Grinding a concrete floor: grinding options with different equipment

In the process of carrying out repair work, preparatory activities occupy a special place. One of them is grinding the concrete floor. It is used to remove the old layer, level the surface and prepare it for decorative finishing by painting, varnishing or finishing with polymer-based coatings. Polished concrete floors are widely popular in retail and warehouse premises, in public premises with high traffic - educational institutions, theaters and hotels, in utility and even residential premises. In other cases, by grinding the concrete, it is possible to properly level and prepare the base for laying the floor covering.

Sanding concrete floor

Concrete and its properties

Thanks to its unique operational and technical characteristics, concrete has become widely used in various construction industries. It is concrete that often allows you not to limit your imagination in implementing the most unusual and daring architectural solutions. Concrete structures have the highest strength, durability and withstand any operational impacts.

Concrete mortar

Concrete is used in construction in the following form:

1. As the main building material, concrete is used in the manufacture of foundations, floor slabs, enclosing and other structures.
2. As a fixing solution for fastening building blocks and other elements.
3. As a filler.
4. As an insulating material.
5. As a finishing material.

Note! When producing concrete, it is possible to adjust its basic properties in order to match the composition to operating conditions. For this purpose, various additives and composition manufacturing technologies are used.

The process of creating a concrete base

Products, structures and surfaces made of concrete are reliable and durable. The plasticity of concrete mortar allows you to create seamless monoliths of any shape. True, when pouring a large area (for example, in a warehouse), it will be necessary to provide compensation gaps (seams). A seamless concrete floor has high hydro-, sound- and heat-insulating properties, which allows significant savings on additional insulating materials and increases the comfort of a person’s stay in such a room.

Structure of a hardened concrete surface

By using additives with a water-repellent effect, it is possible to increase the water resistance of concrete. Therefore, it is widely used for the construction of structures used in the open air - retaining walls, bridges, dams, dams, water pipelines, wells, swimming pools, porches of private houses and public buildings. Unlike wood, concrete does not support the development of microorganisms in its structure.

Mosaic concrete floor is highly decorative

Concrete has an affordable price, so it is most often preferred, and its wide range of applications allows it to solve a variety of construction problems.

conclusions

Concrete polishing technology is a modern, reliable and most promising way to create flooring. This technology eliminates the need to apply any coating to the concrete base, which completely eliminates peeling, peeling or wear of the corresponding coating.

The hardness of polished flooring is almost the same as that of granite.

Polished concrete is practically no different in appearance and technical characteristics from natural stone floors . Accordingly, the wear resistance of polished concrete floors is significantly higher compared to all other traditional floor coverings. Thanks to these characteristics, polished concrete floors can be used in areas where there is heavy traffic of people or heavy loading equipment.

The nuances of polished concrete technology from Adele are shown in the video:

Purpose of grinding

In the context of modern trends in which the construction industry is developing, the distribution and popularity of concrete floors is not inferior to other coatings. Moreover, concrete floors are relevant for some interior styles - loft, grunge and other industrial styles.

Loft style interior

Expert opinion

Afanasyev E.V.

Chief editor of the pol-exp.com project Engineer.

Thanks to grinding, the concrete surface acquires an aesthetic appearance and a lot of positive qualities. Polished concrete floors have the following advantages:

1. Simple and affordable maintenance to keep the surface in working condition.
2. Reliability, high strength and long service life.
3. Excellent compatibility with most finishing materials.
4. Versatility - such floors are used both indoors and outdoors.
5. Waterproof and resistant to chemicals.
6. High mechanical strength and resistance to abrasive loads.

Concrete floors that have gone through the grinding stage are found in commercial, warehouse, and industrial buildings; they can be found in office buildings, educational or medical institutions, and in the lobby of a station. Such floors are equally popular in multi-storey and private housing construction, in the design of courtyard areas, in the arrangement of garages and utility buildings.

Interior of a modern store

Note! Mosaic concrete floors are especially decorative when decorative chips and coloring pigments are added to the solution. In this case, it is possible to create not only solid surfaces, but also colored patterns. Sanding such a floor is one of the final stages.

