RU2595284C1 - Fibrous nanocement and preparation method thereof - Google Patents

Fibrous nanocement and preparation method thereof Download PDF

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RU2595284C1
RU2595284C1 RU2015119759/03A RU2015119759A RU2595284C1 RU 2595284 C1 RU2595284 C1 RU 2595284C1 RU 2015119759/03 A RU2015119759/03 A RU 2015119759/03A RU 2015119759 A RU2015119759 A RU 2015119759A RU 2595284 C1 RU2595284 C1 RU 2595284C1
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portland cement
nanocement
clinker
cement
fiberglass
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RU2015119759/03A
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Russian (ru)
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Борис Эмануилович Юдович
Сергей Алексеевич Зубехин
Христофор Авдеевич Джантимиров
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Акционерное общество "Научно-исследовательский центр "Строительство", АО "НИЦ "Строительство"
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Abstract

FIELD: technological processes.
SUBSTANCE: fibrous nanocement, containing in wt%, alite portland cement clinker or alite portland cement, sulphate-calcium component (in terms of SO3), powdered modifier - organic water-reducing agent in combination with hardening accelerator, as well as mineral additive (10.4-93.4):(1-7):(0.6-2.5):(3-88), including as sulphate-calcium - natural gypsum stone, as organic water-reducing agent with hardening accelerator - polymethylene naphthalene sulphonate with sodium sulphate, at specific surface area of 400-700 m2/kg. As a component of mineral additive nanocement includes glass-fibre material of silicate or aluminosilicate composition and/or waste glass-fibre production (wt%) 3-28 in form of fragments of microfibres or microthreads with length of 0.05-10 mcm.
EFFECT: invention is intended to improve quality characteristics of process, specifically increasing compression strength and tensile bending strength, crack resistance and corrosion resistance of materials and articles based thereon.
10 cl, 3 tbl

Description

The invention relates to the field of building materials and products, namely, to fibrous nanocement and a method for its manufacture. It can be used in the construction materials industry, mainly in the cement industry, as well as in the construction industry.
According to the prestandard of the Russian Federation / Project 112 PNST "Nanocement all-construction" 2013. 30 p. /, nanocement is cement obtained on the basis of Portland cement clinker, gypsum or its derivatives, mineral additives, as well as an organic modifier based on polymethylene naphthalene sulfonates, by co-grinding these components until the modifier forms nanoshells on particles of Portland cement clinker in an altered state. Sulfonates (naphthalene-, melamine-, improved lignosulfonates) are mainly used as a modifier.
Nanocement is a new generation of cement compared to Portland cement, which is an internationally recognized fact under its former name - “binder of low water demand”. All previous names of new-generation cements obtained by nanocapsulating particles (including the concepts of grafting and gluing modifier nanoshells onto clinker particles when mechanochemical activation is combined with a clinker and modifier co-grinding) - VNV, TsNV, PTs PKZ, etc. - can be combined with one name - nanocements.
RUSNANO OJSC made a decision (2008 / Website of the Russian National Nanotechnology Network http://www.rusnanonet.ru/tesaums/ru/PAGEN/) that for this name it is sufficient to have elements of nanostructured sizes in cement (from 0.1 up to 100 nm, in this case, nanoshells). This approach is adopted below in the present description.
Nanocement / Ioudovitch V.E. is known from the prior art. et al. 1997, op.cit. / containing (in wt.%): Portland cement clinker, calcium sulfate component (in terms of SO 3 ) and a powdery modifier, including an organic water-lowering agent (93.5-96.9) :( 2.5-4): (0.6-2.5), respectively, with a mechanically activated state of the components, characterized by the completeness of chemisorption of the specified modifier on Portland cement clinker, and a specific surface of 400-600 m 2 / kg Mechanical activation is carried out during co-grinding, and both the selection of the initial mass, the ratio of the indicated clinker and modifier, and the specific surface within the specified range are designed to guarantee the completeness of the binding of the mentioned organic water-reducing agent in the finished product. The control of the completeness of binding is carried out under an optical microscope. A free modifier (spherical particles of brown or dark yellow color) is considered a rejection sign.
The advantages of this technical proposal are known from its description and are described in detail in the literature. So, in accordance with this technical solution, nanocement is produced in Podolsk, Moscow. region., the factory of the company "Consolit-Tsemdekor" (the former Podolsky Experimental Plant NIIITsement) according to TU 5744-002-00369-97 / http://www.cemdecor.ru/vnv.html/. The advantages of this cement, produced under the name “binder of low water demand” without mineral additives of class 72.5, known from the literature / Ioudovitch, V. E. et al., 1997, op. cit .; Yudovich B.E. et al., 1997, cit. cit. / briefly described by manufacturers as follows: concretes (mortars) made using VNV I 72.5 have significant advantages compared to analogues on Portland cement:
- provide a strength class from B60 to B100 (it is impossible to produce such high-strength concrete on the basis of other cements using conventional technology; it is necessary to use pressing, mixing under vacuum, etc., which are unrealistic to use in mass production);
- characterized by a high intensity of curing, which allows you to abandon heat-moisture treatment and get the strength necessary for stripping for 12-24 hours (cements are known that allow to obtain a similar effect, but their technology has not yet been mastered);
- characterized by reduced water demand by mortar and concrete mixtures by 25-30% with equal mobility (plasticizer additives can reduce water demand by only 10-15%);
- they have high sulfate resistance (the sulfate resistance coefficient is not lower than that of concrete based on sulfate-resistant cement, but clinker firing for the latter requires particularly highly qualified personnel, since the calcined material forms a highly porous layer, which is hardly heated by the fuel combustion torch and does not allow any operator errors defective ovens);
- have reduced heat during curing.
The disadvantage of this technical solution is that with the growth of strength (grade, grade), nanocement, like all other cements, acquires increased fragility. It is estimated by a number of indicators, the simplest of which is the ratio of the strength of nanocement in cement-sand mortar or concrete based on it under compression to the tensile strength in bending in prism samples (beams) on two-point supports. This indicator of fragility, proposed in 1960, used below in our description, is recognized as the most objective at present. Contrary to expectations, in spite of an increase of approximately 30% in tensile strength during bending, nanocement shows a similar fragility to Portland cement, since the compressive strength in its samples is also increased by about 30%. This disadvantage (brittleness of materials), characteristic of Portland cement, is more noticeable in nanocement, since the latter is used in openwork, thin-walled structures made of high-strength concrete, where crack opening even at shortest distances gives corrosive agents of the environment access to the surface of steel reinforcement.
The prior art analogue of the present invention is known - nanocement containing (in wt.%): Portland cement clinker, a calcium sulfate component (in terms of SO 3 ) and a powdery modifier, including an organic water-reducing agent and a hardening accelerator (86.1-95, 9) :( 2.5-4) :( 0.6-2.5) :( 1-7) respectively, obtained by joint grinding, or, which is the same, by co-grinding the components to a specific surface of 400-700 m 2 / kg In this case, both co-grinding and the indicated values of the specific surface are designed to guarantee the completeness of the binding in the finished product of the mentioned organic water-lowering agent with the clinker ingredient into an adhesive (chemisorption) compound [RF Patent No. 2029749, 1995]. Indeed, with a normal specific surface area of 400 m 2 / kg and reduced (in particular, at 370-395 m 2 / kg), as shown by control experiments at a number of cement plants and a grinding plant in the city of Sergiev-Posad at the Sergiev-Posad plant of concrete goods, the probability of the appearance of a free modifier in the samples in the product of normal dispersion is approximately 10%, but increases to 20-25% with the indicated decrease in dispersion. The growth of the specific surface to 600-700 m 2 / kg reduces the probability of the appearance of a free modifier to 2-3%, but does not completely exclude it. Nevertheless, the provision on the mechanically activated state of components, characterized by the completeness of chemisorption of the specified modifier on Portland cement clinker, can be considered relevant to this technical solution. Its advantages are the complex of positive effects of nanocement mentioned above. The disadvantage is that the completeness of binding of the water-reducing component to the clinker ingredient is not directly controlled, and in the presence of a free organic component in the finished product, the technical properties of the latter sharply deteriorate [Ioudovich et al., 1997, op. cit .; Yudovich B.E. et al., 1997, cit. Op.]. This is most clearly manifested in strength after steaming - in standard cement-sand samples in the absence of mineral additives in the composition of nanocements, the presence of a free modifier reduces the compressive strength by more than an order of magnitude (12-15 times), and tensile strength in bending - by 5 -10 times. Of course, nanocement is intended primarily for naturally hardened concrete due to the achievement of concrete strength at the age of 1 day of 30 MPa or more, up to 50 MPa. Steaming in such cases should be applied only with significant cement savings, in particular, double. For such concretes, the presence in the nanocement of a free modifier in an amount of more than 0.3% is fatal - they go to marriage. But even with 0.1% free modifier, a five-fold decrease in tensile strength during bending means an increase in the probability of cracking in products during heat-moisture treatment (TVO) up to 50%, which increases the yield of defective products from heavy concrete to 70%, and from non-autoclaved cellular , in particular, foam concrete - up to 100% (this data is reported in the open press for the first time). It follows that additional measures are needed to increase crack resistance in order to ensure the reliability of achieving the above-mentioned complex of positive properties of nanocements in the construction complex of the country.
