The slump test is commonly used to measure the workability of concrete by determining the amount it subsides after a standardized cone-shaped mold is removed. The test involves filling the mold with concrete in layers and tamping it, then removing the mold and measuring the subsidence. There are three types of slump results: true slump is an even subsidence, shear slump is uneven with one side sliding down more, and collapse slump indicates a lean mix. Recommended slump ranges are provided for different types of construction.

1. TALAVIYA MALAY

2.  Slump test is the most commonly used test of
measuring workability of concrete.
 It can be employed either in laboratory or at site of
work.
 It is used conveniently as a control test and gives an
indication of the uniformity of concrete from batch
to batch.

3.  The apparatus for slump test consists of a metallic
mould in the form of a frustum of a cone with internal
dimension as follow
Bottom diameter = 20 cm
Top diameter = 10 cm
Height = 30 cm

4.  The internal surface of the mould is thoroughly cleaned
and freed from superfluous moisture and adherence of
any old set concrete before commencing the test.
 The mould is placed on a smooth, horizontal and non-
absorbent surface.
 The mould is filled with concrete in 4 equal layers.
Each layer is tamped with 25 strokes of tamping rod.

5.  After the top layer has been tamped, the concrete is
struck off level with a trowel and tamping rod.
 Then, the mould is removed by lifting it slowly and
carefully in a vertical direction. This allows the
concrete to subside. This subsidence is referred as
slump of concrete.

6.  True slump
 shear slump
 collapse slump

8.  True slump : If concrete subsides evenly it is called
true slump.
 Shear slump : If one half of the concrete cone slides
down, it is called shear slump. The shear slump is
measured as a difference in height between the height
of the mould and the average value of subsidence.
 Collapse slump : The collapse indicates a leaner mix.

9. NO Types of construction Recommended slumps in mm
Minimum Maximum
1 pavements 25 50
2 Mass concrete structures 25 50
3 Unreinforced footing 25 75
4 Cassions and bridge deck 25 75
5 Reinforced foundation, footing and
walls
50 100
6 Reinforced slabs and beams 30 125
7 columns 75 125

10. Malay Talaviya