During concrete pouring, hundreds of bubbles can occur, which in turn substantially weaken the concrete structure. Hence, vibrating is a crucial step in most concrete projects. Concrete vibrators are not only recommended but have also become a building code requirement nowadays. Vibrators will help eliminate the air bubbles by vigorously shaking the poured concrete.
What is concrete vibrating?
It is the process of vigorously shaking concrete to remove air bubbles from poured concrete. Concrete vibrating is done to give a high-quality, level finish free of any defects. Concrete vibrating must be done as soon as the concrete is poured.
Except for self-compacting concrete, most structural components and concrete slabs need to be vibrated. A concrete hammer or hand screed can be used as a vibrator to remove air bubbles during small-area concrete pouring. For large-area pouring, roller screeds are recommended, as they are the best way to remove excess water and air bubbles.
How does concrete vibrating work?
Concrete vibrating is done by vibrators, especially for large-area concrete projects. They are usually air-driven and electric. The methods of concrete vibration can be grouped into the following categories:
1} Surface vibration
In the surface vibration technique, the vibrators are directed onto the surface of poured concrete. This is done manually. Although it has a limitation of a slab depth of 6 inches or less, it gives a smooth surface and desirable appearance to the finished concrete.
2} Formwork vibration
This vibration technique involves the process of mounting the vibrators towards the outside of poured concrete. It is mostly used in precast concrete construction. For large pours, these vibrators are usually placed 6 feet apart.
3} Internal vibration
Internal concrete vibrators are handled by a single operator. It is commonly used, and the process is relatively simple. In this technique, the operator pushes a probe-like internal vibrator into wet concrete and later withdraws it.
Step-by-Step process to vibrate concrete
The best technique to vibrate concrete is the internal vibrating technique. The vibrator is withdrawn slowly at 1 inch per second. If the bubbles still emerge when the vibrator is withdrawn, then vibrating the concrete must be continued. Listed below is a step-by-step process to follow when vibrating concrete.
1} Ensure that the area has not been previously vibrated by another worker.
2} Immerse the vibrator head deeply into the concrete and hold it in the same position for about 15 seconds.
3} Turn the vibrator on only after the tip is fully submerged.
4} Withdraw the vibrator at an average rate of 1 inch per second.
5} Every time you insert the vibrator to cover the surrounding areas, ensure to overlap the previous radius.
6} Always keep a spare vibrator handy during the vibration process in case of any mishap.
7} Do not bend the vibrator excessively.
8} Stop vibration when no air escapes from the concrete and the surface develops a smooth and sheen effect.
Conclusion
Concrete vibrating is an essential step while you pour concrete in construction projects. To achieve the best results, the vibrating process must be done as soon as the concrete is poured. At Lura Screed, we have some of the best roller screeds that help concrete vibrate. To learn more, reach out to us!