Slump Test

• The slump test is used to measure the workability of freshly made concrete. If concrete is made on the plant, a slump test is done on the plant itself.
• Equipment for slump tests can be easily carried on site. No specialist is required for the slump test. Therefore slump test is used more.
• The method of the slump test is simple and easy. Therefore slump test is used more in fieldwork.
• According to IS code, the nominal aggregate size in fresh concrete in the slump test should not be more than 38 mm.
• The slump test of each batch of concrete mixer can be prepared. During construction slump test is done to get uniform quality of concrete.
• The water-cement ratio can be improved with a slump test.
• The slump test gives good results for the workability of concrete with a 25 to 125 mm slump.

Apparatus of Slump Test

1. Slump Cone

2. Temping Rod

3. Baseplate

Procedure of Slump Test

• First, take the slump cone and tamping rod to the place where the workability of the concrete is to be checked.
• The inside surface of the slump cone is then cleaned. Oil is applied to the inner surface of the slump cone so that the concrete can slide comfortably into the slump cone.
• The slump cone is then placed on a flat surface. The concrete is then filled layer-wise into the slump cone. Each level is pressed 25 times with a temping rod.
• The top layer is finished with a towel after the concrete is filled up in the slump cone. Now the slump cone is slowly lifted upwards, so the concrete slowly settles down.
• The distance between the surface of the slump cone and the surface of the concrete is called a slump.

Type of Slump

1. True Slump

2. Shear Slump

3. Collapse Slump

4. Zero Slump

Factors Affecting of Slump Test

1. The ground should be level for the slump test. If the ground level is not level, then slump results are not correct.
2. The slump test depends on the weather. As a result, it is not accurate in hot weather.
3. Depending on the surface of the slump cone, if the surface inside the slump is rough, the result will not be true.
4. Transport plays an important role in the slump test.
5. Water cement ratio pan plays an important role in the slump test.

Advantage of Slump Test

1. The equipment for the slump test is light in weight.
2. The method of the slump test is easy.
3. The equipment of the slump test can be easily transferred.
4. The slump test can be done both in the field and in the laboratory.
5. The result of the slump test is obtained fast.
6. Equipment for the slump test is cheap.
7. Only one man is required for the slump test.
8. The slump test gives good results for the workability of concrete with a 25 to 125 mm slump.
9. A slump test is done to maintain the consistency of materials like aggregate, sand and admixture, etc.

Disadvantage of Slump Test

1. The slump test does not show workability for very wet and dry concrete.
2. It does not give workability even in the concrete of hard mixing.
3. The workability of the concrete in each batch varies.
4. In this type of test, sufficient compaction should be done with the temping rod.
5. Different results are obtained on the site and the plant.
6. The surface of the base plate for the slump test should be free from vibration.
7. Concrete should not be filled together in the slump test. It should be compacted about the level.
8. Depending on the surface of the slump cone, if the surface inside the slump is rough, the result will not be true.
9. The surface of the base plate for the slump test should be free from vibration.

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What Is a Slump Test?

Why Is the Slump Test Important?

What Equipment Is Used in the Slump Test?

What Are the Types of Slump?

What Factors Affect the Slump Test?

What Are the Advantages of the Slump Test?