Polymer concretes. Technology for the production of products from polymer concrete Polymer concrete technology

Cement-polymer concrete is obtained by adding various high-molecular organic compounds, the so-called water-dispersed polymers, to the standard concrete composition. Their category includes such polymers as vinyl acetate, vinyl chloride, styrene. It can also be water-soluble colloids and latexes: polyvinyl alcohols, epoxy polyamide and urea-formaldehyde resins. Polymers are introduced into the composition of cement-polymer concrete during the preparation of concrete.

Cement-polymer concrete acquires its unique characteristics due to the presence of two active components: organic and mineral binders. The binder contributes to the formation of a cement stone, which fastens loose aggregate particles into a monolith. As water is removed from the cement-polymer concrete, a thin film is formed on the surface, which has excellent adhesion and adhesion of the internal particles of the solution. This contributes to the solidity of cement-polymer concrete, which makes it more resistant to increased loads. In addition, cement-polymer concrete acquires such properties as increased tensile strength, high frost resistance, wear resistance and water resistance.

The strength of cement-polymer concrete increases if the concrete is preliminarily kept in dry air conditions, at which the humidity is not more than 40-50%. Air with a high percentage of humidity reduces the unique characteristics of cement-polymer concrete.

The technology for preparing cement-polymer concrete is similar to conventional concrete. It is recommended to use cement-polymer concrete for floors, roads, finishing compositions, corrosion-resistant coatings.

Polymer concrete (P-concrete)- this is concrete, in the preparation of which polymer resins are used as a binder or they are part of the binder in significant quantities and significantly affect the property of the material. Fillers are usually sand and gravel. To save expensive resins, finely ground fillers can be introduced into the composition of the material. P-concretes are subdivided into polymer-cement concretes (binder cement + water-soluble polymer additive), polymer-silicate concretes (binder liquid glass + furyl alcohol or diisocyanates), concrete polymers (concrete impregnated with polymers) and polymer concrete itself.

In turn, polymer concretes are: on thermosetting resins (carbamide, phenolic, polyester, furan, polyurethane, epoxy) and thermoplastic resins (inden-coumarone methyl methacrylate). In addition, P-concrete is divided into super-heavy, heavy, light and ultra-light.

Urea-formaldehyde (urea) resins such as "KM" (fixer m) and "UKS" (universal carbamide resin), MF-17, M-60, M-19-62, and others resistant to acids, but not sufficiently resistant to alkalis. They are obtained as a result of the polycondensation reaction of urea and formaldehyde in an aqueous or aqueous-alcoholic medium. Hardeners are oxalic, citric, acetic, sulfuric, hydrochloric, phosphoric acids, chlorides: ammonium and zinc, preferably hydrochloric acid animite, which is highly soluble in water and UKS resin.

Furfural acetone resin FAM or FA (TU 6-05-1618-73);

Unsaturated polyester resin PN-1 (MRTU 6-05-1082-76) or PN-63 (OST 6-05-431-78);

Urea-formaldehyde KF-Zh (GOST 14231-78);

Furan-epoxy resin FAED-20 (TU-59-02-039.13-78);

Methyl ester of methacrylic acid (methyl methacrylate monomer) MMA (GOST 16505).

As hardeners for synthetic resins are used:

For furfural acetone resins FAM and FA - benzenesulfonic acid BSK (TU 6.1425);

For polyester resins PN-1 and PN-63 - isopropyl benzene hydroperoxide GP (TU 38-10293-75);

For urea-formaldehyde CF-Zh - aniline hydrochloride SKA (GOST 5822);

For furan-epoxy resin FAED-20 - polyethylenepolyamine PEPA (TU 6-02-594-70);

For methyl methacrylate MMA - a system consisting of technical dimethylaniline DMA (GOST 2168) and benzoyl peroxide PB (GOST 14888).

Cobalt petrate NK (MRTU 6-05-1075-76) is used as a hardening accelerator for polyester resins.

As plasticizing additives should be used:

Katapin (TU 6-01-1026-75);

Alkamon OS-2 (GOST 10106);

Melamine-formaldehyde resin K-421-02 (TU 6-10-1022-78);

Sulfonated naphthalene formaldehyde compounds - plasticizer C-3 (TU 6-14-10-205-78).

