Slump Testing, Concrete

Slump Testing

The concrete slump test is a very simple procedure to measure the workability of fresh concrete. Because it involves low-cost tools and can be quickly done in situ, it is used extensively on most construction sites. By measuring the consistency of fresh concrete before it sets, this test can indicate improperly mixed material.

The concrete slump value determined in this test is used to find the water-cement ratio in mixes. By measuring the difference between the mold height and the height of the specimen, researchers are able to evaluate the concrete consistency. The test is carried out from batch to batch to ensure uniformity of different loads. For more information on concrete slump testing, please read our Concrete Slump Testing blog.

In most cases, the test is conducted according to the ASTM C143 specification. The slump test equipment required includes:

Standard Slump Cone – Cone shaped mold that can be made of steel or plastic and should measure 8" (203mm) dia. at base, 4" (102mm) dia. at top and 12" (305mm) high.

Slump Base Plate – The slump cone will sit on the base during the test and it should include bolt-on clamps to hold the cone steady during testing. A base plate with a handle will make it easier to remove and can also be used as a guide to measure the slump.

Graduated Tamping Rod – Used to both tamp the concrete mixture and measure the amount of slump.

Additional accessories that are not required, but can increase efficiency are:

Scoops – A round nose scoop with bowl dimensions 8.25" (210mm) length x 5.25" (133mm) width x 3" (76mm) depth.

Funnels – An aluminum funnel will assist in filling.

Brushes – Used to clean the concrete off of testing equipment after the test is complete.

Trowels – A forged steel trowel will assist in filling.

Humboldt's Concrete Slump Chart provides a range of slump values and their applications. For instructional information, please read our blog on Concrete Slump Testing.

If you have questions or need help selecting equipment, please call us at 1.800.544.7220 or use our Ask Humboldt form.