Grout floor screed

Arrangement of concrete screed includes several stages. The final step is to grout the floor screed using special equipment. After grouting, the concrete surface acquires characteristics, due to which it can withstand significant loads - both shock and abrasion. So that you can get just such a result, we will consider in this article in detail how step-by-step grouting is performed and what should be taken into account.

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The purpose of the grout

When concrete pouring hardens, heavier fractions of crushed stone and sand fall down. Cement milk and small particles are on the surface. When moisture dries, the surface is covered with bumps and voids, it looks quite unattractive. In addition to external shells, voids are formed in the upper part of the concrete, reducing the bond strength of the filler elements. The upper layers exfoliate and quite large potholes are obtained. Even costly repairs do not guarantee complete restoration of a uniform and durable floor covering.

You can mitigate these shortcomings with a grout. This process is rather complicated and requires highly skilled employee. Its essence lies in the fact that the upper concrete layers are compelled by force. At the same time, the strength of the concrete layer and its resistance to wear increase.

Important! Often in the grouting process, additional reinforcing grouting mixtures (toppings) are used.

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Work algorithm

The entire grouting process is divided into 2 stages:

• Coarse (preliminary).
• Finishing.

Rude

The first stage of grouting the floor screed is performed 3-7 hours after the concrete mixture is poured.

Important! The degree of hardening of the concrete should be such that the depth of the footprints does not exceed 4 mm.

Coarse grout includes 2 passes of the grout in a mutually perpendicular direction. First of all, they process the areas near walls, columns and doorways, since the hardening of concrete occurs much faster.

Finishing

The completion phase is 10-15 hours from the end of the preliminary processing. The degree of readiness of concrete for finishing grouting can be determined by applying a palm to it. If the hand remains clean, you need to start finishing grouting. At the same time, the floor acquires a mirror shine and looks perfectly smooth.

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Applicable equipment:

• Rotary trowels with electric or gasoline drive.
• Manual or automatic appliances distributing topping.
• Rotary vane machines, popularly known as “helicopters”.
• Edging technique, which is used to process screeds near columns or walls.

Device principle

Distinguish between trowels single and double rotor. Machines differ in the way they are controlled:

• The operator controls the single-rotor machine with a long handle. The mass of a single-rotor device varies between 35 and 70 kg, so it is quite portable and versatile.

Important! Advantages of single-rotor technology: mobility, convenience, maneuverability and good quality grout.

• The two-rotor car does not resemble a helicopter, but rather a small car. It is used in large areas.The main control feature is the lack of contact between the person and the machine.

Important! Cons - high cost and not enough good maneuverability.

Wall (edging) machines are convenient for working in corners, near walls, in the area of ​​doorways. Their feature is the small diameter of the working tool. This technique is equipped with low-power electric motors, so the consumption of electricity is economical.

Tool diameter

The main classification feature for trowels is the diameter of the working tool used:

• The universal diameter is 900 mm.
• In rooms with a complex configuration and small area, disks with a diameter of up to 600 mm are used.

Important! The finishing stage is performed using paddle “helicopters” for grouting concrete with stiffeners. The blades cut off the protruding sections of the screed. The floor turns out perfectly smooth and smooth.

• Equipment with a small disk is advisable to use in a room with columns and a large number of angles.

Important! A two-rotor machine is optimal for a spacious room. The simultaneous operation of two disks allows you to process a significant area.

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Technology and materials used

Before proceeding to grout, arrange a technological pause. It is necessary in order for concrete to gain the necessary strength. The duration of such a pause is 4-20 hours. During this time, the concrete sets in such a way that a footprint of a maximum depth of 4 mm remains on the surface. Now consider the technology of grouting concrete “helicopter” in more detail.

Coarse grout

It is carried out several times in mutually perpendicular directions. When the trowel rotates, the concrete is compacted. The number of passes depends on the quality of the concrete and on the thickness of the poured layer. After a sufficient amount of cement milk has been obtained, the concrete surface is covered with a topping - grout mixture. Topping distribution is made by special trolleys.

Important! Hardening with topping is mainly used for floors with a significant load (markets, warehouses, production halls, car parks).

Trolley Requirements:

• The presence of a special container for loading the mixture.
• Equipped with screws to grind stagnant mixture.
• Wide wheels that do not leave a deep rut on fresh concrete.
• Special dampers for dosed topping feed.

The first stage of applying the sealant is approximately ⅔ of the total volume. Then they wait for some time necessary to soak the mixture with moisture. The darkening of the mixture is a signal that the grout can begin.

Important! Estimated consumption of topping per square meter is:

• For light and medium loads - from 3 to 5 kg.
• For a significant load - from 5 to 8 kg.

A single-rotor technique is used to mix the mixture with cement milk. After it was possible to achieve uniform mixing of the composition with cement milk, two-rotor heavy equipment, the mass of which is 350-400 kg, is launched.

Applicable mixtures

Portland cement, modified additives and polymeric materials are the basis of most of the grout compositions. As fillers, substances of increased strength are used: corundum, quartz sand, basalt, etc.

The choice of one or another option depends on the purpose of the room:

• Quartz hardener is used for floors designed for medium and light loads (shopping, entertainment centers).
• A hardener with corundum is used for floors with a planned high load (industrial enterprises, large gas stations, warehouses). The cost of corundum hardener is higher than quartz, but the service life is longer.

Important! Polymer additives reinforce the concrete layer, giving it additional strength.The composition of the grout mixture may include dyes that allow not only to strengthen the concrete floor, but also to create a decorative effect.

Finish grout

At the final stage, they use specialized equipment with blades. The minimum number of passes is 2. The direction of movement of the machine with different passes is mutually perpendicular. The interval between the blades and the floor level is:

• In the first approach, from 5 to 10 mm.
• In the second approach, from 20 to 25 mm

When finishing grouting, the surface of the floor is not only smoothed to a mirror state, but also a qualitative compaction of the mixture occurs. At the same time, the strength of concrete becomes such that there are no footprints on it. Such work can only be done using special equipment. Grouting the floor screed with your own hands in a “makeshift” way is not suitable here.

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How to eliminate cracks in concrete?

Cracks in concrete significantly affect the performance of the coating. The causes of cracking are various, but in any case, repair work is necessary. Timely repair prevents the crack from spreading and the entry of debris and moisture into it:

• With a small number of cracks and an opening size not exceeding 2 mm, you can limit yourself to repair with ordinary paint or polymer-cement test.
• If the magnitude of the opening increases over time, use a polymer-cement composition or synthetic resins.
• With significant cracking, the injection method is used.

Important! The most reliable composition is obtained from a combination of polymer-cement and epoxy materials. First, grout the floor screed with glue (epoxy), and then apply the mortar or polymer cement dough to the fresh coating.

• To strengthen wide cracks, metal brackets are used with an interval of 0.25 m in combination with a repair compound. Then the surface is wiped using a single-rotor technique. It helps to mask on the floor all the roughness associated with the repair.

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Stock footage

The use of specialized grouting technology is the most progressive and inexpensive way of surface treatment. After the finishing procedure, the floor is perfectly clean and smooth, without even dust. The use of coloring compounds gives the floor an aesthetic appearance. The combination of such operations as laying and grouting the floor screed helps reduce construction time. Another advantage of technology using topping is its versatility and the ability to use it on different objects.