In this article we consider the difference between Power Trowel Polishing and Concrete Grinding. In particular we show how a Power Trowel can be used in different ways to produce a high quality, smoother Concrete Floor.
What is power trowel?
A Power Trowel, sometimes called a power Float, is a piece of light construction equipment used by construction companies and contractors to apply a smooth finish to concrete slabs.
It is supplied with a series of blades which, in normal use, scrape the surface of newly laid concrete to provide a flat and level finish. There are two types of Power Trowel, walk behind and ride on.
A walk behind power trowel is, as its name suggests, is a simple machine that is pushed or pulled. An example of this is the Power Trowel BT120 from Beton Trowel NV.
A ride on machine allows the operator to sit on the machine and cover a larger area in less time. An example of this is the Ride On Trowel BT900 from Beton Trowel NV. The Power Trowel uses liquid in the grinding and polishing process to reduce dust.
What is a concrete grinder?
A concrete grinder, or perhaps more accurately a concrete floor Grinder, is a machine made specifically to grind the surface of a previously cured concrete surface.
The concrete grinder is heavier than a power trowel and is rarely supplied as a ride on machine.
A good example is the Husqvana PG 820. The concrete grinder can be used with or without water as the machine is equipped to collect dust.
What is power trowel polishing?
Now the clever thing about a power trowel is that the scraping blades can be replaced by diamond grinding pads.
This allows the power trowel to be used as an effective machine for both Power Trowel Polishing and for Power Trowel Grinding.
However, if the floor is in a very bad state or very uneven then a Concrete Grinding machine is preferred.
Power Trowel Polishing vs Grinding
What is the difference. Well in reality nothing. It is a case of the grade of the diamond pads, also called grits, used the the process.
CEO of Becosan, Kenneth OlsenThe higher the grit number, the smoother the finish. For grinding a grit of grade 30 or 60 is used. For polishing we are talking about grits in excess of 200. For the very finest of finishes we would complete the polishing process with grits graded at 3000.
Imagine you have a 10,000m2 floor that you want to bring up to a high quality, polished concrete surface. The first key question is – what is the state of the floor.
If it is uneven, has protruding steel or a significant depth of concrete must be removed then grinding with a Concrete Grinder is the preferred option.
However, if the floor is basically in a good state then a power trowel can be used to grind away the micro roughness and afterwards polishing can begin with increasing finer grades of grits.
The grinding and polishing process with a power trowel creates a good deal of slurry – water with particles of concrete dust in suspension. This must be ecologically disposed of.
The liquid must first be collected in a large container. Left for a few hours the concrete particles will separate out from the water. This can be siphoned off and when the ph is adjusted to neutral this can be drained away. The residual sand will be disposed of by the appropriate facility provided by the local authority.
Advantages of Power Trowel Polishing
Power trowel grinding and polishing is much faster than a concrete grinder. Roughly speaking a power trowel can polish 10 times faster than a concrete grinder.
The machines are also much cheaper. A walk behind power trowel will cost in the region of 2,000€ whereas a concrete grinder might cost as much as 25,000€.
Disadvantages of Power Trowel Polishing
As we have said there is a limit to the Power Trowel’s ability to grind a concrete floor and if it is in a very bad state a Concrete Grinder must be used. But even if the floor is ground and polished to a high standard there is more you can do.
The perfect combination: Power Trowel Polishing and BECOSAN®
Here at Becosan, we recommend, that once the floor has been ground to the required standard the BECOSAN® Concrete Densifier should be applied over the entire surface to reinforce the concrete.
This lithium silicate densifier binds the surface of the concrete together and allows the concrete to withstand heavy traffic.
And after the polishing phase is complete then we apply the BECOSAN® Concrete Sealant making the floor much more resistant to the absorption of liquids leaving the surface stain free for many years.
A final polish and you have a hard, flat, smooth and beautiful concrete floor that will maintain its sparkle for many, many years.