1.4. Guidelines for Finishing

So, there are also machines to do the finishing job. We call them as power floats or power trowels. So, you can see here, it look like a spider. That is why it is also called a spider. It looks like a spider. So, basically there are rotating blades inside. See these rotating blades inside helps you to finish the concrete surface.

Power floats and power trowels are specialized machines designed for finishing concrete surfaces. They have rotating blades that help achieve a smooth finish. The nickname 'spider' for these machines comes from their shape, which resembles that of a spider. These machines are efficient and help ensure high productivity during the finishing process.

Imagine using an ordinary kitchen whisk to stir batter vs. using an electric mixer. The whisk gets the job done, but the mixer does it faster and smoother; similarly, power floats and trowels can complete the job of finishing much quicker and with better results than manual methods.

The same machine you can use it for both floating as well as troweling. As I told you, when you do the floating, you have to keep the blades flat. When you do the troweling which you are going to do in a delayed manner, there you need to apply more pressure. So, you slightly angle the blade and use it.

Power floats and trowels can perform two main functions: floating and troweling. Floating is done with the blades kept flat, while troweling involves applying more pressure with a slight angle to the blades. This differentiation is important for achieving the desired surface finish at different stages of the concrete setting.

Think of a painter using a flat brush for broad strokes on the wall (floating) and a pointed brush for fine details (troweling). Each brush serves a different purpose, just as the angled blades of a trowel do.

So, basically, this helps you to have a very high productivity. Obviously, with these machines, when compared to manual finishing with simple tools. With this power trowels and power floats, I can have a very high productivity.

Using power floats and trowels significantly increases the productivity of finishing concrete compared to manual methods. Manual finishing can cover an area of 30 to 60 square meters per day, while machines can achieve up to 140 square meters per day. This drastic increase in coverage allows for quicker project timelines and reduced labor costs.

Consider how much time it would take to manually shovel snow off a driveway versus using a snow blower. The machine speeds up the process immensely, similar to how power trowels enhance concrete finishing productivity.

So, the actual productivity depends upon the size of the power trowel. It depends upon the diameter of this circular area. So, greater the diameter, you can cover more areas. So, the productivity will be high.

The size of the power trowel, indicated by the diameter of its circular area, directly affects productivity. A larger diameter allows the machine to cover more surface area in less time, leading to higher productivity levels. This makes it essential to choose the right machine size based on the project requirements.

Imagine using a larger pizza cutter for a big pizza versus a smaller one; the larger cutter will speed up the cutting process. Similarly, larger trowels help finish concrete quicker.

So, generally the window of the finishing period is between the initial set and final set. So, the concrete should have dried up well and it should be free of bleed water.

Timing is crucial when finishing concrete. The optimal finishing period is between the initial set and final set stages. During this time, the concrete must not be saturated with water and should be sufficiently dried to withstand the weight of finishing equipment. This ensures the best finish and prevents damage to the concrete.

It's like baking a cake; you need to wait for the cake to cool down before icing it. If you ice it too early, the moist cake will ruin the icing. Similarly, waiting for concrete to set properly is essential.

How to test whether the concrete is ready for the troweling or finishing? Simple guidelines are available in the ACI manual. If you put your foot on the concrete, the indentation allowed, the maximum indentation allowed is only 1/4 inch or 6 mm.

To check if concrete is ready for finishing, one can perform a simple foot test. If a person's footprint leaves an indentation greater than 1/4 inch (6 mm), then the concrete is not sufficiently set. For machine finishing, the limit is even stricter, at only 1/8 inch (3 mm). This ensures that the concrete can handle the machinery's weight without deforming.

Think of testing a sponge's firmness before using it; if it's too soft, it won't perform well. Similarly, checking the hardness of concrete ensures it can support finishing without damage.

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