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Various tests for workability of concrete at construction sites i.e slump test, Vee-bee test, Compaction factor test and its recommended values are given below.

What is workability of concrete and What are tests is generally performed at site for its determination? And what are its recommended values for different purposes?

Workability of concrete describes the ease or difficulty with which the concrete is handled, transported and placed between the forms with minimum loss of homogeneity.

Workability is important because, if

i. the concrete mixture is too wet, coarse aggregates settle at the bottom of concrete mass and as a result concrete becomes non-uniform composition,

ii. the concrete mixture is too dry, it will be difficult to handle and place it in position

Tests for Workability of Concrete

Workability of concrete mixture is measured by:

a) Vee-bee consistometer test

b) Compaction factor test

c) Slump test

The first two tests are laboratory tests while the third test is the field test.

Concrete Slump Test

This test is carried out with a mould called slump cone whose top diameter is 10cm, bottom diameter is 20 cm and height is 30 cm. the test may be performed in the following steps:

1. Place the slump mould on a smooth flat and non-absorbent surface.

2. Mix the dry ingredients of the concrete thoroughly till a uniform colour is obtained and then add the required quantity of water.

3. Place the mixed concrete in the mould to about one-fourth of its height.

Slump test

4. Compact the concrete 25 times with the help of a tamping rod uniformly all over the area.

5. Place the concrete in the mould about half of its height and compact it again.

6. Place the concrete up to its three fourth height and then up to its top. Compact each layer 25 times with the help of tamping rod uniformly. For the second subsequent layers, the tamping rod should penetrate into underlying layers.

7. Strike off the top surface of mould with a trowel or tamping rod so that the mould is filled to its top.

8. Remove the mould immediately, ensuring its movement in vertical direction.

9. When the settlement of concrete stops, measure the subsidence of the concrete in millimeters which is the required slump of the concrete.

Measurement of slump

Figure: Measurement of slump

Suitability of Slump Test:

The slump test is suitable only for the concrete of high or medium workability.

Recommended Values of Concrete Slump Tests for Various Purposes:

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

 

Read More:

What Is Workability of Concrete? Workability vs. Strength of Concrete

Concrete Slump Test – Procedure and Results

Factors Affecting Workability of Concrete

Concrete Workability – Slump & Compacting Factor Values and Uses

Vee-Bee Test to Determine Concrete Workability using Consistometer

About Gopal MishraVerified

Gopal Mishra is a Civil Engineer from NIT Calicut and has more than 10 years of experience in Civil Engineering and Construction. He is the founder of The Constructor.

Comments ( 31 )

  1. Whats is slump require for road payment…?
    as per morth or standard it is 20 to 40 but, ot os nt possible to lay concrete in mumbai region.so plz help me…..

  2. Gurpinderjit Singh Nigah hello frnd. environment situation 2.Rm c transfer and height of placing location,material quality,design mix,machinery & instrument various factor are effect on slump.and first 2 factor we are face max.on site.

  3. Hmm a lot difference between an engineer & an architects. But both work depends on each other.

  4. Y not possible ? What problem you face in this slump ?

  5. please write something on contract management

  6. AS PER SITE SLUMP NOT POSSIBLY 80 TO 150MM

  7. Salvador 'Grizzly' Montoya
    Jun 6, 2014 at 12:47

    Aqui no tiene nombre propio

  8. where did u get these recommended values of slump? do u mean that all other concretes are not vibrated by saying concrete to be vibrated in point no.6 of recommended slump values

  9. Parniyan Salari
    Dec 1, 2013 at 11:13

    Never knew architects would get their hands dirty

  10. Refreshing theory of Engineering….

  11. yar da allah da para us ye ho maaf kai kana….

  12. Karthikeyan Alagesan
    Sep 28, 2013 at 05:02

    For piling

  13. Thia is nor a fact. You may try to time loss for every one. Is not it

  14. Useful and very well explained

  15. based to which slandered that informations?

  16. can any body help me to provide the accurate productivity of these below:
    * 30 cum RCC work how much mason,labor,water man required.
    *which machinery is used? and its productivity
    * steel reinforcement 100 kg how many steel fitter and helper required in how many hours.

  17. Nestorio V. Briones
    Sep 27, 2013 at 15:34

    what action to be taken if the concrete mix during actual pouring failed to the required slump? the truck mixer to be returned to batching plant or it can rectify it at site until required slump is attained?

  18. 20 to 40mm slump is practically not possible in paving roads manually.

  19. Concrete for canal lining.

    70 to 80 mm.

  20. Rohtash Verma Hisar
    Mar 19, 2013 at 16:46

    gd.

  21. Normal Concreting Slump Around 75+/-25.

  22. what is the required slump for concrete paver canal lining machine.

  23. Mohsin Abdakhan
    Jan 4, 2013 at 19:20

    High 60 to 180.

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