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Tests on Fresh Concrete

Advances in Concrete Technology

(1724906)

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S ITARAMBHAI

N ARANJIBHAI

P ATEL

I NSTITUTE OF

T ECHNOLOGY &

R ESEARCH

C ENTRE,UMRAKH,BARDOLI

Presented under Subject:

Gujarat Technological University

Nisarg Mahendrabhai Mistry Enrolment No.- 130490749011

ME Construction Management

Contents

1. Workability Test Methods for Concrete.

2. Definitions.

3. Classes of Workability Measurements.

4. Compaction Factor Test

5. Slump Test

6. Kelly Ball Test

7. Vebe Consistometer Test

8. Flow Table Test

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Workability Test Methods for

Concrete

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Definitions

• Workability:

It is that property of freshly mixed concrete or mortar that determines the ease

with which it can be mixed, placed, consolidated, and finished to a

homogenous condition.

• Confined Flow Tests:

The material flows under its own weight or under an applied pressure through a

narrow orifice.

• Free Flow Tests:

The material either flows under its own weight, without any confinement or an

object penetrates the material by gravitational settling.

• Vibration Tests:

The material flows under the influence of applied vibration. The vibration is

applied by using a vibrating table, dropping the base supporting the material, an

external vibrator, or an internal vibrator.

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Classes of Workability Measurements

• The multitude of workability test methods can be divided into categories

based on several different classification schemes.

• Generally the assessment of workability can be classified into three classes, as

shown in Table .

• The majority of workability test methods fall into Class II and Class III

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Compaction Factor

Test

• Apparatus - Consist of a rigid frame

that supports two conical hoppers

vertically aligned and mounted

above a cylinder,

• Top hopper is slightly larger than

the bottom hopper & the cylinder is

smaller in volume than both

hoppers.

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Apparatus for max. aggregate size 20 mm

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Compaction Factor

Test Methodology Top hopper is filled with

concrete (Not Compacted)

door on the bottom of the top hopper is

opened

concrete is allowed to

drop into the lower hopper

All concrete fallen from top hopper

Lower hopper door

opened

All Concrete from lower hopper to cylinder

Mass of Concrete in cylinder is recorded

& it is compared to mass of fully compacted

conc.

(vibrated)

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Interpretation

• A larger apparatus is available for concretes with maximum aggregate sizes

of up to 40 mm. The results of the compaction factor test can be correlated to

slump, although the relationship is not linear.

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Slump Test

• The slump test is the

– most well-known

– widely used test method to characterize the workability of fresh

concrete.

– inexpensive test

– used on job sites to determine rapidly whether a concrete batch should

be accepted or rejected.

– widely standardized throughout the world

• Apparatus:

– Mold in the shape of a frustum of a cone

– Base diameter of 8 inches, Top diameter of 4 inches, Height of 12

inches.

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Methodology

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Mold Filled with conc. (3 layers of equal vol.)

Each layer compacted with 25

strokes of temping

Rod

slump cone mold is lifted

vertically upward

change in height of

the concrete is measured

Type of slump is Recorded (One from

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All Concrete from lower hopper to cylinder

Mass of Concrete in cylinder is recorded

& it is compared to mass of fully compacted

conc.

(vibrated)

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Types of Slump

Procedure

Interpretation

• The only type of slump permissible is the “true” slump, where the concrete

remains intact and retains a symmetric shape.

• The slump test is not considered applicable for concretes with a maximum

coarse aggregate size greater than 1.5 inches. For concrete with aggregate

greater than 1.5 inches in size, such larger particles can be removed by wet

sieving.

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Consistency Grade Slump (in mm) Recommended method of Compaction

Stiff (K1) 0-60 Mechanical compaction like vibration

Plastic (K2) 60-130 Mechanical or Hand compaction(Rodding

,Tampering )

Flowing (K3) 130-200 Hand Compaction

Self Compacting (K4) >200 No Compaction

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Kelly Ball Test

• The Kelly ball test was formerly

standardized in ASTM (American

Standards for Testing and Materials) C360-

92: “Standard Test Method for Ball

Penetration in Freshly Mixed Cement

Concrete.”