Polymer concretes are very dense and resistant materials in various aggressive environments. Polymer concretes based on epoxy resins have the highest strength and universal resistance; epoxy resins include ED-5, ED-6, ED-16, ED-20, ED-22 and compounds with rubbers, furan (furan-epoxy resin FAED-20) and others resins. To plasticize the composition, dimethyl phthalate, dibudyl phthalate and others are used as a plasticizer, which are introduced in an amount of 15-20% by weight of the resin. Hardening catalysts are tertiary amines, antimony chloride, fluorine compounds and others. For cold curing, polyethylenepolyamine, hexamethylenediamine or liquid polyamides are used.

Furan resins (FA, FAM, 2-FA and others) are obtained by the condensation of furfural and furfuryl alcohol with phenols and ketones. They are the cheapest. The FA monomer obtained by the interaction of furfural and acetone in an alkaline medium has found the greatest distribution in construction.

Furfural, urea and fillers from acid-resistant rocks serve as starting products for obtaining furfural-urea resins. Ferric chloride is used as a catalyst, and aniline is used as a hardening accelerator.

Crushed stone from natural stone or crushed gravel can be used as a coarse aggregate for heavy polymer concrete. Crushed stone and crushed stone crushed from gravel must meet the requirements of GOST 8267, GOST 8268, GOST 10260-74.

The use of crushed stone from sedimentary rocks is not allowed.

As large porous aggregates for polymer concrete, expanded clay gravel, shungizite gravel and algoporite crushed stone should be used that meet the requirements of GOST 9759, GOST 19345, GOST 11991.

For the preparation of high-density heavy polymer concrete, crushed stone of the following fractions should be used:

With the largest diameter equal to 20 mm, crushed stone of one fraction of 10-20 mm should be used;

With the largest diameter equal to 40 mm, crushed stone from two fractions of 10-20 and 20-40 mm should be used.

The composition of polymer concrete is selected empirically. In accordance with the recommendations of Yu.M. Bazhenov, first, experimentally select the most dense mixture of aggregates and filler and lignimal voidness, and then determine the consumption of resin and hardener. In this case, the amount of resin is set such that it provides a given mobility of the concrete mixture. Typically, the resin consumption exceeds the void volume of the microfiller by 10-20%.

It is better to establish the composition of polymer concrete using the method of mathematical planning of the experiment, varying the content of sand, filler, resin and hardener.

After performing the experiment, processing the results obtained on a computer and obtaining the dependences of the properties of polymer concrete on the above factors, it is possible to calculate the optimal composition of the material with the required characteristics (table).

On the basis of carbamide and other resins and light aggregates (perlite, cellular glass bisipor and others), it is possible to obtain extra light polymer concrete with an average density of 70 to 500 kg/m 3 and strength up to 5 MPa.

Table 11 - Characteristics of polymer concrete.

Hardening of molded products should occur at a temperature of at least 15 ° C and normal humidity of the surrounding air for 28 days, for products made of MMA polymer concrete - within 3 + 1 day

To accelerate the hardening process, products made of polymer concrete should be subjected to heat treatment, which should be carried out in dry heating chambers. Dry heating should be carried out by electric heaters, steam registers.

The duration of exposure in the forms of polymer concrete products before stripping and subsequent heat treatment should be at ambient temperature:

17+ 2 o C………………12 h.

22+ 2 o C………………8 h.

more than 25 o C…………..4 hours

Stripped polymer concrete products must be subjected to heat treatment according to the following modes:

For polymer concrete FAM (FA), PN, KF-Zh: temperature rise up to 80 + 2 o C - 2 hours, exposure at a temperature of 80 + 2 o C - 16 hours, lowering the temperature to 20 o C - 4 hours.

For FAED polymer concrete: temperature rise up to 120 + 5 ° C - 3 hours, exposure at a temperature of 120 + 5 ° C - 14 hours, lowering the temperature to 20 ° C - 6 hours.

Heat treatment of polymer concrete products with a volume of at least 0.2 m 3 is allowed to be carried out in molds according to the following modes:

+ +

+ +

For polymer concrete FAM (FA), PN, KF-Zh: exposure at 20 ° C - 1.5 hours, temperature rise to 80 + 2 o C - 1 hour, exposure at a temperature of 80 + 2 ° C - 16 hours, lowering the temperature to 20 ° C - 4 hours.

For FAED polymer concrete: exposure at 20 ° C - 1.5 hours, temperature rise to 120 + 5 ° C - 2 hours, exposure at a temperature of 120 + 5 ° C - 14 hours, lowering the temperature to 20 ° C - 6 hours.

MMA polymer concrete products must not be subjected to heat treatment.

With an appropriate feasibility study, it is advisable to use polymer concrete for the manufacture of structures operating in highly aggressive environments (chemical plants) (chemically resistant floors, trays, sewers, pickling baths, drain wells, chemically resistant pipes, etc.) or located under the influence of electric currents (traverse of power lines, contact supports and similar structures with high electrical resistance).

