RU2738150C1 - High-strength powder-activated concrete - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to construction materials and can be used in production of structures and articles from concrete on cement binder for buildings and structures of civil, industrial and special purposes. High-strength powder-activated concrete contains composite portland based on portland cement clinker in amount of 70 %, finely ground granulated slag 26 %, dihydrate gypsum 3 % and sodium fluoride 1 %, filler - fine powder of quartz, limestone and so forth, with specific surface area of 600 m²/kg, filler - quartz sand of fraction of 0.63–5.0 mm, Melflux 2651 F hyperplasticiser and tempering water. As tempering water contains activated water, which has passed electrochemical and electromagnetic activation with introduction of oxide-hydroxide compounds of aluminium and iron in amount of 2…10 g/m³.

EFFECT: technical result consists in creation of high-strength powder-activated concrete with low consumption of cement clinker and high biological stability due to rationally selected composition, which includes composite binder and activated brewing water.

1 cl, 3 tbl

Description

The invention relates to building materials and can be used in the production of structures and products from concrete on a cement binder for buildings and structures for civil, industrial and special purposes.

There is a known method of activating water for mixing concrete mixtures, which includes passing carbon dioxide through it at a temperature of 0 ° C to 50 ° C and an overpressure of 0.15 to 6 MPa to the degree of dissolution of carbon dioxide 5-45 ml per 1 liter of water (RU 2388729, IPC C04B 40/00, C02F 1/66, publ. 10.05.2010).

The known method is aimed at obtaining activated water with abnormal wetting ability, which allows either to reduce its content, or to reduce the amount of cement in the concrete mixture, without violating the water-cement ratio regulated by the technical conditions. The method does not reflect the degree of influence of the activation of mixing water on reducing the consumption of cement in concrete mixtures. Biological stability has not been established. The compositions described in the description of the invention do not apply to high-strength concretes.

A known method of preparing concrete mixtures, including the mechanochemical activation of mixing water with the addition of nitrate-nitrite-alkaline water for 1 min, mechanochemical activation of cement containing 60-70% of pre-activated mixing water, in a mixer for 1.5-2 minutes and subsequent mixing in mixer with sand, gravel and the rest of the activated mixing water for 2 minutes. Washed coarse sand is used as a fine aggregate. Mechanical activation of mixing water and the additive used is carried out in a mechanochemical activator at 1100 rpm (RU 2361848, IPC C04B 40/00, publ. 20.07.2009).

The known solution is based on the task of reducing the consumption of Portland cement and increasing the compressive and tensile strength of concrete, but the compositions do not belong to high-strength concretes and there are no indicators of biostability.

A known method of preparing concrete mixtures by mixing cement, mineral aggregates and mixing water, activated by a magnetic field or simultaneous, joint action of a magnetic field and electric current. In this case, the activation of the mixing water is performed by a magnetic field of 630 ÷ 640 kA / m with an activation time of 0.9 ÷ 0.11 s. And with an increase in the moisture content of the aggregates, the activation time is increased to 0.16 ÷ 0.18 s, or the magnetic field strength to 660 kA / m, or both the activation time and the magnetic field strength are increased, focusing on the maximum plasticization of the concrete mixture. In the case of activation by the combined effect of a magnetic field and an electric current, the current value is set at 0.18-0.2 A with an increase to 0.5 or 20-25 A with an increase to 250 A, depending on the design of the apparatus (RU 2508273, IPC C04B 40/00, C02F 1/48, publ. 27.02.2014).

This method, according to the description of the patent for the invention, allows you to increase the plasticity of mixtures, reduce energy consumption by lowering the temperature of thermal and moisture treatment and reduce the time of exothermic holding, but there is no data on the degree of influence of the activation of mixing water on reducing the consumption of cement in concrete mixtures and the strength characteristics of concrete ...

Known biocidal additive for concrete and mortar, containing as an active component a bioactive ester based on monosubstituted polyethylene glycol, while it contains a mixture of mono- and bis-esterified polyalkylene oxide and an inorganic derivative of sulfuric acid (RU 2527439, IPC C04B 24/02, C04B 103 / 67, publ. 08/27/2014).

The known method does not consider the issues of reducing the quantitative content of cement binder and the use of additives in the composition of high-strength concrete.

A known method of cement production, containing Portland cement clinker, tailings of sulfuric acid processing of boron-containing mineral raw materials and an alkalizing additive in the form of dry bulk material (RU 2371405, IPC С04В 7/52, С04В 22/00, C04B 103/60, publ. 27.10.2009 ).

