Concrete Vibrators

Concrete vibrator application

What is a vibrator?

Vibrators are the indispensable machine of the construction industry. Vibrators are devices that produce vibrations used during concrete pouring in order to place concrete into the mold without gaps.

What is the importance of the vibrator in concrete casting? How should concrete be compacted?

• During the mixing of concrete materials in ready-mixed concrete facilities and placing fresh concrete in place, some air is spontaneously (unintentionally) compressed into the concrete mixture.
• Fresh concrete, which contains some trapped air space, is in a state of concrete that has not completely filled the mold in which it is placed and has a low density. Immediately after the concrete is placed in its place, the trapped air must be removed as much as possible. The process of removing the trapped air inside the fresh concrete is called "compressing the concrete".
• As a result of the development of concrete technology, the compression of ready-mixed concrete is done by mechanical methods. In determining the compression method to be applied, some factors such as workability of fresh concrete, form shapes and sizes, frequency and amount of reinforcement to be included in concrete should be taken into consideration.
• In order to get rid of the air inside the fresh concrete placed in the mold in the ready-mixed concrete sector and to turn the concrete into a less hollow concrete state, the vibration process applied to the concrete is done with vibrating mechanical tools called vibrators.
• The events in the compression of the concrete with the vibration method take place in two stages. In the first stage, the mortar in the concrete liquefies and moves towards the bottom with the effect of vibration, and in the second stage, the trapped air in the concrete comes out. The event in the second stage takes place almost simultaneously with the event in the first stage.
• The main purpose of vibrating fresh concrete is to place the concrete in the mold. No matter how much you vibrate the fresh concrete, some air gap will definitely remain in the concrete, depending on the grain diameter. In some special cases, additional air is created in the concrete by means of air entraining additives. Even such concrete must be placed in the mold by vibration.
• During the vibration process, the concrete is given the force resulting from the vibrator's eccentric vibration. This force is distributed in the form of wave motion in concrete. In this way, the particles in the concrete repel each other and provide compression and settling in the mold. In case of excessive fluidity and excessive vibration of the concrete, the fine and coarse material is separated from each other and the homogeneity of the concrete is deteriorated. In such a case, the material that settles to the bottom is coarse material.
• If the water-cement ratio is low, the effect of vibration on strength is very high, and in the case of 0.6 and above, it is almost negligible.

Benefits of Vibration Application :

• Concrete placement becomes easier.
• More dense and homogeneous concrete is obtained.
• The adherence between concrete and reinforcement is better.
• Higher strength concrete is obtained.
• When the mold is removed, we get smoother edge lines in concrete.

What are the benefits of applying vibration to fresh concrete?

• Since it is easy to place concrete, it provides economy.
• A more dense and homogeneous concrete is obtained.
• It ensures smooth formation of clear edges of the edges in the concrete, which is molded.
• Higher strength concrete is obtained.
• In reinforced concrete, better adherence is provided between concrete and reinforcement.
• Higher durability is achieved.

What should be considered in vibrator application?

• The depth of the concrete layer should not exceed the length of the plunger end of the vibrator to be used. Every concrete layer should be subjected to vibration.
• The vibrator should be immersed in the fresh concrete perpendicularly (maximum 10 degrees inclined from the vertical axis.)
• The plunger tip of the vibrator should be immersed to the full depth of the fresh concrete layer, even a few cm into the previous layer.
• The distance between the points where the vibrator tip will be immersed is generally around 40 - 50 cm and 75 cm. should not exceed.
• The plunger tip should not be kept close to the side surfaces of the concrete formwork.
• The plunger tip should be immersed quickly in fresh concrete, it should not be kept in the concrete for too short or too long (normal time is 5 - 15 seconds).

Alıntıdır.