It is possible to manufacture wear-resistant coatings of dams, mine shafts, annular collectors of underground structures, tanks for storing aggressive liquids and other similar structures from polymer concrete.

Long-term tests show that the ultimate strength of fine-grained polymer concrete based on FA resin is 0.45, based on FAM - 0.5, and FAM-d - 0.6.

Concrete polymer - This is a material obtained as a result of the impregnation of traditional concrete with polymers, followed by their polymerization.

Concrete polymers are obtained by impregnating concrete with polymers of epoxy and polyester resins (polyethylene, polypropylene, polyvinyl chloride, polymethyl methacrylate, styrene, etc.) and copolymers, of which compositions based on acrylic and methacrylic monomers are most widely used. The strength of the concrete polymer is influenced by the structure and strength of the original concrete, the type, composition and properties of the impregnating composition, the modes of drying, vacuuming, impregnation of the material and the polymerization of monomers.

In the factory, the most appropriate artificial drying of concrete to a moisture content of 0.1 ... 0.2% by weight at a temperature of 105 ... 150 ° C (convective, radiation, high-frequency, electric, combined). Incomplete drying of the original concrete reduces the strength of the concrete polymer.

For the purpose of the most complete impregnation of concrete after drying, it is evacuated at a residual pressure in a vacuum chamber of 6.67 ... 1333 Pa for up to one hour. The vacuum mode is set empirically for each type of concrete. The more moisture, air, steam is removed from concrete during vacuuming, the denser its impregnation and greater strength will be.

The most important operation is the impregnation of concrete with monomers. The impregnation of material with small capillaries occurs mainly under the action of capillary forces. Impregnation of concrete with large pores by capillaries. Better carry on under pressure

1 MPa. The greater the porosity of the original concrete and the greater the degree of air, steam and moisture removed from it, the more complete its saturation with monomers and the higher the strength of the concrete polymer. This process is influenced by the properties of the monomer (viscosity, surface tension, wetting angle), its temperature and the nature of porosity.

For complete impregnation of heavy dense concrete, monomer 2 ... 6% by weight is required, for impregnation of lightweight concrete on porous aggregates - up to 30 ... 68%, cellular concrete - up to 102 ... 117% (table).

The final operation is the polymerization of the monomer in concrete (thermocatalytic and radiation). The first method is most widely used in the production of concrete polymers.

Perhaps, if necessary, surface impregnation of concrete, as well as impregnation of individual sections of structures in order to compact and strengthen concrete, increase the density of the protective layer of reinforcement and its safety.

By structure, the concrete polymer is a capillary-porous body in which the pores and capillaries are filled with a hardened polymer that has good adhesion to the solid phase and volumetrically reinforcing the silicate base. Its structure depends on the structure of the original concrete, the properties of the polymer and the processing mode. The pores of concrete polymer closed in shape are close to spherical. In pores with a size of 200 ... 600 microns. there is an unfilled central spherical zone. The polymer fills all the pores, cracks and irregularities on the surface of the aggregate, penetrating into the cement stone and aggregate, which significantly increases their adhesion to each other, the strength of the material in tension and bending, since the tensile strength of the hardened polymer is much greater than that of concrete (for polymethyl methacrylate up to 80, and polystyrene up to 60 MPa (Table.) For the same reason, the adhesion of concrete polymer with reinforcement increases several times (Table).

The polymer, as it were, seals the defects in the structure of concrete and binds its various sections, increasing the density and strength of the material. The concrete polymer on methyl methacrylate is characterized by a small number of macropores. The number of macropores is also less than that of concrete. No shrinkage cracks are observed in the “polymer – cement stone” contact zone. Thus, a dense, monolithic structure of the material with fewer defects is created, which determines the nature of its destruction under load. The concrete polymer collapses almost instantly with a loud crack and expansion of elongated fragments. The nature of the fracture is brittle. Since the mortar treated with the polymer is stronger than the coarse filler, the destruction occurs along the mortar and the filler.

The compressive strength of a concrete polymer depends mainly on the strength of the original concrete, the type and properties of the monomer, drying modes, evacuation, the degree of impregnation and polymerization. The higher the strength of the original concrete, the lower the degree of its hardening.

To a large extent, the strength of the concrete polymer depends on the content of the polymer in the vapor space of the concrete. The higher the degree of concrete impregnation, the greater the strength of the concrete polymer. With an increase in the amount of cement stone in the original concrete, its degree of hardening increases. In high-strength concrete polymer, coarse aggregate is the weak link. And therefore fine-grained Concrete polymers (up to 200 MPa) have higher strength.