The disadvantages of the known composition of the cement should be attributed to insufficiently high strength indicators and low biological resistance.

Known reaction-powder ultra-strong fiber concrete containing Portland cement PC 500 D0 (gray or white), superplasticizer based on polycarboxylate ether, silica fume with amorphous glassy silica content of at least 85-95%. In addition, it includes ground quartz sand (microquartz) or ground stone flour from dense rocks with a specific surface area (3-5) · 10 ³ cm ² / g, fine-grained quartz sand of a narrow granulometric composition of fraction 0.1-0.5 ÷ 0.16 -0.63 mm, as well as the fiber content of steel steel cord (diameter 0.1-0.22 mm, length 6-15 mm), basalt and carbon fibers, has a specific cement consumption per unit of concrete strength no more than 4.5 kg / MPa, and the specific fiber consumption per unit of increase in tensile strength in bending does not exceed 9.0 kg / MPa has a high density with a new recipe and with a new structural and topological structure, and concrete has a ductile (plastic) nature of destruction (RU 2012113330 , IPC S04V 28/00, publ. 10.10.2013)

The disadvantage of this technical solution is the lack of data on the indicators of the biological resistance of composites.

Known mixture for the manufacture of high-strength concrete, containing a complex additive, consisting of the following components: 20% solution of polycarboxylate polymer (CP-WRM) having a pH value of pH = 6 and a density of 1.029 g / cm ³ , a high molecular weight polymer compound with a molecular weight of more than 600 g / mol, density 0.98 g / cm ³ and pH = 6.5, a colloidal solution (sol) of silicic acid with a density of 1.014 g / cm ³ and pH = 3.5 (RU 2684264, IPC С04В 28/04, C04B 24/26, C04B 24/24, C04B 22/08, C04B 111/27, publ. 04.04.2019).

A mixture for the production of ultra-high-strength concrete with a low cement content is known from the prior art, containing Portland cement, the particles of which have a D50 of 2 to 11 μm; microsilica; mineral additive A1, the particles of which have a D50 of 15 to 150 microns. Mineral additive A1 is selected from slags, pozzolanic additives or siliceous additives such as quartz, mineral additives of siliceous limestone, limestone additives such as calcium carbonate, or mixtures thereof. The invention also relates to a mixture containing the specified hydraulic binder and sand, to a hydraulic composition containing the specified mixture and water. In addition, the invention relates to a shaped product for the construction industry containing the specified hydraulic binder or the specified mixture of hydraulic binder and sand (RU 2683295, IPC С04В 28/04, C04B 14/06, C04B 14/28, C04B 18/14, C04B 7 / 52, C04B 111/20, C04B 103/50, publ. 03/27/2019).

In the known method, high strength characteristics are achieved with a low cement content. The disadvantages include the laborious technology of obtaining a hydraulic binder and unexplored indicators of the biological resistance of composites.

Known high-strength fine-grained concrete based on a composite binder with the use of technogenic raw materials of quartzite sandstone, containing: Portland cement, an active additive, filler, filler, plasticizing additive and water. As an active additive, alumina cement and microsilica are used, as a filler - technogenic raw material quartzite sandstone, as a filler - quartz sand and screenings of crushing of quartzite sandstone, as a plasticizing additive - hyperplasticizer Melflux 2651 F and water (RU 2627811, MPK С04В published on August 11, 2017).

In the known solution, it is claimed to obtain high-strength fine-grained concrete with low consumption of Portland cement and low water absorption while maintaining its high strength and density. However, in this case, the indicators of the biological resistance of composites have not been studied.

The closest technical solution to the claimed invention is high-strength powder-activated concrete, which is obtained from a mixture containing a binder, quartz sand, a filler - finely ground quartz or limestone powder, a hyperplasticizer of the Melflux 2651 F brand and mixing water (Kalashnikov V.I. is a new generation of powder-activated concrete / V.I. Kalashnikov // Building materials. - 2012. - No. 10. - P. 70-71).

In the prototype in high-strength powder-activated concrete indicators of biological resistance have not been studied.

The technical result consists in the creation of high-strength powder-activated concrete with a reduced consumption of cement clinker and increased biological resistance due to a rationally selected composition, including a composite binder and activated mixing water.

