How to check the workability of concrete?

Workability of concrete by Slump Cone Test -

¨      Clean the internal surface of the slump cone

¨      Place it on a level surface

¨      Fill the sample in 4 equal layers

¨      Tamp each layer with 25 strokes by tamping rod

¨      Strokes of above layer should penetrate in to the bottom layer

¨      After completing the top layer, Level the top with trowel or tamping rod

¨      Lift the mould slowly in vertical direction

¨      Measure the level difference between mould height and highest point of the concrete and note down the slump in mm

¨      Slump requirements

*  For manual pour                -           30 – 80mm

*  For pumping concrete       -           80 – 120mm

¨      To find cohesiveness of concrete

*  Tamp the rod gently in sides of base plate

*  If concrete slump decreases further gradually, it is good cohesive concrete

¨      Test should be completed within 2 minutes