When samples heated to +150 o C are cooled to +20 o C, their strength is completely restored. And when the specimens heated to +200 o C are cooled to +20 o C, their strength becomes 10% less than the original one. To obtain a concrete polymer that could retain its properties at a temperature of +200 ° C and above, it is necessary to use special heat-resistant compositions.

The tensile strength of concrete polymer increases in comparison with the original concrete by 3 ... 16 times and with an increase in the amount of monomer in concrete (up to 19 MPa).

Table 12 - Influence of the initial strength of concrete on the strength of concrete polymer.

The introduction of ash and other similar additives into concrete has little effect on the strength of the concrete polymer, which allows saving up to 50% of cement.

In order to significantly accelerate hardening, up to 5% CaCl 2 can be introduced into the original concrete, which is not dangerous for reinforcement after impregnation of concrete with a polymer, since the latter protects steel well from corrosion.

The modulus of elasticity of the concrete polymer is 30…60% higher than that of the original concrete. The limiting deformations of the concrete polymer are 2 times, and the crack resistance is 2 ... 5 times higher than that of the original concrete. Creep and shrinkage of concrete polymer are several times less than that of concrete. The average density of a concrete polymer is greater than that of concrete for the increase in monomer - by 3 ... 10% for heavy concretes and by 10 ... 70% - for light ones on porous aggregates.

The water absorption of a concrete polymer of optimal composition is 5...6 times less than that of traditional concrete (up to about 1%), and the softening coefficient is close to unity. In this regard, the frost resistance of concrete polymer increases several times and can reach 5000 cycles of freezing and thawing. However, this depends on the type of polymer.

Concrete polymer of optimal composition is resistant to sulphate, magnesia, alkali and salt media, as well as dilute acids, with the exception of hydrofluoric acid. But concentrated acids (sulfuric, hydrochloric, nitric) destroy it.

The polymer impregnation of lightweight concrete on porous aggregates, cellular and gypsum concrete significantly improves their properties, in particular, increases their density, strength and reduces water absorption.

Table 13 - Data on the strength of lightweight concrete and concrete polymers.

Table 14 - Improvement of properties of various concretes after impregnation with polymers.

Table 15 - Properties of concretes and concrete polymers.

In accordance with the feasibility study and taking into account the above characteristics, the concrete polymer can first of all be used for the manufacture of structures operating in aggressive or harsh climatic conditions.

Innovative technologies delight us more and more every day. New developments also affected the construction industry. In particular, the creation of new building materials, among which polymer concrete is in great demand. It is a mixture, the composition of which consists of various polymeric substances, and not of the cement or silicate that has long been familiar to us. This material has a lot of positive properties, due to which it is superior to conventional building mixtures.

Polymer concrete: characteristics

Due to the huge number of its positive properties, the cement-polymer mixture justifiably deserves respect among builders. Using this material, any specialist will appreciate its strength and durability. Polymer concrete does not give in to moisture, does not deform, perfectly reacts to temperature changes and bad weather. Dries quickly and adheres well to any surface. This material has a high resistance to stretching, good air permeability. It is not affected by any chemical reactions.

But the most important of all the properties of polymer concrete is that it is environmentally friendly, does not pollute the environment and does not harm human health in any way. The polymer mixture is allowed to be used even in the construction of public catering facilities, various grocery outlets, as well as other food industry buildings.

Advantages and disadvantages

A huge number of positive properties extols the cement-polymer mortar over conventional concrete. Due to the rapid solidification with polymer concrete, after a few days, the first work can be done, which cannot be said about ordinary material. Concrete of the new sample is much more enduring, stronger. For complete hardening, one week is enough for him, and not a month, as for ordinary cement.

Among the positive properties of the polymer mixture is waste-free production. Previously, all agricultural and construction waste was simply thrown away or buried in the ground, thereby polluting our nature. Now recycled material is used for the manufacture of polymer concrete. The use of such technology not only solves the problem of waste disposal, but also protects the environment from pollution.

This building material, unfortunately, has its drawbacks. Among the negative properties, one can single out the inclusion in the composition of artificial materials. The second negative point is the expensive cost of some additives necessary for the preparation of polymer concrete. Due to this, the price of the finished product rises.

