Only a true slump is of any use in the test. A collapse slump will generally mean that the mix is too wet or that it is a high workability mix, for which the slump test is not appropriate. Very dry mixes having slump 0 -- 25 mm are typically used in road making, low workability mixes having slump 10 -- 40 mm are typically used for foundations with light reinforcement, medium workability mixes with slump 50 -- 90 mm, are typically used for normal reinforced concrete placed with vibration, high workability concrete with slump > 100 mm is typically used where reinforcing has tight spacing, and / or the concrete has to flow a great distance.
degree of workability is high when slump is
> 100 mm