RU2399598C2 - Mixture of making light concrete and light concrete - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to construction and construction industry and can be used in production of hydraulic mineral composite binding materials, variety of dry construction mixtures, for making light concrete and heat insulation articles for making building enclosures. The mixture for making light concrete contains the following in pts. wt: 40-50 composite hydraulic binder - pearlite-limestone-gypsum mixture of the following composition in pts. wt : expanded pearlite with specific surface area S_spec=5500-7500 cm²/g, particle size of 10-20 mcm 70-80, quick lime S_spec=3500-4500 cm²/g, particle size of 30-60 mcm, hemihydrate gypsum S_spec=3500-4500 cm²/g, particle size of 30-60 mcm 2-6, and 40-60 aggregate-crushed expanded pealite. Light concrete made from the said mixture also contains the following in pts. wt: Hardening accelerator - sulphate or chloride of an alkali or alkali-earth metal 0.33 and water with aqueous/solid phase ratio equal to 0.9-1.1.

EFFECT: higher efficiency of environmentally clean articles for constructing heat-saving building enclosures, including for high seismic activity conditions.

2 cl, 6 tbl, 1 dwg

Description

The claimed invention relates to the construction and construction industry and can be used in the production of composite mineral binders, hydraulic mineral composite binders, varieties of dry building mixtures (CCC) of lower grades for finishing work, the manufacture of mixtures of especially lightweight concrete (OLB) and products of thermal insulation and structural purpose for the construction of building envelopes of buildings and structures, including for conditions of increased seismicity.

The technical result of the implementation of the claimed invention consists in obtaining an improved mineral composite binder composition (binder composition), a hydraulic siliceous-calcium oxide-gypsum hemi-binder (hydraulic binder) and ARS based on them, as well as in the use of the corresponding useful physicochemical and other properties, aggregate characteristics , particle size distribution, phase state of components, conditions and forms of their maximum manifestation, for example, in the form of dry products: a binder composition for preparing a mixture of concrete, which is absent on the market of hydraulic binder grades 300, 200, 150, 100 for the preparation of mortars, or in the form of a highly effective ARS and technological, economical, environmentally friendly products made from it for the construction of heat-saving building envelopes.

In terms of the claimed invention:

- “astringent composition” - composition of dry components “astringent + aggregate”;

- “a mixture of particularly lightweight concrete” - “cementitious compound + water component” in the state prior to curing, referred to in practice as “ready-mixed concrete”;

- “particularly lightweight concrete” - the product of the curing of “a mixture of particularly lightweight concrete”.

The term “binder composition” also corresponds to the formula “hydraulic binder + reactive mineral structure-forming aggregate”, which, when reacted with water and a solution of active substances, can form a strong and particularly light solid, and “hydraulic binder” is an independent fine component of the specified binder used , for example, as an adhesive composition for building joints of wall fencing blocks made of OLB with increased geometric accuracy their size or performing finishing work.

The objective of the claimed technical solution when achieving a technical result is the use of factors that guarantee the receipt of a binder with fundamentally new useful properties, namely:

- the use of physico-chemical properties of the components and parameters, including the technological properties of the specified binder, providing the desired useful result;

- a fundamentally new look at lime and active mineral additives (AMD), which, thanks to the ability to hydrate hardening, make it possible to turn them into quick-hardening and high-strength binder;

- the ability to combine in various ratios the components of the binder with an active filler to obtain a composition that provides the required properties of the final product;

- modern grinding technology, which allows to process raw materials with a high degree of dispersion and modify, according to the will of the technologist, the grinding and activation scheme;

- the use of the claimed technical result to obtain a marketable multifunctional product.

The essence of the claimed technical solution consists in the use of the astringent properties of lime in combination with AMD, for example, products of thermal and mechanical processing of vitrified volcanic rocks, or siliceous industrial waste, and regulatory additives to obtain the desired product, characterized by a set of new useful properties.

Such compounds have long been known. In the history of ancient Rome, for example, materials made from a mixture of lime and clay shards of volcanic origin (terracotta) were practiced.

The claimed technical solution is aimed at improving and expanding the potential capabilities of a known binder and compositions based on it using modern technical means, scientific and technological achievements and experience of the applicant. The technical solution can contribute to the development of the raw material base of the construction industry primarily on the basis of explored and ready for industrial development deposits of perlite raw materials, for example, Khakayuk, Zayukovsky, the Republic of Kabardino-Balkaria.