Application

Due to the presence of many positive properties, polymer concrete has a fairly wide range of applications. It is used in landscape design, laying out paths and terraces. Walls are finished with a similar mixture, both from the outside and from the outside, they decorate stairs, fences, plinths. Such material easily lends itself to manual work. Various shapes, figures, decorative elements are obtained from it. Its beauty is that it is easily painted after drying.

The use of such a building mixture is suitable for pouring floors. Polymer concrete floors will serve as an excellent protection against moisture. Polymer concrete floors will keep your home warm.

Kinds

Given the technical characteristics and composition, new generation concrete is divided into:

• Polymer cement. This type of concrete has excellent strength. A similar material is used in the construction of airfields, finishing slabs and bricks.
• Plastic concrete. It exhibits the property of excellent resistance to acid-base reactions and temperature imbalance.
• Concrete polymer. This building mixture differs from others in that the ready-made, frozen block is impregnated with monomers.

These substances, filling the holes and defects of the material, provide it with durability and resistance to sub-zero temperatures.

Also, depending on the type of construction work, experts divide polymer concrete into filled and frame molecular. The first type allows the presence of such organic materials as quartz sand, gravel. These materials perform the function of filling voids in concrete. In the second option, the concrete remains with unfilled voids. And the connection between the particles of concrete is carried out by polymeric substances.

The use of concrete made from cement is limited. A polymeric binder that determines such properties of products made of polymer concrete such as chemical resistance and vibration resistance, allow the use polymer concrete and designs from polymer concrete where traditional concrete would fail

Polymer concrete it is produced as follows: sand, limestone, talc, crushed waste from the production of composite materials, such as fiberglass, etc., are mixed with a binder (polyester resin). Coarsely dispersed fillers in polymer concrete - crushed stone up to 50 mm in size and sand with a grain size up to 5 mm. In order to reduce consumption binder and the cost of products, as well as to regulate their properties, a finely dispersed filler is introduced into polymer concrete withparticle size less than 0.15 mm (barite, quartz, andesite flour, etc.). The composition of polymer concrete may also includeblowing agents, Surfactants, flame retardants, dyes, etc.
With a high degree of filling (70 - 80%), inexpensive products with high physical and mechanical characteristics are obtained. Filler, such as sand, gives products durability, resistance to abrasion loads, but greatly increases their weight. In the production of such products, it is necessary to choose a resin with a reduced viscosity. The production parameters should be such that the filler is evenly distributed throughout the volume of the product, does not precipitate due to the difference in the density of the filler and resin. It is also necessary to degas the mixture to prevent the formation of cavities inside the product, which can lead to a decrease in strength. The disadvantage of polymer concrete products is their unaesthetic appearance, which makes it impossible to use these products as decorative elements in the design of premises, etc.

Application of polymer concrete:

Cladding panels;

Foundations for industrial equipment;

Noise-absorbing structures;

Mooring edges and breakwaters;

Water tanks;

Drainage structures;

Road curbs and fences;

Railway sleepers;

Stairs;

Restoration and protection of existing concrete structures;

Capacities and reservoirs for chemically active substances;

Drainage sewers of chemical enterprises.

The development of the chemistry of synthetic binders and polymers predetermined the emergence of a new material in the construction industry, known as polymer concrete. And although the first patents for its manufacture appeared 80 years ago, the novelty received practical application only in the 60s of the last century. As the name implies, the developers managed to obtain a building material based on resins and polymers, which, in terms of composition and characteristics, can completely replace modern cement and slag-cement concretes.

What is polymer concrete

Often, building terms can confuse a non-specialist or a novice builder, a lover of building with his own hands. At the household level, polymer concrete includes all types of building materials, which include cement, water and polymer resin.

In fact, the technology of building polymers divides such materials into several groups:

• Polymer concrete is a mixed composition, which includes mineral ballast or filler, polymer binder, hardener, stabilizer and adhesive, without the use of cement and water;
• Polymer cement concrete - a material obtained by adding a water-soluble polymer composition to the composition of the parent cement mortar or concrete;
• Concrete-polymer materials are hardened concrete or cement stone subjected to additional processing with liquid or vapor polymers, usually the composition of the liquid includes styrene with a catalyst, which polymerizes in the thickness of the concrete mineral matrix.

For your information! Polymer concretes obtained on the basis of thermosetting and epoxy resins are also called plast concretes.

The properties of polymer concrete depend on the composition of the used binder, resin, filler and method of preparation. Such materials are successfully used not only in construction, but also in mechanical engineering, in the chemical industry and even in the production of household items and furniture. The technology of using various mineral fillers to reduce the cost of producing castings from synthetic resins began to be used in the 80s of the last century, and at the beginning of the 21st century, almost 80-90% of plastic products are made using polymer concrete technology, which contains resin and finely ground ballast powder.

