Polymer concrete on acrylic resins. Fundamentals of polymer-cement concrete and plast concrete technology

Modern needs of the construction industry contribute to the emergence of newer and more advanced materials. So, polymer concrete has recently begun to gain great popularity. We will tell you about this unique composition further.

Properties

History reference

As we said, this material is innovative. However, there is evidence that it was used several thousand years ago in the construction of the Egyptian pyramids. Of course, we are talking only about similar technology.

The blocks from which the pyramids were built consisted of the following components: silt from the Nile River, limestone, gravel, trusted salt, ash and crushed lime. As a result, they were able to stand for so long without cracking. At the same time, the so-called “tan” did not form on them (any natural stone becomes covered with it over time).

Advantages

Now it's time to get acquainted with the advantages of this know-how:

• . Even cutting reinforced concrete with diamond wheels will hardly cope with its task.
• Long life span. Significantly higher than that of its ancestor.
• Very low shrinkage during drying.
• High compressive strength. This allows you to withstand enormous loads.
• Resistant to almost all acids.
• The technology of polymer concrete is fundamentally different from all known. The fact is that only environmentally friendly raw materials are used in its production.

Interesting: the permeability of this material is comparable to natural granite. Today, only he can boast of such dignity.

• Polymer concrete products have low greenhouse gas emissions.
• Withstands temperature fluctuations. It retains all its properties even when heated to 1300 degrees.
• Does not wear out over time and does not crumble.

Among all this variety of advantages, there is one drawback - the high price. However, the situation is likely to change in the future. The fact is that this is a new technology, which means that for some time its cost will be significantly reduced.

Specifications

The wild growth in popularity is due to the fact that polymer concrete has very high characteristics that leave all its main competitors out of business. Let's get acquainted with them:

Important! The values ​​presented above are controlled by building code 525–80 of 01/01/81.

It is also worth bringing to your attention the chemical resistance to various substances:

From the data in this table it can be seen that this material meets all standards of chemical resistance. This means that the polymer protection of concrete floors is highly effective. Therefore, this technology is often used in industry.

Cooking

Now consider how to independently prepare polymer concrete. In fact, this is a simple procedure that will require you only to strictly observe the proportions.

Ingredients

Consider what we need:

1. Potassium hydroxide. These are hygroscopic crystals, colorless and odorless. They instantly blur in the air, so they must be stored in a vacuum package and taken out before use.

This substance is very aggressive, that is, it strongly affects the mucous membrane and skin. For this reason, the instruction prescribes to wear protective equipment (glasses, gloves, respirator) when working with it. Otherwise, there is a high risk of damage, especially to the eyes.

1. Liquid glass(Surely many of us, after reading this phrase, will think about the element that fills our windows). In fact, these are colorless crystals without any odor. They consist of silicic acid and alkaline potassium.

You can buy it at the nearest agricultural store. The fact is that gardeners often use liquid glass to fertilize various crops.

1. fly ash. This ingredient can be obtained independently (by burning some solid fuel) or bought ready-made at a hardware store. Experts say that the addition of ash makes polymer asphalt concrete 75% stronger and more durable.
2. Chilled water at room temperature. It must not contain any impurities. If you add tap water, then you need to let it stand for a while.
3. In addition, you can use any additives (for example, slag or dye). This is necessary in order to obtain an attractive texture and improve the characteristics of the mixture.

Instruments

Now consider what tools you will need:

• already mentioned remedies.
• Container for mixing ingredients (preferably glass).
• Wooden spatula for mixing.
• Electronic balance. Remember that it is very important to observe all proportions. If we are talking about a small amount of solution, then a simple kitchen scale will do.
• Casting mold.

cooking secrets

It is time to answer the question of how to make polymer concrete with your own hands.

So, to prepare 1 liter of the mixture, we observe the following proportions:

1. Potassium hydroxide - 160 g.
2. Liquid glass - 200 g.
3. Ash - 540
4. Water - 100 ml.
5. Slag (it is needed to give special strength, it is not necessary to add it) - 300 g.
6. Special cement for polymer concrete - 20% of the total volume.
7. Additives as desired (their consumption should be indicated on the package).

