | Vibrated Concrete | 12-25mm |
| 6 | Huge Mass constructions | 25-50mm |
Slump Test Values
| Workability | Compaction Factor | Slump (mm) |
|---|---|---|
| Very Low | 0.78 | 0 – 25 |
| Low | 0.85 | 25 – 50 |
| Medium | 0.92 | 50 – 100 |
| High | 0.95 | 100 – 175 |
Concrete Slump Range
Concrete slumps have ranged from 4 to 6 in.
Slump of Concrete
Slump is the measure of concrete consistency and fluidity. It shows the flow and overall workability of freshly mixed concrete. Simply put, the higher the slump, the wetter the mix. Four-inch (4”) slump is very common with normal weight concrete and is a good for pumping.
True Slump
True slump refers to general drop of the concrete mass evenly all around without disintegration. Shear slump indicates that the concrete lacks cohesion. It may undergo segregation and bleeding and thus is undesirable for the durability of concrete.
Types of Slump
There are three types of slump that may occur in a slumps test, namely, true slump, shear slump and collapse slump. True slump refers to general drop of the concrete mass evenly all around without disintegration. Shear slump indicates that the concrete lacks cohesion.
Slump Value of Concrete
| Sr.No. | Types of concrete | Slump |
| 1 | Concrete for road construction | 20 to 40 mm |
| 2 | Concrete for tops of curbs, parapets, piers, slabs, and wall | 40 to 50 mm |
| 3 | Concrete for canal lining | 70 to 80 mm |
| 4 | Normal RCC work | 80 to 150 mm |
| 5 | Mass concrete | 20 to 50 mm |
| 6 | Concrete to be vibrated | 10 to 25 mm |
Slump in Concrete
Slump is the measure of concrete consistency and fluidity. It shows the flow and overall workability of freshly mixed concrete. Simply put, the higher the slump, the wetter the mix. Four-inch (4”) slump is very common with normal weight concrete and is a good for pumping.
Slump Cone Test Procedure
Place the mould on a smooth horizontal non-porous base plate. Fill the mould with the prepared concrete mix in 4 approximately equal layers. Tamp each layer with 25 strokes of the rounded end of the tamping rod in a uniform manner over the cross section of the mould.
Slump Cone Test Equipment
The slump cone test is a widely used test in civil engineering and construction to measure the consistency or workability of fresh concrete. The equipment required for conducting a slump cone test includes:
- Slump cone
- Base plate
- Tamping rod
- Measuring scale or tape
- Stopwatch
- Clean water
- Trowel
- Non-absorbent gloves
Slump Cone Test Standards
There are several standards that provide guidelines and specifications for conducting the Slump Cone Test. The most widely recognized standards for the Slump Cone Test are:
- ASTM C143/C143M
- AASHTO T 119
- BS EN 12350-2
- IS 1199-1959
Slump Cone Test Results
The slump test result is expressed in millimeters (mm) and represents the difference in height between the original height of the concrete and the height of the slumped concrete after the cone is removed. The slump value indicates the degree of flow or stiffness of the concrete.
Slump Cone Test Values
The slump cone test is a widely used test in the construction industry to measure the consistency and workability of fresh concrete. It determines the flow characteristics of concrete by measuring the slump, which is the amount of settlement or deformation that occurs when a conical-shaped sample of concrete is subjected to the removal of a slump cone.
Types of Slump Test
There are three types of slump that may occur in a slumps test, namely, true slump, shear slump and collapse slump.
True Slump Value
If the concrete slumps evenly it is called true slump. If one half of the cone slides down, it is called shear slump. In case of a shear slump, the slump value is measured as the difference in height between the height of the mould and the average value of the subsidence.
Concrete Slump Chart
The concrete slump chart, also known as the slump cone test, is a widely used method to measure the consistency or workability of fresh concrete. It determines the degree of flowability and cohesiveness of the concrete mixture, which is important for proper placement and compaction during construction. However, as an AI text-based model, I’m unable to provide visual charts or images. Nevertheless, I can describe how a typical concrete slump chart is structured and provide you with some general information.
Slump Test Range
The range of slump values can vary depending on the specific application and project requirements. Different types of concrete mixtures, such as those used for heavy structural elements or for highly flowable self-compacting concrete, may have different slump requirements. Additionally, construction specifications or industry standards in different regions may also specify specific slump ranges.
What Is Slump in Concrete?
In the context of concrete, “slump” refers to the consistency or workability of the material. It is a measure of how easily the concrete can be mixed, placed, and compacted without segregation or excessive bleeding of water.
What Is True Slump?
In a true slump the concrete simply subsides, keeping more or less to shape. In a shear slump the top portion of the concrete shears off and slips sideways. In a collapse slump the concrete collapses completely. Only a true slump is of any use in the test.
What Is Shear Slump?
Shear slump: If one-half of the cone slides down in an inclined plane, it is called a shear slump. Shear slump indicates lack of cohesion in the concrete mix. Shear slump may occur in the case of a harsh mix. Collapse slump: In this case, fresh concrete collapses completely.
Slump Cone Test How Many Layers
The steel slump cone is placed on a solid, impermeable, level base and filled with the fresh concrete in three equal layers. Each layer is rodded 25 times to ensure compaction. The third layer is finished off level with the top of the cone.
What Is the Recommended Slump for Rcc Work?
The recommended slump for reinforced concrete (RCC) work can vary depending on several factors such as the type of construction, the specific requirements of the project, and the construction practices followed in a particular region. However, a common range for slump values in RCC work is between 50mm and 100mm (2 inches to 4 inches).
Here are some general guidelines for slump values in RCC work:
- Foundations and Footings: Slump values between 50mm and 75mm (2 inches to 3 inches)
- Columns and Beams: Slump values between 75mm and 100mm (3 inches to 4 inches)
- Slabs and Pavements: Slump values between 75mm and 100mm (3 inches to 4 inches)
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Good presentation
Thank you
But would have dropped the sketches of the types of slump results