The first grinding is carried out 5 days after pouring the concrete solution. The final one is performed after the concrete base is completely ready, that is, after its final hardening.

Dry grinding method

Note! Cement laitance appears on the surface of a new poured concrete floor, which must be removed before grinding. When working with an existing concrete surface, it is sufficient to remove the old concrete layer by grinding.

Operator control of a self-propelled machine

Using grinding, you can not only eliminate unevenness, but also remove other defects and contaminants. Regardless of how long ago the concrete floor was made, grinding it transforms the surface, looks fresher and has better adhesive properties.

As a result of grinding, the concrete surface becomes suitable for applying any material that requires a perfectly flat base. For example, self-leveling floors require a responsible approach to preparatory measures, during which the base is ground and damaged areas of the upper concrete layer are removed.

Also, a surface that has been damaged by grinding is restored, the damaged layer is removed, and the surface acquires improved performance qualities.

Hand-held devices allow you to treat hard-to-reach areas

It is worth remembering that untreated concrete can absorb moisture, which over time will lead to its destruction. Grinding can solve this problem and increase the water resistance of the concrete surface.

Important! Grinding should not be taken as a salvation from any imperfections in the concrete surface. If the floor is uneven, has waves and significant differences in height, then the grinding machine is powerless here, since it moves very close to the floor surface and requires its evenness.

If the concrete surface is polished after the grinding stage, then such a floor is used as a finishing coating. In particular, this includes the previously mentioned mosaic concrete floors. If polishing is not expected, then the concrete floor retains its roughness and is treated with impregnations, protective and decorative coatings.

Grinding is required when it is necessary to renew an old concrete floor when it has been subjected to high wear and tear with freezing and thawing of water that has entered the concrete structure, during which the destruction of the top layer has occurred. By removing such a layer, you can get a renewed, durable surface, eliminating the complex repair work of pouring a new screed.

Mosaic floor in a warehouse

It is worth noting that any concrete coating can be subjected to grinding, regardless of the time of its manufacture. Moreover, if this type of processing is planned, then this fact is taken into account when manufacturing the working composition.

With the help of multi-colored fillers and dyes, mosaic floors are unique in their design

The function of filler in concrete in the manufacture of mosaic coverings is performed by fine crushed rock. It is worth taking a responsible approach to the choice of filler: if its density is too high, abrasive finishing will be difficult, and low density will reduce the strength of the coating. Thus, floors with marble chips are easier to sand than those containing granite or gravel filler. Fine marble and granite chips allow you to create aesthetically attractive concrete surfaces after they are ground and polished.

Floors made from marble chips are widely used to create floors in shopping and office centers, theaters, museums, warehouses, industrial and even residential premises. Read in detail about the process of installing mosaic floors made of marble chips in a special article.

Main areas of application of concrete polishing technology

Concrete is a natural material. Its main components are Portland cement, which is made from limestone and clay, and fillers (sand, gravel, crushed stone), obtained by crushing various rocks. Concrete also contains water, which ensures its hardening reaction. But, despite its naturalness, concrete has some flaws.

First of all, it has a rather unsightly appearance. For example, a concrete floor without any coating does not look very aesthetically pleasing. In addition, during operation such a floor becomes quite dusty . Now all these defects can be easily eliminated by grinding and subsequent polishing of concrete. Modern polishing technology allows you to preserve the naturalness of concrete, while eliminating all its main disadvantages.

Thanks to polishing, concrete began to be used as an independent floor covering

The visual characteristics of a polished concrete floor are almost identical to the external characteristics of natural stone. This floor looks truly beautiful and expensive, and its technical characteristics provide high resistance to mechanical and other influences. As practice shows, floors made of polished concrete successfully withstand both intense pedestrian traffic and the movement of heavy forklifts , therefore they are ideal for public entertainment venues and industrial workshops.

Currently, polished concrete floors are widely used in:

• production and warehouse premises;
• office buildings and business centers;
• supermarkets and boutiques;
• restaurants, bars and cafes;
• exhibition halls and museums;
• garages, parking lots;
• medical and educational institutions;
• sports complexes;
• hotels, train stations and airfields;
• residential premises.

