Concrete slump test

Introduction

The slump test is an indication of how workable a concrete mix is. A target slump was set (100±20 mm) for the concrete mixes and the superplasticizer dosage was varied so as to achieve this target slump.

Procedure

The test is carried out using a mould known as a slump cone or Abrams cone. The cone is placed on a hard non-absorbent surface. This cone is filled with fresh concrete in three stages, each time it is tamped using a rod of standard dimensions. At the end of the third stage, concrete is struck off flush to the top of the mould. The mould is carefully lifted vertically upwards, so as not to disturb the concrete cone. Concrete subsides. This subsidence is termed as slump, and is measured to the nearest 5 mm.

Filling Slump	Compacting Slump The mould is filled in three equal layers, and each layer is tamped with 25 strokes using a tamping rod.
Levelling Slump The slump is then levelled when filled completely and the extra concrete is cut off	Mould removal The mould is finally lifted vertically and slowly, so as to impart minimum lateral or torsional movement to the concrete.
Mould Removed	Measuring Slump The slump is defined as the difference in the height of the test specimen and the slump cone

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Concrete Slump Test

Filling Slump

Compacting Slump

The mould is filled in three equal layers, and each layer is tamped with 25 strokes using a tamping rod.

Levelling Slump

The slump is then levelled when filled completely and the extra concrete is cut off

Mould removal

The mould is finally lifted vertically and slowly, so as to impart minimum lateral or torsional movement to the concrete.

Mould Removed

Measuring Slump

The slump is defined as the difference in the height of the test specimen and the slump cone