To obtain construction grades of polymer concrete, compositions based on five main varieties of synthetic resins are used:

• Phenol-formaldehyde and urea-formaldehyde polymers;
• Epoxy matrices, including those modified with furan resins;
• Methacrylate and polyvinyl acetate polymers;
• Furfural acetone matrix, or FAM for short;
• Polyester and polyurea resin.

For your information! FAM is one of the few types of binders used for the production of so-called faizol-concrete, which has unique properties to dampen and dissipate vibrations by an order of magnitude better than the most viscous grades of cast iron.

The composition of furfural acetone resins includes volatile substances with a very unpleasant odor that can cause suffocation and headache, which are pronounced carcinogens. Therefore, they are used only for the production of polymer concrete, conservation of steel structures of pipelines and communication systems. For residential premises, polymer concretes are most often used, which include polyester resins, epoxy and methacrylate oligomers.

In the composition of polymer concrete, the resin content is relatively small, from 10 to 15%. The rest is a mineral filler - marble chips, ground ash, crushed dolomites, calcites, granulated vermiculite, clinker and ordinary Portland cement. Rarely enough, resin with an organic filler based on modified wood fibers mixed with chopped basalt fiber is used as part of polymer concrete.

Why change ordinary cement mortar to polymer concrete

Modern grades of concrete based on cement and sand work well in huge masses, where the static load is constant and there are no shocks, vibrations or complex bending moments or torsional forces. In all other cases, it is necessary to introduce special additives into the composition, use reinforcement with expensive metal, make multilayer structures, or completely replace cement concrete with metal or polymer concrete. In some cases, it is technologically easier to cast a part of the building structure from polymer concrete than to use reinforced concrete. For example, during the construction of product pipelines.

If we compare the characteristics of polymer concrete with ordinary concrete, we can name five advantages of using polymers:

• 3-4 times higher bending strength, torsion and alternating dynamic load. The resin in polymer concrete makes the material behave like metal;
• The presence of polymers in the composition ensures low water absorption and high frost resistance of polymer concrete structures;
• Polymer concretes of certain grades, containing fine particles, have low thermal conductivity; if necessary, they can be used without insulation even in the manufacture of floors and ceilings of the basement floor, basements;
• Good machinability by cutting, drilling, without the risk of chipping or cracking;
• Epoxy resins in the composition of polymer concrete make them inert to chemically active substances, organic solvents, gasoline, oil, chlorinated hydrocarbons, hot and sea water. In shipbuilding, cladding, floors, floorboards, protective panels and deck elements are made from polymer concrete.

For your information! The main "value" of the polymer concrete composition is the possibility of obtaining a high quality casting, without shells, striae, cracks, with "programmed" mechanical and strength characteristics. Characteristics are easily adjusted by changing the composition of the material.

For example, in the manufacture of a pipeline, polymer concrete is used with the addition of polyvinyl alcohol or liquid glass. Alcohol in the composition of concrete improves the wettability of cement grains, removes air from the intergranular space and helps the hydration process. After casting the pipeline due to the intense binding of water, the inner surface of the concrete pipe quickly dries up and becomes covered with cracks. To make it strong, hard and wear-resistant, concrete is treated with a liquid solution of polystyrene in styrene. The result is a surface that rivals cast iron in terms of performance and durability.

Today, the cost of polymer concrete is still quite high, so there is no talk of a complete replacement of cement in the composition of the material, but as new resins are developed, the prospect of switching to polymer concrete becomes more and more real.

Features of the use of various grades of polymer concrete

Most people will be surprised to learn how many household items are polymer concrete in their composition. For example, artificial stones, sculptures, decorative elements and facing tiles for stone finishing are made from polyester resin and filler from finely ground natural stone - gabro, basalt, marble, calcite. Tabletops and window sills are cast under the stone from inexpensive polymer concrete, the cost of a similar product made of natural marble or granite will cost 2-3 times more.

Communication elements are made from epoxy polymeric concretes - pipes, tanks, wells, catchment trays and even entire collectors. With the help of polymer cement casting, it is quite easy to repair concrete load-bearing structures, seal the screed and restore the tightness of the container. Polymer concretes, which include epoxy resin, have exceptionally high adhesion, so they are often used to repair holes and joints in concrete panels in high-rise buildings.

