RU2213070C1 - Cement raw meal, method of manufacturing portland cement with lowered shrinkage from portland cement clinker obtained by fire caking of indicated raw meal and a method for manufacturing cementing material suitable to repair concrete and to strengthen grounds being fine fraction of indicated portland cement - Google Patents

Abstract

FIELD: manufacture of building materials. SUBSTANCE: invention can be applied in cement production, building industry, geotechnical and hydroengineering construction, and in restoration operations. Cement raw meal, containing lime, silicate, and ferrous ingredients as well as 0.03 to 0.5% of strontium compounds (calculated as oxide), alkali metal oxides, and sulfur trioxide, contains its strontium compounds within lime ingredient in the form of calcite-strontianite (strontianite, celestine) and with silica modulus of mixture 0.5-1.25 and weight ratio of alkali metal oxides (calculated as sodium oxide) to sulfur trioxide equal to 0.7-1.5. Raw meal further contains 0.15 to 0.5% barium compounds (silfide, whitherite, barite calculated as barium oxide). Lime saturation ratio of clinker is 0.9-1.15. This raw meal is caked by firing in oxidative atmosphere until contents of 0.05-0.8% free calcium oxide and 0.01-0.3% iron monoxide are obtained. Resulting clinker is jointly ground with gypsum component at weight ratio 100: (0.3-6), respectively, to achieve specific surface 250-700 sq.m/kg (taking into consideration criterion of minimum shrinkage of samples made from cement paste in wet air medium). Gypsum component is calcium sulfate in the form of naturally-occurring gypsum stone including 0.01 to 1.5% clayey admixtures. When grinding, 0.5 to 40% active mineral agent with 6-12% moisture and moisture-reducing component are added, weight ratio of clinker to this component being 100:90.3- 2.5). Moisture-reducing component is selected from following group: salt of product prepared by condensation of naphthalenesulfonic acid with formaldehyde or melamine-containing resins with formaldehyde; industrial- grade lignosulfonate optionally modified by phenol-formaldehyde resin; complex salts of alkali-earth metals and acid (sulfuric, formic, acetic acid) with low-molecular (C3- C5) monosaccharides; and paired mixtures of indicated materials. Grinding is carried out in vented disintegrator at aspiration degree controlled by absence of dusting at inlet mouth and in presence of expansion agent added at weight ratio of clinker to that agent 100:(0.5-4). Expansion agent is preliminarily prepared mixture of sulfoaluminate clinker or aluminum sulfate, film-former, and etching agent, said film-former being waterproofing agent selected from higher fatty acids, drying oil, wax, vegetable oils, and solutions of any of indicated materials in mineral oil, and said etching agent being selected from puruvic acid, levulinic acid, mesoxalyc acid, aldonic acids, aromatic acids, their acid derivatives, unsaturated carboxylic acids, hydroxyacids, carbocyclic compounds, dicarboxylic compounds, anhydrides of indicated acids, resin acids in double mixtures with above-indicated substances, alcohols, aldehydes, double and triple mixtures of indicated substances (secondary products and wastes containing thereof), the three agent components being taken at weight ratio 100:(2.5-30):(2-20), respectively. Cementing material for repairing concrete and strengthening grounds is obtained as aspirated and then precipitated material when performing grinding in vented disintegrator, its specific surface being 400-2500 sq.m/kg. Composition of this fraction is controlled by varying ratio of components in Portland cement and mechanical conditions of disintegrator operation until content of strontium and barium compounds achieves 0.2- 0.6%. EFFECT: reduced shrinkage of Portland cement in absence or at reduced content of expansion agent and increased strength of cementing material. 18 cl, 2 tbl, 3 ex

Description

 The invention relates to the field of building materials, namely to cement raw mixes and to methods for the manufacture of cements from clinkers obtained by firing before sintering these mixtures, as well as cementing materials for concrete repair and soil strengthening, and can be used in the cement industry, construction industry, geotechnical and hydraulic engineering construction, as well as during restoration work.

