Concrete Slump Test – Experiment Procedure

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The strength of any building mainly depends on the quality of the materials used.

Concrete is a macro content. Even though we have tested its micro contents such as sand, cement, blue metal, and water. The mixing method and proportioning of the micro-ingredients may affect the strength of the concrete.

Concrete Slump Test

Scope

The Scope of this field test is to ensure the concrete’s workability and consistency before casting it. The purpose of this test is to avoid using the low-quality concrete mix for casting.

We all use mostly RMC on site. So it is our responsibility to ensure that the concrete is in good quality.

Required EquipmentConcrete Slump Cone Model

  • Slump Cone Model
  • Trowel
  • Tamping Rod
  • Square Pan

Cone Mould Size should be

  • Top Diameter – 10 cm
  • Base Diameter – 20 cm
  • Height – 30 cm 

Procedure to do the slump test

  • The Inner surface of the cone should be free from dust & moisture.
  • Apply one coat of oil inside.
  • Ensure the place is smooth and horizontal where you going to place the cone.
  • First, fill up the cone with concrete 1/4th of the height.
  • Tamp the concrete layer with 20-25 times with help of tamping rod.
  • Then follow the same procedure by placing 1/2 & 3/4 of concrete respectively.
  • Once you fill the cone up to the top. Gently remove the cone from the concrete. Refer the pictures.
Tamping Procedure Removing Cone Procedure Measuring Cone Procedure

Test Results

The result of this slump test value should be recorded in millimeters. The resulting slump can be in different range.

Types of Slump and Ranges

Definition – Slump is the gap between the mold top (after removal) and the top of result concrete.

Types of concrete slump

RANGEASPECT
Collapsed SlumpThe concrete collapses completely. This indicates very the concrete is too wet. Not suitable for casting
Shear SlumpPart of the concrete (top portion) slips sideways as shown in the picture. We have to reconduct the test again
True SlumpConcrete slides down evenly keeping more or less to shape. This is the right slump that we used to measure.

Conclusion

Allowable Slump Values

WORKALLOWABLE RANGE
Slab
50 mm to 150 mm
Column
Beam
Wall
Mass Concrete25 mm to 75 mm

Experiment Video

Hope you enjoyed the content. Happy Learning 🙂