Advantages of polished concrete floors

After sanding, the surface becomes smooth and even.

Floor grinding is carried out mainly using special installations called grinding machines. Surfaces that have undergone this treatment have the following advantages:

1. A surface with increased strength and resistance to mechanical loads.
2. Economical surface care and the ability to repeatedly restore the exposed concrete layer in order to renew and improve performance properties.
3. Improving the appearance, increasing the aesthetics of the surface and the ability to create a decorative coating with colored patterns.
4. Excellent compatibility with most finishing materials.
5. Versatility of use and the ability to withstand a wide variety of operating conditions: high humidity, severe frost, chemicals and other adverse influences, both indoors and outdoors.
6. Resistant to high loads from vehicles and equipment, high traffic.

Work must be carried out using personal protective equipment

Grinding with the help of special equipment is not a cheap type of work, but this is the only drawback that should not be a reason for abandoning these measures that increase the operational capabilities of a concrete floor. In addition, if you use a hand tool for grinding, then if you follow the basic technological points, you can do the work yourself, saving on the services of a specialist.

Scope of application

These floors are used:

1. In administrative buildings.
2. In production workshops.
3. In warehouse premises.
4. In supermarkets.
5. In sports facilities.
6. In cultural centers, exhibition halls, cinema foyers.
7. In hotels, restaurants.
8. As open areas under a canopy in a private house.

Concrete floor in a hangar

Grouting fresh screed

There is a special technology for working with fresh screed, which is practiced within 4-20 hours from the moment of pouring. It allows you to create durable, wear-resistant coatings for commercial and industrial facilities and even floors for open areas. For work they use a grinding helicopter - a special type of trowel. It is manual or self-propelled, equipped with a diesel, electric or gasoline engine.

This technology helps compact the top layer of the poured screed. First, rough cleaning of the concrete is done using cement-based toppings. After 10-16 hours, finish grinding is carried out with rubbing in dust-removing impregnations. For a decorative effect, toppings with added pigments are applied over the screed.

Beginning of work

According to the most common technology for grinding a concrete floor, this stage of work should begin from 10 to 15 days after the concrete is poured. It is during this time interval that the concrete has sufficient strength and the fractional fillers located inside it in the form of crushed stone, granite, gravel or marble chips are already securely fixed in the concrete mass, and during grinding they will remain securely in place.

Working with a compact tool will take longer

As previously noted, grinding is performed in several stages. The first can be performed 3–5 days after pouring concrete. During this period, the surface strength will already be sufficient so that protruding irregularities can be removed by grinding without “burrowing” too deeply so as not to disturb the position of the filler.

The effect of concrete processing by grinding

Safety precautions

To avoid injury and keep the instrument safe, you need to follow simple recommendations:

• Before starting work, inspect the device for damage, cracks in the housing, and reliability of wire insulation;
• put on protective clothing and shoes, gloves, goggles and a respirator in advance;
• ensure good lighting of the workplace;
• when replacing wheels and attachments, be sure to disconnect the device from the network;
• If vibration or a burning smell appears, stop grinding immediately.

If you strictly follow the technology, you can create a beautiful, monolithic and perfectly smooth floor with your own hands, which will not be inferior in strength to stone. Considering its wear resistance, long service life and ease of operation, it is probably worth mastering the simple technique and applying it in practice.

Processing options

Regardless of the structure of the concrete surface, one type of equipment is used for grinding it, suitable for working with concrete and stone.

Wet processing

There are two technologies: wet and dry. In the first case, it is a mosaic floor with marble or other types of filling. When carrying out the wet grinding process, abrasives are used that ultimately make it possible to obtain a surface that is perfectly smooth and shiny, as if the polishing stage had been completed. The disadvantage of this technology is associated with the formation of wet sludge on the floor surface during operation, which interferes to some extent with quality control of the actions performed.

Dry processing is associated with a high level of dust formation

The dry grinding method is more convenient in this regard, since the cement dust generated during the work can be effectively removed by connecting an industrial vacuum cleaner to the grinding machine. As a result, the quality of the work performed will be visible and the likelihood of mistakes will be reduced.

