Method of preparing construction mixture
SUBSTANCE: invention relates to preparation of construction mixtures, primarily fine-grained concrete mixtures and mortars which harden in natural conditions or under steam curing. Disclosed is a two-step method of preparing a construction mixture using mineral filler, a plasticising additive, sand and binder. The first step comprises mixing the binder - portland cement M500 D20, mineral filler - silicon carbonate gaize, 55-65% sand and 60-70% hardening water to obtain a homogeneous mixture, and the second step comprises adding to the obtained mixture the remaining sand, plasticising additive - superplasticiser SP-1 and the remaining water, and finally mixing to obtain a homogeneous mixture of given workability.
EFFECT: reducing consumption of expensive materials without reducing strength of the obtained material.
The invention relates to a process of making mixes, mostly fine-grained concrete mixes and mortars, hardening under natural conditions or under heat and moisture treatment.
The main disadvantage of the traditional method of making fine-grained mixtures is the increased consumption of cement.
Widely known method of preparing fine-grained mixtures with mineral fillers, such as fly ash, limestone powder, sand introduced into the mixture to conserve cement (Y. Bazhenov M concrete Technology. - M.: Higher school, 2003, S. 287).
The disadvantage of this method of making fine-grained mixtures is their high water associated with high dispersion of mineral fillers and contributing to increased consumption of cement.
To reduce water demand fine-grained mixtures of dispersed fillers used plasticizing agents.
A known method of preparation of the concrete mixture (patent RU 1760981 A3, SW 40/00, 07.09.1992,, bull. No. 33), according to which the process of making concrete mixture includes mixing in high-speed turbulent mixer of cement, filler, water, and complex chemical additives containing superplasticizer MT-AR and nitrate of sodium or calcium, mixing obtained is mixed with fractionated quartz sand in a low-speed mixer until smooth. In this first mix in high-speed turbulent mixing of the water with filler is a highly active silica fume with a specific surface area (20-40)·103cm2/g, then give three fractions of quartz sand with a module size of 2.2-2.5; 1.0 to 1.5 and 0.05-0.5 and mix with water and a filler, after which the mixture is injected comprehensive Supplement with electrolyte and conduct final mixing in a low-speed mixer.
The method provides high strength properties of fine-grained concrete, but complex in execution, which limits its wide application.
Closest to the claimed technical essence is a way of preparing the mixture (see patent RU No. 2373171 C2, SW 40/00 published 20.11.2009,).
This method includes two stages of preparing a fine-grained mixture of: at the first stage receives a mixture consisting of mineral fillers, plasticizing agents, sand and water, and the second stage to the resulting mixture add astringent and do the final mixing.
The disadvantage of this method is the increased consumption of cement and plasticizing agents.
The objective of the proposed invention is to reduce the consumption of expensive materials.
The invention consists in that in the method of preparation of the straw is tion mixture, includes two stages, with the use of mineral fillers, plasticizing agents, sand and binder, on the first stage of the mixed binder is Portland cement M500 D20, mineral filler - carbonate-siliceous flask, 55-65% sand and 60-70% of the mixing water to obtain a homogeneous mixture, and the second stage to the resulting mixture add the remaining sand, plasticizing additive - superplasticizer SP-1 and the rest of the water,and finally mix them until a homogeneous mixture of a given workability.
As a mineral filler used crushed carbonate-siliceous flask.
As plasticizing agents used superplasticizer POLYPLAST SP-1.
The technical result will be a reduction of 15% of cement consumption and 25% plasticizing agents without compromising the strength of the material obtained.
The result is achieved that the method of preparation of mixes, including two stages of mixing of the components in the first stage mix binder (Portland cement M500 D20 (GOST 10178-85*) Circassian cement plant, mineral filler (carbonate-siliceous flask), 55-65% sand and 60-70% of the mixing water, and the second stage to the resulting mixture add the remaining sand, superplasticizer POLYPLAST SP-1 istalol water, then finally stirred until a homogeneous mixture of a given workability.