Known cement raw material mixture for firing Portland cement clinker, including lime, silicate and glandular ingredients [1]. The disadvantage of this technical solution is the relatively low strength obtained from the specified clinker Portland cement - grades up to 500 according to GOST 10178-85 with a specific surface according to the method of breathability 250 - 320 m ² / kg

 To date, the prior art knows the mineral composition of the lime and silicate ingredients of the cement raw material mixture, including basic mineral impurities [2, 3]. The influence of the mineralogical composition of these ingredients on the quality of Portland cement clinker calcined from the mixture is also known [4, 5].

 Also known is a cement raw material mixture for roasting Portland cement clinker, including calcareous, silicate, and ferruginous ingredients, in which the aragonite mineral or its mixture with calcite (both of these minerals are calcium carbonates, differing only in the crystal lattice symmetry) as a calcareous ingredient [6]; their joint use allows to accelerate the process of their decarbonization and solid-phase reaction of interaction with other ingredients of the specified raw mix. The tradition of using certain natural minerals as small constituents of a cement raw material mixture, begun by introducing fluorspar (mineral fluorite) into a cement raw material mixture in 1932 (C. Sanada, T. Nishi, Japan) in order to accelerate sintering during roasting of Portland cement clinker, was significantly developed, up to the use of multicomponent mineralizers [7].

It is known that impurities, including heavy elements with large atoms, stabilize individual minerals of Portland cement clinker [8]. Cements with reduced shrinkage and increased frost resistance are characterized by an increased content (wt.%) In clinker of dicalcium silicate - up to 30 and aluminoferrite phase 16-25 [9], designated using the reduced notation commonly used in cement chemistry: А - Al ₂ O ₃ , С - CaO, S - SiO ₂ , F - Fe ₂ O ₃ , as well as R ₂ О - Na ₂ O + 0.568 K ₂ O as follows: dicalcium silicate, or white - C ₂ S, aluminoferrite phase C ₂ (A, F), or C ₄ AF. The other two main phases of clinker - tricalcium silicate, or alite - C ₃ S and tricalcium aluminate - C ₃ A are carriers of early cement strength, and C ₃ S - and strength in the later stages of hardening. It is precisely in the C ₄ AF and C ₃ S phases that impurities of compounds heavier and more basic than those of calcium of the second period — calcium analogs — strontium (Sr) and barium (Ba) [10] are usually concentrated [10], and the relative basicity of strontium oxide is 1, 09, barium oxide 1.12 in comparison with the relative basicity of calcium oxide 1.07 and the relative basicity of a eutectic clinker melt with a eutectic point at 1338 ^o С equal to 1 (in [11] the indicated data on relative basicity were calculated and a definition of this characteristic is given ki based on the electronegativity of atoms according to L. Pauling). In looser and more active crystal lattices of the C ₃ S and C ₃ A phases, the impurities of heavy metals are difficult to maintain: they easily decompose in their presence, and the content of such impurities in the active phases is significantly lower than in more passive and stronger crystal lattices of C ₂ S and C ₄ AF. This is a common situation known in the art.

Closest to the invention, the technical solution (prototype) is a cement raw material mixture containing lime, silicate and ferruginous ingredients, as well as strontium compounds in terms of oxide in an amount of 0.03 - 0.5% by weight [12]. These compounds are introduced, according to the authors of this work, to accelerate hardening and increase the strength of cement prepared from Portland cement clinker obtained by firing before sintering the specified raw mix. It should be noted that the increase in cement strength, as is known [13], is linearly associated with an increase in the elastic modulus of cement products — cement stone, mortar, and concrete, and the latter increase at equal shrink stresses reduces shrink deformations. Hence we conclude that the introduction of strontium compounds leads to a decrease in cement shrinkage. In this case, however, mixed results were recorded in [12]: in the sources cited there it is known both an increase in the hardening rate and strength of cements, including strontium compounds, and the absence of a positive effect of the latter; Thus, the authors of this work and a number of other researchers did not find an increase in the hardening rate and strength of cements when strontium compounds were introduced into the cement raw material mixture both in the indicated range of their content in clinker and in large quantities. At the same time, a review of the prior art in this work and the authors ’own data indicate that sometimes conditions are created for heavy calcium analogs to enter the crystal lattices of active clinker minerals, primarily C ₃ S. Thus, the ambiguity of the results obtained with the introduction of strontium compounds in the cement raw material mixture, there is the result of the lack of data on the conditions ensuring the entry of heavy elements into the C ₃ S structure in the resulting clinkers, and, accordingly, the method that provides technological The conditions for this, as well as the lack of data on the concentrations of these heavy calcium analogs selected in a raw material mixture selected for this method. This is the main disadvantage of the technical solution according to the prototype.