The basis of the proposed technical solution is well-known scientific, technical and technological information from the theory and practice of the formation of an artificial stone-like body, a carrier of the strength of cement concrete. In addition, the construction science and technology know the properties of mineral raw materials that are in a different physicochemical and aggregate state, with the optimal selection of which such qualities of composite building materials can be ensured as their astringent properties, specified strength, density, frost resistance, water resistance and other regulatory characteristics. Basic information used in the claimed technical solution:

Mineral binders are known - powdered building materials, capable of forming plastic dough when mixed with water, which hardens with time under appropriate conditions and turns into a stone-like body with a characteristic set of properties (magnesia binders and acid-resistant cement are the exception). Binders (hereinafter referred to as binders) are divided into air binders and hydraulic binders. In the framework of the claimed technical solution, the first ones are considered gypsum binders, the second one includes hydraulic lime, as well as other materials of natural and technogenic origin with multifunctional properties, for example, granular metallurgical slag in the form of crushed stone or grinding. Multifunctionality consists in the fact that they can serve as a filler, an active mineral additive, a plasticizer, a filler, and in some cases (for example, fly ash of TPPs) and / or in combination with other components, as an independent binder.

AMD is known - inorganic natural and artificial materials with hydraulic properties. The main quality that determines their suitability in the production of binders as an active mineral component is the phase-chemical composition, namely:

- the presence of glass phase (vitrification),

- the presence of fine free lime (CaO),

- the content of particles of finely divided anhydrite (anhydrous gypsum),

- content of other active components.

When mixed in finely divided form with hydrated lime and semi-aquatic gypsum, AMD forms a dough when mixed with water, which, after preliminary hardening in air, can continue to harden under water. Such materials include diatomites, tripoli, flasks, ashes, tuffs, tracks, vitrofirs, etc., used in the production of cement. High hydraulic activity is characterized by fly ash of thermal power plants, granulated slags, vermiculites containing up to 95% of the vitreous phase. The ash is dominated by a glassy fraction in the form of spherical particles up to 100 microns in size. The high internal chemical energy of the glass provides it with increased solubility, resulting in the formation of metastable supersaturated solutions and their crystallization. Crystal hydrates, in turn, cause hardening of AMD. The process is particularly intensified in the presence of lime and gypsum. Another important property of AMD is determined by their specific surface.

So, for example, at S _beats = 5000 ÷ 7000 cm ² / g, their water demand sharply decreases, which has a beneficial effect on the more complete use of water in the process of CaO hydration, a significant decrease in the normal density of the knitting dough and, consequently, an improvement in the strength and other qualities of the mixtures.

In the framework of the claimed technical solution, a special AMD group is considered as an example: obsidian, perlite - a natural glassy rock with the ability to swell when heated quickly. Its varieties are classified depending on the degree of water saturation and swelling: obsidian, perlite proper, pechstein, porous perlite.

A number of other AMDs also have multifunctionality: waste from the production of rough ceramics (cement); waste from the production and crushing of substandard expanded clay, sinter; finely ground cullet, etc., which together with the ashes of thermal power plants and slags are considered as a reserve group of components that can be used in the claimed technical solution.

The properties, nature of manifestation and mechanism of action of cement binders are known. The name cement clinker means the product of sintering of the charge (limestone, clay, marl, nepheline sludge, blast furnace or electrothermophosphoric slag, ash TPP, etc.), which provides the formation of calcium silicates 70-80%, aluminate and aluminoferrite phase 20-30%.

It is also known that one of the minerals of cement clinker alite C ₃ S releases lime, Ca (OH) ₂ , into the solution during hydrolysis. Due to the low solubility of Ca (OH) ₂ (1.3 g / L), the solution is rapidly saturated with lime, which slows down the further hydration of alite. Dissolved amorphous silica SiO _{2 of} an active mineral additive binds Ca (OH) ₂ to calcium hydrosilicates, thereby creating conditions for the hydrolysis of new portions of alite. The intergranular space is filled with a gel of hydrosilicates. Saturation with Ca (OH) ₂ crystals and Ca ⁺⁺ ions leads to the formation of hydrates, which fill the intergranular space, and plastic dough begins to lose mobility (cement setting). Semi-aquatic gypsum CaSO ₄ · 1 / 2Н ₂ О is also involved in the hydrosilicate hardening of concrete, which is introduced as an additive and plays a double role. In the process of molding and pre-exposure of products, gypsum serves as a moderator of lime hydration, and in the process of heat treatment, as a component of the binder, it participates in the formation of calcium hydrosulfoaluminates in the low-sulfate form in the hardening structure. Strong and fragile contacts arise between hydrate crystals, leading to intergranular space germination by neoplasm crystals (gel → sol). A skeleton is formed that blocks further shrinkage. Simultaneously with the filling, the frame is also compacted with a growing volume of crystalline hydrates and gel, because the chemical reaction lasts a long time.

