Cement-polymer concrete. Polymer concrete. Polymer concrete: composition, types, features, application technology and reviews
Polymer-cement concrete is an artificial stone material, the binders of which are polymer and cement, and the fillers are sand and crushed stone. Unlike conventional concretes with modifying additives (GKZh-94, Winsol), which, due to small quantities, practically do not change the structure of concrete, the polymer content in polymer-cement concretes is quite high. This makes it possible to obtain materials with new properties. They have less weight, are frost-resistant, have slightly greater strength than conventional ones, and have increased wear resistance. Polymer cement concrete is produced in three ways:
by introducing into concrete the mixture of aqueous dispersions of polymers (polyvinyl acetate or synthetic rubber), decaying into concrete mixture with the release of water, while the dehydrated polymer acts as an additional binder;
by adding water-soluble monomers and polymers (furan and polyvinyl alcohols, epoxy, phenol-formaldehyde resins, etc.) to the mixing water, followed by their curing in concrete by heating or using hardeners;
impregnation of concrete to the required depth with low-viscosity polymers (urea, ethinol varnish, styrene), which cure directly in the concrete.
Fillers for polymer-cement concrete are quartz or crushed sand, as well as crushed stone of strong and dense rocks with a particle size of no more than 20 mm. Polymer cement fine-grained mortars are also used.
The optimal content of a polymer such as polyvinyl acetate is from 15 to 20% by weight of cement in terms of dry matter. Wherein the best way The properties of both cement and polymer are used. With this dosage, the continuity of the cement gel is maintained in polymer-cement concrete, and the polymer, enveloping the cement joints and aggregate grains, additionally glues them together. As the polymer increases, the continuity of cement new formations is disrupted, which reduces the strength of polymer-cement concrete.
The optimal content of water-soluble urea polymer S-89, as well as epoxy polymers DEG-1 and TEG-17, is about 2% relative to the weight of cement. In this case, the water-cement ratio of the concrete mixture can be reduced to 0.29-0.30 without compromising its workability, as well as durability in aggressive environments. By using various polymer components, it is possible to obtain polymer concretes that are resistant to petroleum products, fats and salt solutions. Polymer cement concrete is used for the construction of wear-resistant floors, airfield pavements, tanks for petroleum products, as well as monolithic structures for work in aggressive environments.
To prepare polymer cement mixtures, paddle mixers or vibrating mixers are used. During mechanical mixing, the mixture is saturated with air, and small pores are formed in the concrete, evenly distributed throughout the volume. Due to the fact that polymer-cement concrete is still used in small volumes, their mixtures are prepared in mixers located near the place of installation. Polymer-cement mixtures have high viscosity, so vibrating them at low frequencies (3000 kol/min) is ineffective. Air is not removed from the concrete, its structure becomes excessively porous and loose. High-frequency vibration is more appropriate, and for hard mixtures, compaction and vibrocompression.
Polymer-cement concretes prepared with aqueous dispersions of polymers are kept in air-dry conditions, while concretes with additives of epoxy and urea polymers quickly harden in humid conditions.
Plastic concretes are artificial conglomerates produced entirely using organic polymer binders. They are essentially plastics with mineral fillers of varying sizes.
The binders in plastic concrete are low-viscosity thermosetting polymers (phenol-formaldehyde, furan, polyester and epoxy), which, with the addition of hardeners and under certain conditions, harden, gluing the components into a strong conglomerate. Typically, plastic concrete with compositions 1:5-1:15 (polymer: filler by weight) is used.
To cure polymers, Petrov's kerosene contact, sulfonic acids and mineral acids, polyethylene polyamine, diethylenetriamine, etc. are used.
Clean sands with a grain size of 0.6-2.5 mm and a content of clay and dust particles of no more than 0.5% are used as fillers. Crushed stone and gravel must also be dry and clean and have a particle size of no more than 20 mm. Besides crushed granite andesite and barite, as well as crushed tripoli and graphite are used as fillers, depending on the purpose of the plastic concrete.
The strength properties of plastic concrete are determined by the properties of the binder and filler, as well as the adhesion between them. Plastic concrete has high strength, especially in tension and bending. Thus, the flexural strength of some plastic concretes based on epoxy polymers reaches 350-450 kgf/cm2.