Specifics of the procedure

Of all the finishing floor covering options, polishing is the most durable method.
There are no additional materials or adhesive layers here, since the processing is carried out directly on the top layer of concrete pouring. The resulting result makes the floor very solid and attractive - an ordinary concrete screed produces a very smooth and glossy surface that looks solid and requires virtually no maintenance (regular wet cleaning is required).

Types of equipment

The choice of equipment is influenced by the frequency of its use and the area of ​​the objects. In many construction stores you can find equipment from different manufacturers and capacities, both for domestic use and for professional activities when working on large facilities.

The drivers on which the grinding tools are attached move in opposite directions during the grinding process.

Undoubtedly, professional equipment is of a higher class and can provide better grinding results. Grinding machines of this level are distinguished by a planetary mechanism, represented by a large disk with auxiliary wheels equipped with diamond nozzles that carry out synchronous movement. At the same time, the floor surface acquires ideal evenness due to the complex trajectory of the diamonds when the wheels rotate in the opposite direction.

Mosaic Floor Grinding Machine

The essence of the design of the grinding machine is the presence of a rotating unit, with abrasive parts attached to it, which remove the top concrete layer and create a smooth surface suitable for further processing.

Self-propelled unit, controlled by an operator, designed to work over large areas

The following work is performed using a grinding machine:

1. Level the surface of a freshly laid concrete screed or floor covering.
2. Remove the outdated, worn out and old concrete layer that is beginning to collapse.
3. Level the surface for subsequent finishing.
4. Eliminate minor differences in height, protruding irregularities, remove pores and other minor imperfections.
5. They increase the adhesive qualities of the surface for further application of putty, varnish and polymer compounds.

Professional industrial unit

Grinding machines have the following advantages:

1. The equipment is equipped with adjustment of the rotation speed of working parts.
2. When using wet technology, it is possible to supply liquid in a certain amount.
3. The machine is equipped with a dust collector, which allows you to carry out work with minimal contamination.
4. A wide range of models suitable for both domestic and professional use.
5. Floor grinding work using special equipment is carried out efficiently in a short time and does not involve serious labor costs.
6. Grinding using special units is highly accurate - the error can be no more than 2 mm.
7. The products are characterized by simple operation and simple maintenance - no special skills or prior training are required to operate the equipment.
8. Using interchangeable nozzles of different sizes, you can adjust the level of roughness of the concrete surface and bring the result of the work to perfection.
9. Models from foreign manufacturers are highly reliable, they are not afraid of serious dynamic loads, so we can talk about a long service life of such equipment.

The use of grinding machines is associated with several disadvantages, namely: during operation, a large amount of cement dust is formed (dry technique) and wet sludge (wet technology). It is also worth noting the high cost of not only the equipment itself, but also consumables - nozzles.

Dry grinding is fraught with large dust formation

Note! Each individual model of grinding machine has its own design features that affect its performance, performance, advantages and disadvantages.

The cost of professional equipment is quite high, so purchasing it for home use is not advisable.

Working with corner manual equipment

For household use, a grinder is used as a grinding tool. It costs less than professional equipment and, on the one hand, is even more convenient, as it allows you to process hard-to-reach areas. For grinding, the grinder is equipped with an abrasive disc of not too large a diameter or a diamond-coated bowl.

Working with an angle grinder

Note! The weight of the grinding machine directly affects the quality of the work performed.

To polish the floor, if provided, a special machine is also used. It is small in size and easy to use. The working mechanism is similar to the design of a grinding machine, while “budget” models do not have a planetary mechanism; the work is carried out using one diamond disk with a diamond attachment.

The hand tool is equipped with an ergonomic handle and a connection pipe for connecting a dust collector

Among professional models and their “budget” analogues, the leaders are products from European and American manufacturers. The quality of domestic equipment is somewhat lower.

Professional craftsmen prefer European-made equipment - the most popular are models from the Italian brand Klindeх, among which there are floor grinders. The mechanism of such a machine is planetary, represented by a large circle and three bowls equipped with diamond cutters. The movement of the bowls with cutters and the circle occurs in opposite directions - as a result, the surface becomes highly smooth.