Pre-milled cements have a surface of 2000 ÷ 3000 cm ² / g and contain grains> 30 microns in size up to 30-40%, which hydrate only superficially and practically do not participate in the formation of cement stone strength. Grains with a grain size of 60 μm or more remain inert in the composition of mortar or concrete for years, i.e. are essentially ballast.

Table 1. Cement grain hydration rate: Minerals Depth of hydration, mk 3 days 7 days 28 days 6 months C ₃ s 3,5 4.7 7.9 fifteen C ₂ S 0.6 0.9 1,0 2.7 C ₃ A 10.7 10.7 11,2 14.5 C ₄ AF 7.7 8 8.4 13,2

The phenomenon of contraction in the process of cement hardening is a change in volume during hydration. For conventional systems with H / C = 0.7, the solid phase in the initial period is -30%, the liquid phase is 70%, at the end of hydration the ratio changes vice versa: the solid phase - 70%, the liquid phase - 30%.

For systems with cement consumption, for example 250 kg / m ³ , contraction is 20 l / m ³ and can be either positive or negative.

Table 2. Heat of hydration: Minerals C ₃ A C ₃ S C ₄ AF C ₂ S

Heat of hydration

The average heat dissipation per day is - 20-40 cal / g, after 3 days - 45-70 cal / g.

From a generalization of the above and other data, it follows that the nature and mechanism of action of cement (clinker) binders are based on the ability of calcium hydroxide Ca (OH) ₂ and dissolved amorphous silica SiO ₂ AMD to enter into chemical interaction with the formation of insoluble hydrosilicates at the final stage, hydroaluminates and hydroaluminoferrites of calcium, the so-called cement stone, carrier strength and other properties of composite materials such as concrete. In this case, the main role in the manifestation of the building properties of concrete is given to systems on alite, aluminate cements and depending on their degree of dispersion.

Known for high efficiency of application in the technology of dense and non-autoclaved cellular concrete of finely ground multicomponent binders (TMB) obtained by joint grinding of PC and AMD to S _beats = 5000 ± 500 cm ² / g. As AMD it is possible to use volcanic glasses, cullet, fly ash, etc. The amount of AMD varies from 0 to 70%. Stable maximum strength values are established for the compositions depending on the degree of vitrification and chemical composition of the additives. The best performance is given by the use of volcanic glasses containing 70-80% vitrified particles and 70-75% silica. The strength of such compositions is due to the activation of cement grains in the process of joint grinding. Fine grinding and amorphization of the mineral additive not only compensates the PC dilution by 50-70%, but also provides a higher (50-70%) strength compared to the initial PC. In the presence of AMD, hydration of PC grains proceeds faster and more fully, which is the reason for obtaining concrete with increased strength with a significant reduction in PC consumption (up to a specific consumption rate of 110-120 kg / m ³ ).

Also known are the properties, the nature of the manifestation and the mechanism of action of composite mineral calc-silica binders based on lime and ground quartz sand. The formation of neoplasms in this case, as a special type, is possible only in conditions of autoclave hardening and is not considered in the claimed technical solution.

Patent studies have identified similar objects.

Known hydraulic lime-belite, or so-called hydraulic lime-containing binder with AMD and additives of Ca, Mg, Na chlorides, which has undergone pilot industrial production in accordance with TU 21-31-34-80 by firing artificially prepared and ground carbonate-siliceous mixtures in a rotary kiln.

The disadvantages of the binder should include: later than the alitic period of curing and high energy costs for its production. In addition, this type of binder is a type of clinker cement and is not included in the same group as the claimed technical solution.

Known building mixture for the device of the road base, SU 796300 A, Е01С 7/10, 01/15/1981, which contains fly ash of TPP (siliceous component), limestone-shell rock (carbonate component) and cement (inorganic binder) in a given ratio.

The mixture is characterized by low activity of the carbonate component, heterogeneity of the structure, and insufficient operational reliability.

