Slump test and consistence class
Enter the measured slump and get the result as EN 12350-2 reports it, the EN 206 consistence class, and - if the concrete was ordered by a target slump - the range it should fall in. No sign-up.
When the concrete was specified by a target value instead of a class.
EN 206 slump classes
- S1: 10-40 mm
- S2: 50-90 mm
- S3: 100-150 mm
- S4: 160-210 mm
- S5: ≥ 220 mm
Result
Enter the measured slump to see the class.
For guidance only. A test report must follow the full procedure of EN 12350-2, including the sampling of EN 12350-1.
How the slump is measured and classified
The cone (300 mm high) is filled in three layers, each rodded 25 times, and lifted straight up in 2 to 5 seconds. The slump is the drop of the highest point of the concrete below the height of the cone:
h - slump (mm) · 300 - height of the cone (mm) · hconcrete - height of the highest point of the slumped concrete (mm)
Only a true slump - the concrete stays mostly intact and symmetric - counts. The result is recorded to the nearest 10 mm and placed in its EN 206 class: S1 10-40 mm, S2 50-90, S3 100-150, S4 160-210, S5 from 220 mm.
Worked example
The highest point of the concrete is 177 mm above the base plate: 300 − 177 = 123 mm, recorded as 120 mm - class S3.
Questions engineers ask
Which slump class is used for what?
S1 and S2 suit stiff concrete compacted by vibration (pavements, precast), S3 is the most common class for reinforced concrete on site, S4 and S5 are for pumped and heavily reinforced work. The class is set by the specifier under EN 206.
What is the tolerance on a target slump?
When concrete is specified by a target slump, EN 206 allows ±10 mm for targets up to 40 mm, ±20 mm from 50 to 90 mm and ±30 mm from 100 mm upwards.
When should the slump be measured?
On a sample taken per EN 12350-1 at delivery, and the whole operation, from the start of filling to lifting the cone, must take no more than 150 seconds. Consistence changes with time, so the time of the test is recorded.
Recording slump for every truck?
LabFlow takes the slump on the phone at the pour, even offline, keeps it with the cubes cast from the same truck, and prints it on the report next to their strength.