From methacrylate filled with ground glass powder and marble dust, it is possible to obtain such a high-quality imitation of natural stone that professional restorers borrowed and used this material for work. Large granules of marble or calcite can be introduced into the composition. On the basis of polymer concrete, all polymer plasters, putties, tile adhesives, grouts are made, that is, almost all materials for decorative finishing of houses.

Separately, it is necessary to remember about self-leveling floors. In this case, quartz sand crushed into dust is used instead of glass filler. The most expensive brands, which include forced-curing modified methacrylate, after hardening, give a perfectly smooth surface that is superior in strength to a cement screed.

How to make the simplest polymer concrete at home

In order to prepare polymer concrete with your own hands, you will need two components, resin and filler. For the simplest version of polymer concrete, you can use epoxy glue or resin, hardener and filler. It is best to use cement, washed and dried river sand or granite dust in the composition of the material, which you can get hold of in any workshop for the manufacture of monuments.

The resin is diluted with acetone or an alcohol-acetone mixture. Different brands of epoxy resin require their own brand of solvent, so for the preparation of polymer concrete, it is necessary to choose a thinner. A hardener is added to the resin, stirred and a thinner is added to the composition. After 10 minutes, the filler can be added in small portions to the adhesive mass. After another 3-10 minutes of mixing, the polymer concrete will be ready for use.

Conclusion

Similarly, it is possible to prepare polymer concrete based on PVA, acrylic resin and sand, oil paint and cement filler. Finally, you can add a mixture for self-leveling floors to the composition, which will allow you to use the material for casting parts for finishing ceilings and walls, columns, stucco moldings, pilasters. In any case, such a composition will be cheaper, and the quality of the products will be no worse than that of purchased options.

(otherwise, cast stone) is a material that combines the strength and beauty of natural stone with an affordable price (thanks to cheap mineral additives) and ease of manufacture. The possibility of using almost any aggregate (sand, granite and marble chips, glass and many others) guarantees variety. And the presence of a polymer binder makes them durable, exposed to water and overheating.

Let's consider typical technological processes for the manufacture of polymer concrete, as well as the possibility of creating it yourself.

What will be required?

To get the product you need:

• A filler of a sufficiently large fraction (sand, crushed stone, coarsely crushed glass).
• A finer grinded aggregate that reduces the cost of the material. It is a powder of graphite, quartz or andesite.
• Binder - it will need about 5 percent. In this capacity, one of the polymer resins is used. For example, polyester (unsaturated), urea-formaldehyde, furan, epoxy.
• Hardeners, plasticizers, special modifiers, dyes.
• Mold release lubricant and top coat gel coat.

Production methods

The production process can take place in batch or continuous technology.

• In the first case, the containers used for the manufacture of the material must be washed after each completed cycle. But it is possible to make polymer concrete in the most ordinary bucket or concrete mixer.
• Continuous technology is used mainly in large industries. At the same time, special injection molding machines, dispensers and automatic mixers work together, organizing a single chain.

The following video talks about the manufacture and spraying of lightweight polymer concrete:

Process

To make a cast stone, you will need a mold well coated with a special release agent (otherwise it will be impossible to remove the finished product). The form can be made of silicone, fiberglass, metal or even chipboard (budget option).

1. A layer of gelcoat of the desired color is applied to the release paste.
2. A composite mixture is placed inside the mold, consisting of the above ingredients, previously well mixed in a concrete mixer. In large industries, where the volumes are very solid, the mixture is put into the mold using a concrete paver. If the products are small, and the technological process is periodic, then this is done manually.
3. Now it is necessary that the laid mixture is subjected to vibration (vibration compaction). This procedure takes approximately two minutes. At the plant, a resonant vibration platform is used for this, at a small production site - a vibrating table.

Under production conditions at the plant for the production of polymer concrete, if necessary, heat treatment is carried out for faster hardening of the parts. In other cases, they wait for the natural completion of this process.

We will talk about machines, molds and other equipment for the production of polymer concrete products below.

Necessary equipment

Features of choice and costs

Those who dream of aiming at continuous technology and solid volumes by organizing large-scale industrial production will need special conveyor equipment. Which will include machines for dosing, mixing, casting, finishing, as well as a mechanized warehouse.

All this will cost a tidy sum of several million dollars. If we confine ourselves to turnkey branded equipment, then the costs will be much less - from 30 to 50 thousand dollars.

But still, it is not always possible to find money for a purchase, especially in our difficult time. However, you can get by with even lower costs. If you purchase all the necessary machines and other things separately. And something to make yourself. Below is more about this option.