Plastic concrete is practically waterproof and frost-resistant; They resist wear well and are resistant in aggressive environments. For example, their resistance to acids is 10 times higher than that of conventional concrete.
It is advisable to use plastic concrete for waterproofing and anti-corrosion linings. They are used to produce wear-resistant floors, in airfield pavements, as well as for the construction of parts of buildings and structures operated in aggressive environments.
Plastic concrete mixtures are prepared in small volumes directly at the places where they are laid due to their rapid hardening. IN paddle mixer fillers are loaded, then polymer binders. After 3-4 minutes of mixing and obtaining a uniform mass, the hardener is introduced and mixed for 5-8 minutes.
The prepared portion of the mixture is immediately put into the case. It is compacted by compaction or bayonet.
Plastic concrete hardens better in dry conditions at 50-100° C. Increase relative humidity above 60% reduces the strength of plastic concrete, especially on polyester polymers. Compositions based on epoxy polymers are less sensitive to high humidity. The heating time of laid plastic concrete is 4-8 hours, depending on the type of polymer and the composition of the mixture. When plastic concrete hardens, it shrinks, the amount of which depends on the type and amount of polymer.
→ Concrete mixture
Technology for the production of polymer concrete products
In accordance with the developed and accepted classification by composition and method of preparation, U-concrete is divided into three main groups:
- polymer cement concrete (PCB) – cement concrete with polymer additives;
- concrete polymers (BP) – cement concrete impregnated with monomers or oligomers;
- polymer concrete (PB) – concrete based on polymer binders. Polymer cement concrete (PCB) is a cementitious
concretes, during the preparation of which 15–20%, in terms of dry matter, are added to the concrete mixture, polymer additives in the form of aqueous dispersions or emulsions of various monomers: vinyl acetate, styrene, vinyl chloride and various latexes S KS-30, S KS- 50, SKTs-65, etc.
Polymer-cement concretes have high adhesion to old concrete, increased strength in air-dry conditions, increased water tightness and water resistance. Polymer solutions do not contain large crushed stone, and polymer mastics contain only mineral flour.
Rational areas of application for such concretes are wear-resistant floor coverings under dry operating conditions, restoration concrete structures, repair of airfield pavements, masonry mortars etc. When producing floors, various dyes can 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 hardened polymer. Pore space filling cement concrete carried out by impregnating it with low-viscosity polymerizing oligomers, monomers or molten sulfur. Used as impregnating oligomers polyester resin type GTN-1 (GOST 27952), less often epoxy ED-20 (GOST 10587), as well as monomers methyl methacrylate MMA (GOST 20370) or styrene. The following are used as hardeners for synthetic resins: for polyester resin PN-1-hyperiz GP (TU 38-10293-75) and cobalt naphthenate NK (TU 6-05-1075-76); for epoxy ED-20 – polyethylene polyamine 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 cobalbite naphythenate, dimethylaniline. Styrene also self-polymerizes at elevated temperatures.
The manufacture of BP products or structures includes the following basic operations: concrete and reinforced concrete products are dried to 1% humidity, placed in a hermetically sealed container or autoclave, where they are vacuumized, then a monomer or oligomer is poured into the autoclave, impregnation is performed, after which the impregnating layer is drained. Polymerization of a 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. With the thermocatalytic curing method, hardeners and accelerators are introduced into the monomers or oligomers. Depending on the required conditions, the product is impregnated completely or only surface layer to a depth of 15-20 mm.
The impregnation time of concrete is determined overall dimensions products, depth of impregnation, viscosity of monomer or oligomer. The time of thermocatalytic polymerization at a temperature of 80-100 °C is from 4 to 6 hours.
The diagram of a plant for the production of concrete-polymer products is shown in Fig. 7.4.1.
Concrete and reinforced concrete products, dried in chambers (12), are fed by an overhead crane (1) into an impregnation tank (10), in which the products are vacuumized and subsequent impregnation takes place. Then the product enters the container (3) for polymerization, and then the polymerized products arrive at the curing 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).