Known mineral mixture for road construction, RU 2 2549 436 C1 Е01С 7/10, 08/27/2005. Bull. Number 24. The mixture has been improved in relation to the previous mixture in terms of the composition of the components, their ratio, the coarseness modulus of the carbonate-siliceous components, and variants of the inorganic binder.

The known technical solution has the same disadvantages as the previous one. In addition, the solution is focused on achieving a particle size modulus of carbonate-siliceous components of less than 1 without specifying the particle size and the technique of bringing the materials to a specific aggregate state. The siliceous component is declared in the form of ash and slag waste from the hydroelectric power station without indicating drying and pre-milling in order to activate, which suggests the presence of spherical fragments with a particle size of 100 microns or more in their ash and slag parts. Hence an additional conclusion about the insufficiently high activity of the components, which is confirmed by the inclusion of Portland cement in the composition of the mixture, as well as the limited scope of its application.

A known method of producing a binder, application RU 94031141/33 A1 SB 35/14, publ. 05/27/1996. The initial oxide mineral material is partially subjected to sequential fine grinding with a particle size of 0.05-30 microns and mixing with the remaining dry grinding powder, which reduces the energy consumption of binder production and improves its quality.

The well-known technical solution has a local organizational and technological character, it is known in the technique, but it is of little use in the industrial production of binders, it can be used in an outsourcing system in the goods market, for example, in the processing of cement to higher grades.

The disadvantages of the method are two-stage fine grinding of materials and, as a consequence, an increase in the share of costs, including energy.

A known method of obtaining autoclave-free especially lightweight concrete on cement binder, RU 2132835, C1 С04В 38/10, С04В 40/00, publ. 1999.07.10.

The method is based on the use of polystyrene foam (PPS) granules as structural elements forming a skeleton, packing of granules in a pasty composition consisting of cement, TPP ash, lime-boiling water, water into which technical foam is introduced to reduce its density. The expected technical result is to reduce production costs, reduce the combustibility of the material and the absence of precipitation of the concrete mass after pouring.

Significant disadvantages of the known technical solution are: the complexity of the composition, the availability of technological steps for the manufacture and operation of PPS granules, technical foam, the use of a high-speed concrete mixer for joining cement-polystyrene dough with foam, ash and lime, which inevitably leads to a “collapse” of the foam mass , the destruction of the granules of the faculty, the increase in density and the deterioration of the physical and mechanical characteristics of ARS.

In the claimed invention, the disadvantages of the known technical solutions are eliminated using the beneficial physicochemical properties of the active binders and the optimal technological conditions for their manifestation, namely:

1.1. A mineral composite binder composition is proposed, which ensures the formation during hydration, wt.%: Calcium silicates 70-80, aluminate and aluminoferrite phases 20-30, including:

- hydraulic silica-calcium oxide-gypsum hemihydrate binder,

- active structural aggregate, in the following ratio, parts by weight:

hydraulic binder - 40-50 active structural aggregate - 40-60;

and forming in combination with the water component at W / T = 0.9-1.1 and additives (if necessary) a mixture of especially lightweight concrete.

The hydraulic binder contains silica, calcium oxide, regulating components, the activity of which is ensured by their material, chemical, aggregate, particle size distribution and the conditions of the highest solubility and reactivity of the particles, including:

expanded perlite - S _beats = 5500-7500 cm ² / g, particle size 10 ÷ 20 microns,

quicklime - S _beats = 3500-4500 cm ² / g, particle size 30 ÷ 60 microns,

gypsum gypsum - S _beats = 3500-4500 cm ² / g, particle size 30-60 microns,

when the ratio of the components, respectively, wt.%: (70 ÷ 80) :( 18 ÷ 26) :( 2 ÷ 6) and a density of 400 ÷ 450 kg / m ³ .

Aggregate is expanded perlite crushed stone fr. 10-20, bulk density 250-300 kg / m ³ .

The role of the dispersed silica component of the hydraulic binder is that dissolved amorphous silica of the active mineral additive binds Ca (OH) ₂ to calcium hydrosilicates, thereby creating the conditions for the formation of an artificial stone-like body in the hardening concrete structure.

The value of the calcium oxide component in the hydraulic binder is the full use of hydration hardening (we mean hydration of all active CaO introduced into the mixture) inside the molded product while maintaining optimal humidity and temperature in it, excluding both quenching of CaO beyond the exposure time and overheating and overdrying of the hardening structure of concrete by the heat of its hydration. It is known that products made under the condition of complete hydration hardening of lime are distinguished by increased strength, frost resistance, and durability. This type of hardening is realized at an early stage of product manufacturing, in the period of post-mold exposure.