Mortar according to the invention is prepared as follows. In accordance with the formulation is dosed by weight and loaded into the mixer Portland cement, mineral filler (carbonate-siliceous flask), 55-65% sand and 60-70% of the mixing water. These components are mixed until a homogeneous mixture. In the second stage metered and added to the mixer the remaining sand, superplasticizer and the rest of the water, followed by final mixing of all components until a homogeneous mixture of a given workability.
Introduction in a mixture of superplasticizer POLYPLAST SP-1 with a part of the mixing water in the second stage allows without deterioration of the workability of the mixture to reduce dosage of the additive and to reduce the consumption of binder (Portland cement) without reducing the strength of the material obtained.
The invention is illustrated by the following example.
For implementing the method using the following materials:
1. Portland cement M500 D20 (GOST 10178-85*) Circassian cement plant.
2. River sand for construction works (GOST 8736-93) liventsovskaya substation field with a module size of 1.32.
3. Superplasticizer - POLYPLAST SP-1 (TU 5870005-58042865-2005).
4. Mineral filler is crushed to a full pass through sieve No. 008 carbonate-siliceous flask Maslovsky Deposit. This flask has a light yellow color. The rock is dense, with signs of stratification, microporous. With a gentle kick breaks the plane of deposition. The average density of 1.35-1.55 g/cm3true of 2.45-2.55 g/cm3. When wet strength properties of rocks greatly reduced. The fracture pluralistic. Reacts with 10% hydrochloric acid. In the water do not soak. The bulk of the rock is composed of opals colloidal-fine-grained structure. Terrigenous melkorazdroblennuyu material submitted by the acute-angled beans and slabokislogo quartz size of 0.01-0.05 mm in an amount of about 10%. The carbonate component is represented mainly organic and pelitomorphic calcite. As a small impurities are grains of pyrite (0.04 to 0.07 mm), also observed Slovenie units and lamellar crystals with a pearl sheen similar to group minerals zeolites.
For the preparation of mortars method proposed in the mixer is metered in accordance with the recipe and download 55-65% sand, Portland cement, mineral filler - carbonate-siliceous flask and 60-70% of the mixing water, then stirred until homogeneous, MESI. In the mixture entering the remainder of the sand, superplasticizer POLYPLAST SP-1 and the rest of the water, followed by final mixing until a homogeneous mixture of a given workability.
To obtain comparative data also prepare mortar for the prototype method: in the first stage receive a mixture of fillers, plasticizing agents, sand and water, and the second stage to the resulting mixture add cement and finally mix them.
Cooked easily workable mixtures (repliva cone on a standard shaker table 110 mm) made samples-balocchi size 40×40×160 mm curing 28 days in normal conditions with heat and moisture treatment (TWT) after a two-hour pre-exposure mode 2+6+2 at a temperature of isothermal aging at about 85°C. the Cured samples are subjected to strength tests of the conventional methods.
The mixes prepared with the compared methods, and the results are given in the table.
Analyzing the table presents the test results, we can conclude that the boundary limits of the flow of sand in the first stage of the mixing process are 55-65% of the total consumption in the mixture, and limits the flow of water mixing in the first stage - in the range of 6070% of the total consumption for cooking mixture (compositions No. 3, 4, 5). Going beyond the specified limits as in most (composition No. 2) and lower side (part No. 5) reduces the strength characteristics of the material obtained.
The test results shown in the table, indicate that the proposed method provides the possibility of reducing the consumption of Portland cement by 15% and superplasticizer POLYPLAST SP-1 by 25% without a decrease in strength as compared with the known method.