BPs 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 to 180-200 MPa; water absorption in 24 hours is 0.02-0.03%, and frost resistance increases to 500 cycles and above; abrasion resistance and chemical resistance to solutions of mineral salts, petroleum products and mineral fertilizers increases significantly.
Rice. 7.4.1. Diagram of a plant for the production of concrete-polymer products: 1 – cranes; 2 – reservoir for hot water; 3 – polymerizer; 4 – auxiliary premises; 5 – vacuum pump; 6 – steam supply system low pressure; 7 – containers for catalyst; 8 – compensation tanks; 9 – tanks for monomer storage; 10 – reservoir for impregnation; 11 – refrigerators; 12 – drying chambers; 13 – control post; 14 – platforms for curing concrete
Rational areas of application of BP are: chemical and wear-resistant floors 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: the complex technology for their production, which requires special equipment and, as a consequence, their high cost. Therefore, BPs 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 designed for use in load-bearing and non-load-bearing, monolithic and prefabricated chemical-resistant building structures and products mainly at industrial enterprises with the presence of various highly aggressive environments, the manufacture of large-sized vacuum chambers, radio-transparent, radio-tight and radiation-resistant structures, for the manufacture of basic parts in the machine tool and mechanical engineering industry, etc.
Polymer concrete and reinforced polymer concrete are classified according to the type of polymer binder, medium density, type of reinforcement, chemical resistance and strength characteristics.
The compositions of the most common polymer concretes in construction 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 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 urea resin KF-Zh (GOST 1431); the following are used as hardeners for synthetic resins: for furan resins FA or FAM-benzenesulfonic acid BSK (TU 6-14-25-74); for furan-epoxy resin FAED - polyethylene polyamine 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 coarse 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%.
Should be used as fine aggregates quartz sands(GOST 8736). It is allowed to use screenings when crushing chemically resistant rocks with a maximum grain size of 2-3 mm. The acid resistance of fine aggregates, as well as crushed stone, must be no lower than 96%, and the content of dust, silt or clay particles, determined by elutriation, must not exceed 2%.
To prepare 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; the use of ground agloporite is allowed. The specific surface area of the filler should be in the range of 2300-3000 cm2/g.
As a water-binding additive in the preparation of polymer concrete using the KF-Zh binder, gypsum binder (GOST 125 as amended) or phosphogypsum, which is a waste product from the production of phosphoric acid, is used.
Fillers and aggregates must be dry with a residual moisture content of no more than 1%. Fillers contaminated with carbonates, bases and metal dust are not allowed for use. The acid resistance of fillers must be at least 96%.
If necessary, polymer concrete is reinforced with steel, aluminum or fiberglass reinforcement. Aluminum reinforcement is used mainly for polymer concrete based on polyester resins with pre-tensioning.
The materials used must ensure the specified properties of polymer concrete and meet the requirements of the relevant GOSTs, technical specifications and instructions for the preparation of polymer concrete (SN 525-80).
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, and ovens.
The temperature of fillers and fillers before feeding into dispensers should be within 20-2 5 °C.
Resins, hardeners, accelerators and plasticizers are pumped from the warehouse into storage tanks by pumps.
Dosing of components is carried out by weighing dispensers with dosing accuracy:
resins, fillers, hardeners +- 1%,
sand and crushed stone +-2%.
Mixing of the components of polymer concrete mixtures is carried out in two stages: preparation of mastic, preparation of 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 molding polymer concrete products consists of the following operations: cleaning and lubricating molds, installing reinforcing elements, laying polymer concrete mixture and molding products.
Lubricant metal molds carried out with special compositions in % by weight: emulsol -55...60; graphite powder – 35…40; water -5... 10. It is also possible to use solutions of bitumen in gasoline, silicone lubricants, and a solution of low molecular weight polyethylene in toluene.
Concrete pavers are used to lay, level and smooth 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 providing a pressure of 0.005 MPa.
The duration of vibration is determined depending on the hardness 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. It is more effective to compact polymer concrete mixtures on low-frequency vibrating platforms with the following parameters: amplitude 2 - 4 mm and vibration frequency 250 - 300 per minute.