The presence of semi-aquatic gypsum in the composition of the hydraulic binder is necessary to slow down the hydration of lime (eliminating the effect of false setting), and during the heat treatment it participates in the formation of calcium hydrosulfoaluminates in the low-sulfate form or the formation of an artificial stone-like body in the solidified concrete structure.

The siliceous component of the binder and the active structural aggregate are characterized by a single substance.

As an active structural aggregate, the binder composition contains expanded perlite crushed stone of the same origin, chemical composition and technological processing as the calcium oxide component of the hydraulic binder. The filler is distinguished by high porosity, vitrification and silica content. The indicated properties are manifested, in addition to structure formation, in the form of absorption of excess water in the first stage of hardening, the so-called self-vacuum effect (absorbent function), and also as a reagent in the chemical interaction of the filler with dissolved calcium oxide hydrate (adsorbent function). The indicated properties of the filler provide enhanced technological and physical qualities of the ARS and products based on it.

1.2. Proposed for the mixture of Example ARS-insulating products for construction purposes average density of 600-650 kg / m ³ in air-dry condition in a system of "hydraulic binder + filler + water" in a ratio in parts by weight .: (42.2: 48.8: 42.2); it is possible to take a hardening accelerator as an additive, a water-soluble salt — sulfate or chloride of an alkali and alkaline earth metal, parts by weight - 0.33, and the specified concrete is obtained by separate technology in devices with a spiral working body, while the aggregate is preliminarily saturated by spraying an aqueous fraction of a calcium hydroxide solution with a pH value of 10 ÷ 13 and mixed with a binder solution prepared by adding the remaining volume by spraying water.

2.1. Requirements for hydraulic binder components.

- Perlite expanded dispersed:

Genesis type - water-containing (Н ₂ О 1.0 ÷ 5.5%) glasses and vitreous rocks of volcanic origin, subject to heat treatment.

Chemical composition,%: SiO ₂ 69.39 ÷ 73.82 Al ₂ O ₃ 12.82 ÷ 15.85 Fe ₂ O ₃ + FeO 1.12 ÷ 1.58 Cao 1,0 ÷ 1,17 R ₂ O 6.34 ÷ 7.9

It is produced by crushing expanded pearlite crushed stone with a bulk density of 250-350, as well as using and processing pearlite rock swelling waste products: powder, dust collection products, low-swollen fractions, followed by their transfer to a finely dispersed state with S _beats. = 5500 ÷ 7500 cm ² / g.

Table 3. glass phase content, wt.% 70 ÷ 80 degree of swelling, not less 5-7 fineness of grinding, microns 10 ÷ 20

- quicklime dispersed:

Table 4. Components, Metric Quicklime Grade not lower Content% Active CaO + MgO, not less than 3 70 Active MgO, no more 5 Blanking rate, min 5 ÷ 8 Exit after blanking, k 3 ÷ 3,5 Bulk density, kg / m ³ 800-850

Lumpy calcium quick-acting quicklime lime bowel is crushed, finely ground to values S _beats = 3500 ÷ 4500 cm ² / g, corresponding to passing through sieve No. 008 of at least 90% of the mass of the sifted sample.

The supplier of ground quicklime high calcium lime (CaO + MgO activity = 90%) is Kamysh-Burunsky iron ore plant, Kerch, the Republic of Ukraine.

- dispersed gypsum gypsum:

gypsum semi-normal normal hardening gypsum (β - CaSO ₄ · 1/2 H ₂ O hemihydrate) grades G-2 ÷ G-7. The finished product in the form of a finely ground powder with S _beats = 3500 ÷ 4500 cm ² / g, with a residue on sieve No. 02 - not more than 2% by weight.

Table 5. Setting time, min: the beginning is not earlier 6 end no later thirty Bulk density, kg / m ³ 950-1000

In the Krasnodar Territory, the supplier of marketable gypsum (β - hemihydrate CaSO ₄ · 1/2 Н ₂ О) is the joint venture OJSC Kuban Gypsum - Knauf, in the village of Psebay, in the Mostovsky district.