Closest to the present invention (prototype) is nanocement containing the components: alite Portland cement clinker, calcium sulfate component (in terms of SO 3 ) and a powdery modifier that includes an organic water-reducing agent in combination with a hardening accelerator in May. the ratio of 100: (1-7) :( 0.6-2.5) with a degree of aggregation of particles of the mixture of 5-15 vol. % and humidity up to 3%, as well as mineral additives - active and fillers in May. a ratio of from 100: 5 to 100: 850 when co-grinding the mixture of components to a specific surface of 400-700 m 2 / kg [RF Patent No. 2207995, 2002]. At the same time, mineral additives are introduced both during joint and separate grinding, followed by mixing. Since the chemisorption of the indicated water-reducing component is carried out only on Portland cement clinker, the introduction of mineral additives in the first stage, that is, with the joint grinding of the components, or in the second stage, where the joint grinding continues when introducing the mineral additives, or pre-ground mineral additives are added to the mixture of the remaining components , - is not significant, - the completeness of the indicated chemisorption does not change. However, the distribution of particles with a completely closed water-reducing component surface changes - its uniformity with the introduction of additives increases, which increases the uniformity of the cement and, consequently, its reliability.
Recount from May. ratio in wt. % of the composition of nanocement with mineral additives according to the prototype allows us to formulate its material composition as follows: nanocement contains (in wt.%) alitic Portland cement clinker, or Portland cement, a sulfate-calcium component (in terms of SO 3 ), a powdery modifier that includes an organic water-reducing agent in combination with a hardening accelerator, as well as mineral additives - active and fillers (10.4-93.4) :( 1-7) :( 0.6-2.5) :( 3-88). Under the mineral additives in the prototype refers to all provided in the standards of mineral additives except active mineral additives sedimentary passage. More specifically, the allowable mineral additives are listed below.
The completeness of the binding in the finished product of the mentioned organic water-lowering agent with a clinker component into an adhesive (chemisorption) compound is characterized by the indicated minimum degree of particle aggregation. The norm of the degree of aggregation of particles 5-15 vol. % refers to purely clinker nanocement. Hydraulically active mineral additives and fillers from the groups: I - active silica: crushed or granular or ground silicate block; silica fume in powder or granular forms; II - granulated blast furnace slag, fuel slag, fly ash, volcanic ash, pumice, tuff, quartz sand, feldspar sand, granite screenings, ore dressing tailings, cullet, brick fight, expanded clay or glass ceramite dust - vary the degree to different aggregation. In the presence of mineral additives of the first group, the degree of aggregation of particles of nanocement increases by about 1 / 5-1 / 3 of the above value, and of the second group - by about 1 / 8-1 / 5, since the intensity of intrinsic adsorption forces and the ability to aggregation of additives of the second group is reduced.
The advantage of this technical solution is the saving of clinker in equal-strength cements and concrete based on them, the reduction of CO 2 emissions during decarbonization of a smaller fraction of calcareous raw materials during roasting to obtain nano-cement with a low content of clinker component in cement, and at the same time achieving high strength properties. The disadvantage - the fragility of cement, mortar and concrete - remains the same. It has to be taken into account that it substantially depends on the completeness of binding of the water-lowering agent to the clinker component. And the completeness of binding is caused not only by co-grinding conditions, but also, as it turned out in practice, and with the adsorption ability of the clinker component, determined not only by the mineralogical composition of the clinker, but also by its phase composition, and the latter - by the presence of impurity phases remaining in the unburnt clinker. The presence of a free modifier in nanocement on a clinker of reduced adsorption ability is most clearly manifested in durability after steaming - in standard cement-sand samples, and to a greater extent - in the absence of mineral additives in the composition of nanocement. Strength after heat-moisture treatment (TVO) according to the standard mode (2 hours - holding at normal temperature 20 ± 2 ° C; 3 hours - raising the temperature to 85 ° C, 6 hours - isothermal heating, 2 hours - cooling) sharply decreases in the presence of free modifier, for whatever reason, it remains in nanocement.
This disadvantage is absent in nanocement according to the present invention. It consists in the fact that a fibrous nanocement containing (in wt.%) Alite Portland cement clinker, or alite portland cement, a calcium sulfate component (in terms of SO 3 ), a powdery modifier, an organic water-lowering agent in combination with a hardening accelerator, and mineral additive (10.4-93.4) :( 1-7) :( 0.6-2.5) :( 3-88), including natural gypsum stone as a calcium sulfate component, as an organic water-reducing agent with hardening accelerator - polymethylene naphthalenesulfonates with sulfate on Tria, with surface areas of 400-700 m 2 / kg as a mineral additive component comprises silicate glass fiber material or aluminosilicate composition and / or fiber glass production waste (wt.%) in the form of fragments 3-28 microfibres or microfilaments length 0.05 -10 microns.
In an embodiment of the invention, said alitic Portland cement clinker, or alitic Portland cement, includes phosphoric anhydride in soluble form in an amount (wt.%) Of 0.01-0.15.
In another embodiment of the invention, said alite Portland cement clinker, or alite portland cement, includes fluoride compounds in soluble form in terms of fluoride anion in an amount (wt.%) Of 0.01-0.1.
In a further embodiment of the invention, said alitic Portland cement clinker, or alitic Portland cement includes free calcium oxide in an amount (wt.%) Of 0.01-0.5.
In an embodiment of the invention, said alitic Portland cement clinker, or alitic Portland cement includes alkali metal compounds in terms of Na 2 O in an amount (wt.%) Of 0.05-0.6.
In another embodiment of the invention, as a mineral additive, fiber Portland cement includes materials from the groups: I - active mineral additives: granulated blast furnace slag, fuel slag, fly ash, volcanic ash, or slag, pumice, heavy and light scrap, including cellular concrete, expanded clay, expanded clay or glass expanded clay dust, waste heat-insulating material, brick fight; H-fillers: quartz sand, feldspar sand, sand dune, sowing crushing of granites and / or quartzites and / or igneous rocks and / or ore dressing tailings, quartz flour, stone dust, tare and / or technical and / or building glass as well as the battle of construction, including plumbing ceramics.
In a further embodiment of the invention as a component of mineral additives - glass fiber material is a silicate or aluminosilicate fiber cement includes materials from the groups: I - aluminosilicate staple fiber comprising, calculated as oxides (wt%.) SiO 2 54 ± 2, Al 2 O March 14 ± 2, B 2 O 3 7.5 ± 2.5, MgO 2.5 ± 2, CaO 21 ± 4.5, Na 2 O 1 ± 0.5; II - silicate staple fiber containing in terms of oxides (wt.%) SiO 2 SiO 2 71 ± 3, Al 2 O 3 0.5 ± 0.25, MgO 3 ± 0.5, CaO 8 ± 2, Na 2 O 15 ± 1.5; III - a mixture of fiberglass materials from these groups; IV - waste from the production of fiberglass material from these groups and / or waste from the production of ferrous fiberglass material in an amount (wt.%) 10-90 of the amount of waste including, in terms of oxides (wt.%): SiO 2 50 ± 3, Al 2 O 3 15 ± 2, Fe 2 O 3 5.5 ± 1.5, FeO 6 ± 1.5, TiO 2 1.5 ± 0.5, MgO 6 ± 1, CaO 8 ± 2, (Na 2 O + 0 , 58 K 2 O) 4 ± 1.5.
The essence of the invention lies in the fact that the fibrous nanocement transfers the material made on its basis from ordinary concrete or mortar to the discharge of composites. This material is characterized by increased values of strength, especially tensile bending, due to a sharp (an order of magnitude) increase in the induction period of fracture from tearing apart from each other of the finite elements of their microstructure, including microfibers and / or microfilaments, compared with those observed in the destruction of ordinary concrete or building solution. This increase is due to increased resistance to tear-off fracture of the microfiber component pulled out from the elements of the submicrostructure of cement or mortar surrounding the fracture crack head.
The concept that the fiber length must be above the critical one arises when considering an elastic, elastoplastic or (with stretch) plastic matrix. With a brittle, in addition, granular structure, it, as can be seen from the above, is not applicable, since in the latter case it is required to block the accumulating microcracks during their development long before the appearance of macrocracks. The induction period corresponds to the first stage - the accumulation of microcracks, which characterizes the conditional fracture toughness from the point of view of elasticity theory. It can be estimated by measuring three-dimensional or linear microdeformations of the destructible sample with strictly axial loading of the samples in both stages with suitably equipped presses, or simplified by fixing the duration of the indicated induction period.