The strength gain 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 ovens at a temperature of 80–100°C. In this case, the rate of rise and fall of temperature should be no more than 0.5 - 1°C per minute.
A typical technological flow diagram for the factory production of polymer concrete products is presented in the graph (Fig. 7.4.2).
Rice. 7.4.2. Technology system production of polymer concrete products on a production line. 1 – aggregates warehouse; 2 – bunkers for receiving crushed stone and sand; 3 – drying drums; 4 – dispensers; 5 – concrete mixer; 6 – vibration platform; 7 – heat treatment chambers; 8 – stripping post; 9 – warehouse finished products
The preparation of a polymer concrete mixture occurs in two stages: in the first stage, the binder is prepared by mixing resin, microfiller, plasticizer and hardener, in 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. The mixing time of the loaded components is no more than 30 s.
The polymer concrete mixture is prepared by sequentially mixing dry aggregates (sand and crushed stone), then the binder is fed into a continuously operating concrete mixer. Mixing time of aggregates (dry mixture) 1.5-2 minutes; dry mixture of aggregates with a binder – 2 minutes; unloading polymer concrete mixture – 0.5 min. Sand and crushed stone are fed into the concrete mixer using dispensers. 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 technological process, when it is necessary to stop the reaction of polymer structure formation. 164
The polymer concrete mixture is fed into the concrete paver hanging type with a mobile hopper and a smoothing device that 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. Vibration compaction time 2 min.
Laying and vibration compaction of the mixture is carried out in a closed room equipped supply and exhaust ventilation. Simultaneously with the molding of polymer concrete structures, control samples measuring 100X100X100 mm are molded to determine the compressive strength of polymer concrete. For each polymer concrete product with a volume of 1.5 - 2.4 m3, three control samples are made.
Heat treatment of polymer concrete products. To obtain products with specified 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, type PAP, which ensures uniform temperature distribution throughout the entire volume.
After heat treatment, finished products are automatically moved by a conveyor into the technological bay, removed from the mold and sent to the finished product warehouse. The freed mold is cleaned of foreign objects and polymer concrete residues and prepared for molding the next product.
Quality control should be carried out starting with checking the quality of all components, correct dosage, mixing, compaction and heat treatment modes.
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 homogeneity after 20 - 30 minutes. After vibration compaction, the polymer concrete mixture begins to heat up to a temperature of 35 - 40°C, and massive structures– up to 60 – 80°С. Insufficient heating of polymer concrete indicates unsatisfactory quality of the resin, hardener or high humidity of fillers and fillers.
To determine the control strength parameters of polymer concrete, samples are tested in accordance with GOST 10180 and instructions SN 525 - 80.
When carrying out work on the manufacture of products and structures from polymer concrete, it is necessary to comply with the rules provided for by the chapter of SNiP on safety in construction, sanitary rules organizations technological processes, approved by the Main Sanitary and Epidemiological Directorate of the Ministry of Health and the requirements of the Instructions for the technology of manufacturing polymer concrete (CP 52580).
Polymer concrete (also called cast or artificial stone, polymer cement, concrete polymer and plastic concrete) is an alternative type of concrete mixture in which a polymer (synthetic resin) is used instead of the standard binder. Thanks to this component and cheaper mineral fillers, the composition is highly resistant to moisture and frost, but at the same time the price of cast stone is lower. Let's take a closer look: polymer concrete - what is it and is this material really worth using in construction as a replacement for conventional concrete?
To answer this question, we first determine what components plastic concrete includes.
Composition of polymer concrete
The lion's share of the polymer cement composition is occupied by filler and it is added in two types at once:
- Ground – talc, graphite powder, andesite flour, ground basalt, mica and other raw materials.
- Coarse – gravel, crushed stone, quartz sand.
Important! When producing cast stone, metal dust, cement lime and chalk should not be used.
Resin is used as a “fastening” component:
- furan-epoxy (must meet the requirements of TU 59-02-039.13-78);
- furfural acetone (FAM), meeting the standards of TU 6-05-1618-73;
- urea-formaldehyde (corresponds to GOST 14231-78 standards);
Polyester resin is often used to hold the filler together, as it is cheaper than others. It is also allowed to use methyl methacrylate monomer (methyl ester) that meets the standards of GOST 16505.