Method of preparation of mixes, including two stages, with the use of mineral fillers, plasticizing agents, sand and a binder, characterized in that the first stage mix binder is Portland cement M500 D20, mineral filler - carbonate-siliceous flask, 55-65% sand and 60-70% of the mixing water to obtain a homogeneous mixture, and the second stage to the resulting mixture add the remaining sand, plasticizing additive - superplasticizer SP-1 and the rest of the water and finally mix them until a homogeneous mixture of a given workability.
SUBSTANCE: method comprises electrochemical treatment of mains water in three-chamber electrolysis unit with ion-selective membranes by alternating asymmetric current. Meanwhile the electrolysis unit anode is made from shungite. During the electrochemical treatment of water in the anode and in the anode chamber the ultrasonic oscillations are exited, the frequency of which exceeds the cavitation threshold frequency within a range from 20 kHz up to 100 kHz, and the intensity of the named ultrasonics is in the field of stable cavitation from 1.5 W/cm2 up to 2,5 W/cm2. Water treatment is stopped at achieving of density of particles of hydrated fullerene 10-3-10-4%.
EFFECT: improvement of frost resistance of concrete mix, increase of cement hydratation level and strength of cement stone in early periods of curing.
SUBSTANCE: method of activation of concrete mixing water by its modifying with carbon fulleroid nano-particles with its consecutive ultrasonic processing comprises the placement of shungite into a vessel with water, the mass of shungite amount no less than 1% of water mass, and ultrasonic oscillations are excited in water with the frequency in the range from 20 kHz to 100 kHz, from 1.5 W/cm2 up to 2.5 W / cm2, and 10-3-10-5% and water and shungite are subjected to named ultrasonic oscillations within 5-10 minutes until achieving of density of fullerene, emanated from shungite into activated water, then the activated water is passed through the filter and is used as a concrete mixing liquid, and the shungite bottoms are left in the vessel, which is filled with the next portion of water and the procedure of concrete mixing liquid activation is repeated.
EFFECT: improvement of physic-mechanical characteristics of concrete, decrease of water consumption or cement consumption without affecting the concrete strength.
1 ex, 1 tbl
SUBSTANCE: invention relates to methods of activating hardening water of cement-based composites. The method of activating hardening water of cement-based composites includes treating tap water in a plasmatron with low-temperature nonequilibrium plasma in a period of time ranging from 1·10-2 s to 5·10-2 s.
EFFECT: high efficiency and degree of activation of water in order to speed up hydration and strength gain in the early stage of concrete hardening.
FIELD: process engineering.
SUBSTANCE: invention relates to production of inorganic heat-resistant rustproof composites in production of plastics, antirust and lubing materials for construction, electrical engineering, etc. Proposed method comprises mixing of inorganic natural material, liquid glass, dolomite powder and additive, mix forming and thermal treatment. Used is liquid sodium glass, its density making 1.28-1.42 kg/m3, as inorganic natural material, that is, montmorillonite modified by organic substance. Said additive represents a hydrated cellulose fibre shaped to 5.0-20.0 mm long staple impregnated with 30%-aqueous solution of iron, zinc, copper and aluminium sulphates taken in the ratio of 1.0:0.5:0.5:1.0 in flushing bath for 70-80 minutes. Then, said fibre is squeezed to moisture content of 60-65% and dried at 120-140°C to remove 95-98% of residual moisture. Components are mixed by mechanical activation for 8-10 minutes, mix being formed and annealed at temperature increase from 140°C to 1300°C for 30-40 minutes. Note here that montmorillonite is modified by the product of interaction between caprolactam or its oligomers with butyl stearate. Mix contains components in the following ratio in wt %: modified montmorillonite - 20-60, liquid glass - 20-30, dolomite - 10-35, cellulose fibre - 10-15. This invention is developed in dependent clauses.
EFFECT: higher fire resistance, lower heat conductivity factor, antirust properties.