In accordance with [Rabinovich F. N., 2004, cit. cit.], the strength increases with an increase in the total shear surface of the grains, that is, with a decrease in their size, but only in the case when the microfibre density does not decrease with a decrease in the size of the grains. It is this position that explains the most important advantage of fiber cement, which is also the first basic element of the novelty of the present invention in terms of cement composition: no matter how small the volume of “grains” of the material structure, the microfibre density in each of them will not decrease, since the length and size of the minimum grains ”, according to / Ulm F.-J. // XX Convegno Nationale Int. Gruppa Frattura. Torino 24-26 guigno 2009. Proceedings. P. 3-10 /, on the fact of the coalescence of "grains", that is, microaggregates of calcium hydrosilicates, the basis of cement stone, have an order of magnitude equal to the size of the particles of a fine fraction of cement. F. Ulm in the last cited work believes that such intergrowth of microaggregates occurs under conditions of protection against atmospheric carbon dioxide. It is in such conditions that cement stone, mortar and concrete based on nanocement harden / Yudovich B.E. The main laws of hydration and hardening of Portland cement. // Sat Academic readings, eating. 100th birthday A.V. Volzhenskogo "Development of theory and technology in the field of silicate and gypsum materials." Part 1. M .: MGSU. 2000, p. 20-33 /. This theoretically determines the indicated length of glass fibers in materials (3-10 μm), leaving an excess over the particle size of the fine cement fraction (0.3-5 μm / IV / Kravchenko et al., High-strength and especially quick-hardening Portland cement for their anchoring in the hydrated layer) M.: Stroyizdat. 1971.208 p. /). In practice, this position has been fully confirmed in experiments, the characteristics of which are given below in the description section of the present invention by a method for manufacturing fibrous nanocement. The lower limit of the length of microglass fibers or microfilaments (0.05 μm) refers to their fraction, which inevitably results from abrasion (see the description of the method for manufacturing fibrous cement according to the present invention).
Alite Portland cement clinker and Portland cement based on it include tricalcium silicate (3CaO · SiO 2 , in the abbreviated notation C 3 S - alite) in the calculation according to V.A. Kindu / Quick reference of a cement plant technologist. Ed. I.V. Kravchenko, T.G. Meshik. M .: Stroyizdat. 1974. 304 s / amount of 60 wt. % and more / Okorokov S.D. The interaction of minerals of Portland cement clinker in the process of cement hardening. L .: Stroyizdat, 1945 .-- 150 p. /.
The use of such clinker and cement in the present invention is due to data on the predominant chemisorption of sulfonate type modifiers when they are co-milled with the indicated clinker and cement precisely on alite, in a smaller amount on the aluminoferrite phase (C 4 AF) and the complete absence of their chemisorption on C 2 S -white and C 3 A - tricalcium aluminate. Therefore, the use of non-alitic or low-alumite clinker or cement as the basis for fibrous nanocement would increase the likelihood of a free modifier in the finished product with a decrease in the quality of concrete.
In the four following embodiments of the invention, the usual limitations are imposed on the composition of the clinker part of the fibrous nanocement in terms of the content of soluble aggressive impurities in relation to fiberglass, which should be limited in the manufacture of any glasscement materials to ensure their durability: phosphate compounds in terms of phosphoric anhydride in an amount of not more than 0.15 wt. %, fluoride compounds in terms of fluoride anion in an amount of not more than 0.1 wt. %, free calcium oxide in an amount of not more than 0.5 wt. %, alkali metal compounds in terms of Na 2 O in an amount of not more than 0.6 wt. %
A natural question arises: with a high total alkalinity of cement stone, judging by the pH of the liquid phase freshly squeezed out of it under a press, from 10.5 (with low-clinker initial cement) to 13.5 (on highly alkaline clinker cement without mineral additives) / Kurbatova I.I. Modern methods of chemical analysis of building materials. M .: Stroyizdat. 1972. 178 p. Butt Yu.M., Timashev V.V. Portland cement: mineralogical and particle size distribution, modification and hydration processes. M .: Stroyizdat. 1974. 326 p. Volzhensky A.V. Mineral binders. Technology and properties. M .: Stroyizdat. 1979. 480 s / can minor (within fractions of wt.%) acidic impurities listed above be of importance for the resistance of fiberglass in such an alkaline cement stone? More precisely, why in practice do they destructively affect fiberglass in cement stone without being neutralized by high total alkalinity? This unanswered question was asked in the work / Rabinovich F.N., Klishanis N.D. The resistance of glass fibers to the effects of hydrated cements // Izv. USSR Academy of Sciences. Ser. Inorganic materials. 1982. No. 2. S. 323-329 /. The answer lies in the fact that cement stone is not a matrix, but, being a granular material, has local corrosion activity, and in some microzones adjacent to fiberglass it is acidic, in others it is alkaline (compared to neutral pH = 7), depending from phases directly in contact with the fiber. An attempt of a similar answer to the question is contained in the well-known work / Pashchenko A.A., Serbia V.P., Paslavskaya A. etc. Reinforcing of inorganic binders with mineral fibers. M .: Stroyizdat. 1988.201 p. / and more specifically, in the article / Meytin Yu.V. et al. Using the method of small cement blocks in assessing the durability of fiberglass cement // Tr. Gos. Institute of glass. 1989.S. 48-50 /.
The fundamental advantage of the present invention over the prior art is due to the reliance on this new approach. It was first mentioned in the work / Yudovich B.E., Dzhantimirov X.A., Zubehin S.A. Prospects for the use of composite materials based on cement matrices // Alitinform 2013 No. 1 (28) P. 20-28 / and lies in the fact that the outer shell of calcium hydrosilicates (CSH) in the stone of nanocement are siloxane chains (triads of silicon-oxygen groups) of composition -O -Si-O-Si-O-Si-O-. They are the ones that directly contact in the "nanocement - glass fiber" system with the surface of the glass fibers, and not the calcium-oxygen or calcium-hydroxyl-oxygen chains (with inclusions of individual silicon-oxygen tetrahedrons) present on the surface of calcium hydrosilicates in hardening Portland cement. These calcium-containing chains on the surface of Portland cement hydrates are the main corrosive agents for fiberglass in cement stone. Nanocement does not have this corrosive agent. This is the main reason for the fundamental advantage of nanocement as the basis of glass cement over the prior art. In the composition of the nanocement stone, fiberglass is really resistant, regardless of their share in the total volume of the stone and the presence in it of active mineral additives that reduce the overall alkalinity of the medium. The first test with the introduction of 2% by volume of fiberglass into the nanocement system in the work / Yudovich B.E. et al., 2010, cit. Op. / showed its durability over the next three years, and new experiments with a high content of fiberglass in a nano-cement base, described below in the description of the present invention, in turn, showed that the concept of the resistance of fiberglass over time in a medium of nano-cement stone is no longer considered as the basis when choosing the composition of the composite (recall that in the world-famous works of F.N. Rabinovich / 3rd ed., 2004, cit. cit.; 4th ed., 2013 /, the coefficient of fiberglass resistance in a Portland cement stone is introduced in according to which part of the fiber in time successively drops out of the calculated mass). In the stone of the fibrous nanocement according to the invention, the mineral fiber does not corrode. Therefore, in the present invention, the volumetric content of fiberglass in a nanocement stone is first increased to 3-30%, which is not possible in a conventional Portland cement stone, since massive corrosion of such a material volume would destroy all surrounding material. Accordingly, no special chemical requirements are imposed on fiberglass in the present invention, because there is no corrosive effect on fiberglass, and the economic requirements of the minimum cost of fibers come to the fore, which is characteristic of fibers of the compositions of the selected groups.
With regard to the waste of ferrous glass fiber material in an amount (wt.%) Of 10-90 amounts of waste, including, in terms of oxides (wt.%): SiO 2 50 ± 3, Al 2 O 3 15 ± 2, Fe 2 O 3 5, 5 ± 1.5, FeO 6 ± 1.5, TiO 2 1.5 ± 0.5, MgO 6 ± 1, CaO 8 ± 2, (Na 2 O + 0.58 K 2 O) 4 ± 1.5 , then the glandular waste of this composition is the waste of basalt fiber, as well as the waste products of the fluxes of olivines, pyroxenes and other metabasites (a group of minerals of medium basicity from igneous volcanic lavas and magma, in contrast to the admixtures of highly basic accessory minerals such as cal btsit or apatite). These fiberglass wastes are well known, but in view of the reduced brittleness and increased corrosion resistance imparted by iron oxides, they are significantly more expensive than ordinary fiberglass wastes from the first and second groups, therefore, as part of such a widespread and inexpensive material as cement, applicable only to a very limited extent.
