Theory

• IS 1199 talks about the methods of sampling and analysis of concrete that covers the one of the most important workability test on concrete- the slump cone test.

• Workability is the property of freshly prepared concrete which determines the amount of useful internal work necessary to produce complete compaction.

• The slump cone test specifies the procedure to be adopted either in the laboratory or during the progress of work in the field for determining the consistency of concrete where the nominal maximum size of aggregate does not exceed 38 mm.

• The slump cone test is based on the principle that the consistency of fresh concrete can be assessed by the behaviour of a concrete sample when it is subjected to controlled conditions of temperature and humidity.

• Based on the slump value obtained or the slump obtained, the behaviour of concrete mix can be predicted like a slump with very less slump value in mm or zero slump indicates a stiff mix with lower w/c ratio and similarly a comparatively high slump value indicates a mix with higher w/c ratio.

APPARATUS SPECIFICATIONS

a) Mould- The mould for the test specimen shall be in the form of the frustum of a cone having the following internal dimensions:

The mould shall be constructed of metal (brass or aluminium shall not be used) of atleast 1.6 mm thickness and top & bottom shall be open & at right angles to cone axis, and must have a smooth internal surface, a typical mould is shown in the figure.

b) Tamping rod- The rod should be of steel, 16 mm in diameter, 0.6 m long, rounded at one end.