Note! Equipment with greater weight has more power and provides better efficiency.

Among the professional tools for renovating concrete surfaces, we can highlight trowels, which craftsmen call “helicopters.” With its help, the concrete surface acquires an ideal condition. Units of this type are two-rotor, represented by large machines with an operator's chair, and single-rotor - in the form of hand-held devices.

Floor sanding helicopter

Types of grinding equipment

Grinding machines on the modern construction market are represented by a wide range of industrial and manual grinding machines. To differentiate these products, there are two main criteria: the purpose of the product and its design features.

Treatment of hard-to-reach places

Classification by purpose

Despite their design features, grinding machines have different purposes.

Table 1. Classification by purpose

Classification depending on design

Of the most popular models that differ structurally, the following options can be noted.

Table 2. Classification depending on design

Table 3. Features of working on a multifunctional machine equipped with Frankfurt

How to choose a grinding machine: basic rules

When choosing a grinding machine, you need to take into account many factors, among which the first place is occupied by the purpose of the equipment, which allows you to solve a range of specific tasks at the site. When this parameter is determined, we begin to select a tool based on power, speed and working diameter of diamond discs or the moving mechanism of the belt equipment.

Considering the volume of upcoming events, manual or industrial type of equipment is chosen.

Hand tool

When choosing a grinding machine, preference should be given to reputable manufacturers and brands, such as Makita, AEG, Stern, Bosch. Products from Chinese manufacturers, of which quite a lot have appeared recently, are compact in size and attractive in price - before purchasing them, it is recommended to read the reviews on the relevant Internet resources, as well as read the opinions of professional craftsmen on specialized forums. It is also important that the store where the equipment is purchased gives a guarantee on it.

Makita brand equipment is popular among professional craftsmen

Manual equipment includes grinders with a power not exceeding 1.8 kW. Their advantage lies in increased maneuverability, which allows processing of any surface. However, it is impossible to complete a large amount of work at once - the machine will overheat, so you will need to periodically take a break from work (approximately every 3 hours).

The disk contains all the necessary information

When choosing grinding equipment for working with concrete, the main criteria should be:

1. Installed power of the unit. The level of equipment functionality is affected by the drive power and the ability to change its parameters.
2. Machine weight. The smaller it is, the more convenient it is to work in manual mode.
3. The dimensions of the disk-type nozzle or the grain size of the tape - these parameters are selected depending on the quality of the desired result.
4. Rotation speed of the working mechanism - equipment performance depends on the number of revolutions per minute.
5. You need to pay attention to the brand, the popularity of the manufacturer, the build quality, the presence of additional equipment, the level of vibration and noise during operation of the mechanisms, the ability to connect and the presence of a vacuum cleaner to remove cement dust.

Multifunctional equipment

There is no need to rush and purchase the first model you like - such equipment is represented by a wide range and allows you to choose the necessary tool by comparing the characteristics of several devices:

1. For rough grinding of concrete surfaces, machines are used with a speed of 300 rpm, equipped with a coarse abrasive. While machines designed for polishing concrete or stone surfaces are equipped with a mechanism with small diameter disks rotating at a speed of 50 rpm.
2. The best option would be equipment that makes it possible to regulate the speed of the grinding tool, which makes it more functional and convenient to use.
3. A big advantage will be the presence of additional equipment (water extractor, dust collector) of the device, which will simplify the work with it and maintain its performance by protecting the internal mechanisms from excess moisture and dirt. Such equipment can be built into the main unit or have the ability to be connected, like hand-held machines that have special connections for connecting an industrial vacuum cleaner.

Note! When choosing grinding equipment, take into account the area of ​​the room and the technical characteristics of the concrete.

Elimination of defects by grinding

With prolonged use of a concrete floor, defects are likely to appear on it. They need to be eliminated as early as possible, regardless of the causes. To get rid of the problem, part of the concrete is cut out to a depth of at least 2 cm. The cavity thus obtained must be cleaned, then primed and filled with any mixture for sealing.