Important! As you mix, the mixture will heat up due to the release of carbon dioxide, so don't be alarmed.

The ingredients must be mixed in the following order:

1. Pour clean water into the container.
2. Add cement to it.
3. Then we pour ash, slag and liquid glass in equal proportions.
4. Then add the rest of the ingredients.
5. Now, using a construction mixer, you need to mix everything thoroughly. Remember that the mass should be perfectly homogeneous. Otherwise, polymer concrete will not be durable.
6. The resulting mixture can be poured into a mold or formwork for solidification.

It will completely harden only after 3 weeks. Only after this period it is possible to carry out any operations with it, for example, diamond drilling of holes in concrete.

It is worth noting that experiments to create ideal proportions are ongoing to this day. In this regard, people often begin to change recipes on their own. Therefore, you can try yourself in this path.

Afterword

Now you know what polymer concrete is. However, if any nuances remain unclear to you, then there is no reason to be upset (.

In the video presented in this article, you will find additional information on this topic, which will allow you to better understand everything.

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 heavy polymer concrete of high density, 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 the 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 the 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, alkaline and salt media, as well as dilute acids, except for 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.

polymer concrete

In the process of development of building technologies, new materials and concrete mixes appear, for the preparation of which special fillers are used. This allows you to create durable composite materials with high performance, decorative properties. Polymer concrete - one of these compositions, is gaining popularity in the market of building materials.

The material, along with the traditional components - sand and gravel, includes polymer resins based on epoxy, furan, polyester as a binder. Polymer concrete is in demand in the construction industry, it is used to create sculptures, make original furniture, as well as in the ritual sphere.

Polymer concrete (cast stone, polymer cement, concrete polymer, plast concrete, plast concrete) was invented in America as a stronger and more durable alternative to ordinary concrete

Polymer concrete has a number of significant advantages associated with improved mechanical characteristics compared to conventional concrete, resistance to aggressive environments, lightness, and an expanded color palette that allows imitation of natural stone. Consumers of the composite are convinced that it is a reliable composition with a wide range of applications. We will consider the material in detail, delve into the technology, evaluate the advantages and disadvantages, and study the recipe.

Material advantages

Composite concrete, due to the peculiarities of the formulation, has a number of positive characteristics. They are used in various situations where the use of traditional concrete will not provide the desired result.

The main advantage of the composite:

• Increased resistance to moisture penetration into the composite array. Water drops quickly evaporate from the surface of the material, I do not have time to saturate it with destructive moisture.
• Resistance to significant temperature changes, allowing polymer concrete to maintain integrity, regardless of the duration and number of freezing cycles.

  

  This material is one of the new types of concrete mixtures, where instead of silicate or cement (used during the preparation of ordinary concrete), a polymer is used.

• The resistance of the material to aggressive substances, chemical reagents, which allows the use of polymer concrete in various areas without surface protection using special coatings.
• The possibility of restoring mechanically damaged sections of the composite array using a restoration mixture.
• Increased strength characteristics with a relatively small mass of the composite, allowing the production of various products with extended performance properties.
• The absence of roughness on a perfectly smooth, absolutely non-slippery surface of the material. This property allows the artificial stone to remain clean for a long time, and, if necessary, various contaminants are easily removed from the surface of the material.
• Expanded color range of polymer concrete imitating natural marble, malachite, granite. The created artificial stone is difficult to distinguish from the real one, which makes it possible to provide a wide range of applications for the composite.
• The possibility of recycling, use in the manufacture of technological waste, which significantly reduces the cost of products manufactured in conditions of waste-free technology.



Pros: strength, low weight, impact resistance, elasticity is many times higher than that of conventional concrete

Weak sides

Along with the positive aspects, polymer concrete has disadvantages:

• susceptibility to the effects of open fire and elevated temperature, causing the destruction of the material;
• increased, when compared with concrete, price, due to the cost of purchasing special resins.

