Slump cone test for workability ?

Slump cone test for workability ? 
Concrete slump test or slump cone test is to compose the consistency or  workability  of concrete mix ready at the laboratory or the construction site during the procedure of the work.

Slump-cone-test-detail

 slump cone test is the most simple workability test for concrete, involves general cost and provides instant results.Generally concrete slump cone test value is used to search the workability, which indicates w/c ratio, but there are more factors including, mixing methods, dosage, admixtures  properties of materials etc. also effect the concrete slump value.

Slump cone test propertises

The concrete slump cone test quantify the consistency of fresh concrete previous  it sets. It is featured to check the workability of freshly ready mix concrete, and therefore the ease with which concrete flows in casting time. It can also be used as an indicator of an inaccurate mixed batch.
slump-cone-test
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Apparatuses for slump cone test 1.slump cone
 2.
 non porous base plate
 3. measuring scale
 4. tempering rodThe mold of slump cone  test  mold height 30 cm, bottom dia 20 cm and top dia 10 cm and tamping rod is of steel 16 mm dia and 60cm long and rounded steel bar.

Procedure for Slump Cone Test 

  • Clean the inner surface of the mould and apply  shuttering oil properly.
  • Place the mould  horizontal   non porous base plate.
  • Filling mould with the ready concrete mix in 4 almost equal layers.
  • Tamping each layer with 25 strokes of the rounded temping rod. For the next layers, the tamping should impale into the underlying layer.
  • Remove the extra concrete in top of mold with a trowel.
  • Raise the mould from the concrete instantly  in vertical direction.
  • Measure the slump as the difference between the height of the mould and that of height point of the specimen being tested so this is full process of slump cone test.
    type of slump
  1. True Slump – True slump is the only slump that can be measured in the test. The measurement is taken between the top of the cone and the top of the concrete after the cone has been removed so this is not possible in site during construction .
  2. Zero Slump – Zero slump is signal of very low water-cement ratio, which results in dry mix concrete. These type of concrete is generally used for road and highways project.
  3. Collapsed Slump – collapsed slump is signal of too high  water-cement ratio , i.e. concrete mix is too wet or it is a high workability mix, for which a slump test is not suitable.
     4. Shear Slump – The shear slump signal that the result is incomplete, and concrete to be retested.

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  Slump cone test value
Workability
                                                 Slump (mm)
Very Low
0 - 25
Low
25 - 50
Medium
50 - 100
High
100 - 175

How to find volume of slump cone
Bottom Diameter = 20 cm
Top Diameter = 10 cm
Height = 30 cm
Volume of Frustum = πh(R² + Rr + r²) / 3
       = 3.14 x 0.3 (0.1² + 0.1 x 0.05 + 0.05²) / 3
       = 0.0055 Cubic Meter
In this formula  you can easily calculate  volume for Slump cone test at Site.

conclusion of slump cone test-    this is  right slump that we used to measure. Conclusion. Allowable Slump Values ., 50  to 150 mm

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