<P> The concrete then slumps (subsides). The slump of the concrete is measured by measuring the distance from the top of the slumped concrete to the level of the top of the slump cone . </P> <P> The slumped concrete takes various shapes and according to the profile of slumped concrete, the slump is termed as true slump, shear slump or collapse slump . If a shear or collapse slump is achieved, a fresh sample should be taken and the test repeated . A collapse slump is an indication that the mix is too wet . </P> <P> 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 . </P> <Table> <Tr> <Th> Collapse </Th> <Th> Shear </Th> <Th> True </Th> </Tr> <Tr> <Td> In a collapse slump the concrete collapses completely . </Td> <Td> In a shear slump the top portion of the concrete shears off and slips sideways . </Td> <Td> In a true slump the concrete simply subsides, keeping more or less to shape . </Td> </Tr> </Table>

Degree of workability is high when slump is