Anchoring of microfibers in the composition of cement material (stone, mortar, concrete) in the "nanocement - fiberglass" system begins from the moment the fibrous nanocement is mixed with water due to the chemical bonds of the fibers with the surface of the first hydrated neoplasms on the alite surface nanoblocks at the very beginning of the avalanche hydration process of the fibrous nanocement after mixing it with water before and after laying it with water and other components of the mortar and concrete in the mold. Moreover, the astringent properties of nanocement are higher than that of any other hydraulic binders / Yudovich B.E. and others // XXIII All-Russian (VII-th International) meeting of the heads of laboratories of cement plants. Proceedings. M. Instron. 2010, sect. /]. Accordingly, it is able to bind the largest number of mineral additives, one of which is glass microfibers and / or microfilaments. Their surface at the initial moment of mixing the fibrous nanocement with water is smooth, only moistened with water. It does not contain extraneous adsorbed particles, as well as carbon dioxide molecules, since it is protected from the latter by a continuous outer layer of hydrocarbon chain residues of polymethylene naphthalene sulfonates from organomineral shells that are on the particles of the clinker component of the fibrous nanocement / M.Ya. Bikbau. Discovery of the phenomenon of nanocapsulation of dispersed substances // Bulletin of Ross, Academy of Sciences. sciences. Ser. Physics. 2012. No3. S. 27-35 /. These shells are three-layered with an external (first) diffuse layer of fragments of modifier hydrocarbon chains attached by the ends (functional groups) to the second layer - a nano-shell of a fused modifier with alite nanoblocks dissolved in it and impurities of an intermediate substance (the main one mentioned in the cited source) located above the etched with this shell as an acid third layer of alite nanoblocks. The first, a hydrophobic layer, protects the remaining layers beneath it on the clinker particle and the mineral fiber in the composition of the nanocement, which he switched to during grinding (see the description of the method for carrying out the invention) from water and provides sufficient flowability of the fibrous nanocement to use silo for its storage. The second layer (melting nano-shell) protects not only the clinker part of the fibrous nanocement from atmospheric carbon dioxide, but, most importantly, it also protects the hydration products of this cement from it. And this completely changes the phase composition of hydrates. The main Ca hydrosilicate in them is afvillite C 3 S 2 H 3 with the mentioned siloxane chains / Yudovich B.E., 2000, cit. Op. /. Its refined structural formula is [Ca 12 (H 2 O) 8 ] [SiO 4 ] 4 [SiO 2 (OH) 2 ] according to / Rastsvetayeva R.K. et al. Refined structure of afvillite from the North Baikal region. // Crystallography. 2009.V. 54. No. 3. from. 451-455 / does not contain CaO groups. For tobermorite, the main calcium hydrosilicate in Portland cement, above dry ice, the structural formula is Ca 2 [SiO 2 (OH) 2 ] 2 CaO according to / Brunauer S. et al. Hydration of tricalcium silicate and J3-dicalcium silicate in the temperature range of 5 - 50 ° С / Chemistry of cements. Ed. H.F.U. Taylor M .: Publishing. lit. by page 1969.S. 214-232 /. The above shows that the main hydrosilicate of the stone of nanocement afvillite, not including the CaO and Ca (OH) 2 groups, provides thanks to the siloxane groups the absence of corrosion of fiberglass in the composition of the nanocement stone. The predominance of siloxane three-membered chains at the external phase boundaries of the stone, bonded to the glass fiber by polar covalent bonds, ensures the stability of the glass fiber in the stone and the possibility of introducing into its composition up to 30% of the weight of the glass fiber. In contrast, Portland cement stone is dominated by less strong polar bonds with mineral components, namely with glass fiber through the (HO) Ca (OH) groups that corrode the glass. Therefore, fiberglass in an amount of more than 2 wt.% Should not be introduced into Portland cement stone. % to avoid corrosion and its products, swelling stone and leading to its destruction much earlier than the loss of continuity of fiberglass from calcium corrosion. The absence of corrosion of fiberglass in the stone of nanoportland cement provides (despite the high specific surface) long-term preservation of the properties of fiberglass nanocement, in particular, strength class. The only mass fiber input restriction is the loss of flowability of the fibrous nanocement depending on the size of the glass fibers or glass fibers. With a maximum length of 10 μm, flowability is not lost up to 30 wt. % fiberglass material, although, as shown below in the description of the method, the optimal content of fiberglass to the maximum tensile strength in bending below this level.
The functions of layered nanoshells on clinker particles of fibrous nanoc cement in relation to glass microfibers are as follows: the first layer protects the surface of the fiberglass from water and atmospheric carbon dioxide during the milling process, the second anchors microfibers during cement mixing with water and immediately during the avalanche hydration of alite nanoblocks (third layer) the latter, in addition, binds the fibers with hydrates into a reinforcing mesh, cross-linking the cement material into a composite. This composite, unlike ordinary concrete, exhibits bonding properties to a much greater extent than ordinary cement stone, hence the increase in tensile strength in bending, which characterizes a decrease in brittleness, etc.
The essence of the invention becomes clearer from the following experimental results, according to which the claimed positive effects, especially the absence of corrosion of fiberglass in a medium of fibrous nanocement, are indeed confirmed.
However, this requires the use of a method of manufacturing fiber cement, described below.
The prior art method for the manufacture of nanocement by grinding to a specific surface of 400-600 m 2 / kg of Portland cement clinker, or Portland cement, calcium sulfate component - natural gypsum stone, modifier - organic water-reducing component, namely polymethylenenaphthalene sulfonates, natural or siliceous mineral additives technogenic when they are contained in the finished product (in wt.%): (30-70) :( 2.5-4) :( 30-70) :( 0.6-2.5), respectively, including joint grinding to specific surface 300 - 390 m 2 / kg Portland ent clinker, or Portland cement, gypsum, a modifier and the first part of a siliceous mineral additive, namely 5-28 wt. %, and subsequent domol of the mixture with the rest of the specified mineral additives / RF Patent No. 2371402, 2006 /. The advantage of this technical solution, in addition to saving the clinker part and a corresponding reduction in fuel consumption for clinker firing and reducing emissions of CO 2 , NO x and others, is to improve the distribution of the mineral additive by the mass of nanocement due to two-stage grinding, and with a higher hardness of the mineral additive compared with a Portland cement clinker component - in the intensification of grinding of the latter, which provides an increased yield of the adsorption-active fraction of the clinker component and an increase in its amounts molecular adsortsionnoy ability, which may increase the degree of binding of the modifier during the joint grinding nanotsementa components. The disadvantage of this method is the difficulty in maintaining the exact mass ratio of the clinker part of the nanocement and mineral additives with fillers or in the absence of the latter. To select and maintain the exact ratio of these components in nanocement, it is necessary to pass them through a dispenser unit, either through weight conveyors, or a long calibration of transport devices before the milling using multiple chemical analysis of mixtures, which requires increased engineering and operator labor. In short, this method is not technologically advanced in factory production.
An analogue of the present invention is a method for the manufacture of nanocement, including the mantle of the obtained nanocement, exhibiting water separation in a cement paste or in standard cement-sand mortars, until the water separation ceases at a given water-cement ratio (W / C) / RF Patent No. 2029749, 1995 /. The milling was carried out by lengthening the time of the first grinding stage occasionally, in cases where an unacceptably increased (more than 15%) water separation was noted, which is considered a sign of the presence of a free modifier in nanocement, which is unacceptable. The disadvantage of this method is the instability of the process. Usually this is the result of the mill being unprepared for fine grinding: the average diameter of the bodies in the grinding charge is large, the range of vacuum regulation is insufficient, the diameter of the openings (slots) of the discharge grill is too large, its free cross-sectional area is excessive, the predetermined ratio of cement components to the metering system is not fully supported, etc. P. Finally, if the amendments in all of the above areas could not compensate for the main possible shortcoming of the preliminary stage of the technological process - clinker incomplete burning, now very common, and the reduced adsorption capacity of the clinker part of nanocement caused by it, then we had to use this method. It represents the last reserve to prevent the release of marriage.
According to the prototype of the present invention, a two-stage grinding method of nanocement, in which the Portland cement clinker, calcium sulfate component and a modifier comprising an organic water-lowering component, polymethylene naphthalene sulfonates, are ground in the first stage, and then an active mineral additive and / or filler are additionally introduced into the composition of the said nanocement or separate grinding with subsequent mixing at mass ratios of Portland cement clinker and active mineral additives and / or filler from 100: 5 to 100: 850 with its hygroscopic humidity of 0.013 wt. % / RF Patent No. 2207995, 2003 /. This method is used in cases where the water separation of nanocement is prevented when clinker is highly alkaline by increasing the water demand of the composite nanocement due to the active mineral additive (considering, along with the usual active mineral additives, also the addition of silica fume) and / or slowing down the settling of the nanocement-water suspension when using cast concrete mixtures with high H / C values (more than 0.5) by means of fillers (fillers) of different dispersion, including by joint o domol with a clinker part of cement or separately ground, followed by mixing in the second stage of domol with nanocement without an active mineral additive or in its presence. In the preparation of nanocement by grinding milled portland cement, which usually does not contain mineral additives, this method is effective and is used on an industrial scale, in particular, at the Sergiev Posad plant for the manufacture of nanocement (Portland cement with a dense contact zone, PCC PKZ / TU 5730-001 -86664502-2009 /), details in publication / Yudovich B.E., Zubehin S.A. Low water cement and Portland cement with a dense contact area. // International Analytical Review Alitinform (Alitinform). 2010. No3. S. 20-23. Number 4. S. 22-26 /.
