Fresh concrete does not compact by itself because the poor fluidity cannot surpass internal friction. Only vibration can overcome this force.
In fact, vibration promotes:
- Surfacing of air bubbles captured in the concrete;
- Displacement of aggregates resulting in a reduced cavity and giving high density and perfectly even material;
- Adhesion of the concrete to the reinforcement armature bars or any inner structural inserts.
Benefits of using vibrators on concrete:
- High mechanical strength
- Low-level porosity and therefore permeability to water and aggressive agents contained therein
- No cracks inside the cement and near the reinforcement armature bars
- Completely filled formwork
- Longer life cycle of the concrete
- High aesthetic results
Concrete Consolidation Types
Immersion vibrators (or vibrating needle for concrete)
In construction, for example, of flooring for industrial use, walls, pillars and slabs, flexible and easy to use vibrating devices must be used. In such cases, the immersion vibrator, also called the vibrating needle, is chosen because it was designed for use in contact with cement; therefore such use is also defined direct internal vibration.
External electric vibrators
High frequency electric vibrators are used on building sites and in the production of prefabricated buildings to obtain high quality manufactured parts with exposed cement, with excellent results from the point of view of aesthetic appearance and resistance against atmospheric agents. Vibration is transmitted indirectly to the cement through formworks or moulds.