2.2. Placeholder Requirements.

Expanded perlite rubble fr. 10-20 mm, GOST 10832-91

Table 6. Degree of swelling, not less 5-7 glass phase content, wt.% 70-80 Bulk density, kg / m ³ 250-350 Chemical composition as for the one-nature perlite component of clause 2.1 Grading averaged without subdivision Coefficient of thermal conductivity 0,043-0,058

Suppliers of perlite raw materials are Greece, the Republic of Ukraine, the Republic of Armenia, and a number of enterprises in Russia.

In figure 1. The preparation of the binder composition is presented. The scheme provides for the possibility of obtaining a building product of various functional purposes, including:

- individual dry components for independent use;

- a hydraulic binder in the form of a CCC of an expanded nomenclature of grades in strength, for example, M 300, 200, 150, 100;

- dry binder composition for the preparation of, for example, OLB of various grades in strength.

The option of separate preparation of a hydraulic binder in the form of CCC and aggregate has the advantage that the CCC is a ready-to-use building composition, which in the development of the claimed invention is used for laying and monolinging joints and pairing elements of enclosing structures made from OLB based on the declared binder composition. As an example, the problem is solved as follows.

In fine grinding machines (items 1, 2, 3), which are mainly aggregates of shock-abrasive, vibration-abrasive, shock-vortex, jet or other action, the components of the hydraulic binder are brought to a specific surface: lime and gypsum - S _beats = 3500 ÷ 4500 cm ² / g, heat treatment products of perlite - S _beats = 5500 ÷ 7500 cm ² / g. At the same time, among other stated requirements, the perlite grinding fineness should not exceed 10-20 microns, lime should be quenching, and gypsum should be normally hardening.

Expanded perlite after heat treatment passes the classification (item 4), the purpose of which is to separate the product in accordance with the trademarks. Dust fractions and perlite powder, as production waste, and low-swollen fractions with a density of "250 ÷ 350", as having the lowest cost, are sent for additional grinding (item 2). The prepared components enter the intermediate bins (pos. 5, 6, 7). Perlite fr. 10 ÷ 20 from the classifier (item 4) without separation into subfractions enters the hopper (item 8).

From intermediate bunkers (items 5, 6, 7) components

- perlite expanded dispersed,

- quicklime dispersed lime,

- dispersed gypsum gypsum

in the stated ratio, wt.% (70 ÷ 80) :( 18 ÷ 26) :( 2 ÷ 6) through weighing batchers (item 9) enter a high-speed homogenizer-activator (item 11) of continuous or cyclic action for mixing up to homogeneous state and mechanochemical activation of the mixture. Processing time depends on the type of unit adopted, but not less than 3-5 minutes. The duration of the activation effect (increasing the brand in strength by 10-30% due to giving the mixture an additional energy potential) is not more than 7 days, which is a specially considered technological parameter.

The prepared mixture from pos. 11 is sent to the storage bin of the finished product (pos. 12), from where it is selected through the weight batcher (pos. 9) for the preparation of ARS, dry binders (pos. 13) or for the packaging of CCC .

Pearlite crushed stone from the intermediate supply hopper (pos. 8) through the volumetric dosing batcher (pos. 10) goes to the preparation of ARS, dry binder compositions (pos. 13) or for other purposes.

The technical task of preparing OLB based on the declared cementitious composition is carried out on the example of the production of heat-insulating and structural products with an average density of 600-650 kg / m ³ in an air-dry state for building envelopes as follows.

Use a mineral composite binder in the form of a system of "hydraulic binder + structural aggregate + water component + additives" in the ratio, parts by weight: (42.2: 48.8: 42.2: 0.33). Water consumption is taken by selection from the ratio, W / T = 0.9-1.1. If necessary, a hardening accelerator, a water-soluble salt — sulfate or chloride of an alkali and alkaline earth metal can be taken as an additive.

The technological process for preparing ARS is carried out in a separate way using a concrete mixer and forced action mortar mixer with an adjustable rotation speed of a spiral working body. In this case, the working volume of the concrete mixer is taken with a loading factor of at least 1.6, and the closed type mortar mixer is 2.0. The workflow is carried out in the following process sequence.

Pearlite crushed stone is loaded into a concrete mixer, with constant stirring, 1 / 4–1 / 3 of the volume of the aqueous fraction of the calcium hydroxide solution is introduced by spraying with a pH value of 10–13, after which it is finally mixed for 5–10 sec.

