4 TYPES OF VIBRATORS COMMONLY USED FOR CONCRETE COMPACTION
Vibrators are normally used as a manner of compacting concrete on site. In the case of vibration, compacting gets effected via a reduction in inner friction between diverse particles of concrete due to oscillation of debris which ends up in a dense and compact mass of concrete.
Vibrations can either be
Produced within the interior of the concrete the usage of Internal vibrator, or
Produced in concrete by means of vibrating formwork the use of Shutter shape vibrators, or
Produced on the surface of concrete the use of Surface vibrators, or
Produced inside the complete concrete mass using the Vibrating table.
TYPES OF VIBRATORS USED FOR CONCRETE COMPACTION
Therefore vibrators are generally of four unique types, which includes:
Internal or Immersion or Poker or Needle Type Vibrator
Shutter shape or External Type Vibrator
Surface or Screed or Pan Type Vibrators
Vibrating Tables
1. INTERNAL VIBRATOR
They are also referred to as immersion, poker or needle vibrators. They essentially include an energy unit and a long flexible tube on the top of which a vibrating head is attached. Power is furnished by means of an electric powered motor, compressed air or petrol engine. The long tube houses a flexible shaft which rotates an eccentric weight inside the vibrating head. The frequency of the vibrator is about seven hundred cycles according to the minute.
The vibrating head is inserted inside the concrete. They are only as the vibrating head comes into intimate touch with concrete.
2. FORM VIBRATORS
They are also known as outside vibrators. They are clamped to the formwork horizontally and vertically at an appropriate spacing not exceeding ninety cm in both directions. As the work progress, they may be shifted. They vibrate the concrete from the vibration of the bureaucracy and therefore much strength is wasted.
They are used handiest if the use of inner vibrators is not attainable as in the case of thin and congested sections, arches and tunnel lining, etc.
3. SURFACE VIBRATORS
They are also called screed or pan vibrators. They are clamped to the screen. They vibrate the concrete from the floor on the time whilst screeding (striking off) of the concrete is carried out. They are effective only if the intensity of concrete is up to 20 cm. If the depth is more they can be used in aggregate with internal vibrators. They are used for long horizontal surfaces inclusive of pavements and slabs.
4. VIBRATING TABLES
These are rigidly built metal platforms established on steel springs and driven through electric motors. The concrete is placed in molds installed on the platforms and securely clamped to the vibrating table, in order that mold and concrete vibrate in union.
Vibrating tables are used for compacting stiff and harsh mixes utilized in precast structural individuals in factories and laboratory specimens.
