Concrete Slump Testing

Here is a step-by-step procedure for performing a slump test on concrete, which is used to assess the workability or consistency of fresh concrete before it sets:

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🔧 Equipment Needed:

1. Slump cone (Abrams cone): 300 mm height, 200 mm base diameter, 100 mm top diameter

2. Tamping rod: Steel rod, 16 mm diameter, 600 mm long with rounded ends

3. Base plate: Rigid, non-absorbent (metal or plastic)

4. Measuring scale or tape

5. Scoop for placing concrete

6. Trowel (optional)

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🧪 Step-by-Step Procedure:

1. Prepare the Test Surface

• Place the base plate on a level and clean surface.

• Wet the base plate and the inside of the slump cone to prevent concrete sticking.

2. Place the Slump Cone

• Position the slump cone upright in the center of the base plate.

• Step on the footpieces to hold it firmly in place.

3. Fill the Cone with Concrete in 3 Layers

• First Layer: Fill one-third of the cone (approx. 100 mm height).

  • Tamp 25 times using the tamping rod uniformly over the surface.

• Second Layer: Fill to two-thirds height (approx. 200 mm).

  • Again, tamp 25 times, penetrating slightly into the first layer.

• Third Layer: Fill the cone to the top.

  • Tamp 25 times, penetrating slightly into the second layer.

  • Slightly overfill the cone and level it off with a trowel or rod.

4. Remove the Cone

• Carefully lift the cone vertically upward in 5 to 10 seconds without any side movement.

• Do not disturb the concrete while lifting the cone.

5. Measure the Slump

• Place the cone next to the concrete (but do not tamp it again).

• Lay a steel rod or scale across the top of the cone.

• Measure the vertical distance from the underside of the rod to the highest point of the concrete.

• This is the slump (in mm).

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✅ Notes:

• Test should be performed within 5 minutes of sampling.

• Avoid vibration or shaking during the test.

• Perform at standard temperature (typically 27 ± 2°C unless otherwise specified).