The objective of the invention in the part of the cement raw material mixture is to create cement with reduced shrinkage, the latter property being achieved by introducing impurities of strontium compounds, as well as barium - heavier and more basic compared to the predominant calcium cations - in the hydrosilicate and hydrosulfoaluminate frames of cement stone by adjusting the composition the specified raw mix, providing enrichment with heavy analogues of calcium structure C ₃ S, which eliminates the instability of the results, known from prior art.

This problem is solved in that the cement raw material mixture containing lime, silicate and ferrous ingredients, as well as strontium compounds in terms of strontium oxide in the amount of 0.03-0.5% by weight, alkali metal oxides and sulfur trioxide, it contains strontium compounds in the calcareous ingredient in the form of natural minerals from the group of calcitostrontianite and / or strontianite and / or celestin with an alumina module of the specified mixture of 0.5 - 1.25 and wt. the ratio of alkali metal oxides in terms of sodium oxide Na ₂ O and sulfur trioxide 0.7-1.5.

 In an embodiment of the invention, the mixture further comprises barium compounds in the form of sulfide and / or witerite and / or barite in terms of barium oxide in an amount of 0.15-0.5 wt.%.

 In another embodiment of the invention, the coefficient of saturation of lime in terms of Portland cement clinker is taken in the range of 0.9-1.15.