The hydraulic binder is loaded into the mortar mixer and, with constant stirring, is introduced by spraying 1/2 of the remaining volume of water. The mixture was finally stirred for 2 minutes and the solution was incubated for 3-5 minutes, after which it was re-mixed for 2 minutes.

The prepared solution is loaded into a concrete mixer and the rest of the water is introduced by spraying with continuous stirring. Mixing time of at least 2.0 minutes until a homogeneous mixture is obtained. At this stage, a hardening accelerator previously dissolved in it is introduced into the mixing water.

The total time for preparing the mixture of OLB according to separate technology should not be less than 8 ÷ 10 and more than 10 ÷ 12 minutes. The prepared mixture of OLB is sent to the post forming products intended for the construction of heat-saving enclosing structures of buildings and structures.

Tasks solved by implementing the above technological scheme:

- inclusion of particularly lightweight concrete binder and hydraulic binder as components of a mixture of ready-to-use reactive components that form an artificial stone-like body called OLB at the final stage of hardening, which is an alternative to the high-cost firing process for producing clinker binders, also oriented to the use of AMD ;

- the use of the beneficial properties of the binder composition, hydraulic binder and their components, including:

* ground perlite:

- low resistance to fine grinding;

- high solubility and reactivity of amorphous silica particles with a size of 10-20 μm, which, when combined with calcium hydroxide, provides the formation of hydrosilicates, hydroaluminates and hydroaluminoferrites of calcium, structural elements of the stony body, which, in turn, is due to the chemical composition of AMD, including:

SiO ₂ - 69.39 ÷ 73.82

Al ₂ O ₃ - 12.82 ÷ 15.8

Fe ₂ O + FeO - 1.12 ÷ 1.58 and others;

* lime:

- hydration heat used to heat the mixture;

- ductility, providing reduced energy consumption;

* semi-aquatic gypsum:

- overcoming the effect of false setting (slowing down the hydration period);

- ensuring dimensional stability and accelerating the terms of formwork removal;

* structural aggregate:

- high reactivity provided by the chemical composition of material of a single origin with ground perlite;

- ensuring structural stability and non-shrinkage of the ARS;

- high water absorption (self-evacuation effect), ensuring uniformity and completeness of hydration of the components, improving the technological and physical properties of the ARS, as well as increasing the formwork resistance when forming products from the ARS;

- low density of the material, which ensures the declared density of the ARS;

* hydraulic binder:

- low density of the material, which ensures the declared density of the ARS;

- independent use of the material as a CCC, including for filling joints and joints during the installation of products from OLB for heat-saving building envelopes;

- the practical possibility of manufacturing binders lowered grades 300, 200, 150, 100, absent in the market of building materials;

- an analogue of the cheapened alite aluminate clinker binder.

* astringent composition:

- a finished product for use, for example, with the use of concrete mixers and other construction equipment;

* OLB:

- the possibility of manufacturing highly effective single-layer products for construction, for example, heat-saving building envelopes.

Claims (2)

1. A mixture for the manufacture of lightweight concrete, comprising a composite hydraulic binder-perlite-lime-gypsum mixture and an expanded perlite aggregate, characterized in that it contains expanded perlite macadam and the specified astringent composition as a specified aggregate, parts by weight:
specific perlite expanded surface - S _beats = 5500 ÷ 7500 cm ² / g, particle size 10-20 microns 70-80 quicklime S _beats = 3500 ÷ 4500 cm ² / g, particle size 30-60 microns 18-26 gypsum gypsum S _beats = 3500 ÷ 4500 cm ² / g, particle size 30-60 microns 2-6
in the following ratio of components, parts by weight:
specified binder 40-50 specified placeholder 40-60 2. Lightweight concrete obtained from a mixture comprising a composite hydraulic binder-perlite-lime-gypsum mixture, expanded perlite aggregate and water, characterized in that the mixture contains expanded perlite crushed stone, the specified astringent composition, weight parts :
specific perlite expanded surface - S _beats = 5500 ÷ 7500 cm ² / g, particle size 10-20 microns 70-80 quicklime S _beats = 3500 ÷ 4500 cm ² / g, particle size 30-60 microns 18-26 gypsum gypsum S _beats = 3500-4500 cm ² / g, particle size 30-60 microns 2-6
and additionally a hardening accelerator — sulfate or chloride of an alkali or alkaline earth metal in the following ratio of components, parts by weight:
specified binder 40-50 specified placeholder 50-60 specified accelerator 0.33 water up to W / T 0.9-1.1

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