To make the surface of the concrete screed really durable and beautiful, apply grinding and polishing. To do this, use a manual or stationary machine for grinding concrete, and if professional equipment is too expensive for you, then the concrete grinder is taken for rent. We will talk about the features of the treatment of floors such machines.
Grinding concrete screeds
Отшлифованные по современной технологии полы можно встретить практически повсеместно: это торговые центры, выставочные павильоны, холлы гостиниц и офисных центров, больницы и поликлиники, вокзалы, а также склады, производственные помещения, холодильные камеры и прочие места скопления людей или зоны повышенной нагрузки на поверхность напольного покрытия (читайте также статью «Бутобетон – особенности и применение»).
Such popularity and distribution is explained by the fact that after competent grinding with grinders, the concrete acquires increased strength, moisture resistance and practicality. In addition, the coating becomes inert with respect to aggressive chemical environments, is not afraid of exposure to petroleum products, surfactants and solvents, and does not react to the presence of dilute acids and alkalis.
Another important property that acquires the floor after treatment is visual appeal and even beauty. This is especially true for concrete with fillers in the form of marble chips and small gravel, since after polishing they become especially beautiful and have an original pattern on the surface. It should also be noted ideally smooth glossy surface, which is not dusty and does not require time-consuming or costly care.
So, we can identify the main directions and goals for which produce concrete grinding:
- Removal of the top layer, which has the lowest strength and consists of almost pure cement and cement jelly. Also removed the old layer with numerous damages, dirt, impurities, corrosion and efflorescence;
- Alignment of small differences, protrusions, flows, making the floor plane almost perfect evenness;
- Blockage of fine pores and imparting water repellency to the material. After opening the main layer of concrete stone, it is treated with special reinforcers and primers, which, after machining, make the surface of the stone waterproof;
- Giving the floor surface extra strength. Grinding together with chemical treatment with fluates and primers makes the surface particularly durable, and it can withstand increased mechanical loads, including from the wheels of heavy vehicles, goods, equipment, and a dense flow of pedestrians;
- Achieving aesthetic appeal by leveling and polishing the surface to a glossy shine. Numerous inclusions of gravel or stone powder after polishing look especially beautiful and create an interesting unusual mosaic on the floor.
Note! In contrast to the usual destination, grinding concrete is aimed primarily at achieving technical results - high strength, wear resistance, moisture resistance, and only the second at achieving aesthetic effect.
Grinder on concrete allows you to prepare the surface for self-use and for processing finishes requiring high quality foundations. Polymeric self-leveling floors, 3D floors, some types of linoleum, laminate or parquet can be referred to such coatings.
When used independently, ground floor is treated with polyurethane or epoxy varnishes, special impregnations, thin-layer paints and other finishing materials. You can also leave the surface without treatment.
Tool and materials
Now we will tell you which concrete is better polished and which tool should be used for this. Let's start with the tool (learn here how to drill a concrete wall with a drill).
For high-quality processing of the screed, a special machine for grinding concrete is used, which has a complex planetary mechanism for the most high-quality processing. This mechanism consists of counter-rotating faceplates or cross-arms, on which abrasive segments or diamond cutters-frankfurts are installed, which are satellites rotating against the traverse rotation.
Such a complex movement ensures maximum density and quality of grinding. As the abrasive elements wear out, the mechanism goes down and presses against the surface with the necessary effort. Also, such devices are equipped with industrial dust extraction, water supply and removal system for wet grinding, some models have self-propelled chassis.
The electric motor has a system of protection against overloads and short circuits, as well as a starting system under load. Power is supplied from the mains of 380 V.
The power of the unit can be from one to ten kilowatts, there are also more powerful models. The price of such a machine can be from tens to hundreds of thousands of rubles, so more often such equipment is rented.
For the treatment of small areas using hand-held machines, and for large-volume premises - self-propelled. The quality of work is directly dependent on the mass of the device, because it is quite difficult to find a good car that is easier than 130 - 150 kg.
Note! Doing your own hands using the floor using Bulgarians and other types of hand tools does not give such a result as professional equipment and is used only for hard-to-reach places or self-repair of apartments, floor installation in garages, playgrounds and tracks in summer houses, etc.
Now let's talk about concrete. The most suitable for grinding are brands M150 - M300, since they have sufficient strength and respond well to processing. At the same time, grinding of more durable grades is possible, however, excessive hardness of these materials increases the consumption of rubbing parts, electricity and time, respectively, the cost of such work will be higher.
Note! It is possible to grind both new and old concrete screeds. The only condition is the age of the solution for at least 7 days, otherwise the material does not have enough time to gain sufficient strength and the cutters pull the rubble from the thickness of the screed, leaving the potholes and sinks. The ideal age is from 7 to 21 days.
Also important is the composition and size of crushed stone: fine stone of limestone origin is best, granite and gravel are also acceptable, and slag crushed stone is considered too soft for the floor. One of the best fillers is marble crumb, which belongs to limestone materials.
Auxiliary materials may also be needed for work: fluidizing and hydrophobic impregnations, primers, tinting additives, repair compounds and mastics, sealants for cracks and interchangeable diamond frankfurt of various grain sizes.
Performance of work
Grinding can be made both on the closed, and on the open areas.
High qualifications from the operator is not required, it is enough to perform a sequence of actions and not to violate the rules that the instruction contains:
- Old concrete must be prepared. To do this, remove any coatings from its surface with cutters with a grain size of 30–35 or manually and repair defects. Potholes are completely removed with excision of neighboring areas with poor quality material, using reinforced concrete cutting with diamond circles or diamond drilling of holes in concrete;
- Then produce a rough grinding cutters with a grain of 40. Its purpose is to remove the top layer (cement milk, old damaged and dirty concrete) to a depth of 3 centimeters and level the surface;
- After that, dust is cleaned from the surface using an industrial vacuum cleaner and a reinforcing compound is applied to it.. This can be fluation or treatment with special primers, most often used a set of tools that strengthen, close the pores and change the color of the material;
- When the floor is treated with chemicals, proceed to polishing. To do this, the cutters are changed to fine-grained - 400 and above;
- After finishing sanding, you can polish with nozzles with a grain size of 1400 - 1500 to give the surface a glossy shine.;
- In the end, the floor is opened with polyurethane or other wear-resistant varnish or is finished with a polymer coating, paint, etc.
Note! Before starting work, make sure that the upper layer does not contain reinforcement, otherwise you can ruin the mechanism and diamond nozzles.
Шлифовка бетонных полов позволяет значительно повысить не только качество и привлекательность их поверхности, но и сделать их прочными, водостойкими и значительно продлить срок эксплуатации стяжки (см.также статью «Пенополистиролбетон – все, что нужно знать о данном материале»).
The video in this article demonstrates the process of processing a concrete floor with a grinder.