A rule is used to level this area. After waiting for the mixture to completely harden, you need to sand the surface until it is even. In case of serious damage, it is worth applying the repair composition in several layers, one of which will be quartz sand, ideal for such situations.

Sometimes too deep cracks appear on the concrete surface, and the method for eliminating them looks a little different. It is necessary to use a diamond disc to cut a crack at least five centimeters deep into the coating so that the damaged concrete can be removed. The deepened and cleaned area is filled with the selected mixture for repair, after which all that remains is to sand the surface according to the already known scheme.

Conclusion

Sanding concrete floors is a good remedy for minor damage and uneven surfaces. If desired, this work can be done with your own hands, but caution and attentiveness will be required - failure to comply with concrete grinding technology or violation of safety rules can lead to problems.

If everything was done correctly, the resulting concrete floor will have maximum mechanical strength, abrasion resistance and moisture resistance. In addition, the next renovation will not be discussed in the near future, and the good visual characteristics of the coating can be used to implement a variety of design solutions.

Rating of popular brands of grinding machines

Splitstone GM-245

The manufacturer is Russia. The equipment is characterized by high power and affordable cost.

Splitstone GM-245

pros

1. The design of the traverse ensures the absence of vibration of the cutting and load-bearing elements, provides the ability to process a wide range of materials with the required parameters of microroughness and quality of the processed surface.
2. The ability to use additional cargo and high engine power provide enormous productivity.

Minuses

Due to the lack of a planetary rotating mechanism, they provide a high-quality effect only when working with relatively flat surfaces.

Splitstone GM-245

SO-307

The manufacturer is Belarus. Allows you to work with surfaces that have smooth wave-like changes. Used on an industrial scale. This model is the most powerful and productive in the line of similar equipment.

SO-307

SO-307

pros

1. Affordable price.
2. Durable metal construction.
3. High performance.
4. Powerful electric motor.
5. Mobility.
6. Easy to move and transport.

Minuses

Mosaic grinding machine SO-307 is not intended for use in explosive areas.

Husqvarna PG 530

Country of origin: Sweden. Used when working on medium-sized objects.

Husqvarna PG 530

pros

1. The electrical cabinet contains a digital control unit with a display and keyboard. The module allows you to control the operation of equipment.
2. The handles are adjustable for convenience.
3. The Redi Lock system makes it easy to change diamond tools.

Minuses

Very high cost.

Husqvarna PG 530

Note! If granite filler or gravel is added to the concrete, then quite powerful equipment will be required, unlike a surface with marble chips, which can be easily ground.

As for polishing equipment, it has more compact dimensions and is equally used in large objects, in houses when processing screed and in apartments.

Popular Polishing Tools

Price for Makita BO3711

Makita BO3711

Price for angle grinder-125/1100

UShM-125/1100

Price for angle grinder Metabo WEV 10-125 Quick

Angle grinder Metabo WEV 10-125 Quick

Price for Hammer PSM 300

Hammer PSM 300

Price for BISON ZOSHM-450-125

BISON ZOSHM-450-125

Using a grinder when grinding concrete

Features of material selection

A surface made of concrete with any technical characteristics can be sanded. In this case, the main condition is the absence of obvious irregularities on the surface of such a floor (hills, potholes) that have a height of more than 5 mm. The characteristics of the mortar for pouring the floor are selected depending on the purpose of the room, its area and operating conditions.

Creating a screed

Taking into account the purpose of the concrete floor, the material for its manufacture is selected as follows:

1. In industrial and warehouse premises, as well as for open-air areas, concrete grades M150–M300 are used.
2. Concrete grade M300 with filler in the form of fine crushed stone will have maximum strength and wear resistance.
3. A fine aggregate fraction (for example, marble chips) will be the key to easy and quick grinding of the concrete floor surface.

Consumables for angle grinders

The result of the work greatly depends on the quality of the attachments used - circles, cups, Frankfurts. When choosing consumables, you need to take into account their specific purpose and application features.

Grinding discs

Wheels, or disks, have a flat surface on which an abrasive is applied. Depending on the purpose and type of material to be grinded, the grain size of the disc is selected. Wheels with coarse and medium diamond grits are used for grinding rough concrete bases.

