Dictionary of Moisture Protection & Restoration

how to make a slump test using a 12-inch-high sheet metal cone that is open at both ends. The bottom of the cone is 8 inches in diameter, and the top is 4 inches in diameter. Start the slump test by moistening the inside of the metal cone. Then place the cone on a flat smooth surface with the large end down and fill it with concrete sample in three layers. Tamp each layer before you add the next. After the cone is completely full, lift the cone so the wet concrete slumps down. Measure the height of the concrete cone. Subtract this height from the original 12-inch height to give the slump.

If the number is high, the concrete is a wet mix. If it’s low, the concrete is a dry mix. Recommended slumps for different types of concrete work are shown in the chart below. If the concrete is not thoroughly vibrated (tamped), increase the values in the table by 50%. However, the slump should never be more than 6 inches.

62