3 cl, 3 ex, 1 tbl
SUBSTANCE: method of producing a composite material consists in the fact that a cavity of a casing construction is filled with very rigid concrete, produced by mechanic activation of a cement composition. The cement composition includes 30% of cement of grade PC-500DO-N, 7.5% of microsilica, 1.8% of an expanding additive EA-H, 20% of river washed sand with the fineness modulus Mf 5, 40% of basalt gravel with a size up to 30 mm, 0.7% of an ethylene glycol-based superplasticiser. Mechanic activation is carried out in blade mixers of a forced type with a frequency of blade rotation not less than 60 rpm for not less than 20 min. Highly-strong concrete is poured into the cavity of the casing construction, and is simultaneously consolidated by vibration processing. Then, to exclude steam discharge from it, the cavity of pouring is closed. Autoclave solidification of concrete, consisting in the fact that the entire construction is evenly heated to a temperature of nearly 200°C to solidify it, is realised. The construction is exposed to the said temperature for 12 hours. After that, it is gradually cooled to room temperature and kept at the said temperature until complete hydration of cement takes place. And, finally, mechanical processing of basic surfaces is realised.
EFFECT: simplification of technology of the material production.
SUBSTANCE: invention relates to a powdered composition of a construction material, preferably dry mortar for industrial production, and especially to tile adhesives, joint filler, putty, waterproofing slurry, repair mortar, levelling mortar, reinforcing adhesives, adhesives for heat-insulation composite systems, mineral plaster, fine putty and seamless floor systems, which contains an ester of A) 2-ethylhexanoic acid and B) an alcohol with a boiling point of at least 160°C. Further, the invention discloses the production of said products, as well as use of esters according to the invention in powdered compositions of construction materials for reducing dust formation. The invention is developed in subclaims.
EFFECT: reducing dust formation, reducing the degree of release of organic compounds during storage and use of construction materials.
14 cl, 1 tbl
SUBSTANCE: method of preparing the concrete mixture, consisting in mixing of cement, aggregates, water, and aqueous suspension of complex modifier of the following composition, wt %: silica fume 40-70; chemical additives 2-10; water - the rest, which is dried prior to mixing in the air stream to obtain powder consisting of granules, according to the invention, the aqueous suspension of complex modifier before mixing is subject to drying under the influence of continuous electromagnetic field of ultra-high frequency of 400-1000 MHz from microwave oscillators and heated air stream of microwave oscillator cooling to obtain powder with grains of size up to 500 microns and moisture of 9-12%; then the dried powdered complex modifier and cement are subjected to dispersion and disaggregation via exposure to pulsed electromagnetic field of ultra-high frequency of 1000-3000 MHz lasting 1-1.5 seconds, till the obtention of ultrafine powder of complex modifier with size of 60-100 nm, moisture of 1-8% and cement of size 0.1-5 microns, after that they are mixed, ground together and activated, form the disaggregated and activated mixture of cement and complex modifier, which is mixed with filler and water, concrete mixture is obtained; this mixture is subjected to the influence of powerful pulsed electromagnetic field of ultra-high frequency of 400-1000 MHz with duration of 1100÷nanoseconds.
EFFECT: increase of strength of concrete mixture.
SUBSTANCE: method of tempering moulding mixtures includes mixing dry components and preparing tempering water by passing said water between electrodes while applying an alternating or constant potential difference with rate or strength of current which provides charge saturation density of water that has passed between the electrodes of not less than 825 kC/m3, saturating the tempering water during electrolysis with Fe3+ ions of the electrode until saturation of the water with iron ions reaches 30-35%. Ascorbic solution is first added to said water in amount of 0.1 g/l.
EFFECT: increasing mobility of moulding mixtures without increasing the total amount of tempering water, thereby considerably improving operational characteristics of the finished articles and saving binding materials.
