How many layers should the slump cone be filled in?

Three equal layers by volume (approx. 1/4, 1/2, and full height).

How many tamping strokes are required per layer?

25 strokes per layer using a 16 mm diameter tamping rod with a rounded end.

How fast should the slump cone be lifted?

It should be lifted vertically upwards in a steady motion taking exactly 5 to 10 seconds.

Where do you measure the slump from?

Measure the difference between the height of the mould and the highest point of the slumped test specimen.

IS 1199 Part 3

: 2018

Fresh Concrete - Methods of Sampling and Testing - Part 3: Determination of Compacting Factor

CurrentEssentialTesting MethodMaterials Science · Concrete

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This standard specifies the procedure for determining the workability and consistency of fresh concrete using the slump cone test. It is universally used by engineers on construction sites to verify that delivered concrete has the specified fluidity before it is placed.

Specifies the procedure for determining the compacting factor of fresh concrete.

Quick Reference Values

Top diameter of slump cone100 ± 2 mm

Bottom diameter of slump cone200 ± 2 mm

Height of slump cone300 ± 2 mm

Tamping rod diameter16 ± 1 mm

Tamping rod length600 ± 5 mm

Number of layers for filling3 equal layers (by volume)

Tamping strokes per layer25 strokes

Time to lift the mould5 to 10 seconds

Total time to complete testMax 150 seconds from start of filling

Key Formulas

Compacting Factor = m1 / m2 (where m1 is the mass of partially compacted concrete, m2 is the mass of fully compacted concrete)

Practical Notes

The slump measurement is taken from the highest point of the slumped concrete to the underside of the tamping rod placed over the mould.

If the concrete shears (one half slides down along an inclined plane) or collapses completely laterally, the test is invalid and must be repeated from the same batch.

The base plate must be placed on a level, rigid, and horizontal surface free from vibrations.