Obtained in this way, nanocement meets all the requirements of the latest standard for cements for transport construction / GOST R 55224-2012 Cements for transport construction. Technical conditions M .: 2013. 8 pp. /, See details in the work / Sivkov S.P. et al. / Innovations in the construction and construction industries. Sat scientific works of NIIIMosstroy. Vol. 55. M.: Publishing. "Science-Business-Parity." 2013. S. 54-60 /, with the exception of standards for the content of organic additives - not more than 0.15 wt. % (here we mean grinding intensifiers, the introduction of which into nanoportland cement is not allowed according to / cit. doc. TU 2009 /) and specific surface - not more than 350 m 2 / kg. Limiting the specific surface area of cement for transport construction at this level is illogical. Note that the initiative to develop this Russian standard belonged to f. Lafarge in 2011 / Sivkov, 2013, cit. Op. /, but it is precisely the representative of f. “Lafarge” this norm of the standard was strongly criticized at the meeting in NIIMosstroy in November 2013, the reports of which formed the basis / Sat. scientific Proceedings, 2013, cit. Op. /. Critic from f. Lafarge, previously sotr. NIIMosstroy S.V. Moshkovskaya reproached the authors of GOST for not taking into account the array of experimental data on the fineness of grinding (specific surface) of cement accumulated over the past 60 years, in which the optimum specific surface lies above 450 m 2 / kg. Indeed, G. Kühl, N. Zement-Chemie. Band 3. Berlin [sn]. Verlag Technik. 1961.678 s. /, in the third volume of his three-volume work “Chemistry of Cement”, known throughout the world, indicated in 1961 that the specific surface area of ordinary Portland cement produced in the world lies in the range of 250-300, and quick-hardening - up to 350 m 2 / kg . But, as you know, due to the saving of grinding energy in modern mills, the specific surface (S y ) of ordinary cements by 2010 increased in the EU countries to 320-380 m 2 / kg and quick-hardening cements (BTC) class 52.5 (BTC type III according to ASTM) - up to 450-650 m 2 / kg / VDZ Überprüfung. Düsseldorf. 2012 /. Orientation in the modern standard, where the BTC is provided for, to the outdated norm on the specific surface, referring to the end of the 50s of the last century, is at least unintelligible. It is taking into account the production experience of production in the USSR at 10 cement plants of high-strength and especially quick-hardening Portland cement / I.V. Kravchenko et al., 1971, cit. Op. / the minimum specific surface area for them was not less than 380 m 2 / kg with an optimal particle size distribution characterized by the content (wt.%) of the middle fraction (5-30 μm) and the fine fraction (less than 5 μm) 55-70 and 15-25 respectively / Portland cement is particularly quick-hardening. RTU 110-63 Gosstroy of the Ukrainian SSR. RVTU 5011-65 Gosstroy of the RSFSR. These were the first TUs in the world for Portland cement of normalized mineralogical (wt.%) Composition C 3 S 60-65, C 3 A 5-8, other phases were not normalized, and the normalized particle size distribution described above. Thus, the experience in the production of cement with S y 400 m 2 / kg and above was developed on an industrial scale. The grinding regime developed in those works was repeated during the release of the first pilot industrial lots of VNV (or, what is the same, TsNV or nanocement) in 1989 at the Zdolbunovsky cement-slate plant, in 1990 - at the Belgorod cement plant, and then - at 4 other cement plants in 1991. In the first technical conditions at VNV / TU 21-26-20-92 An astringent of low water demand. Specifications / contained the standard for minimum S y 400 m 2 / kg. This document was developed by three institutes - co-authors: NIIITsement, VNIIZhelezobeton, NIIIZhB. It was proposed not to inform about the participation of TsNII-26 of the Ministry of Defense in this civil document, but the participation of this institute should be mentioned here. In these TUs, VNV-100 compositions (purely clinker cement) were provided, as well as compositions with 70, 50 and 30 wt. % of the clinker part, grades, respectively, from 1000 (corresponds to the modern strength class 82.5) to grade 150 (corresponds to the strength class 12.5, currently not provided for in TU). In TU at the PCZ PKZ [2009, cit. op.] the standard for the minimum specific surface area is the same — 400 m 2 / kg, and the particle size distribution of the purely clinker production TsNV≡nanocement complies with the requirements / RTU 1963, cit. doc / according to the results of studies of the grain composition of production batches of VNV 1989-91 Yudovich B.E. / Proceedings of the Research Institute of Cement. 1992. Issue. 104.S. 266-279 /. Therefore, in the prototype patent, the minimum level S y is also set to not lower than 400 m 2 / kg with an upper limit of 700 m 2 / kg.
The disadvantage of the prototype method under consideration, as well as previous technical solutions, is the fragility of the mortar and concrete obtained on this nanocement, which is only slightly reduced compared to the original Portland cement, despite the increased strength of nanocement in standard samples, as well as solutions and concrete based on it.
The present invention for the first time eliminates this common disadvantage of the considered group of technical solutions. It consists in the fact that in the method of manufacturing a fibrous nanocement by grinding a mixture comprising (in wt.%) Alitic Portland cement clinker, or Portland cement, a sulfate-calcium component (in terms of SO 3 ), a powdery modifier with an organic water-reducing agent in combination with hardening accelerator, as well as a mineral additive: (10.4-93.4) :( 1-7) :( 0.6-2.5) :( 3-88), and containing as a calcium sulfate component - natural gypsum stone, as a powdery modifier - an organic water-lowering agent with skoritelem hardening - polimetilennaftalinsulfonatami with sodium sulfate, with surface areas of 400-700 m 2 / kg, grinding is carried out in two stages, the first of which co-ground Alitova said Portland cement clinker or Portland cement Alitova, calcium sulfate component is particulate and an organic modifier dewatering hardening agent and accelerator - polymethylene naphthalenesulfonates in combination with sodium sulfate, and in the second stage, mineral is additionally introduced into the composition of the ground mixture w additive with joint or separate grinding followed by mixing by using as a component of said mineral additive fiberglass material (wt. %) 3-28 in the form of fibers and / or threads and / or pads of silicate or aluminosilicate composition, and / or waste fiberglass production in the form of fibers and / or felt and / or mats and / or fragments and mixtures thereof, and the second stage mode grinding is pre-selected under optical microscopic control to obtain in the finished product fiberglass material in the form of fragments of microfibers and / or microfilaments with a length in the range of 0.05-10 microns, adjusting the specified length by grinding time by reducing it when the length of the portion of the fragments of microwaves curl and / or microfilaments beyond the lower limit and increases when going beyond the upper limit of the specified range.
In an embodiment of the invention, in the second stage, together with the fiberglass material, the active mineral additive and / or filler is ground in quantities (wt.%) From 0.5 to 70.
In another embodiment of the invention, as an active mineral additive or filler, crushed together with a fiberglass material, take a material with a Mohs hardness not higher than the indicator corresponding to the hardness of an alite Portland cement clinker in the composition of the grinding mixture, or clinker, taken to produce alite Portland cement in the composition of the specified charge.
In a further embodiment of the invention, the duration of the induction period of fracture of samples from a standardly made and stored cement-sand mortar based on a controlled fibrous nanocement between the moments of stopping the growth of the load on the press when testing the compressive strength of three prism samples 4 × 4 × 16 cm of 28 days of age from the specified solution and their decay, ranging from 3 to 12 s on Wed frontier edge arithmetic mean of six measurements by increasing the proportion of glass fiber in the fibrous material at lower nanotsemente specified duration of the induction period, or by reducing it with a longer duration of the latter.
The main element of the novelty of the invention in terms of the method of manufacturing fibrous cement is that the fibrous material added to the grinding mixture and introduced into the grinding unit, despite the well-known fragility of the glass, does not turn into powder when it is ground in a cement mixture with heavy metal grinding media, but It remains in the form of fibers, only two to three orders of magnitude smaller than the original fibrous material. This result is provided by three physical effects:
1) by sliding the grinding bodies along the surface lubricant layer, provided by a diffuse layer of low molecular weight polymethylene naphthalene sulfonate molecules (200-300 Da), attached to the organomineral nanoshells that arose at the first grinding stage and surrounding all particles of the clinker part of cement. In this case, both the aforementioned diffusion layer and the nano-shells on the particles of the clinker component of cement are elements of the aforementioned lubricant, which ensures the transition of the operating mode of grinding media from shock to shear, replacing in this particular case the abrasion observed in ordinary fine grinding along with impact grinding and prevailing at the stage of fine grinding of ordinary cement / Deshko Yu.I. etc. Grinding materials in the cement industry. Ed. 2nd. M .: Stroyizdat. 1966.271 p. /;
2) the disclosure of inter-fiber bonds up to the threads in the shear grinding mode. This explains the separation of fibers into smaller and shorter ones down to the threads. The main factor is the diffusion of the lubricant along the fractal boundaries of the fiber sections on the threads / Addison P.S. et al. Fractal Cracking of Concrete: Parameterization of Spatial Diffusion. // Journal of Engineering Mechanics, Vol. 125, No. 6, 1999, - pp. 622-629 /.
Both of these effects are manifested only in the second stage of grinding in the presence of a modifier, the water-lowering agent of which is not fully connected, that is, in the process of co-grinding the fibrous material with nanoc cement. With conventional Portland cement, fibrous material, when co-milled, is much more likely to become powder due to abrasion. The second novelty element of the method according to the invention consists in the partial replacement of abrasion by sliding the grinding bodies along the milled charge in the second grinding stage. This effect, in addition to polymethylene naphthalenesulfonates, can be provided by other surfactants, which also contribute to the opening of intermolecular bonds such as hydrogen, including glycerol ether derivatives.
