Concrete processing: ways to improve coating performance

In order to improve the quality of coatings and monolithic structures, various processing of concrete is very often used today - of course, it cannot protect against damage under extreme loads, but wear and tear will decrease, and the service life after such measures will increase quite significantly.

There are quite a few technologies for such processing. Below we describe those of them that are most relevant to the masters engaged in private construction.

Impact before solution polymerization

Seal by bayonet or vibration

Despite the fact that under the treatment usually imply an impact on the already frozen material, measures to increase the strength and durability can (and should!) Be taken immediately after pouring:

• As soon as the concrete is distributed on the formwork, it must be compacted.. The easiest way to do this is by splicing with a steel rod or a thin pipe with a rolled tip.

Note! The optimum weight is from 1.5 to 4 kg: a lighter tool sticks poorly, and when working with heavier ones you will get very tired.

• In the process of processing the tool is stuck into the solution, and then pulled out, shaking from side to side.
• We perform bayonet, moving from the edge to the middle, with a step of about 10 cm. At the same time, crushed stone is compacted, and air bubbles come to the surface.

This technique has one drawback - it is quite time consuming.

That is why the vibratory compaction of concrete is used during large-scale works:

• A vibrating attachment that oscillates is immersed in the material.
• Oscillations are transmitted to the concrete mix, thereby reducing the friction between its particles.
• The fluidity of the material increases, which contributes to its compaction by raising the liquid to the surface and reducing the amount of air entrained.

Note! In some cases, the instruction recommends limiting the duration of vibro-processing, since it leads to the deposition of filler in the lower layers of the fill, as a result - to the formation of areas with a heterogeneous structure.

As a result of the removal of air by vibrating or sticking with a steel rod, the density of concrete increases. In addition, the increase in fluidity contributes to a more intimate contact between the cement mortar and reinforcement, which also contributes to the strengthening of the structure.

Polymerization at high temperatures

The technology described above is usually used when casting monolithic structures. However, during the manufacture of building blocks of concrete can improve the mechanical characteristics of products.

To do this, we need to activate the processes of curing, which are directly dependent on the degree of heating of the material and the rate of hydration. And if, with natural drying, we cannot provide optimal conditions for hardening, then the heat and humidity treatment of the blocks allows us to optimize this process.

To reinforce concrete products, autoclaves of various designs are commonly used:

• After the initial curing, concrete products are removed from the forms. Since at this time they are quite fragile, this should be done carefully.
• Then the blocks are stored on special pallets and placed in the chamber of the autoclave.
• The autoclave is closed with an airtight lid with a heat-insulating layer. This design allows you to maintain an elevated pressure in the system and prevents heat loss.
• Then the pressure in the chamber is increased by forcing air, and the blocks themselves are exposed to hot steam treatment. At the same time, each product is heated to the full thickness, and the process of cement hydration is accelerated many times.

Typically, for a full set of strength, intensive heat treatment lasts about 8 hours, after which the temperature decreases. The total autoclaving time is from 10 to 20 hours, depending on the type of concrete mix.

Improvement of concrete pavement

Surface grinding

However, even after the material hardens, it can be improved. To smooth the surface and prepare the material for impregnation, painting or varnishing, concrete is often ground.

If you plan to do it yourself, then you should work using the following algorithm:

• When we process a new coating, it should be done only after it has gained design strength. Attempts to grind the still non-frozen solution will cause the material to crumble.
• To align the old floor or other surfaces you need to clean them from the remnants of the finish.
• After that we need to take care of the availability of the tool. The greatest efficiency is demonstrated by machines with abrasive disks based on diamond grains, but they are characterized by a higher price.

• Concrete, which will later be hidden under a layer of finishing materials, is subjected to dry grinding. The result will be a matte surface, on which the colors and impregnations fit perfectly.

Note! In the process of dry processing a large amount of dust rises into the air, so you need to work in a respirator and goggles. Noise-proof headphones, too, will not be superfluous.

• Wet grinding is used for polymer and mosaic coatings. Through the use of thin abrasives, it turns out the surface is indistinguishable from polished, and does not require additional decoration. True, the complexity of this technique is much higher.

Varnishing and impregnation

If the concrete surface is planned to be used without finishing, then it must be protected both from mechanical effects and from moisture. Such protection can be realized only with the use of impregnations or varnishes.

The technology of applying these formulations is quite simple:

• To begin with, we perform surface cleaning of dirt, washing away the cement milk and opening all the pores to the maximum. If the finish is applied to concrete that has been in operation for a long time, it may be necessary to blast clean and seal the cracks with non-shrinking compounds.

Note! Impregnation and varnishes are not intended to strengthen the breakaway fragments, because large repairs should be done in advance.

• After cleaning, apply a protective composition. For this, Teksol clear varnishes, Ashford Formula, Xtreme Hard and their analogues, antifungal materials NEOMID BIO, etc.
• For drawing we use a wide brush or roller on a long handle. The consumption of material for each tool is individual, so the work should be guided by the manufacturer's recommendations.

As a result, polymer components bind fine particles of concrete and clog pores. This contributes to the overall strengthening of the surface and the prevention of moisture penetration into the deeper layers.

After complete polymerization of the impregnation or varnish, they can be polished using soft felt discs on a grinding machine. In principle, this operation is not mandatory, since with the active exploitation of concrete, the characteristic velvet shine appears by itself after about six months.

Restoration of road surfaces

We should also mention how you can extend the life of a concrete or asphalt roadway. In the process of arranging it, the classical processing technique is usually used - alignment with beacons and compaction with vibratory installations. In some cases, a furrowed texture is also applied using special brushes.

But the surface treatment of asphalt concrete pavement, carried out to compensate for wear, suggests the following algorithm:

• Laying a layer of bitumen emulsion on the canvas.
• In the thickness of the liquid material we fall asleep granite rubble. The optimal use of the fraction of 5-10 mm with a cubic structure.
• We roll the material with pneumatic rollers, after which we leave until the emulsion is fully polymerized.

In principle, the result is not concrete, but this coating may well withstand operational loads for a long time.

Conclusion

Processing of concrete floors, screeds, monolithic structures, etc. usually done in order to reduce their wear and prevent damage. Quite often, it is very laborious, but the result is fully consistent with the effort expended. The video in this article contains more detailed information on this issue, therefore, before starting work it is worth getting acquainted with it.