In addition, the cast stone contains hardeners, plasticizing additives and coloring components. They must also meet the requirements for chemical additives (GOST 24211).
Depending on the quantity and type of components, polymer concrete of different qualities can be obtained.
Types of polymer concrete
Depending on what kind of filler (or rather its fraction) you added to the casting stone solution, you can get the material to create lightweight decorative elements, and for the construction of more massive structures.
Based on this, the following classes of polymer concrete are distinguished:
- Super heavy. The density of such concrete is from 2.5 to 4 t/m 3. As a filler for super heavy building material use components measuring at least 2-4 cm. This type of concrete is used for the construction of structures that are subject to high pressure ( bearing structures, foundation).
- Heavy (density from 1.8 to 2.5 t/m3). This type of plastic concrete is suitable for the production of decorative cast stones that imitate marble and other expensive stones. The size of the heavy polymer concrete aggregate should not exceed 2 cm.
- Easy. Since the density of such material is 0.5-1.8 t/m 3, it is usually classified as structural-thermal insulation class concrete. This type of concrete polymer is distinguished by high performance heat saving. The filler used for its preparation is the same fraction as for heavy polymer concrete, only its quantity changes.
- Ultralight. The density of this composition is from 0.3 to 0.5 t/m3, so it is used for thermal insulation works and during the construction of internal partitions. The fillers most often used are various shavings, perlites, cork and polystyrene with a fraction of no more than 1 cm.
Healthy! Most often, polymer concrete is used for the manufacture of: kitchen countertops, sinks, window sills, columns, steps, monuments, fireplaces, fountains, floors, vases and much more.
There is also the easiest fake diamond, with a filler size of no more than 0.15 mm. This material has found application in the production of decorative elements.
Properties of polymer concrete
If we compare concrete polymer with ordinary concrete, it is worth noting the fact that in many of its characteristics the composition with the addition of resins bypasses conventional mixtures. Polymer concrete has the following properties:
- density – 300-3000 kg/m3;
- resistance to compression – from 50 to 110 MPa;
- bending resistance – from 3 to 11 MPa;
- abrasion in the range of 0.02-0.03 g/cm 2 ;
- temperature limit – from 60 to 140 0 C;
- elasticity – from 10,000 to 40,000 MPa;
- thermal conductivity coefficient – 0.05-0.85 W/m K;
- moisture absorption volume – 0.05-0.5%;
The strength characteristics of polymer concrete are 3-6 times higher than those of conventional concrete. The same applies to tensile strength, which is almost 10 times higher for concrete polymer.
It is also worth taking into account the chemical passivity of modern concrete composition, which is determined according to GOST 25246-82. From this normative document it follows that at 200 0 C Celsius, the chemical resistance of concrete polymer components to nitric acid will be no less than 0.5%, and to hydrochloric acid, ammonia or calcium solution of at least 0.8%.
Based on this, we can conclude that polymer concrete, which contains resins, has all the qualities necessary for the construction of various objects.
Advantages and disadvantages of casting stone
Polymer cement is often used in the construction of structures that cannot be made from ordinary concrete due to its fragility. Thanks to the polymer composition, structures will be less susceptible to deformation or destruction.
In addition, polymer concrete has the following advantages:
- Due to the high water resistance and resistance of the concrete polymer to changes temperature conditions, water droplets on the surface of the finished product evaporate almost immediately, as a result of which cracks and other defects do not form.
- The surface of the polymer cement remains smooth throughout its entire service life, so polymer concrete products do not get dirty.
- The variety of colors allows you to create products from this material, stylized as expensive ones. natural breeds(granite, marble and others).
- The material is recyclable with the possibility of reusing concrete polymer.
- Designs from this lightweight concrete do not require additional processing.
Speaking of disadvantages modern material, then it is worth highlighting the following disadvantages:
- Flammability of polymer concrete.
- The high cost of some binding components (however, if you use ground flour as a filler, the costs will be significantly reduced).
- It is not always possible to find on sale everything necessary for the production of such a composition.
Speaking about the production of polymer concrete, it is worth considering possible options production of such concrete.