Components of polymer concrete

If you want to prepare polymer concrete at home, study the composition of the composite. To prepare polymer concrete, use the following ingredients:

• A binder, which is used as urea-formaldehyde, polyester, epoxy and furfural acetone resins.
• Large-fraction crushed stone filler. The size of the crushed stone fraction required for the formation of the composite can be up to 4 centimeters, however, crushed stone 1-2 cm in size should make up the bulk of the composition.
• Screened and cleaned quartz sand. The size of quartz particles should not exceed 5 mm, the presence of clay inclusions, dust is not allowed.

  

  For polystyrene concrete (where polystyrene is taken as a filler), there are standards

• Crushed graphite powder with a particle size of not more than 0.15 mm, quartz flour, used as a ground filler, which reduces the need for expensive resins.
• Building gypsum used in the presence of urea-formaldehyde resin in the composite formulation.
• Surfactants, additives with antiseptic properties and ingredients that increase the volume of the array, increase the thermal insulation properties of the finished composite.

Classification

Polymer concrete, depending on the concentration of the filler, the share of which in the total volume is up to 80%, is divided into classes:

• especially heavy, cubic meter, which weighs from 2500 to 4000 kg;
• heavy, with a density of 1800-2500 kg/m3;
• light with a specific gravity of 500-1800 kg/m3;
• lightweight, the mass of a cubic meter does not exceed 500 kilograms.

Scope of use

(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.

In the conditions of production 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 the form (certainly equipped with handles) with their hands 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:

→ Concrete mix

Technology for the production of polymer concrete products

In accordance with the developed and accepted classification according to the composition and method of preparation, P-concrete is divided into three main groups:
- polymer-cement concretes (PCB) - cement concretes with additives of polymers;
- concrete polymers (BP) - cement concrete impregnated with monomers or oligomers;
- polymer concrete (PB) - concrete based on polymer binders. Polymer cement concretes (PCB) are cement
concretes, during the preparation of which 15–20% is added to the concrete mix, in terms of dry matter, polymer additives in the form of aqueous dispersions or emulsions of various monomers: vinyl acetate, styrene, vinyl chloride and various latexes C KS-30, C KS- 50, SKTs-65, etc.

Polymer cement concretes have high adhesion to old concrete, increased strength in air-dry conditions, increased water resistance and water resistance. Polymer solutions do not contain large gravel in their composition, and polymer mastics contain only mineral flour.

Rational areas of application of such concretes are wear-resistant floor coverings under dry operating conditions, restoration of concrete structures, repair of airfield pavements, masonry mortars, etc. In the production of floors, various dyes are allowed to be added to polymer-cement concretes and mortars.

Concrete polymers (BP) are cement concretes, the pore space of which is completely or partially filled with a cured polymer. Filling the pore space of cement concrete is carried out by impregnating it with low-viscosity polymerizable oligomers, monomers or molten sulfur. As impregnating oligomers, polyester resin of the GTN-1 type (GOST 27952), less often epoxy resin ED-20 (GOST 10587), as well as methyl methacrylate MMA monomers (GOST 20370) or styrene are used. As hardeners for synthetic resins, the following are used: for polyester resin PN-1-hyperiz GP (TU 38-10293-75) and cobalt naphthenate NK (TU 6-05-1075-76); for epoxy ED-20 - polyethylenepolyamine PEPA (TU 6-02-594-80E); for metal methacrylate MMA - a system consisting of technical dimethylaniline DMA (GOST 2168) and benzoyl peroxide (GOST 14888); for styrene (GOST 10003) - organic peroxides and hydroperoxides, or azo compounds with accelerators such as cobalbit naphitenate, dimethylaniline. Styrene also self-polymerizes at elevated temperatures.

