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How to workability test of concrete by slump cone? What is true slump?What is zero slump? What is shear slump? What is Slump cone test?

Slump cone test: This test is performed to determine the workability of fresh concrete. 

Appratus: In this test we take a mould of cone shape which top dia is 100mm and bottom dia is 200mm and height is 3000mm. For the compaction of concrete we take a tamping rod of 16mm dia and 600mm length.

Procedure of slump cone test:

Clean the internal surface of the mould.

Fill the mould with concrete in four uniformly layers.

Tamp each layer with 25 strocks to the tamping rod.

Distribute the strocks uniformly over the entire cross sections of the mould.

The rod should be penetrate every underlaying layer.

Strike off excess concrete after the top layer with trowel.

Remove the mould slowly and vertically.

The concrete will slump or slide.

Measure the height of slump in mm.

Now, take a sample from ready mixed pland and experment proced acording to above procedure and compare its slump value with following conditions which are given below.

Find the workability of concrete by the slump value:

1. When the degree of workability - Extremly low

It is moisture earth.Slump value is 0 mm.

Compacting factor 0.65 to 0.70

Vee-Bee degree less than 20 secomd.

Its can be used for precast paving slabs. Its consitency

2. When the degree of workability - Very low. 

Its consitency is very dry concrete.

Slump value 0 to 25 mm

Compacting factor 0.70 to 0.80

Vee-Bee degree 12 to 20 secomd.

Its can be used for blinding concrete, shallow sections.

3. When the degree of workability - low

Its consitency is dry concrete.

Slump value 25 to 50 mmCompacting factor 0.80 to 0.85

Vee-Bee degree 6 to 12 secomd.

Its can be used for mass concreting, highly reinforced, slab sections, beams, columns, flors, hand placed pavement, canal lining, strip footings.

4. When the degree of workability - Medium.

Its consitency is plastic concrete.

Slump value 50 to 100 mm

Compacting factor 0.85 to 0.95

Vee-Bee degree 3 to 6 secomd.

Its can be used for heavely reinforced slab sections, beams, walls, columns, sleep form work.

Slump value 100 to 175 mm.

Compacting factor 95 to 1.

Vee-Bee degree 0 to 3 secomd.

Its can be used for trench fill and in site piling.

5. When the degree of workability - High

Its consitency is plastic concrete.

Slump value 50 to 100 mm

Compacting factor 0.85 to 0.95

Vee-Bee degree 3 to 6 secomd.

Its can be used for heavely reinforced slab sections, beams, walls, columns, sleep form work.

Slump value 100 to 175 mm.

Compacting factor 95 to 1.

Vee-Bee degree 0 to 3 secomd.

Its can be used for trench fill and in site piling.

6. When the degree of workability - Very high

Slump value >175 mm.

Used as termie concrete.

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