What is Compaction | Method of Concrete Compaction | Type of Concrete Compaction.
What is Compaction ?
mixing of concrete, transporting of concrete and placing of concrete Void (air)
is likely to get entrapped in the fresh concrete. Compaction of concrete is
a process followed to remove the entrapped air from the concrete.
The lower the workability, concrete mixes have a higher amount of
entrapped air that contain a higher percentage of entrapped air and therefore
will require more compacting efforts then higher workable mixers.
is very important in our concreting. Durability becomes more important than strength of concrete. Inadequate
compaction increases the permeability of concrete resulting in easier
Penetration for aggressive chemicals in the solute, which attack the concrete
and important reinforcement attack, reducing the durability of concrete and
reinforcement. That’s why we always have 100% compaction in concrete.
Note – If 5% void remains in our concrete than our concrete will be
reduced the strength about 30% and 10% void remains in our concrete than our
concrete will be reduced the strength about 50%.
100% compaction in concrete and maximum density with reasonable
compacting efforts available at sites.
Method of compacting of concrete
- Hand Compaction
- Mechanical Compaction
- Compaction by Pressure and Jolting
- Spinning Compaction
Hand Compaction
Hand Compaction – Hand compaction of concrete is generally used for the unimportant concrete
work, of a small magnitude. In other things hand compaction is also used for
that case where a large quantity of reinforcement is used. In the large
quantity of reinforcement mechanical compaction cannot be normally compacted
of concrete. Hand compaction is done for the rodding, ramming and tamping. This
is a hand compacted tool. The consistency of
concrete is maintained at a higher level.
Hand Compaction tools
- Rodding
- Ramming
- Tamping
Rodding
Rodding – In this method a piece of bamboo, iron rod is used for rodding for
compaction of concrete.
The thickness of the concrete layer is limited to about 15 cm to 20 cm.
Rodding is poking the concrete with a roughly 2 m long, 16 mm diameter rod at
sharp corners and edges to pack the concrete between the reinforcement.
Ramming
Ramming – Ramming is used for the compaction of plain concrete, ground floor
construction or un reinforcement foundation
concrete.
Ramming compaction is not used for the reinforced concrete, above ground floor construction and where the
support of the formwork. If we used a ramming compaction upper floor construction
reinforcement and formwork may fail.
 |
| Courtesy – interconex.us |
Tamping
Tamping – Tamping is used for the
compaction of roof, floor slab or road pavement. where the thickness of
concrete is comparatively less and the surface is smooth and level. The wooden
cross beam has to hit the top surface by the concrete. Wooden cross-section
beam of 10 cm Ⅹ 10 cm is used in tamping compaction.
 |
| Courtesy – youtube.com |
Mechanical Compaction
Mechanical Compaction – Hand compaction is
complete only when we have sufficient workability in concrete. Only then the
hand compaction process is completed in good manner. But on the other hand our
concrete structure also becomes low strength due to more water cement ratio.
but when high strength is required in our concrete it is necessary to have a
stiff concrete with low water cement ratio. To compact such concrete mechanical
compaction (vibrator) is to be used.
For the use of vibrator low slump about stiff mixes for
production of high quality concrete with required strength and impermeability. Vibrator is very important if we have a bad aggregate, bad shape and
texture.
Types of concrete vibrator
- Needle Vibrator
- External Vibrator
- Table Vibrator
- Surface Vibrator
- Roller Vibrator
- Platform Vibrator
Needle Vibrator
Needle Vibrator – Needle vibrator is also called internal vibrator, Poker vibrator or
Immersion vibrator.
Internal vibrator is the most commonly used vibrator in our construction
site in comparison of another vibrator.
In this vibrator needle is penetrated into the concrete and vibrator is
started until all the voids are not removed.
We have many types of needle vibrator is available whose diameter Varies from 20 cm to to 75 cm and needle vibrator length Varies from 25 cm to 90 cm.
According to construction site we used all these type of vibrators, If our
construction site is bigger we use vibrator with maximum diameter. and if the construction site is less thickness then
we use a small diameter needle vibrators.
External Vibrator
External vibrator – External vibrator is also called a formwork
vibrator. External vibrator is used for the complicated members or where
reinforcement Is highly congested.
Formwork vibrators are used for columns, walls and precast units. External vibrating device is attached with the outside of the formwork and formwork is transferred to the
vibration to the concrete. External vibrator consumes more power compared to the comparable Needle vibrator due to the above reason. Formwork vibrators will give a better and smooth finish.
Table Vibrator
Table vibrator – Table vibrator has powerful vibrating units. In a table
vibrator, vibrator machine is clamped into the table and vibrator transfers to
the vibration into the table. Table Vibrator is used for the compaction of
concrete cube and other packing material kept on the table gets vibrated.
Surface Vibrator
Surface Vibrator – Surface vibrators are also called Screed board vibrators.
Surface vibrators used for thin slab concrete members like, roof slab, floor slab and Road surface. Surface vibrator is is effective for about 15cm thin concrete members.
Surface vibrators are mounted on Screed Board and generally used for compacting, levelling and finishing the bridge floors, roof floor, road slab, bridge floor etc.
In thin concrete members needle vibrators, External vibrators and other types of vibrators are not easily effective. In such conditions, a surface vibrator is to be used. Generally Floor slabs and roof slabs are compacting for surface vibrators.
Roller Vibrator
Roller Vibrator – Roller vibrators are used for the compacting of dry concrete and lean concrete. Hence, this type of concrete is called Roller compacted concrete.
Roller vibrators are generally used for very heavy construction Like dams, road pavement bridges etc.
 |
| Courtesy – Vijay trading company |
Platform Vibrator
Platform Vibrator – Platform vibrator is the same as the table vibrator. but is available in large size compare to table.
Platform vibrator is used for the compacting of railway sleepers and manufacturing of prefabricated concrete elements.
Pressure and Jolting
Pressure and jolting – Pressure and Jolting compaction methods are used for compacting hollow blocks, Cavity blocks and Solid concrete blocks. In this method very dry concrete is vibrated, Pressed and also given jolts.
This compaction Method concrete having very low water cement ratio gives high yielding strength.
Compaction by Spinning
Compaction by Spinning – Pressgfjhfjtyftgfghfgfhfghdh
Pingback: What is brick | Size of bricks | Composition – Types of brick | Brick bond | Type of brick bond – civilnotebook.com
Pingback: Piles | Types of Piles | Concrete Piles | Steel Piles | Timber Piles | Composite Piles | Advantages & Disadvantages Of Piles - civilnotebook.com
Pingback: What is brick | Size of bricks | Composition - Types of brick | Brick bond | Type of brick bond - civilnotebook.com
Pingback: Spread Footing | 6 types | Advantages and disadvantages