The concrete preparation and application process requires a wide variety of specialized tools, especially when it comes to industrial-scale work. In many cases, you’ll need everything from trowels and brooms to bull floats and brushes.
However, there’s one tool that is all-too-often overlooked on construction sites today – the concrete vibrator. This oversight is noteworthy because it is simply not possible to achieve proper concrete compaction without one.
If you’re not familiar with the tool just yet, that’s okay. This guide will introduce you to it in general as well as highlight four different sub-types that you’re likely to encounter on an industrial jobsite. With that knowledge in mind, you’ll be better able to select your tools judiciously when your task involves laying down and finishing concrete.
What Is a Concrete Vibrator and How Does It Work?
First and foremost, you may be wondering what a “concrete vibrator” even is.
In essence, a concrete vibrator is any number of specialized construction tools that are designed to rapidly agitate a freshly poured concrete slab. This is done to “shake” air bubbles out of the concrete’s interior, thus preventing them from remaining there during the setting process.
This, in turn, decreases the risk of “honeycombing” within the slab, which can negatively impact the slab’s overall structural integrity.
Concrete vibrators come in several different forms, each of which uses a different method to agitate wet concrete in its general vicinity. Some units, for example, use an insert probe to do the job while other units use a strong external force to shake the poured concrete’s frame. Some units even work at the surface level or take hold of the slab’s rebar mesh to internally shake the entire slab.
However, not all of these types are appropriate for every kind of concrete slab.
As such, you should keep in mind the power, size, and frequency of your desired unit before investing in this type of tool. Those who are simply pouring concrete for DIY jobs should also consult a concrete application specialist to determine if the use of a vibrator is even warranted in the first place.
To learn more, read my article about how to vibrate concrete.
4 Types of Concrete Vibrators
In either case, if you decide you need one, you should continue reading to see the most common types of concrete vibrators.
Immersion Concrete Vibrator
By far, this is the most common type of the tool. That is primarily because immersion concrete vibrators are among the simplest to understand and utilize on a construction site.
In essence, these units operate by inserting a long, smooth probe into a wet concrete slump such that it doesn’t touch any reinforcement bars. From there, the probe’s motorized vibrations can properly eliminate air pockets in as little as 10 to 30 seconds.
When it comes to actually using this type of vibrator, it is recommended that you plan out your insertion pattern in advance. That’s because too much vibration in a particular area can cause wet concrete to stratify.
Also, you’ll need to keep in mind that this kind of vibrator can introduce new air pockets if you’re not careful. As such, it is essential that these vibrators always be removed slowly from a patch of wet concrete.
External Concrete Vibrator
An external concrete vibrator is a unique device that, as its name suggests, vibrates a concrete slab from the outside. Specifically, these motorized units are attached to the outside of a slab’s frame and turned on. They then begin to shake the entire slab, allowing air bubbles to be uniformly released.
External vibrators are exceptionally capable when it comes to removing air pockets from large or thick concrete slabs.
For this reason, they see a lot of use in pre-casting settings where an immersion vibrator would be too slow or inefficient. These units do require more set up time as well, making them most practical for completing large-sized slabs and structures.
Surface Vibrator
When it comes to working with shallow, yet broad slabs, surface vibrators are an excellent option. That’s because these units are designed to shake a slab from above, which allows for an even transfer of motion across the entire surface.
That being said, these units are not recommended for thick slabs. Instead, they can be put to good use when performing patch-up jobs on the top of an existing cement structure.
Rebar Shaker
A rebar shaker is a unique type of concrete vibrator that operates just as you’d expect. Using specialized probes, these machines grasp onto a slab’s internal rebar structure and use it for leverage when vibrating the entire slab.
This is particularly useful because air pockets are known to cluster around the rebar structure in the first place. They’re also very useful for shaking concrete in tight spots where other vibrators would be impractical.
Summary
In so many words, a concrete vibrator should be a part of a productive construction team’s tool kit.
Some DIYers could event benefit from renting one while taking part in a project that involves pouring concrete. Whether you’re a pro or a weekend warrior, you should now be able to see which concrete vibrator type is best suited to your upcoming project.
If you are looking to buy one, check my list of the best concrete vibrators on the market today.