Methods for producing cast stone
The process of producing concrete polymer can be continuous or batch.
Continuous production
In this case, we are talking about large-scale production, for which you will need to purchase the appropriate equipment:
- Vibrating table
- Stirrer.
- Compressor system with gun.
- Silicone matrices.
- Hood.
- Grinding and polishing machines.
To purchase everything you need you will have to spend about 250,000 rubles. Even if you take into account that you will make some of the equipment yourself, the most expensive tools will have to be purchased. Therefore, we will not dwell on this production method and will consider a more accessible technology.
Making polymer cement at home
Knowing what polymer concrete is, it becomes obvious why it is most often used for the production of countertops and decorative elements for suburban area This is the material used. Fortunately, you don’t need specialized equipment to produce it at home.
To make polymer cement with your own hands:
- Rinse and clean the filler. After this, dry it until the moisture content of the crushed stone or gravel is 0.5-1%. If you use wet aggregate, the strength of the finished product will decrease.
- Sift the sand and remove impurities from it.
- First pour crushed stone into the concrete mixer, then sand and aggregate and mix the components for 2 minutes.
- Add water and mix everything again.
- Soften the binder component (resin) with a solvent or simply by heating the solid mass.
- Add a plasticizing additive, stabilizers and other components to the resin. Mix them separately from the aggregate for 2 minutes.
- Add hardener.
- Mix all ingredients for at least 3 minutes until you get a creamy mixture.
- Pour the resulting mixture into a paraffin-lubricated matrix or prepared formwork. Try to immediately fill in the volume of composition that will completely fill the mold. Polymer concrete sets very quickly, so you need to act quickly.
- Level the surface and compact the mixture on a vibrating table.
- Wait a day and take it out ready product from the matrix.
At this point, the production of polymer concrete can be considered finished.
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The main difference between polymer concrete and conventional concrete is that during its production, high-molecular organic compounds are added to the initial solution. In simple terms, in the composition of such a solution, the role of a binder is played by resins: epoxy, polyvinyl, polyester, polyurethane, methyl methacrylate or others. Also included in this material to increase various properties add components such as solvents, hardeners, catalysts and others.
This material is used for external or interior decoration various buildings and premises, as well as road construction, landscape design and in the manufacture of various small architectural forms. Due to the ability to vary the consistency of the material during its production, polymer concrete can be used on both horizontal and vertical planes.
Characteristics of polymer concrete
The main components for the production of geopolymer concrete are slag, ash, liquid glass, binding resins. During the polymerization of such a solution, a monolith is formed, which, both in strength and in most other respects, technical characteristics, significantly superior to conventional concrete. Compared to a solution prepared on the basis of Portland cement, it has several advantages:
- increased adhesion to virtually any surface;
- high hardening speed;
- excellent vapor permeability indicators;
- increased resistance to bending and stretching;
- strength and wear resistance;
- resistance to temperature changes and acidic chemical compounds.
Also, this building material is lightweight and completely environmentally friendly. If we talk about disadvantages, then this material has only one. Due to the fact that it was developed not so long ago, and high-quality components are used for its production, it is quite expensive. However, there is every reason to believe that in the very near future it will become the most popular type of concrete used in construction.
Features of the preparation of polymer concrete
In addition to the components already mentioned, PVA glue, latexes and water-soluble resins are most often used as additives for geopolymer concrete. If PVA is used, then only the type that uses polyvinyl alcohol as an emulsifier should be selected.
When this mixture dries, a durable film forms on the surface, which swells over time and absorbs water. That is why during the hardening of the material it is not allowed to come into contact with air with increased content moisture.
The optimal amount of various additives for such a material is most often determined experimentally. However, the security deposit High Quality solution is the correct ratio of cement and polymer components. The volume of polymer components should be no more than 20% of the total mass of cement. And the volume of water-soluble resins is no more than 2% of the mass of cement. The highest quality can be achieved by using polyamide or epoxy resins, as well as polyethylene-polyamine hardeners.
When preparing geopolymer concrete, like regular concrete, you will need a concrete mixer. First, water and cement specially designed for polymer concrete are poured into it (ordinary Portland cement cannot be used, since it does not suit the characteristics). Then slag and ash are added to the solution in equal parts, after which it is thoroughly mixed. After this, polymer components and additives are added.
Most people are sure that polymer concrete and cement-polymer concrete are two names for the same material. In fact, they are completely different building mixtures, having high performance strength.
No cement is added to polymer concrete (plastic concrete), but various polymers act as binders. Portland cements mixed with polymer additives are added to polymer-cement concretes.
There are two types:
1. Filled - high-molecular organic compounds fill the voids between filler particles (gravel, crushed stone, quartz sand).
2. Frame - the voids remain unfilled, and the polymer serves only to bind the mineral filler particles together.
In the first case, the amount of the mixture ranges from 20 to 50%. In the second case, it does not exceed 6%.
It is considered a high-strength material in which aqueous dispersions of polymers (vinyl chloride, vinyl acetate, styrene, latexes, polyamide resins and others) act as performance-improving additives. Their use allows better side change the properties of building materials and improve its technical performance.
Applications, production and sales
Compound
Resins are added to polymer concrete more often than others:
- epoxy;
- polyurethane;
- methyl methacrylate;
- polyvinyl.
Various plasticizers are added to the resins to improve elasticity and increase tensile strength, and hardeners to reduce the hardening time. The composition of cement-polymer concrete also includes Portland cement.
It gets its characteristics from an organic binder. This ensures that loose particles of gravel or crushed stone are bonded together, turning into a strong monolith with a complete absence of cracks. As moisture evaporates, a special film forms on the surface, adding strength and increasing adhesive properties (adhesion to other surfaces).
Thanks to this, polymer concrete becomes extremely resistant even to severe loads, as well as the effects of acids and sudden changes in temperature. Strength becomes even higher if the solution is kept in conditions of low humidity (40-50%).
Characteristics:
- moisture resistance;
- wear resistance;
- high chemical resistance;
- resistance to temperature changes;
- increased tensile strength;
- absence negative influence on living organisms;
- high level of adhesion to surfaces;
- fast hardening;
- good breathability.
The only thing that can become a stumbling block and negate all the advantages of this building material is its high cost. It is unlikely that you will be able to buy polymer concrete cheaply. The price directly depends on the amount of connecting element used. Filled polymer concrete is always more expensive than frame concrete. Additives can be painted in absolutely any color. This also affects the final cost of the building mixture.
Production
The most commonly used additives in the production of polymer concrete are water-soluble resins, PVA and latexes. When ready mix dries, a film forms on the surface of its particles, swelling when exposed to a large amount of moisture. However, this does not affect the strength characteristics.
There is no single correct ratio of components in a recipe yet. But most often, manufacturers mix cement with additives not exceeding 20% of the cement part.
The highest quality cement solution with water-soluble polyamide or epoxy resin and hardener (polyethylene-polyamine).
Manufacturing cement-polymer mixture happens as follows:
1. Special water for polymers with a small amount of cement is poured into the concrete mixer;
2. Added same number ash and slag.
3. The solution is mixed.
4. Polymer and other additives are added.
5. Finally knead.
Application
The material can be used for landscape design(paths and terraces), internal and exterior finishing walls, floors and building facades.
Designers and architects love it because it is easy to form and can be applied by hand and mechanically. A special stamp is applied to the surface of the poured concrete a certain number of times, imitating various natural structures (stone, cobblestone, wood, paving slabs and others). The dried surface can subsequently be painted desired color paints with acrylic base.
They can also be used to decorate fireplace portals, fences, plinths, stairs, swimming pools, borders, barbecue areas, and building facades.
Polymer coatings for concrete can give the material additional improved properties of wear resistance, durability and strength. Thanks to them, the monolith can last more than 20 years.
Manufacturers and cost
In Russia, production and supply are carried out by the following companies: TeoKhim LLC, BASF CJSC (representative of the German concern BASF), DI-Trade LLC, Moscow representative office of DUROCEM ITALIA, Zika LLC (representative of the Swiss company SIKA), LLC "Topbeton"
The price of a polymer concrete self-leveling floor starts at 400 rubles per 1 m2; further increases in cost depend on the cost polymer additives, working conditions and footage.