The essence of the invention lies in the fact that strontium compounds:
1) are used in the form of impurities of strontium-containing natural minerals from the group of calcitostrontianite and / or strontianite and / or celestin to the calcareous ingredient of this mixture. It is this source of strontium compounds that ensures, from the standpoint of geochemistry (after slowly occurring chemical weathering of the main magmas and redeposition of the products together with calcium sedimentary rocks), the freedom of strontium compounds in these rocks from the impurities of compounds of heavy metals such as cadmium, accompanying them in strontium-containing industrial wastes, thallium, lead and chromium, which are biological poisons. Such a process of the formation of strontium-containing calcareous rocks under alkalization by groundwater of limestone and / or Cretaceous sediments when the latter is isolated both from above, from oxidizing agents penetrating from the earth's surface, and from below, from magnesium impurities moving from below, “pulling together” the crystal lattices of calcareous rocks because smaller crystallochemical radius of magnesium compared with calcium. Similar conditions for the preservation of strontium compounds in calcareous rocks are created in the useful strata of Cretaceous and / or limestone, from below and above surrounded by clay layers or layers containing a little sand or in the absence of the latter. Then, the initial impurities of strontium compounds in the calcareous sediments of shallow ocean, sea or lake basins do not erode and are not removed from the useful strata of the latter, remaining in the form of autochthonous minerals, similar to that found in cement limestones, chalks and marls formed on the outskirts the great ocean of Tethys, which existed in the Cretaceous on the site of Central and Eastern Europe, including the European part of Russia, in particular in the Middle Volga deposits, as well as in the corresponding months the births of the Great Marl-Cretaceous arc, starting in the Novorossiysk region in Russia and continuing through the east of Ukraine (south of Donbass) - marls, Belgorod region of Russia, Volyn in Ukraine, Moldova, Romania, Hungary, Serbia, Croatia - mostly chalk, to the Po valley in Italy with branches of this arc into southern Poland (Lubelskie Voivodeship) - marls, to the southern lands of Germany, in particular Bavaria - marls, and then to the Rhone Valley in France, and to central Italy - mainly marls, and in the Southern Hemisphere created similar conditions in the Southern Hemisphere were found in chalks of New Zealand and southern Australia. Thus, calcareous sediments with impurities of strontium compounds are quite widespread, but these impurities are not taken into account when adjusting the composition of raw mixtures. Therefore, it cannot be argued that raw mixtures with the indicated content of strontium compounds are stably used by cement plants using these strontium-containing lime ingredients. On the other hand, the introduction of strontium-containing minerals separately, in the form of a special ingredient, in particular strontium sulfate, available in spent fireworks, into the cement raw material mixture according to the invention is not allowed, because in this case, regardless of the averaging conditions of the ingredients, the distribution of strontium compounds will not be uniform, and, therefore, most of the strontium will fall practically into the alkaline-sulfate eutectic, regardless of the “alkaline” module and the alumina module of the raw material mixture, and, consequently , Pass advantageously into clinker alyumoferritnuyu phase, where, as already mentioned, positive effect on the properties of the cement may not manifest. In the presence of strontium compounds in the silicate ingredient, due to the presence of aluminum atoms in coordination polyhedra with Sr - O - Al bonds and their earlier compared to similar groups including silicon atoms instead of aluminum, the output of strontium into the liquid phase is extracted into the eutectic and its presence in silicate phases is significantly lower than when it is present in the calcareous ingredient of the raw mix. This is even more true for strontium compounds present in the glandular ingredient. This explains the need for the presence of strontium compounds in the raw material mixture according to the invention mainly in the form of impurities in the lime ingredient;
2) at the indicated values of the alumina module p = Al ₂ O ₃ / Fe ₂ O _{3, the} design content of aluminate phases in the Portland cement clinker obtained by calcining the specified raw material mixture does not exceed 5% of the mass, and there are no aluminate phases near the indicated lower limit p, while all alumina enters the aluminoferrite phase of said clinker. In this case, strontium is more actively involved in the silicate phases of clinker, since eutectic contains little aluminum and, when a silicate phase is embedded in the crystal lattice, the more compact and light weight atomic group Sr - O - Si prevails over the equally compact but heavier group Sr - O - Fe and especially over the Sr - O - Al group loosening the structure. With a larger value of the alumina module in comparison with the indicated interval, strontium destroys the cubic crystal lattice of the aluminate phase and releases calcium from it, forming free lime at a clinker saturation coefficient with lime (hereinafter abbreviated as KN) above 0.85 (as calculated by V.A. Kind) . Therefore, when the values of the alumina module are increased against the indicated range, it is impossible to burn high alite clinkers with increased KN in the presence of strontium, high strength and elastic modulus of cement obtained from such clinkers, while it is known that the higher the elastic modulus of cement stone, all other things being equal conditions less shrinkage deformation of cement stone. With a smaller value of the alumina module of strontium compared to the indicated interval, almost all of the clinker enters the aluminoferrite phase of clinker, which, due to the reduced hydration rate of the latter after mixing the obtained cement with water, practically eliminates the entry of strontium impurity into the hydrosilicate matrix of the cement stone. However, the problem of the invention in this part cannot be solved;
3) at wt. the ratio of alkali metal oxides in terms of Na ₂ O and sulfur trioxide, which is hereinafter abbreviated as the alkaline module of the raw material mixture and obtained by firing Portland cement clinker, equal to about 0.7 - 1.5, the aluminate phase of the clinker is not part of the primary alkaline eutectic . The opposite is observed at a lower value of the specified alkaline module compared to the above range. In the latter case, strontium is extracted by the resulting sulfate-alkaline eutectic from the primary phases, into which it enters from the lime ingredient of the raw material mixture, and is sent in the form of sulfate to the aluminate phase, destroying the latter with the adverse effects mentioned above, and forming strontium-containing calcium sulfoaluminate, in the future soluble in belite and aluminoferrite phase, in both cases removing strontium from actively hydrated clinker phases and sharply reducing its effect on the properties of the cement matrix. With a larger value of this module, instead of the highly basic aluminate phase (C ₃ A) with a cubic crystal lattice, an alkaline calcium aluminate (RC ₈ A ₃ ) appears in the clinker with an orthorhombic lattice that does not accept strontium, but creates an excess of calcium compared to the calculated one, which also interferes with firing highly basic clinkers with a high content of alite (C ₃ S) with the mentioned adverse effects. In this case, strontium is forwarded through the indicated eutectic to the aluminoferrite phase with the loss of its useful role.