The essence of the invention lies in the fact that high-strength powder-activated concrete from the mixture includes a binder, quartz sand, filler - finely ground quartz powder or limestone, hyperplasticizer of the Melflux 2651 F brand and mixing water. The binder contains, wt%: Portland cement clinker 70, finely ground granular slag 26, dihydrate gypsum - 3 and sodium fluoride - 1, the filler has a specific surface area of 600 m ² / kg, and quartz sand is used in fractions of 0.63-5.0 mm, activated water is used as mixing water, with the introduction of oxide-hydroxide compounds of aluminum and iron in an amount of 2 ... 10 g / m ³ , which has undergone electrochemical and electromagnetic activation at a current density in the electrochemical activation chamber of 5.65 ... 43.55 A / m ² and the strength of the electromagnetic field in the working gaps of the electromagnetic activation chamber 24 ... 135 kA / m, with the following ratio of the mixture components, wt%:

Specified astringent 23.13 Filler 23.3-23.39 Quartz sand 44.4 The specified hyperplasticizer 0.21 Mixing water rest

Table 1 shows the recommended modes and their parameters for the preparation of activated mixing water, in table. 2 - compositions of high-strength powder-activated concrete, in table. 3 - test results of powder-activated concrete.

For the manufacture of a composite binder, the following components can be used: Portland cement clinker of OJSC Mordovcement (3CaO · SiO ₂ 59-63%; 2CaO · SiO ₂ 18-18%; 3CaO · Al ₂ O ₃ 6-7.5%; 4CaO · Al ₂ O ₃ Fe ₂ O ₃ 11-12%), finely ground granular slag (GOST 3476-74), dihydrate gypsum of the second grade of the Poretskoye deposit (GOST 4013-82), sodium fluoride (GOST 4463-76). The method of manufacturing a composite binder is as follows. The components are dosed by weight. Then, in the grinding unit, joint grinding of cement clinker, finely ground granular slag, gypsum dihydrate and sodium fluoride is carried out to a specific surface of 300-400 m ² / kg. For the manufacture of concrete, finely ground quartz powder, limestone with a specific surface area of 600 m ² / kg can be used as a filler. They use quartz sand with a fraction of 0.63-5.0 mm in accordance with GOST 8736-2014, a hyperplasticizer of the Melflux 2651 F brand - a polycarboxylate ether of the third generation, manufactured by Degussa Constraction Polymers, SKW Trostberg, Germany.

As activated mixing water, electrochemically and electromagnetically activated water is used that meets the requirements of GOST 23732-2011. Activation of the mixing water of cement compositions is carried out using the installation for non-reagent treatment of water systems UPOVS2-5.0 "Maksmir" (RU 74911, IPC C02F 9/00, publ. 20.07.2008). This installation is a multi-circuit programming system containing three circulation circuits in itself, capable of providing an effect on irreversible flows and allowing to improve the technological process of mixture preparation without significant changes in the technological lines used. The mixing water is processed in the electrochemical and electromagnetic activation chambers of the installation by passing a stream of water in them, which is used later as mixing water, and the water is taken off at the outlet pipeline. In order to achieve high stable values of the degree of activation of mixing water and to obtain it with desired properties, depending on the physicochemical properties of the treated water and productivity, a flexible setup is used. The operating mode of the installation can be selected according to the parameters of the electric current density in the electrochemical activation chamber j in the range of 5.65 ... 43.55 A / m ² and the electromagnetic field strength in the working gaps of the electromagnetic activation chamber H in the range of 24 ... 135 kA / m. Recommended modes and their parameters are presented in table. one.

In the claimed invention, in the process of activation, oxide-hydroxide compounds of aluminum and iron are introduced into the mixing water in an amount of 2 ... 10 g / m ³ , which are formed during its passage between the electrodes of the electrolytic module, one of the electrodes of which is made of steel with an aluminum jacket on it, anode - dissolving with the formation of micellar hydroxide nanostructures with hydroxide ions in the cathode space, containing aluminum and iron ions in a bound form (Table 1). The content of ions in water is determined by an analytical method according to a well-known method (Guidelines for the chemical and technological analysis of water. M .: Stroyizdat, 1973. - 306 p.).

Manufactured three compositions, proposed as an example, high-strength powder-activated concrete, consisting of a composite binder, filler, fine aggregate, hyperplasticizer and activated mixing water (Table 2).

The method of manufacturing high-strength powder-activated concrete is as follows. The components are dosed by weight. Then, a measured amount of a composite binder is introduced into the concrete mixer, mixing water activated according to the established operating modes of the installation, Melflux 2651 F hyperplasticizer, quartz sand of 0.63-5.0 mm fraction, finely ground limestone powder with a specific surface area _. 600 m ² / kg and the resulting raw mixture is thoroughly mixed for 3 minutes.

For research, cubes with dimensions of 10 × 10 × 10 cm are formed from the prepared raw mixture by filling in standard forms 2FK-100 in accordance with GOST 10181-2014. The holding time in the molds is 24 hours. After stripping the molds, the samples are placed in a chamber with normal heat and humidity conditions of hardening for 28 days. Then samples of high-strength powder-activated concrete are tested for compressive strength in accordance with GOST 10180.

Tests for biostability are carried out according to GOST 9.049-91 by method 1 and 3. The following types of molds are used as test organisms: Aspergillius niger, A. flafus, A. terreus, Penicillium cuclopium, P. funiculosum, P. chrysogenum, Paecilomyces varioti, Chaetomium globosum, Trichoderma viride .

The results are shown in table. 3.

The research results confirm that the technical result of the claimed invention is achieved due to the additivity of the effects of using a set of measures to improve the strength characteristics of concrete and its biological resistance. The compositions proposed in the invention contain a rationally selected high-flow rheological matrix with a low yield point with a minimum water content and a low specific consumption of binder per unit of strength (High-performance powder-activated concretes for various functional purposes using superplasticizers / V.I. Kalashnikov, E.V. Gulyaeva, D. M. Valiev [and others] // Building materials. - 2011. - No. 11. - P. 44–47, Kalashnikov V. I. High-strength concretes of a new generation / V. I. Kalashnikov, I. V. Erofeeva // Materials of the XII International scientific and practical conference "Science without borders". - Sheffield, 2016. - P. 82–84, Kalashnikov V. I. High-strength concretes of a new generation with low specific consumption of cement per unit of strength / V. I. Kalashnikov, V. M. Volodin, I. V. Erofeeva // Proceedings of the International Scientific and Practical Conference "Vedeckypokroknaprelomutysyachalety." - Praha, 2015. - P. 65–67). In order to inherit the properties of biological resistance with high-strength concrete, a biocidal composite binder was used (RU 2491240, IPC C04B 7/52, publ. 27.08.2013). Electrochemically and electromagnetically activated mixing water is used to improve the biological stability and rheological properties, and consequently to reduce the content of cement clinker in the compositions of high-strength concretes. Electromagnetic treatment is reduced to the action of Lorentz forces on charged particles of moving water and the direct action of a magnetic field on the magnetic moment of molecules. The processing of natural water by a magnetic field leads to the interaction of the field with particles in the water and having ferromagnetic properties - oxide and hydroxide compounds formed during the electrochemical oxidation of iron. The action of the electromagnetic field contributes to the deformation and (or) destruction of hydrogen bonds between water molecules in aqua complexes (clusters) and, as a result, a change in the value of the surface tension of water. Electrochemical activation is based on the property of solutions subjected to electrochemical action to pass into a nonequilibrium state, exhibiting at the same time catalytic activity and increased reactivity in redox, acid-base and other reactions associated with them. Multivalent aluminum or iron hydroxides formed as a result of electrochemical dissolution of electrodes upon application of an electric field, multivalent and possessing a permanent dipole moment with an increased content of Н ⁺ and ОН ions ^- affect the formation of a crystal hydrate lattice of a solid. Due to the introduction of multivalent aluminum or iron ions into the solution, which have a permanent dipole moment, it becomes possible to promote the formation of crystallization centers. The resulting compounds, which are in the ultradispersed phase (1 ... 100 nm), determine the activity of the water used in the mixing of building solutions. The dispersed phase of oxides and hydroxides of aluminum and iron (anodic products) and calcium and magnesium hydroxides - due to the cathodic reduction of water molecules, form a temporarily stable system of crystallization centers during the transition of cement solutions to the phase of formation of gel structures, which contribute to the formation of a solid phase with a finer crystalline structure ...