The manufacture of BP products or structures includes the following main operations: concrete and reinforced concrete products are dried to 1% moisture, placed in a hermetically sealed container or autoclave, where they are evacuated, then the monomer or oligomer is poured into the autoclave, impregnated, after which the impregnating layer is drained. The polymerization of the monomer or oligomer in the pore space of concrete is carried out in the same chamber or autoclave by heating or by radiation with radioactive Co 60. In the thermocatalytic method of curing, hardeners and accelerators are introduced into the monomers or oligomers. Depending on the required conditions, the product is impregnated completely or only the surface layer to a depth of 15-20 mm.

The impregnation time of concrete is determined by the overall dimensions of the product, the depth of impregnation, the viscosity of the monomer or oligomer. The time of thermocatalytic polymerization at a temperature of 80-100 °C is from 4 to 6 hours.

The scheme of the plant for the production of concrete-polymer products is shown in fig. 7.4.1.

Concrete and reinforced concrete products that have been dried in the chambers (12) are fed by an overhead crane (1) into the impregnation tank (10), in which the products are evacuated and then impregnated. Then the product enters the container (3) for polymerization, and then the polymerized products enter the holding areas (14).

Monomers and catalysts are stored in separate containers (7,9). To avoid spontaneous polymerization of components and impregnating mixtures, they are stored in refrigerators (11).

BP have many positive properties: with the strength of the original concrete (40 MPa), after complete impregnation with MMA monomer, the strength increases to 120-140 MPa, and when impregnated with epoxy resins, up to 180-200 MPa; water absorption in 24 hours is 0.02-0.03%, and frost resistance increases to 500 cycles and more; abrasion resistance and chemical resistance to solutions of mineral salts, oil products and mineral fertilizers increase significantly.

Rice. 7.4.1. Scheme of a plant for the production of concrete-polymer products: 1 - cranes; 2 – tank for hot water; 3 - polymerizer; 4 - auxiliary premises; 5 - vacuum pump; 6 – low pressure steam supply system; 7 - tanks for the catalyst; 8 - compensation tanks; 9 – monomer storage tanks; 10 - reservoir for impregnation; 11 - refrigerators; 12 - drying chambers; 13 - control post; 14 - platforms for curing concrete

Rational areas of application of BP are: chemically and wear-resistant floors of industrial buildings and agricultural premises, pressure pipes; power line supports; pile foundations used in harsh climatic conditions and saline soils, etc.

The main disadvantages of BP include: a complex technology for their production, requiring special equipment and, as a result, their high cost. Therefore, BP should be used in construction practice, taking into account their specific properties and economic feasibility.

Polymer concretes (PB) are artificial stone-like materials obtained on the basis of synthetic resins, hardeners, chemically resistant aggregates and fillers and other additives without the participation of mineral binders and water. They are intended for use in load-bearing and non-bearing, monolithic and prefabricated chemically resistant building structures and products, mainly at industrial enterprises with the presence of various highly aggressive environments, for the manufacture of large-sized vacuum chambers, radio-transparent, radio-tight and radiation-resistant structures, for the manufacture of basic parts in machine-tool and machine-building industry, etc.

Polymer concrete and reinforced polymer concrete are classified according to the type of polymer binder, average density, type of reinforcement, chemical resistance and strength characteristics.

Compositions, the most common in construction, polymer concrete and their main properties are given in table. 7.4.1. and 7.4.2.

Polymer solutions do not contain crushed stone, only sand and mineral flour.

Polymer mastics are filled with one flour.

For the preparation of polymer concrete, the following synthetic resins are most often used as a binder: furfural acetone FA or FAM (TU 59-02-039.07-79); furan-epoxy resin FAED (TU 59-02-039.13-78); unsaturated polyester resin PN-1 (GOST 27592) or PN-63 (OST 1438-78 as amended); methyl methacrylate (monomer) MMA (GOST 20370); unified carbamide resin KF-Zh (GOST 1431); as hardeners for synthetic resins are used: for furan resins FA or FAM-benzenesulfonic acid BSK (TU 6-14-25-74); for furan-epoxy resin FAED - polyethylenepolyamine PEPA (TU 6-02-594-80E); for polyester resins PN-1 and PN-63-hyperiz GP (TU 38-10293-75) and cobalt naphthenate NK (TU 6-05-1075-76); for metal methacrylate MMA - a system consisting of technical dimethylaniline DMA (GOST 2168) and benzoyl peroxide (GOST 14888, as amended); for urea resins KF-Zh - aniline hydrochloride (GOST 5822).