3) The direction of cracks in fiberglass along the threads after the start of fiber separation is called self-similar development of fracture cracks / Mosolov AB and other Self-similarity and fractal fracture geometry // Problems of strength, - 1988. No. 1. - S. 3-7 /. But this self-similar development stops when a fractal crack meets the sections of bending stresses in the fibers generated by the edges of particles of the rest of the charge in contact with them or with bundles of threads. Therefore, the self-similar growth of cracks in the fibers in the composition of the grinding mixture stops when a statistical average diameter of the surrounding particles is reached, which is about 10 microns in nano-cement / B. Yudovich Designing the particle size distribution of high-strength cements. // Proceedings of the Research Institute of Cement. 1992, cit. Op., p. 266-279 /. This is the reason for the average maximum length of glass fibers observed in experiments in the composition of a fibrous nanocement equal to 10 μm. The length of the fibers in the composition of the fibrous nanocement can be regulated by various methods. The simplest of them: shortening the duration of the second grinding stage to lengthen the fibers, and when lengthening the fiber, they are shortened. It is also possible to shorten the fibers by introducing, at the second grinding stage, the addition of quartz sand, of course, also previously ground to a specific surface of 200-250 m 2 / kg.
The second main element of the novelty of the method according to the invention is the final quality criterion, including the proportion of fiberglass and the degree of grinding of the fibrous nanocement, according to the induction period of destruction of samples of material made from it - stone, mortar, concrete. For standardization, a cement-sand mortar is selected in the present invention. The indicated period is due to a slowdown in the development of the main fracture of the fracture of samples from cement-sand mortar containing fibrous material. The slowdown in the development of this crack was first noted in fiber concrete in / Mai Y.W. et al. Slow crack growth and fracture instability of cement composites. // Int. J. Cem. Compos - 1982. - No. 1. - rr. 33-37 / and increases with increasing fiber content / Diamond S. On the Cracking in Concrete and Fiber-Reinforced Cements. / Appl. Fract. Mech Cementitious Composites. Proc. NATO Adv. Res. Workshop, Evanston, Sept. 4-7, 1984. - Dordrecht. - 1985. - pp. 87-140 /. Mi instability is understood to mean the fluctuation of the direction of the main fracture crack in the dispersively reinforced material, causing an increase in the fragmentation of the latter and, consequently, an increase in the specific fracture surface and its additional braking by energy costs for the mentioned fragmentation. The increase in fiber content, according to Damon et al., Complicating the Mi fragmentation at the phase boundaries, inhibits destruction even more significantly.
A positive difference between the behavior during the destruction of cement stone and cement mortar on fibrous nanocement from the above observations of the behavior during the destruction of the same materials on ordinary Portland cement is that an additional initial membrane stage is included in the process of destruction of materials on fibrous nanocement (the concept of it was introduced in / Kaufmann W. et al. Structural Concrete: Cracked Membrane Model. // Journal of Structural Engineering, 1998. Vol. 124, No. 12, pp. 1467-1475 /), caused in this case by temporary stress relief in the head submicrocrack boiling during its contact with organomineralnoj nanotsementa nanoshells on the surface of the particles of FIG. 1, due to the slippage effect. The essence of this phenomenon is that a submicrocrack at the phase contact of the cement stone / organomineral nanoshell (membrane) on the nanocarbon grain first stops, changes direction, then slides along the nanoshell, removing some of the mechanical stresses in the surrounding microvolume. After the cessation of slip, the growth of submicrocracks does not resume immediately. Its development begins again after the passage of a new wave of increasing external stress from the continued growth of external mechanical stress. The described two-stage inhibition of the growth of submicrocracks by organomineral nanoshells around particles of nanoportland cement represents the so-called membrane effect. This effect complements the inhibition of the development of cracks in the stone of nanocement with fiberglass material known braking from conventional microfibers according to Mi et al. and Damon et al.
The second difference from the above mechanism of braking of fracture cracks according to Mie et al. and Damon et al. consists in the fact that the mechanism for inhibiting the development of cracks with fiberglass material in a stone of nanoportland cement is based on the siloxane three-membered chains prevailing at the external phase boundaries of this stone / B. Yudovich. and others. New about the model of cement stone and materials based on it / ХХШ All-Russian (VII International) meeting of the heads of laboratories of cement plants. Proceedings. M .: Stroyizdat. 2010 /, coupled to fiberglass by polar covalent bonds, unlike Portland cement stone with its less strong polar bonds through (HO) Ca (OH) groups. It is the latter that corrode so quickly the usual sodium glass fiber materials used in the present invention that the fibers lose their connectivity after three years / Rabinovich F.N. and others. The stability of glass fibers to the effects of the environment of hydrated cement // Izv. USSR Academy of Sciences. Ser. Inorganic materials. 1982. No. 2. P. 323-329 /, and it is necessary to introduce a special coefficient of active glass fiber elimination, which is compensated by the excessive content of glass fibers in ordinary Portland cement stone. In the stone of nanoportland cement, fiberglass corrosion is not observed precisely in connection with the absence of HOCaOH groups on its interfacial surfaces. Therefore, as mentioned above, there is no corrosion of fiberglass in the stone of nanoportland cement, and excessive input of fiberglass material into the cement stone of nanoportland cement is not required. A stronger bonding of fiberglass and stone of nanoportland cement compared to conventional Portland cement also causes another additional, second mechanism of two-stage braking of the growing submicrocrack. At the first stage of fracture, the crack head crosses two phase boundaries: stone / fiberglass and fiberglass / stone, dividing fiberglass (and stone) into two fragments, and at the second stage, the fiberglass fragment is pulled out of the stone fragment, and two fiberglass / stone interfaces work again. In both stages of fracture, fiberglass nanoportland cement, having increased adhesion at phase boundaries, inhibits the growth of a fracture crack more strongly than fiberglass portland cement.
The invention becomes clearer from an example of its implementation.
Example 1
Starting materials: Portland cement clinker composition (wt.%) SiO 2 23.94; Al 2 O 3 3.60; Fe 2 O 3 3.44; CaO 67.14; MgO 0.76; SO 3 0.34; R 2 O 0.26; including K 2 O 0.18 and Na 2 O 0.14; the amount of 99.48, including p.p.p. 0.21; n 3.40; p 1.05, KH according to B.A. Kindu: 0.89; the content of the remaining small components: Li 2 O≅0, BaO 0.03, SrO≅0, NiO 0.01, CoO 0.01, Mn 2 O 3 0.12, Cr 2 O 3 0.15, MoO 2 0, 02, TiO 2 0.09, P 2 O 5 0.08, Cl 2 0.01, F 2 0. The calculated mineralogical composition of the average samples of the control clinker (wt.%): C 3 S 62, C 2 S 22, C 3 A 4.0, C 4 AF 10.0, impurities - the rest. Calcium sulfate component is a natural gypsum stone containing 95% bis water, impurities - the rest. The modifier is polymethylene naphthalenesulfonate SP-1 of the Novomoskovsk chemical plant, including 10 wt. % Na sulfate. Glass fiber material: I - aluminosilicate (Glass E, wt%.): SiO 2 54.3; Al 2 O 3 14.4; CaO 20.6; MgO 2.1; B 2 O 3 7.3; TiO 2 0.3; Na 2 O 0.8; the sum of 99.8, impurities - the rest; fiberglass material II-silicate (glass A, wt.%): SiO 2 72.1; Al 2 O 3 0.6; CaO 10.3; MgO 2.5; Na 2 O 13.8; the sum of 99.3, impurities - the rest. Active mineral additive - fly ash thermal power plant composition (wt.%): P.p. 3.87; SiO 2 47, l; Al 2 O 3 26.46; Fe 2 O 3 9.62; CaO 5.35; MgO 2.08; SO 3 0.52; Na 2 O 0.74; K 2 O 4.26; Amount 100.
Fillers: limestone containing 95% calcite, silica sand containing 89.7% SiO 2 , the rest in both components of the impurity. In addition, a filler was used - cullet of glass E of the same chemical composition.
The conditions of the method.
Grinding nanocement in a two-chamber laboratory mill with a chamber with a diameter of 0.5 m, a length of 0.28 m. Grinding loading: chamber I balls with a diameter of 60 mm 6 kg; 50 mm 8 kg; 40 mm 8 kg; 30 mm 8 kg, 20 mm 6 kg, total 36.0 kg. Chamber II tsilpebs 53 kg. A portion of a mixture of ingredients 5 kg. Engine power 1.5 kW, engine revolutions 930 min, mill revolutions 48 min -1 .
The grinding was carried out in two stages: in chamber I to a specific surface area of 280-300 m 2 / kg, in chamber II to a specific surface area of 430-450 m 2 / kg.
The results of physical and mechanical tests of cements obtained by the proposed method are presented in table. 12.
Since mineral substances do not enter into a chemical reaction with a superplasticizer, their presence only limits the likelihood of contacts between the crushed particles of clinker and superplasticizer during the grinding process. It follows that grinding in the presence of mineral substances must go on for a longer time, which can be achieved by known methods of grinding technology.
