Slump Test Essay

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(3) Slump Test
Aim:-
To determine the workability or consistency of concrete mix prepared at the laboratory or the construction site during the progress of the work. It is used conveniently as a control test and gives an indication of uniformity of concrete from batch to batch.

Apparatus:-
(1) Metallic mould in the form of a frustum of a cone with internal dimensions as follow:
• Bottom diameter = 20 cm
• Top dia. = 10 cm
• Height = 30 cm
The bottom and top ends of the mould are open, parallel to each other and right angle to the axis of cone. Mould is provided with suitable guides for lifting vertically up.
(2) Metallic sheet on which mould is placed.
• Thickness of the metallic sheet should not be less than 1.6 mm.
(3) Tamping rod for …show more content…

of rod = 16 mm
• Length of rod = 0.6m (with bullet end)

Procedure:-
• The internal surface of the mould is thoroughly cleaned, free 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.
• 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.
• The difference in level between the height of the mould and that of the highest point of the subsided concrete is measured. The difference in height in mm is taken as slump of concrete.

Observations:-
Slump Patterns
• It indicates the characteristic of concrete in addition to the slump value. Following types of slumps may be possible.

(1) True …show more content…

• Three types of compression test specimens are used: cubes, cylinders and prisms. In our country, usually cube and cylinder are used. The concrete grade is based on the 150 mm size cube strength and if the cylinder is tested, the strength should be modified into equivalent cube strength.
• The size of standard cube specimen is 150 mm x 150 mm x 150 mm. If the largest nominal we of the aggregate does not exceed 20 mm, 100 mm x 100 mm x 10 mm size cubes may also be used as an alternative. Sometimes, the test is made on cylinder of size 150 mm diameter and 300 mm height.
• Details covering the preparation and testing of cubes and cylinders are covered in IS: 516 arid summarized below in the form of an experiment that may be conducted in the laboratory.
Aim:-
To prepare and test the concrete cubes and cylinders for compressive strength.

Apparatus:-
(1) 150 mm x 150 mm x 150 mm size cube moulds
(2) 150 mm diameter and 300 mm height cylindrical

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