SUBSTANCE: method to prepare an ash-concrete mix, including mixing of ash, portland cement, sand, crushed stone and water, where ash of hydraulic removal is enriched, then the produced ash jointly with portland cement, gypsum and plasticising additive LTSM-2 is ground in a ball mill to the specific surface of 4500-5000 cm2/g, the produced mix is introduced, 2/3 part of the estimated hardening water quantity, sand and quick lime into a dispersing hydrator and exposed to activation for 1-2 min at speed of blades rotation 100-200 rpm, in the concrete mixer they mix crushed limestone and the remaining part of the hardening water for 1-2 min, then the activated mixture from the dispersing hydrator is charged into a concrete mixer, and by final mixing they produce a concrete mix of homogeneous consistence.
EFFECT: cheapening of a mix, faster process of setting and hardening of an ash concrete mix, increased strength and stability of ash concrete properties, expanded area of recycling of anthropogenic origin wastes.
1 ex, 1 tbl
SUBSTANCE: method to manufacture construction materials based on a magnesia binder includes activation of a magnesia binder, modified filler, plasticiser, pigment by the method of mechanical-chemical modification in solid state under condition of joint impact of pressure and shift deformations. Aqueous solution of magnesium chloride (aqueous solution of bischofite) and filler are added to the activated mix. The magnesia binder is caustic magnesite with addition of electric furnace magnesite. The modified filler in the raw mix is a complex silica-alumina filler including SiO2, Al2O3, CaO, MgO, Fe2O3, FeO, SO3 in different combinations and ratios, modified in solid state with oxide or salt of transition metal by the method of mechanical-chemical modification under conditions of joint impact of pressure and shift deformations, and also the raw mix may additionally contain mica and fibres (natural, polymer, metal, glass). The mix is hardened at the temperature of 10-90°C for 1÷14 h, and macromolecular structures of finished goods are exposed to diffusion process of introduction of oil/water emulsion in presence of a surfactant.
EFFECT: improved physical-mechanical characteristics of construction products with lighter weight of structural construction elements, improvement of decorative properties of finished goods.
FIELD: ceramic binder and ceramic materials made from the same.
SUBSTANCE: ceramic binder is obtained by thermal treatment of raw materials containing (mass %) clay (e.g., clay waste) 20-45; limestone (e.g., limestone waste) 5-30; and ash (e.g., ash from thermoelectric plant) 25-75, at 900-11500C. Method for production of ceramic materials using the claimed binder includes mixing of raw materials, forming, and thermal treatment at 174-2100C under pressure of 0.8-1.6 MN/m2 in saturated water steam.
EFFECT: low-cost ceramic materials with reduced volume weight and high mechanical strength.
2 cl, 3 ex, 3 tbl
FIELD: manufacture of building materials.
SUBSTANCE: quick-hardening bound cement mortar including, vol parts: cement 6-9, water 2-3, aqueous epoxide resin dispersion 1, and hardener 1, said cement being of quick-hardening type and said dispersion additionally containing polyurethane rubber. Quick-hardening cement can be alumina-based cement. In a method of preparing quick-hardening bound cement mortar including mixing cement with aqueous epoxide resin dispersion and hardener on a surface immediately before underwater application, one volume part of water is diluted with one volume part of hardener and stirred, after which one volume part of aqueous dispersion of epoxide resin and polyurethane rubber are added, resulting mixture is agitated and then, depending on particular application, 1 or 2 vol volumes of water are added and, after agitation, resulting composition is used to temper quick-hardening cement, and stirred in low-speed mixer until soft plasticine-type plastic homogenous mass is obtained, after which mortar is held up to 5 min and agitated once more. Escort method of repairing concrete and reinforced concrete underwater structures comprises conveying quick-hardening cement mortar into underwater repair operation zone and manually laying thus prepared mortar onto prepared surface with defective spots. Conveyance of mortar can be accomplished by means of containers or buckets, or yet by means of worm mortar pumps. Invention enables preparation of repair material characterized by dimensional stability, short setting time and fast hardness development, non-diffuseness in aqueous media, waterproofness, frost resistance, crack resistance, resistance to corrosive media (salt and alkali solutions, petroleum products), high adhesion to cement, concrete, and metallic surfaces, and not leading to corrosion of hardware.