Products with different size chips (faceplates) are suitable for removing the first thin layer from any floor. Discs with fine crumbs or a cellular structure (turtles) are suitable for finishing floors. They are usually equipped with a fine polymer abrasive and are very conveniently attached with Velcro.

Sanding cups

These are discs with a recessed center. A similar attachment to a grinder for grinding is used to remove a thick layer from the surface. The purpose of the cups can also be different:

• with a double segment - for removing the upper concrete layer, carrying out rough processing, eliminating serious defects;
• with square pads - for cutting off protruding elements of concrete and removing fairly large pieces, for roughing, for grinding before applying polymer compounds;
• with boomerang pads - for delicate and finishing polishing.

Frankfurt

They are special trapezoidal nozzles. Used to create a glossy smooth finish and mirror-like bases. They have an emery base attachment.

Cutting elements

The choice of cutting elements depends on the grade of concrete strength. So, corundum wheels are suitable for all brands (even M250). For M300 and above, diamond discs are chosen. When using the latter on a surface with low strength (up to 250), rapid wear of the cutting edge will occur, since the surface is highly abrasive.

As for the cutting tool itself, which is used when grinding concrete with any equipment - grinder, manual or industrial grinders, it is very diverse.

Table 4 . Cutting elements

Note! When choosing a cutting element, it is worth considering when the concrete coating was made, its current condition and the properties of the fractional filler.

Green chemicals for polished concrete LITSIL®

Grinding - main steps

The process of grinding a concrete floor consists of several stages. Preparing the surface for grinding consists of the following steps:

1. First of all, it is worth assessing the condition of the concrete floor covering, if present, and the possibility of its complete removal. Grinding with diamond discs can be used.
2. Before starting sanding, the coating is checked for evenness - the results will affect the level of intensity of processing.
3. The surface is checked for the presence of expansion joints and cracks. As a result, local repairs to individual areas may be required.
4. If, after tapping the concrete floor, it turns out that it has sagged or lost its strength, then a new floor structure may be required.
5. If reinforcement or mesh fragments protrude above the floor surface, they are removed.
6. Epoxy compounds can be used to seal minor defects. However, after drying, they should not protrude above the floor surface.
7. According to building codes, the seams between the baseboard and the coating must be sealed. Only after this can you start sanding.

Local surface repair

As mentioned earlier, if the screed is fresh, then you can start sanding it only 2 weeks after pouring, when the filler included in its composition is securely fixed and will not fall out when exposed to the sanding element.

The concrete surface is coated with a hardening compound before grinding. Upon completion of the work, plinths are installed and surface treatment is carried out: polishing and varnishing, due to which the surface is strengthened and acquires an aesthetic appearance.

The first stage of grinding involves the use of diamond elements (grit 6-30).

Diamond elements

Due to this, cement laitance is removed from the surface of the screed and the aggregate is exposed.

If it is necessary to polish the top layer of the screed, 70-grit discs are used for the first stage.

Screed surface with defects

To eliminate defects (potholes, cracks, chips) during the second stage of processing, it will be necessary to use special high-quality repair compounds that fill any cracks during application.

Application of repair composition

Note! Surfaces made of high-grade concrete are polished better than those made of low-grade concrete. This allows you to achieve a deeper gloss.

The quality of concrete surface specularity is better with the highest grade of concrete

The third stage is intended to perform rough grinding using diamond nozzles (grit 50, 70, 120) followed by application of a hardening compound.

Replacing attachments

At the final stage, the surface is polished using segments on a plastic bond with a grain size of 400 - 800. This makes it possible to increase the strength of the concrete floor with little gloss.

Polishing discs

Video - Grinding concrete with a grinder with a diamond disc

Cost of polished floors

The price of a polished concrete floor depends, first of all, on the initial condition of the screed (grade of concrete, hardness, evenness of the surface, the presence or absence of various defects on it). In addition, the cost is influenced by what result the customer wants to receive (matte surface or glossy, colored, decorated, etc.).

Cost of polishing concrete using different technologies: