Polymer concrete

• Polymer concrete - 1. Concrete where the binder is a polyester resin (without cement and water) 2. Concrete based on polymer binders (with cement, but without water)

• Polymer concrete on a polyester resin - consists of marble chips (85%), a binder - polyester resin (15%), modified additives and coloring pigment. There is no cement in this formulation. Artificial stone products are light, moisture resistant, (moisture absorption is only 0.2%, that is, practically absent) resistant to temperature fluctuations (from -50 to +60 degrees C),
• Polymer-cement concrete - In polymer-cement materials, a polymer that is well compatible with the cement paste is added in small amounts (5 ... 15% of the mass of cement) to the concrete or mortar. This corresponds to water-soluble oligomers that cure during the hardening of concrete (for example, water-soluble phenol-formaldehyde polymers) or more often aqueous dispersions of polymers (polyvinyl acetate, synthetic rubbers, acrylic polymers, etc.). Polymer-cement mortars and concretes are characterized by high adhesion to most building materials, low permeability to liquids, very high wear resistance and impact strength. Polymer-cement materials are used for flooring of industrial buildings, aerodrome runways, exterior and interior decoration on concrete and brick surfaces, including for gluing ceramic, glass and stone tiles, the construction of reservoirs for water and oil products.
• Plastobeton is a type of concrete in which thermoset polymers (epoxy, polyester, phenol-formaldehyde, etc.) are used instead of a mineral binder. Polymer concrete is prepared by mixing a polymer binder and aggregates. The binder consists of a liquid obligomer, hardener and finely ground mineral filler, necessary to reduce polymer consumption and improve the properties of polymer concrete. Polymer concrete hardens at normal temperature for 12 ... 24 hours, and when heated, even faster. The main property of plastobeton is high chemical resistance in acidic and alkaline environments. Plastobetony have high strength (Yaszh = 60 ... 100 MPa, Yaizg ~ 2O ... 4O MPa), density, wear resistance and excellent adhesion to other materials. Along with this, plastic concrete is characterized by high deformability and low heat resistance. Their cost is much higher than the cost of ordinary concrete, but despite this, polymer concrete is effectively used for protective coatings and the manufacture of structures operating in the conditions of chemical aggression (chemical and food enterprises), repair of stone and concrete elements (surface restoration, repair of cracks, etc.). P.).
• Concrete polymer - is concrete impregnated after hardening with monomers or liquid oligomers, which, after appropriate treatment (for example, heating), become solid polymers that fill the pores and defects of concrete. As a result of this, the strength of concrete (YaSzh up to 100 MPa and more) and its frost and wear resistance sharply increase. Concrete polymer is practically waterproof. Styrene and methyl methacrylate polymerized in polystyrene and polymethyl methacrylate in concrete are mainly used to obtain a concrete polymer.

Thermosetting polymeric substances used as binders in construction are usually viscous liquids, which are not called correctly “resins”. In chemical technology, these products of partial polymerization (with a molecular weight in the range of 100 ... 1000), having a linear molecular structure and capable of further enlargement, are called oligomers. Thermosetting oligomeric binders include, for example, epoxy and polyester resins, drying oils, rubbers mixed with vulcanizing agents, etc.

Depending on the state of aggregation (physical), polymer binders can be:

• viscous liquids: oligomeric (epoxy, polyester, etc.) and monomeric (furfural, furfural acetone, etc.) binders;
• aqueous dispersions of polymers (latexes of synthetic rubbers, polyvinyl acetate and polyacrylate dispersions, etc.);
• powders and block products (granules, sheets, films): polyethylene, polystyrene, polyvinyl chloride, polymethyl methacrylate.

The same polymer, depending on the synthesis method, may have a different physical state. So, polystyrene can be in the form of granules, fine-grained powder, a solution in organic solvents and an aqueous dispersion.

To obtain polymer-cement materials, aqueous dispersions of polymers and water-soluble powdery polymer products are most convenient; for polymer concretes and polymer solutions — liquid-viscous oligomers and monomers; less often, aqueous dispersions of polymers are used for this purpose.

Compared to cement concretes, polymer and polymer cement concretes have greater tensile strength, less brittleness , and better deformability . They have higher water resistance, frost resistance , abrasion resistance, resistance to aggressive liquids and gases.

It is known that filling resins with dispersed fillers of more than 5% sharply reduces their strength properties (depending on the degree of filling). Plastocements are never used as composites for parts under load. Also, the price of plastic cement is significantly higher than conventional inorganic cement mixtures, which determines their narrow specialization.

Polymer concrete is also called "artificial stone" because of its strength and external similarity. Polymer concrete is used for sealing tanks, putties, primers, in the manufacture of bulk floors, for smoothing irregularities and defects in metal products, in the manufacture of furniture and as a building material.

High-dynamic machine tool manufacturers use polymer - concrete as the material for the frames, frames, machine tool portals, etc., it has a logarithmic damping value 10 times higher than cast iron. The uniqueness of the damping and rigidity of this material, its low mass (3-5 times compared with steel), make it advanced in the mechanical engineering market. ^[one]

Mortar and concrete made from Portland cement have been known worldwide as building materials for 160 or more years. However, cement mortar and concrete have some disadvantages, such as delayed hardening, low bending strength, large cracking upon drying, and low chemical resistance. To overcome these shortcomings tried to use polymers. One of these areas is the creation of polymer-modified mortar (polymer cement) or concrete. For this, a modification of ordinary cement mortar or concrete is applied with such polymer additives as latexes, powder emulsions, water-soluble polymers, liquid resins and monomers. The polymer modified mortar and concrete have a monolithic structure in which the organic polymer matrix and the cement gel matrix are homogenized. The properties of the mortar and polymer-modified concrete are determined by such a joint matrix. In systems modified with latex, powder emulsions and water-soluble polymers, drainage of water from these systems during cement hydration leads to the formation of a film or membrane. In systems modified with liquid resins and monomers, the addition of water stimulates the hydration of cement and the polymerization of liquid resins or monomers.

The first patent for the use of polymer cement was issued to Cresson in 1923. It relates to a coating material with natural rubber latexes, while the patented cement was used as the basis. The first patent of such a system modified with polymer latex was published by Lefebvre in 1924. Apparently, he is the first researcher who intended to create solutions and concrete modified with latex using natural rubber latexes by selecting the composition by mixing. This patent is important from a historical point of view. A similar idea was patented by Kirpatrick in 1925. In the 20s and 30s, mortar and concrete modified with polymers were developed using natural rubber latexes.

On the other hand, in 1932 a patent was issued to Bond, who first proposed the use of synthetic rubber latexes for polymer modified systems. In 1933, a patent was issued to Rodwell, who was the first to use latexes of synthetic resins, including polyvinyl acetate, for modified systems. In other words, the 1930s marked a turning point in the use of latexes as cement modifiers (from natural rubber latexes to synthetic rubber or resin latexes).

In the 1940s, several patents were published for polymer modified systems with synthetic latexes such as polychloroprene rubber latexes (neoprene) and polyacrylic ether latexes. For practical use, solutions and concrete modified with polyvinyl acetate have been developed. Since the late 1940s, polymer-modified mortars and concretes began to be used for coating ship decks, bridge decks, bridges, floors, and also as anti-corrosion coatings. In the UK, Griffiths and Stevens conducted studies on the use of natural rubber modified systems. At the same time, the use of synthetic rubbers in polymer modified systems was of great interest. In 1953, Geist et al. Published a detailed study of solutions modified with polyvinyl acetate and made a number of valuable suggestions regarding the development of polymer-modified systems.

In the 60s, styrene butadiene rubber, polyacrylic ether and polyvinylidenechloridvin or chlorine were used to modify mortars and concrete. Since that time, practical work on the research and development of modified mortars and concrete has advanced significantly in various countries, in particular in the USA, USSR, Germany, Japan and the UK. Accordingly, a significant number of publications have appeared, including patents, books, articles and reports. The main and most important of these studies are listed below.

1. Patents: E.I. du Pont de Nemour & Co. .; Master Mechanics Co. .; American Cyanamide Co. .; Dow Kemi-Kal Co. .; Onoda Cement Co. ..
2. Books: Yu. S. Cherkinsky; Namiki and Ohama; V. I. Solomatova; Satal Kina and others; Paturoeva; Wilson and Crips; ACI Committee 548.
3. Articles: Wagner; Petri dish; Mori, Cavanaugh, Ohama and others; Ohama.
4. Papers presented at major congresses and conferences on concrete polymers.

Recently, polymer latexes such as butadiene styrene rubber, polyacrylic ester, polyvinyl-denchloride polyvinyl chloride, polyethylene vinyl acetate and polyvinyl acetate latexes have become widely used around the world. JIS (Japanese Industrial Standards) was published in Japan, incorporating several standards for the quality and testing methods of cement modifiers and latex type mortars:

• JIS A 1171 Production of a sample for testing a polymer-modified solution in a laboratory
• JIS A 1172 Strength Test of a Polymer Modified Solution
• JIS A 1173 Polymer Modified Solution Cone Sediment Test
• JIS A 1174 Test for determining the specific gravity and air content (gravimetric) of a pure polymer-modified solution

In 1971, Dyke, Steinberg, and others investigated a number of other systems. Donnelly and Duff patented systems based on epoxy resins, respectively in 1965 and 1973. In 1959, a system with a urethane prepolymer was patented.

Methyl cellulose, which is very popular as a water-soluble polymer, is used as a cement modifier, and since the beginning of the 60s it has also been widely used in the production of modified adhesive solutions for ceramic tiles. In this case, the polymer content is 1% or less of the cement used. Shi-bazaki has shown that polymers such as hydroxyethyl cellulose and polyvinyl alcohol are effective as water-soluble polymers for modifying solutions. In 1974, Ramessy and Razl published a general overview of polymer modified systems.

This chapter is devoted to the production technology, properties and application of various modified mortars and concrete. ^[2]

Some types of polymer concrete products:

• Countertops made of "artificial stone". In this case, plastocement is filled with marble or granite chips, which gives it decorative properties.
• Sinks for chemical laboratories. Plastocements have high chemical resistance, which allows them to be used in this way.
• Two-component putties and primers.
• Self-leveling floors.
• Products for equipment, decoration of tombstones and other memorials.
• Artistic scenery (Landscape, interior, architecture).
• Laf
• Fountains, waterfalls, water parks.

• bibliotekar.ru (bibliotekar.ru). POLYMERIC BINDERS
• bibliotekar.ru (bibliotekar.ru). SOLUTIONS AND CONCRETE MODIFIED BY POLYMERS