Acid-resistant crushed stone or gravel (GOST 8267 and GOST 10260) are used as large aggregates. Expanded clay, shungizite and agloporite are used as large porous aggregates (GOST 9759, 19345 and 11991). The acid resistance of the listed fillers, determined according to GOST 473.1, must be at least 96%.

Quartz sands (GOST 8736) should be used as fine aggregates. It is allowed to use screenings when crushing chemically resistant rocks with a maximum grain size of 2-3 mm. The acid resistance of small aggregates, as well as crushed stone, should not be lower than 96%, and the content of dusty, silty or clay particles, determined by elutriation, should not exceed 2%.

For the preparation of polymer concrete, andesite flour (STU 107-20-14-64), quartz flour, marshalite (GOST 8736), graphite powder (GOST 10274 as amended) should be used as fillers, ground aggloporite is allowed. The specific surface of the filler should be in the range of 2300-3000 cm2/g.

Gypsum binder (GOST 125 as amended) or phosphogypsum, which is a waste product of phosphoric acid production, is used as a water-binding additive in the preparation of polymer concretes based on KF-Zh binder.

Fillers and aggregates must be dry with a residual moisture content of not more than 1%. Do not use fillers contaminated with carbonates, bases and metal dust. Acid resistance of fillers must be at least 96%.

If necessary, polymer concrete is reinforced with steel, aluminum or fiberglass reinforcement. Aluminum reinforcement is mainly used for polymer concrete based on polyester resins with pre-tensioning.

The materials used must provide the specified properties of polymer concrete and meet the requirements of the relevant GOSTs, TUs and instructions for the preparation of polymer concrete (SN 525-80).

The preparation of a polymer concrete mixture includes the following operations: washing of aggregates, drying of aggregates and aggregates, fractionation of aggregates, preparation of hardeners and accelerators, dosing of components and their mixing. Drying of materials is carried out in drying drums, ovens, heating cabinets.

The temperature of the fillers and fillers before feeding into the batchers should be within 20-25 °C.

Resins, hardeners, accelerators and plasticizers are pumped from the warehouse into storage tanks by pumps.

Dosing of components is carried out by weight batchers with dosing accuracy:
resins, fillers, hardeners +- 1%,
sand and crushed stone +-2%.
The mixing of the constituent polymer concrete mixtures is carried out in two stages: the preparation of the mastic, the preparation of the polymer concrete mixture.
The preparation of mastic is carried out in a high-speed mixer, with a rotation speed of the working body of 600-800 rpm, the preparation time, taking into account the load, is 2-2.5 minutes.

The preparation of polymer concrete mixtures is carried out in forced mixing concrete mixers at 15°C and above.

The technological process of forming polymer concrete products consists of the following operations: cleaning and lubricating molds, installing reinforcing elements, laying polymer concrete mixture and molding products.

The lubrication of metal molds is carried out with special compositions in% by weight: emulsol -55 ... 60; graphite powder - 35 ... 40; water -5 ... 10. It is also allowed to use solutions of bitumen in gasoline, silicone lubricants, a solution of low molecular weight polyethylene in toluene.

Concrete pavers are used for laying, leveling and smoothing the mixture. Compaction is carried out on vibrating platforms or using mounted vibrators. Compaction of polymer concrete products on porous aggregates is carried out with a weight that provides a pressure of 0.005 MPa.

The duration of vibration is prescribed depending on the stiffness of the mixture, but not less than 2 minutes. A sign of good compaction of the mixture is the release of a liquid phase on the surface of the product. The compaction of polymer concrete mixtures is more efficient on low-frequency vibration platforms with the following parameters: amplitude 2-4 mm and oscillation frequency 250-300 per minute.