Fiberglass wastes were prepared by treating in the presence of a surfactant (glycerol derivative) a mat or fabric in a vibratory mill MB 0.005 balls under a load of 0.5 kg / cm 2 until fiber separation of at least 70% of the mass of material.
The experimental results are presented in table. 2. From the above data it follows:
A. When testing the compressive strength of standard manufactured samples of cement-sand mortars on control cements (grades 400, 500 and 600, grades 32.5, 42.5 and 52.5, respectively (lines 1-3 of Table 2), the ratio r (we denote by this letter the value of R and / R cr according to Table 1 with the indices according to the note ... to it) is in the range 0.09-0.135.This corresponds to the usual values for cement-sand mortars and concrete / Karpenko V.I. , cit. cit. and many others /, and the induction period of destruction (t) is practically absent.
B. For control nanocements that do not contain fiberglass materials (lines 4 and 9 in Table 2), g is in the range 0.12-0.14 depending on the age and storage conditions (heat and moisture treatment) of the samples with a slight increase in τ ( maximum up to 1.5 min), but does not reach the level characteristic of low fragility material.
B. Fibrous nanocements without mineral additives (lines 10-14, Table 2) reach a maximum of m values with a fiber content of 18 wt. % (9 s.) At 28 days of age, although the growth of t up to 3 s begins already at a fiber content of 3 wt. % and continues sequentially until the fiber content is 18%, and generally enters the range of τ≥3 s in the range of fiber content from 3 to 30%. In this series of tests, it was shown that the introduction of fiberglass materials increases the compressive strength of nanocements at the optimum of their content per class (grade), in addition to an obvious reduction in fragility.
D. Fibrous nanocements with mineral additives are relatively little dependent on their physicochemical properties on the type of glass fibers (I, II), judging by the data presented in lines 15-16 and 17-18 of the table. 2. Wastes of fiberglass materials in the composition of fibrous nanocement (lines 19–20 and 21–22 of Table 2) also work approximately similarly, although they are less efficient compared to fibrous materials proper, which can be explained by incomplete separation of fibers in the waste during the milling process . This was in line with our expectations.
D. The main element of novelty and surprise in these experiments was that even with an increased proportion of mineral additives (lines 24-28 of Table 2) in the composition of the fibrous “nanocement 35”, fiberglass materials continue to increase r values and, accordingly, reduce the brittleness of cement solutions, including those with various powdered mineral additives (limestone, quartz sand, cullet), which in terms of hardness (5 on the Mohs scale) did not exceed the level of hardness of the used Portland cement clinker, of which whether all samples prepared nanotsementov (also 5 on the Mohs scale).
From the above data it follows that the objective of the invention has been achieved: a material is actually created - a fibrous nanoc cement, characterized by increased tensile strength during bending, i.e. less brittle, and this is done against the background of a general increased compressive strength characteristic of nanocement, a variety of which is fibrous nanocement.
Persistence in time: from old works it is known / Rabinovich F.N. et al., 1982, cit. Op. /, that the decrease in tensile strength of cement mortars, including fiberglass materials, during bending occurs already during the first 3 months of storage of samples and further increases with a loss after May 6. minimum 20% of initial strength. In this example, the compressive strength and tensile bending strength of the samples of the compositions were determined according to lines 5, 7, 10, 13, 17, and 24. No strength reduction after 6 months of storage was detected, which indicates the absence of corrosion of fiberglass materials in the medium of a solution of fibrous stone nanocement.
Thus, the invention in terms of composition and method of its implementation prepared Notes to tables 1, 2 and 3
Table 1. Physico-mechanical properties of fibrous nanocement according to the invention and control cements
Notes: 1 - designations: ПЦ400Д20 - Portland cement grade 400 (class 32.5), including (wt.) Portland cement clinker - 80, mineral additive - volcanic ash with activity below the limit according to GOST 25094-94 “Active mineral additives. Test methods "- 14.6 wt. hours; gypsum stone 2.5 in terms of SO 3 , or 5.4 wt. h; TMC-60 - finely ground cement, including (wt. Hours) Portland cement clinker - 60, mineral additive (same) - 34.6 wt. hours, gypsum stone 2.5 in terms of SO 3 , or 5.4 wt. hours; NANOCEMENT-55 - Portland cement modified by co-grinding with a modifier (naphthalenesulfonate SP-1 [http://www.polyplast-un.ru/products/stroitelnaya-otrasl/dobavki-dlya-betonov/superplastifikatoryi.html]), is indicated by М in the next, No. 3, column of the table; cement includes (wt.%) Portland cement clinker - 60, mineral additive (same) - 31.5, gypsum stone 3.5 in terms of SO 3 , or 7.5 wt. hours; modifier content - see the next column; 2 - specific surface according to the method of breathability on the device of the Khodakov system (PSC); 3 - normal density of the cement paste; 4 - water-cement ratio (W / C) - for NANOCEMENT - selection according to the cone spread (145 cm) on monofraction sand according to GOST 310.4-81; for other cements - according to the above GOST; 5 - heat and moisture treatment (steaming) according to the 2 + 3 + 6 (85 ° С) +2 (hour) mode - holding, temperature increase, isothermal heating, cooling; 6 - Portland cement clinker: A - unburned, including an admixture of FeO (0.5 wt.%) And mayenite (12СаО · 7Al 2 O 3 ) up to 1.5 wt. % in the presence of 0.4% free lime (such a low content is explained by the presence of a highly calcareous aluminoferrite phase of the open type VD Barbanyagre 3CaO · Fe 2 O 3 , but with an admixture of FeO, which readily binds lime); B - normally burnt clinker that does not contain FeO and mayenite; mineralogical composition (calculated, wt.%): C 3 S (alit) 55, C 2 S (belite) 21, C 3 A (tricalcium aluminate) 5, C 4 AF (aluminoferrite phase) 14, impurities - the rest; 7 - grinding of materials and materials was carried out without a modifier; the modifier was introduced when testing the physical and mechanical properties of materials and materials in the mixing water of cement-sand mortar as a plasticizing additive in the amount of 0.8% of the mass of cement (or 0.8 · 0.6 = 0.48% of the mass of clinker) ..
Table 2. Physico-mechanical properties of fibrous nanocement according to the invention and control cements.
Designations: K - alite Portland cement clinker; PC - ordinary Portland cement according to GOST 10178-85 grade 400 with 20% mineral additives (MD); the designations of these cements according to GOST 31108-2003 see in the note ..., SK - calcium sulphate component - gypsum stone according to GOST 4013-82, MD1 - artificial mineral additive of silicate composition in an expanded interpretation (see in the description of the invention), MDI - natural mineral additive after processing, designations of MD types - according to notes; M - modifier, including hardening accelerator and superplasticizer; S ref is the specific surface of the grinding mixture (mixture of crushed components) before adding fiberglass material, S con is the specific surface of the product; CM - fiberglass material, I - aluminosilicate (data are given for comparison), II - silicate according to the invention, CMI o - waste aluminosilicate fiberglass material (data are for comparison), CMII o - waste silicate fiberglass material according to the invention,
Figure 00000001
- the commodity product provided for in the column “type of cement”, taken as a source material; "+" - is present in the composition of a commercial product taken in the composition of fibrous or control cement; “-” (minus) - absent in the composition of cement ..
Other designations - according to the table. 1, the notes to it and the notes to this table.