List of equipment and devices

So, here is a list of equipment and devices that you can not do without:

• Vibrating table - ready will cost about 27 thousand rubles. If you want to save money, weld the table yourself using two-millimeter metal corners (60s). We weld an industrial-type vibrator to the table - done.
• A stirrer that will combine all the components into a homogeneous mixture. If you purchase a powerful vacuum device of European quality, you will have to pay about 10 thousand dollars. But you can also use a domestic concrete mixer or a construction mixer. It will be much cheaper - the cost depends on the volume and power. Even cheaper is to make a mixer yourself from an iron barrel and an electric drive with a gearbox.
• You will also need a compressor system with a gun. Without it, it will not be possible to apply the gelcoat evenly. The gun costs from 50 to 100 dollars. You can take automobile compressors - two pieces from ZIL will be enough. They are connected in parallel and attached to metal platforms installed on a strong frame.
• Molds made of fiberglass or silicone are not yet widely available for sale. They can be ordered for specific products (for example, window sills) from a specialized company. Or make molds yourself, starting with a cheaper material - chipboard with lamination.
• Without fail, an exhaust hood will be needed - at the casting stage, production is distinguished by harmful fumes. Accordingly, we will also purchase individual protection: gloves, respirators.
• For finishing work, you will need electric tools: grinding and polishing machines. And also a drill, a jigsaw, a grinder, a milling cutter (if necessary).

We will talk about emissions into the atmosphere from the production of polymer concrete below.

This video will also tell about another method of manufacturing polymer concrete:

Air emissions from such production

As mentioned just above, during casting, the release of harmful components is present.

• In particular, it is styrene, which is contained in resins used as a binder. As soon as we open a hermetically sealed container with such a resin, the poisonous gas begins to evaporate.
• In addition, the hardener is also extremely dangerous (as a rule, it is methyl ethyl ketone peroxide). However, it is not volatile and requires only the protection of hands with rubber gloves.

These facts force polymer concrete manufacturers to carefully equip the casting room, making it hermetic, installing a powerful exhaust above the table, not forgetting about their own protection (respirator). And if all these measures are observed, and the air leaving the hood is cleaned, then there will be no emissions into the atmosphere (after all, the room is airtight).

How to make elastic polymer concrete yourself (with your own hands), read below.

DIY creation

And now we will talk about how to make small products from fashionable cast stone on our own, spending a minimum of money. For example, it can be flower pots, countertops, window sills (especially popular, as they are warmer than marble or granite).

Room selection and arrangement

First you need to think about the room - you need 80 square meters of total area. It is advisable to look for a suitable house somewhere on the outskirts. And 12 square meters will immediately have to be fenced off for the casting room, and you will have to try to seal all the cracks as much as possible. So that the styrene does not leak.

In the center of this room we make a table on a frame of iron corners, covering it with a chipboard top. We expose its surface according to the level - this is important! Above the table we install a hood - a metal box with an electric motor.

To make it light, we mount fluorescent lamps on top. In the next room we put the same table - for finishing and other work. Here we will place the tool and containers for drying chalk and sand (metal low boxes).

Required raw materials

Required raw materials:

• River quartz sand (packed in 20 kilograms). It must dry well.
• Sifted chalk - we also dry it.
• Polyester resin - in buckets of 20 liters is bought.
• Hardener, gelcoat, release paste.

Manufacturing process

1. You will need a clean plastic bucket for stirring, a 450-watt perforator and a construction mixer (we will attach a perforator to it by welding a perforating drill - we get a mixer).
2. We make the form from laminated wood boards, making it collapsible. It is convenient to apply the separating paste with a brush, rubbing with a nylon stocking.
3. We dilute the gelcoat with resin (adding 10 percent of it) and apply with a flute brush. We do this twice. We make sure that the hairs from the brush do not stick.
4. After mixing the resin with the hardener in a clean bucket, add 15 percent chalk, and then sand in portions. The mass should become viscous. To remove air bubbles, tap the bucket on the floor from time to time.
5. Once ready, pour the solution into the mold. Now let's smooth the surface: two people take their hands on the form (certainly equipped with handles) and, lifting it, tap it on the table. The mixture is left (for 40 minutes) and exit the casting room.
6. After hardening to a “rubber” state - this can be determined by a very hot surface and a special sound when tapped - we take the product out of the mold (disassemble it) and turn it over with the pouring side down. Let it harden completely, then sand and polish.

Security measures: when weighing the resin, as well as working with it, with the gelcoat and with the mixture poured into the mold, we work only in a respirator, under a hood. We add the hardener with a syringe, wearing rubber gloves.

The following video will tell you how to make polymer concrete with stains with your own hands: