SLUMP CONE TEST



TEST APPARATUS




10 cm. dia. top


20 cm. dia. Base


30 cm. height


 With a graduated steel tamping rod of 16 mm dia. & 600 mm long, rounded at one end.

The base plate has a handle.
Slump cone test is used for the determination of consistency of freshly mixed concrete where maximum size of aggregates does not exceed 38 mm.


This is the simplest & most commonly used test for workability.





PROCEDURE FOR SLUMP CONE TEST


 STEP 1.  

Clean the mould & rest it on a levelled surface.
Fill the cone with concrete in 4 layers



 STEP 2. 
Each layer is tamped 25 strokes with the rounded edge of the 16 mm tamping rod.


 STEP 3. 

The final layer is filled an inch extra and then tamped and levelled.


 STEP 4. 

Lift the cone vertically, so that the concrete is left unsupported.


 STEP 5. 

The Slump is the distance that the centre of the cone top settles.

The workability can be related with the slump as follows for maximum size of aggregates equal to 20 mm:

      
Slump in mm
Workability
0 -12
Very low
12-25
Low
25-50
Medium
50-125
High
125-175 
Very high