EFFECT: improved performance characteristics of cement mortar.
FIELD: no-fines concrete production useful in drainage systems and curb construction building.
SUBSTANCE: claimed method includes mixture preparation containing of Portland cement, water and target additive in wing blender; blending of said mixture with dense coarse aggregate and subsequent laying of obtained concrete mixture. Said aggregate is charged into blender-capsulator, then mixture of Portland cement, water and target additives is fed, and cotreatment is carried out for 1-3 min. Claimed concrete mixture contains (mass %): Portland cement 5-15, said aggregate 82-88, target additive 0-1.0, and balance: water.
EFFECT: simplified technology of no-fines concrete; concrete of improved quality.
3 ex, 1 tbl
FIELD: manufacture of building materials.
SUBSTANCE: method consists in preliminarily affecting only tempering water directly in supply tank of concrete-mixing unit by means of high-voltage electric discharges emerging in interelectrode spaces of electrode system followed by adding chemical additives before mixing tempering water with binder and fillers, all operations being accompanied with active agitation of with mechanical agitator driven from electric motor.
EFFECT: considerably shortened total mixing time, improved quality of mix because of more evenly distributed activated water molecules and chemical additives, and reduced consumption of power on activation of water.
FIELD: manufacture of building materials.
SUBSTANCE: method consists in preliminarily affecting only tempering water directly in supply tank of concrete-mixing unit by means of high-voltage electric discharges emerging in interelectrode spaces of electrode system followed by adding chemical additives before mixing tempering water with binder and fillers, all operations being accompanied with active agitation by means of air bubbles bubbling through water, e.g. from gas collector with nozzles supplied with air from compressor.
EFFECT: considerably shortened mixing time, improved quality of mix, and reduced consumption of power on activation of water.
FIELD: manufacture of large-size cement-fiber plates used for facing buildings and making roof covering.
SUBSTANCE: method comprises steps of mixing cement, sand, micro-filler, reinforcing synthetic fibers, plasticizing additive and water; shaping and drying; using wollastonite as micro-filler. At first in turbulence mixer dry loose components such as cement, sand, wollastonite are mixed. Then reinforcing synthetic fibers are added and composition is mixed. Plasticizing additive and water are added at next relation of ingredients, mass.%: cement, 68 -81; sand, 9.5 -13.5; wollastonite, 9.25 - 12.50; synthetic reinforcing fibers, 0.16 -0.55; plasticizing additive, 0.38 -0.43; water, the balance. Articles are dried in air in natural condition. Polypropylene fibers are used as synthetic reinforcing fibers. Mixing of cement, sand and wollastonite in turbulence type mixer is realized during time period no more than 30 s at using water heated up to temperature no lower than 40°C. Size particle of wollastonite is in range 100 -170 micrometers.
EFFECT: enhanced quality of plates.
5 cl, 1 ex, 1 tbl
FIELD: building materials, particularly for forming heat insulated and structural heat insulated articles, for forming cast-in-place heat- and noise-insulation floor panel filling of cellular concrete.
SUBSTANCE: method involves preparing cellular concrete mix; pouring the mix into mold or formwork; applying additive on cellular concrete mix surface; treating the surface layer with device having rotary disc provided with needles variable in length and heat treating the concrete mix. Cellular concrete mix is prepared with the use of composite gas-foam pore former in tubular mixing means during cellular concrete mix heating up to 45-65°C. Additive is applied on convex concrete surface just after cellular concrete mix heaving. Fibrous agent and/or water-soluble component taken in amount of 2-8% of the cellular concrete mix weight is used as the additive. The surface layer has 2 cm thickness. Disc comprises needles gradually decreasing in length from disc center to periphery thereof. Fibrous agent is asbestos, wool, rock wool and polymeric fiber waste. Water-soluble polymer is polyvinyl acetate, polyvinylchloride, polysterene or polyacryl.