Notes: 1 - setting time of fibrous cement, including, by definition, fiberglass material and / or its waste; 2 - water-cement ratio (W / C) - for NANOCEMENT, composition according to line 3 and compositions according to the prototype — selection according to the cone spread (140-145 cm) on polyfraction sand according to GOST 6139-91; for other cements - according to GOST 31108-2003; 3 - composition according to approx. 1 tab. one; finished cement of the Hrazdan cement plant (Armenia) PTs400D20 in accordance with GOST 10178-62; designation according to GOST 31108-2003: CEM II / AP 32.5; 4 - composition according to note. 3, milling in a laboratory ball mill; in quality corresponds to PTs500D20 in accordance with GOST 10178-62; designation according to GOST 31108-2003: CEM II / AP 42.5; 5 - to the product according to approx. 4 added fiberglass aluminosilicate material of the Resurrection Glass Mill, ground in a vibratory mill for 3 min (in the presence of 1 wt.% Atomized surfactant; an ester derivative of glycerin used to lubricate the dies with fiber release to a length of less than 10 μm CMI (3% cement mass) was used as a surfactant ), thereby bringing the MD content to (14.6 + 3) :( 100 + 3) = 17.1 wt.%, with a K content of 80: 103≈78 wt.%; 6 - nanocement of the Sergiev-Posad grinding plant ( "Portland cement with a dense contact zone" [PC PKZ] according to TU 5730-001-86664502-09; designations of nanocements in a line 3a-3g - according to TU, namely nanocement, at face value including (wt.%): In line 3a, clinker 80-94, MD 6-20; in line 3b, clinker 50-70, MD 21-50; in line 3g clinker 35-79, MD 21-65; PC 500 D0 of the Gornozavodsky cement plant, including (wt.%) clinker 94.6 with C 3 S 62, C 2 S 17, C 3 A 6, was used as the clinker part in this series of experiments , C 4 AF 13, impurities communication CaO 0,5, R 2 O 0.6, P 2 O 5, 0,1, F (fluoride ion) 0.1; gypsum stone 2.5 by SO 3 , or 5.4; in a series of experiments in lines 3-8, ashes of thermal power plants according to GOST 25818-91 of the Revdinskaya TPP were used as MD; sample of 2013, in lines 3d and 3d show the data for nanocement analogues of cements, given in lines 3a and 3c, in which CMI, introduced by note, is used as part of the MD. 4 and 5; 7 - here and below NANOCEMENT according to TU 5733-067-66331738-2012 “Nanoc cement is general building. Technical conditions "; they are standardized: NANOCEMENT 90, including (wt.%): clinker component 90-98, MD 2-10, NANOCEMENT 75, respectively 75-88 and 12-25, NANOCEMENT 55 55-74 and 26-45, NANOCEMENT 35 35- 44 and 56-65, NANOCEMENT 30 30-34 and 66-70. Nanocement, including less than 30 wt. % of the clinker part is not officially standardized and is produced by orders of consumers mainly for non-autoclaved foam concrete; 8 - mixing of nanocement with ground fiber; here and below they took silicate fiberglass from the Voskresensky plant; then the mixture was ground in a vibratory mill (3 min) with a load in the presence of 1 wt. % sprayed surfactant; as a surfactant, an ether derivative of glycerol was used, used to lubricate dies with fiber release; similar results were obtained using a 30% solution of Na naphthalenesulfonate in methyl alcohol; 9 - Clinker K1 of the Pilot Plant of the Research Institute of Cement, now OJSC “Tsemdekor” of the composition (wt.%): C 3 S 60, C 2 S 20, C 3 A 5, C 4 AF 13, CaO impurities sv 0.3, R 2 O 0.6, P 2 O 5 0.15, F (fluorine ion) 0.1; other impurities - the rest; 9a, b - a) grinding in a porcelain mortar the waste of fiberglass material (threads) to an average length of 1 mm, b) then the steps for approx. 8; 10 - joint grinding of nanocement with fiberglass material for a time selected by the maximum length of fiberglass in the grinding product no more than 10 microns under an optical microscope; for the mentioned grinding it was required: 10 minutes in line 10, 13 minutes in line 11, 15 minutes in line 12, 22 minutes in line 13, 30 minutes in line 14; 10a, b - corresponds to 9a, b; line 19 waste: the staff of the Voskresensky fiberglass plant and the container glass battle of the Sergiev-Posad glassworks in a weight ratio of 1: 1; line 20 waste: glass-fiber scrap of the Gus-Khrustalny glassworks and ground quartz sand of the Lyubertsy deposit, passed through a No. 008 sieve (mesh cells 80 μm), in a ratio by weight of 3: 1; in lines 20a and 20b - the same components in different wt. ratios; 11 - as an active mineral additive - fly ash of the Ryazan TPP; 12 - volcanic slag of the Karadag deposit as a mineral additive; 13 - is carried out under contracts with consumers with the coordination of technical indicators without regulation in the regulatory document; 14 - here and in subsequent compositions, the clinker K2 of the Experimental Plant of NIIITsement, now OJSC Tsemdekor, composition (wt.%): C 3 S 65, C 2 S 10, C 3 A 11, C 4 AF 12, CaO impurities sv 0 5, R 2 O 0.6, P 2 O 5 0.15, F (fluorine ion) 0.1; other impurities - the rest. Explanations of impurities - in the text description.
Table 3. Physico-mechanical properties of fibrous nanocement according to the invention and control cements. Continuation of table 2.
Designations: R and - bending strength; R cr - compressive strength; R and / R compress - their ratio, an indicator of crack resistance and wear resistance; τ is the induction period of crack formation, a characteristic of the duration of the latent stage of development (opening) of fracture fractures.
Figure 00000002
Figure 00000003
Figure 00000004
Notes (beginning see table 2): 15 - induction period of destruction (explanations in the text of the description); 16 - a conclusion on the compliance of the duration of the induction period of destruction with the requirements of the claims (≥3 s); 17 - the value was not determined.
Figure 00000005
Figure 00000006
Figure 00000007

Claims (10)

1. Fibrous nanocement containing (in wt.%) Portland cement clinker or Portland cement, natural gypsum stone (in terms of SO 3 ), a powdery modifier - polymethylene naphthalene sulfonate with sodium sulfate, and a mineral additive (10.4-93.4) :( 1-7) :( 0.6-2.5) :( 3-88), with a specific surface area of 400-700 m 2 / kg, characterized in that, as a Portland cement clinker or Portland cement, it contains alite Portland cement clinker or alite portland cement, including the alite phase within 60-65% of the mass of clinker or the clinker part of Portland cement a, a mineral additive comprises silicate glass fiber material composition and / or fiber glass production waste in the form of microfibres or microfilaments fragments 0.05-10 microns length in amounts wt.% 3-28 are recorded as mineral additives.
2. The fibrous nanocement according to claim 1, characterized in that said alite Portland cement clinker or alite portland cement contains phosphoric anhydride in soluble form in an amount, wt.% 0.01-0.15.
3. The fibrous nanocement according to claim 1, characterized in that said alite Portland cement clinker or alite portland cement contains fluoride compounds in soluble form in terms of fluoride anion in an amount, wt.% 0.01-0.1.
4. The fibrous nanocement according to claim 1, characterized in that said alite Portland cement clinker or alite portland cement contains free calcium oxide in an amount, wt.% 0.01-0.5.
5. The fibrous nanocement according to claim 1, characterized in that said alite Portland cement clinker or alite portland cement includes alkali metal compounds in terms of Na 2 O in an amount, wt.% 0.05-0.6.
6. The fibrous nanocement according to claim 1, characterized in that the mineral additive contains materials from the groups: I - active mineral additives: granulated blast furnace slag, fuel slag, fly ash, volcanic ash or volcanic slag, pumice; II - fillers: quartz sand, feldspar sand, sand dune, sowing crushing of granites and / or quartzites, quartz flour, stone dust, battle of container and / or technical and / or building glass.
7. The fibrous nanocement according to claim 1, characterized in that as a component of the mineral additive — glass fiber material of silicate composition — it includes materials from the groups: I — silicate staple glass fiber containing, in terms of wt. %: I - silicate staple fiber containing in terms of oxides (wt.%) SiO 2 71 ± 3, Al 2 O 3 0.5 ± 0.25, MgO 3 ± 0.5, CaO 8 ± 2, Na 2 O 15 ± 1.5; II - a waste product of the specified fiberglass material, III - a mixture of materials from these groups in ratios from 9: 1 to 1: 9.
8. A method of manufacturing a fibrous nanocement according to claim 1, by grinding a mixture including Portland cement clinker, or Portland cement, natural gypsum stone (in terms of SO 3 ), a powdery modifier - polymethylene naphthalene sulfonate with sodium sulfate and a mineral additive, wt.%: (10 , 4-93.4) :( 1-7) :( 0.6-2.5) :( 3-88) to a specific surface area of 400-700 m 2 / kg, characterized in that the mixture contains as Portland cement clinker or Portland cement - alite Portland cement clinker or alite portland cement, including the alite phase in the range of 60-65 % of the mass of clinker or clinker part of Portland cement, and as a component of the mineral additive - fiberglass material of silicate composition and / or waste fiberglass production in the form of fragments of microfibers or microfilaments with a length of 0.05-10 microns in the amount of wt.% 3-28, and grinding is carried out in two stages, at the first of which the specified Portland cement clinker or Portland cement, together with natural gypsum stone and a powdery modifier, polymethylene naphthalene sulfonates in combination with sodium sulfate, are ground together Flax surface of 280-300 m 2 / kg, and in the second step of the obtained milled blend with joint or separate grinding followed by mixing mineral additive is introduced and milled to said specific surface, the second-stage grinding mode previously selected by the optical-microscopic control to obtain in the finished product a fiberglass material - microfibers or microfilaments with a length of 0.05-10 microns.
9. The method according to p. 8, characterized in that as the fiberglass material of the silicate composition, fibers and / or threads, and / or racks, and / or wastes of the specified fiberglass material in the form of fibers and / or felt are introduced into the mineral additive, and / or mats, and / or fragments and mixtures thereof, and the mode of the second grinding stage is preselected under optical microscopic control to obtain fiberglass material in the finished product in the form of microfibers and / or microfilaments, and / or fragments thereof with a length within 0.05 -10 microns, adjustable I specified the length of the period of grinding by reducing it when the length of a portion of microfibers and / or microfilaments, and / or their fragments goes beyond the lower limit and increases when going beyond the upper limit.
10. The method according to p. 8, characterized in that, as an active mineral additive or filler, in the second stage of grinding with fiberglass material, a material with a Mohs hardness not higher than that corresponding to the hardness of Portland cement clinker in the composition of the grinding mixture is introduced into the charge, or the specified clinker, taken for the release of Portland cement as part of the specified mixture.
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