Slump test (WORKABILITY of Concrete)

Updated: May 1, 2020

AIM

To determine the workability of fresh concrete by slump test as

per IS: 1199 - 1959.

APPARATUS


SLUMP CONE

i) Slump cone

ii) Tamping rod


PROCEDURE

i) The internal surface of the mould is thoroughly cleaned and

applied with a light coat of oil.

ii) The mould is placed on a smooth, horizontal, rigid and nonabsorbent surface.

iii) The mould is then filled in four layers with freshly mixed

concrete, each approximately to one-fourth of the height of

the mould.

iv) Each layer is tamped 25 times by the rounded end of the

tamping rod (strokes are distributed evenly over the crosssection).

v) After the top layer is rodded, the concrete is struck off the

level with a trowel.

vi) The mould is removed from the concrete immediately by

raising it slowly in the vertical direction.

vii) The difference in level between the height of the mould and

that of the highest point of the subsided concrete is

measured.

viii) This difference in height in mm is the slump of the concrete.

REPORTING OF RESULTS

The slump measured should be recorded in mm of subsidence of

the specimen during the test. Any slump specimen, which

collapses or shears off laterally gives incorrect result and if this

occurs, the test should be repeated with another sample. If, in

the repeat test also, the specimen shears, the slump should be

measured and the fact that the specimen sheared, should be

recorded.


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