Procedure For Slump Test (Field Test)

The test involves the following Steps:

1. To obtain a representative sample, take samples from two or more regular intervals throughout the discharge of the mixer or truck. DO NOT take samples at the beginning or the end of the discharge.

2. Dampen inside of cone and place it on a smooth, moist, non-absorbent, level surface large enough to accommodate both the slumped concrete and the slump cone. Stand or, foot pieces throughout the test procedure to hold the cone firmly in place.

3. Fill cone 1/3 full by volume and rod 25 times with 5/8-inch diameter x 24-inch-long hemispherical tip steel tamping rod. (This is a specification requirement which will produce nonstandard results unless followed exactly.)Distribute rodding evenly over the entire cross section of the sample.

figure: 1/3 Filled Slump Cone 

4. Fill cone 2/3 full by volume. Rod this layer 25 times with rod penetrating into, but not through first layer. Distribute rodding evenly over the entire cross section of the layer.

figure: 2/3 Filled Slump Cone

5. Fill cone to overflowing. Rod this layer 25 times with rod penetrating into but not through, second layer. Distribute rodding evenly over the entire cross section of this layer.

figure: Fully Filled Cone.

 6. Remove the excess concrete from the top of the cone, using tamping rod as a screed. Clean overflow from base of cone.

figure: Cleaning of Extra/Surcharge Concrete.

7. Immediately lift cone vertically with slow, even motion. Do not jar the concrete or tilt the cone during this process. Invert the withdrawn cone, and place next to, but not touching the slumped concrete. (Perform in 

5-10 seconds with no lateral or torsional motion.)

figure: Lifting of Cone.

8. Lay a straight edge across the top of the slump cone. Measure the amount of slump in inches from the bottom of the straight edge to the top of the slumped concrete at a point over the original center of the base. The slump operation shall be completed in a maximum elapsed time of 21/2 minutes. Discard concrete. DO NOT use in any other tests.

figure: Measuring of  Slump.