• The ASTM standard was discontinued in

1999 due to lack of use. The test has never

been used widely outside the United States

(1992).

• The Kelly ball test provides an indication

of yield stress, as the test essentially

measures whether the stress applied by the

weight of the ball is greater than the yield

stress of the concrete.

• Dimensions are as shown in fig. & weight

= 30 pounds 12

Apparatus Dimensions

Procedure for Kelly Ball Test

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Interpretation

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• The value of slump is 1.10 to 2.00 times the Kelly

ball test reading. It has been claimed that the Kelly

ball test is more accurate in determining consistency

than the slump test

• Advantages:

– The test is faster than the slump test and can be

preformed on in-place concrete to obtain a direct

result quickly.

– It has been claimed that the Kelly ball test

provides more accurate results than the slump

test.

• Disadvantages:

– Like the slump test, the Kelly ball test is a static

test.

– The test must be performed on a level concrete

surface.

– The test is no longer widely used.

– Large aggregate can influence the results.

Vebe Consistometer Test

• The equipment for the test, as shown in

the above figure, was developed by

Swedish engineer V. Bahrner.

• The Vebe Consistometer measures the

remolding ability of concrete under

vibration.

• Vebe test – like slump test measures only

the consistency but more meaningful for

mixtures of concrete with low consistency.

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Procedure

• Vebe test equipment consists

of a

• vibrating table,

• cylindrical pan,

• a slump cone,

• glass or plastic disk

attached to a free-moving

rod,

• The time required to remold the

concrete, from the conical to the

cylindrical shape until the disk is

completely covered with

concrete,

is reported as the Vebe time in

seconds 16

• The flow table test

measures the

horizontal spread

of a concrete cone

specimen after

being subjected to

jolting.

• Introduced in

Germany in the

1930s.

• The frustum of a

cone used to mold

the concrete is

shorter than the

slump cone

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Flow Table Test

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Cone mold is placed in the center of the

plate

Filled in two layers

Each layer compacted with temping rod

Plate is lifted with attached handle (40

mm)

Lifted and dropped 15 times

Horizontal spread of the concrete is

Measured

Procedure

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Flow Table Test

• This method is appropriate for appropriate for highly fluid mixes that exhibit a

collapsed slump.

• The results of the test can be correlated to slump, at the initial horizontal spread,

prior to jolting,.

• Advantages:

– The test is simple and can be used in the field.

– The test quickly provides a direct result.

– The test is dynamic, making it especially appropriate for highly thixotropic

concrete mixtures.

• Disadvantages:

– The test procedure does not represent actual placement conditions—concrete is

typically vibrated, not jolted.

– The test results tend to converge as the number of drops is increased. Near the

end of the test, the properties of the thin layer of concrete do reflect the bulk

properties of the concrete. The results are not given in terms of fundamental

units. An analytical treatment of the test would be difficult.

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References

i. www.aboutcivil.org/Properties-of-concrete-factors-affecting

ii. up.edu.ps/ocw/repositories/PDF

iii. www.ce.berkeley.edu/~paulmont/CE60New/fresh_concrete

iv. 1.bp.blogspot.com

v. www.humboldtmfg.com/product-images/H-3655_lg.jpg

vi. www.xypex.com.au/images/Downloads/test_reports/chloride_resistance/

Dr_Wee_Tiong_HuanStudy_on_Fresh_and_Hardened_Properties_of_Co

ncrete

vii. blog.kryton.com/2013/08/concrete-workability-measurements-the-

slump-test

viii. www.icar.utexas.edu/publications/105/105_1.pdf

ix. elearning.vtu.ac.in/16/ENotes/ConcreteTechnology/unit3-NS.pdf

x. www.concreteplants.com/Images/CPIdocs/ACIGuidelinesForCement.pdf

xi. static.splashnology.com/articles/Texture_Packs_may_2012/Grunge_Con

crete_Textures.jpg

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