Electrochemical and electromagnetic activation contributes to a change in the physicochemical composition of water: pH, content of various ions, wettability, etc. The presence in the liquid phase of the cement paste of various ions and molecules entering the system as a result of exposure to electromagnetic and electric fields on the mixing water in a certain way affects not only the structure of the mixing water, but also the processes of adsorption, dissolution and surface hydration of the resulting solid phase, on properties of the cement composite itself (Theoretical substantiation of concrete production based on electrochemically and electromagnetically activated mixing water / Yu.M. Bazhenov, V.T.Fomichev, V.T. Erofeev, S.V. Fedosov, A.A. Matvievsky, A. K. Osipov, D. V. Emelyanov, E. A. Mitina, P. V. Yudin // Internet Bulletin of VolgGASU. Ser .: Polythematic. 2012. Issue 2 (22). URL: http: // vestnik. vgasu.ru/attachments/1_BazhenovFomichev-2012_2(22).pdf, Fomichev V.T., Erofeev V.T., Emelyanov D.V., Matvievsky A.A., Mitina E.A.Role of products of anode processes during electromagnetic activation of water // Fundamental research. 2015. No. 2 (part 6). P. 1194–11 97, Nikolay Karpenko, Vladimir Erofeev, Denis Emelianov, Valery Fomichev, Alexey Bulgakov Technology, structure formation and properties of foam concrete on activated water of mixing / Proceedings of the Creative Construction Conference (2018) pp. 213-219. DOI 10.331 / CCC2018-028, Emelyanov DV Foam concrete based on electrochemically and electromagnetically activated mixing water: Author. dis. ... Cand. tech. sciences. - Penza, 2013 .-- 23 p.).

The declared high-strength powder-activated concrete based on a composite binder with the use of activated mixing water satisfies all the tasks. Received high-strength concrete with reduced consumption of cement clinker - 16.2 wt. % (prototype - 23.7 wt.%) and high compressive strength at the age of 28 days - 97.5-101.0 MPa (prototype - 81.8 MPa). Thus, in comparison with the known solution, the proposed one allows to obtain high-strength concrete with high biocidal properties.

Table 1

P / p No. Activation mode Current density j , A / m ² Electromagnetic field strength H , kA / m Content of hydroxide compounds of aluminum and iron in activated water, g / m ³ one E + M (1–1) 5.65 24 2 2 E + M (3–3) 22.58 75 6 3 E + M (6-6) 43.55 135 ten

table 2

Structure Component content, wt. % Composite binder Aggregate Filler Hyperplasticizer Mixing water Portland cement Alumina cement Microsilica Cement clinker Finely ground granular slag Two-water gypsum Sodium fluoride Screening of crushing of quartzite sandstone Quartz sand, fraction 0.63-1.25 mm Quartz sand, fraction 0.63-5.0 mm Finely ground quartzite sandstone Finely ground limestone Melflux 2651 F brand hyperplasticizer Non-activated water Activated water * Analog RU 2627811 21,7 2.0 2.0 - - - - 46.5 21.0 - 1.9 - 0.2 4.7 - one - - - 16.2 6.0 0.7 0.23 - - 44.4 - 23.30 0.21 - 8.96 2 - - - 16.2 6.0 0.7 0.23 - - 44.4 - 23.34 0.21 - 8.92 3 - - - 16.2 6.0 0.7 0.23 - - 44.4 - 23.39 0.21 - 8.87

* Water activated according to the modes indicated in the table. one

Table 3

Structure Compressive strength,
MPa The degree of development of molds, point The radius of the zone of inhibition of fungal growth Characteristic
material on
GOST 9.049.91 Method 1 Method 3 R, mm Analogue
RU 2627811 81.8 one 4 0 Not fungus resistant one 97.5 0 2 0 Mushroom-resistant 2 98.2 0 one 0 Fungicide 3 101.0 0 0 2 Fungicide

Claims (2)

High-strength powder-activated concrete from a mixture including binder, quartz sand, filler - finely ground quartz powder or limestone, hyperplasticizer of the Melflux 2651 F brand and mixing water, characterized in that the binder contains, wt%: Portland cement clinker 70, finely ground granulated slag 26, dihydrate gypsum 3 and sodium fluoride 1, the filler has a specific surface area of 600 m ² / kg, quartz sand is used in fractions of 0.63-5.0 mm, activated water is used as mixing water, with the introduction of oxide-hydroxide aluminum compounds and iron in an amount of 2 ... 10 g / m ³ , which has undergone electrochemical and electromagnetic activation at a current density in the electrochemical activation chamber of 5.65 ... 43.55 A / m ² and an electromagnetic field strength in the working gaps of the electromagnetic activation chamber of 24 ... 135 kA / m , with the following ratio of mixture components, wt%: Specified astringent 23.13 Filler 23.3-23.39 Quartz sand 44.4 The specified hyperplasticizer 0.21 Mixing water rest