Concrete Slump Calculator
Current Slump =
Desired Slump =
Estimate the gallons of water necessary to increase the slump of concrete based on the current slump versus the desired slump.
A concrete slump test is easy to conduct and is commonly used to test consistency of concrete between different batch deliveries. It is also used when an engineer's specifications call for a certain slump. The test is conducted with the use of a cone designed and specified for this use.
Step 1 - Place concrete in a cone made for this purpose. NOTE: 3 layers, one layer at a time using a rod to consolidate the concrete at each level. Rod is 5/8in by 24in in length.
Step 2 - Remove the cone. As concrete loses the form of the cone, it will settle (slump) into a final state.
Step 3 - Measure the slump. PLace cone to side of settled concrete. Measure from top of cone to the top of settled concrete. This measurement is the slump
-Volume: Total volume of the batch where this sample has been taken.
-Current Slump: Slump of the concrete, as it is now.
-Desired Slump: Slump that is specified or desired.
-Water: Number of gallons of water to add to this batch of concrete to increase the slump to the desired level.
A truck is delivering 18 cubic yards of concrete. Based on specifications and the previous batch, the slump of this concrete should be 3&1/2in. After an on-site test, the slump of this delivery is determined to be 2in. How many gallons of water should be added?
-Current Slump: 2in
-Desired Slump: 3&1/2in
Add 32.41 gallons.