EFFECT: improved service characteristics of the ready article, reduced time of production due to optimal combination of above mix preparing and mechanical surface treatment operations.
3 cl, 1 tbl
SUBSTANCE: method comprises supplying water and cement or water, cement, and sand to the cavitation mixer, mixing the ingredients in the presence of an activator during 5-15 min, introducing the dry blowing mixture to the solution produced, and further mixing during 15-60 s. The dry blowing mixture is composed of, in mass %, 70 of cement, 12 of pigment aluminum powder, 12 of water-soluble aluminum powder, 2 of antifreeze plasticizer, and 4 of water.
EFFECT: reduced cost and enhanced efficiency.
FIELD: manufacture of building materials.
SUBSTANCE: invention relates to manufacture of polystyrene-concrete parts for use in construction as wall and heat-insulating material. Manufacture of heat-insulation products comprises preparation of molding mix from Portland cement (60.0-65.6%), water, and granulated foamed polystyrene with loose density 10-20 kg/m3 (2.2-4.4%), molding, and heat treatment of products. Invention resides in that molding mix additionally includes microsilica (6.6-12.0%) and superplasticizer S-3 (0.6-0.66), starting mix Portland cement/microsilica/foamed polystyrene is first stirred for 2-3 min, then water containing superplasticizer is added, resulting mix is stirred for further 3-5 min and loaded into molding boxes. Molding involves vibrocompaction and pressing followed by unloading of products from molding boxes and heat treatment: 2 h at 15-25°C, 8 h at 40-60°C, and 1 h at 15-30°C.
EFFECT: reduced consumption of cement, improved placeability and moldability of mix, increased strength of products, and increased productivity.
FIELD: construction industry.
SUBSTANCE: the invention is pertaining to the field of construction industry, in particular, to the production of glass containers, in particular, to the methods of production of an items out of a concrete mix, which may be used in municipal landscape improvement of overall decor accomplishment of the modern town-planning in the form of the decorative fencing, lawns, roads, gardens in front of buildings, flower beds, at paving of territories and in other cases of the landscape design. The technical result is production of the items with a high strength, life duration, frost-resistance, increased chemical durability, watertightness, cement saving due to substitution of its optimum amount for microsilica. The method of production of an item our of a concrete mixture provides for preparation of concrete mixture by stirring of cement, sand, an pigment of organic or inorganic generation, C-3 superplasticizer and water with the subsequent laying of the concrete mixture in the form with an relief insert, placing the form on a molding table, compaction by vibration. At that they use sand with the grade modulus of Mgr-2.4-3.2. The concrete mixture is added with microsilica, and components take in the following ratio (in mass %): cement - 19.5-22.0, the indicated sand - 69.0-69.2, the indicated pigment - 0.7-1.0, C-3 superplasticizer - 0.1-0.21, microsilica - 1.0 3.4, water - the rest. At that first they stir the indicated sand and the indicated pigment for 45-50 seconds, then this mixture is added with the cement and microsilica and again the mixture is stirred during 60-70 seconds, then it is added with water with C-3 superplasticizer and the mixture is stirred for 120- 180 seconds, and compaction by vibration is carried out for 1-2 seconds with the subsequent simultaneous compaction by vibrations and pressure of 10-15 atm during 6-15 seconds. After that the newly formed item is placed in the chamber of the hygrothermal treatment with the temperature 0f 17-23°C and the relative humidity of 90-100 % and keep there for 15-20 hours. At that the form is made out of a steel and the figure inserts are made out of polyurethane.
EFFECT: the invention ensures production of the items with a high strength, life duration, frost-resistance, increased chemical durability, watertightness, cement saving due to substitution of its optimum amount for microsilica.
2 cl, 3 tbl, 1 ex