Compacting Factor Test is mainly used in laboratory to determine workability of concrete. The workability of concrete has also been defined as the amount of work required to place the concrete and to compact it thoroughly. It is not easy to measure the amount of work required to fully compact it. B...
INTRODUCTION
The compacting factor test was devised because they recognised the importance of
achieving full compaction in concrete, and therefore the importance of being able to measure
the ability of the material to be compacted. It is always argued that the work in placing
concrete is composed of that lost in shock and the useful work which is expended in
overcoming the internal friction of the concrete itself and in overcoming the friction against
the mould and the reinforcements. Of these, it is only the loss against internal friction that is
characteristic of the concrete alone and it is this that they used as the basis for a definition of
workability and they set out to measure.
The standard quantity of work is provided simply by allowing the concrete to fall under
gravity through a standard distance. The apparatus consists simply of two conical hoppers
and a cylindrical mould mounted vertically one above the other, the capacity of the top
hopper being greater than that of the lower, which in turn is greater than that of the cylinder.
The internal surfaces are smooth to minimise surface friction.[ CITATION Mus16 \l 17417 ]
The compaction factor is defined as the ratio of the weight of concrete that has been
gravity-filled in a cylinder to the weight of compacted concrete in a similar cylinder.
[ CITATION Wha161 \l 17417 ]It involves dropping a volume of concrete from top hopper to
lower hopper then into the cylinder, struck the surface of the concrete in the cylinder and
weight the cylinder full of concrete, then the amount of concrete is then compared with the
amount that fills the cylinder when the concrete is compacted in layers. The result of the
compaction factor test can be correlated to slump, through the relationship is not linear.
These tests were developed in the UK by Glanville (1947) and it is measure the degree of
compaction. For the standard amount of work and thus offer a direct and reasonably reliable
assessment of the workability of concrete. the test require measurement of the weight of the
partially and fully compacted concrete and the ratio the partially compacted weight to the
fully compacted weight, which is always less than one, is known as compacted factor . For
the normal range of concrete the compacting factor lies between 0.8 - 0.92.[ CITATION
Sye161 \l 17417 ]
OBJECTIVE
To determine the workability of concrete mix by finding the compaction factor.
Figure 1a.4: Tamping Rod Figure 1a.5: Graduated Figure 1a.6:Wood Pan to mix
Cylinder Concrete
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