Compaction Factor Test in Civil engineering

Compaction Factor Test

Aim:

To determine the workability of fresh concrete by compacting factor test.

Apparatus required:

1.Compacting factor apparatus

Formula

 Compaction Factor = Weight of partially compacted concrete / Weight of fully compacted concrete 

Procedure

1.The sample of concrete is placed in the upper hopper up to the brim

2.The trap-door is opened so that the concrete falls into the lower hopper.

3.The trap-door of the lower hopper is opened and the concrete is allowed to fall into the cylinder.

4.The excess concrete remaining above the top level of the cylinder is then cut off with the help of plane blades.

5.The concrete in the cylinder is weighed. This is known as weight of partially compacted concrete.

6.The cylinder is filled with a fresh sample of concrete and vibrated to obtain full compaction. The concrete in the cylinder is weighed again. This weight is known as the weight of fully compacted concrete.

7. From this by applying formula we get the value of compaction factor.

Result:

The value of compacting factor is -----------------.


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Vee-Bee Consistometer test

Vee-Bee Consistometer test in civil engineering

Aim:

    To determine the workability of fresh concrete by using a Vee-Bee consistometer

Apparatus required:

    Vee-Bee Consistometer 

Procedure:

•     A conventional slump test is performed, placing the slump cone inside the cylindrical part of the consistometer.
• The glass disc attached to the swivel arm is turned and placed on the top of the concrete in the pot.
• The electrical vibrator is switched on and a stop-watch is started, simultaneously.
• Vibration is continued till the conical shape of the concrete disappears and the concrete assumes a cylindrical shape.

• When the concrete fully assumes a cylindrical shape, the stop-watch is switched off immediately and time is noted.The consistency of the concrete should be expressed in VB-degrees, which is equal to the time in seconds recorded above.

Result:

    Thus the workability of concrete is determined using  Vee-Bee Consistometer test.

The value is -----------  VB-degrees. 

Slump Test in Civil Engineering

Workability of Fresh Concrete by Slump Test

Aim:

 To determine the workability of fresh concrete.

Apparatus required:

 1.Slump cone (dimensions are

          Top Diameter – 10cm

          Bottom Diameter – 20cm

          Height – 30cm)

2. Tamping rod

3. Oil

4. trowel

Procedure

 

·          The internal surface of the mould is thoroughly cleaned and applied with a light coat of oil.

·          The mould is placed on a smooth, horizontal, and rigid  surface.

·          The mould is then filled in three layers with freshly mixed concrete, each approximately to one-third of the height of the mould.

·         Each layer is tamped 25 times by the rounded end of the tamping rod (strokes are distributed evenly over the cross section).

·         After the top layer is rodded, the concrete is struck off the level with a trowel.

·         The mould is removed from the concrete immediately by raising it slowly in the upward direction.

·         The difference in level between the height of the mould and that of the highest point of the subsided concrete is measured.

·         This difference in height in mm is the slump value of the concrete.

·         This process is done repeatly  by adding various water contents.

 

Types of slumps:

   

           True slump

           Shear slump

            Collapse

 

         

Result:

   

For dry sample, the slump value will be in the range of 25-50 mm.

For wet sample, the slump value will be in the range of 150-175 mm

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