The curing of polymer concrete under natural conditions (at a temperature not lower than 15 ° C and a humidity of 60 - 70%) occurs within 28 - 30 days. In order to accelerate hardening, polymer concrete structures are subjected to dry heating for 6–18 hours in chambers with steam registers or aerodynamic furnaces at a temperature of 80–100°C. In this case, the rate of rise and decrease in temperature should be no more than 0.5 - 1 ° C per minute.

A typical technological scheme for the factory production of polymer concrete products is shown in the graph (Fig. 7.4.2).

Rice. 7.4.2. Technological scheme for the production of polymer concrete products on a production line. 1 - storage of aggregates; 2 - bunkers for receiving crushed stone and sand; 3 - drying drums; 4 - dispensers; 5 - concrete mixer; 6 - vibration platform; 7 – thermal treatment chambers; 8 - stripping post; 9 - warehouse for finished products

The preparation of the polymer concrete mixture takes place in two stages: at the first stage, the binder is prepared by mixing the resin, microfiller, plasticizer and hardener, at the second stage, the finished binder is mixed with coarse and fine aggregates in forced-action concrete mixers. The binder is prepared by mixing dosed microfiller, plasticizer, resin and hardener in a continuously operating turbulent mixer. Mixing time of the loaded components is no more than 30 s.

The polymer concrete mixture is prepared by sequential mixing of dry aggregates (sand and crushed stone), then a binder is fed into a continuously operating concrete mixer. Mixing time of aggregates (dry mix) 1.5-2 min; dry mix of aggregates with a binder - 2 min; unloading of polymer concrete mixture - 0.5 min. Sand and crushed stone are fed into the concrete mixer by batchers. The mixer must be equipped with temperature sensors and an emergency device for supplying water in case of a sudden accident or in the event of a disruption in the process, when it is necessary to stop the reaction of polymer structuration. 164

The polymer concrete mixture is fed into a suspended type concrete paver with a mobile hopper and a smoothing device, which evenly distributes the polymer concrete mixture according to the shape of the product.

The polymer concrete mixture is compacted on a resonant vibration platform with horizontally directed vibrations. Oscillation amplitude 0.4-0.9 mm horizontally, 0.2-0.4 mm vertically, frequency 2600 counts/min. Vibrocompaction time 2 min.

Laying and vibrocompaction of the mixture is carried out in a closed room equipped with supply and exhaust ventilation. Simultaneously with the formation of polymer concrete structures, control samples of 100X100X100 mm are formed to determine the compressive strength of polymer concrete. For each product made of polymer concrete with a volume of 1.5 - 2.4 m3, three control samples are made.

Heat treatment of polymer concrete products. To obtain products with desired properties in a shorter time, they are sent using a floor conveyor to the heat treatment chamber. Heat treatment of products is carried out in an aerodynamic heating furnace, PAP type, which ensures uniform temperature distribution throughout the volume.

After heat treatment, finished products are automatically moved by a conveyor to the technological bay, removed from the mold and sent to the finished product warehouse. The released form is cleaned of foreign objects and polymer concrete residues and prepared for the molding of the next product.

Quality control should be carried out, starting with checking the quality of all components, the correct dosage, mixing modes, compaction and heat treatment.

The main indicators of the quality of the prepared polymer concrete are the self-heating temperature after molding, the rate of increase in concrete hardness, its strength characteristics, including uniformity after 20-30 minutes. After vibration compaction, the polymer concrete mixture begins to heat up to a temperature of 35-40°C, and in massive structures - up to 60-80°C. Insufficient heating of polymer concrete indicates unsatisfactory quality of the resin, hardener or high humidity of fillers and aggregates.

To determine the control strength indicators of polymer concrete, samples are tested in accordance with GOST 10180 and instruction SN 525 - 80.

When performing work on the manufacture of products and structures from polymer concrete, it is necessary to comply with the rules provided for by the head of the SNiP on safety in construction, the sanitary rules for the organization of technological processes approved by the Main Sanitary and Epidemiological Directorate of the Ministry of Health and the requirements of the Instruction on the technology of manufacturing polymer concrete (SR 52580).