 An analysis of the above features of the invention shows that it prevents the stability of the positive effect of the presence of strontium compounds in the raw material mixture known from the prior art, primarily non-compliance with the ranges of alumina and alkaline modules, which was first experimentally established by the authors of the present invention. These conditions for the manifestation of the positive effect of strontium compounds in the raw mix and clinker obtained by its calcination are necessary.

Additionally introduced barium, being a larger and more basic cation compared with strontium, acts in the same direction, but more roughly: instead of C ₃ A, it does not produce C ₂ A ₇ , as in the presence of strontium at lower compared to the optimal range is the value of the alkaline module, and the mineral BaO • Al ₂ O ₃ is barium monoaluminate. In the aluminoferrite phase under the same adverse conditions, in particular at higher alkaline module values compared to the optimal interval, barium enters in a larger amount than strontium. All this was established by the authors of the present invention by the method of a passive experiment in the selective chemical analysis of Portland cement clinkers with impurities of strontium and barium compounds with alumina and alkaline modules varying over wide ranges. For this reason, barium is in these small concentrations in comparison with the concentrations given in the prototype [12], which are a useful additional impurity to strontium. It is noteworthy that in the raw material mixture according to the invention, its positive effect on the properties of cement is manifested at concentrations an order of magnitude lower than the optimal ones known from the prototype. In the range of barium compounds in terms of oxide specified in the invention, this impurity does not yet exhibit a stable positive effect in the technical solution according to the prototype. The reasons for the instability of the beneficial effect of barium oxide in the technical solution according to the prototype, as follows from the above, are the same as for the impurity of strontium compounds. Moreover, the natural origin of the compounds in which barium is part of the cement raw material mixture according to the invention is not as significant as for strontium, precisely because the effect of barium is more pronounced, regardless of which ingredient in the raw mixture it is present. The concentration of BaO in the clinker required to achieve a useful effect in technical solutions known from the prior art cannot be achieved without introducing an additional barium-containing ingredient into the raw material mixture, in particular barite ore or lithoponic waste, while the content of barium compounds in the raw mixture required according to the invention according to the invention is often achieved without such measures, due to the impurities of barium compounds in the calcareous, silicate and ferruginous ingredients, especially in the last day.

An additional prerequisite is the increased value of the KH of the raw material mixture in terms of clinker, which allows to increase the yield of strontium and barium-containing alite in the clinker obtained by firing the raw material mixture according to the invention. It should be noted that for KN values greater than 1, the values of the alumina module of the raw material mixture according to the invention should be in the range of 0.5 - 0.7, which excludes the formation of calcium aluminates and ensures the formation of a portion of the alite of the hyperalite phase C _3.3 - _3.8 S [14], which also includes impurities of strontium and barium, but much more active in interaction with water compared with alite.

 The invention in terms of cement raw mix becomes clearer from an example of its implementation.

Example 1. The conditions for carrying out the invention are as follows. For the preparation of the raw mixes according to the invention, in the first series of experiments carried out under production and laboratory conditions, the raw material department of the cement plant operating by the wet method is used by two-stage grinding, first in a self-grinding mill of the Hydrofol type with a diameter of 7.0 m and a length of 2, 3 m, then in two tube mills with a diameter of 3 m and a length of 8.5 m, single chamber, with a fill factor of 0.27 grinding media. The resulting sludge with the help of correcting pools is adjusted to the required chemical composition, averaged in a horizontal pool with a capacity of 6000 m ³ and pumped into the furnace through nutrient devices. Slurry humidity 35.6%, cone spreadability M.S. Neginsky 49 mm.

Raw Ingredients:
calcareous - limestone with humidity (here and below wt.%): on average 18.4, composition pp pp 41.18, SiO ₂ 2.92; Al ₂ O ₃ 1.10; Fe ₂ O ₃ 0.88; CaO 52.21; MgO 0.53; SO ₃ 0.42; R ₂ O 0.09; including Na ₂ O 0.06; K ₂ O 0.05, amount 99.33 on major oxides, n 2.78; p 2.03, small components: Li ₂ O 0.005, BaO 0.01, SrO 0.08, NiO 0.005, CoO 0, Mn ₂ O ₃ 0.014, Cr ₂ O ₃ 0.02, MoO 0.01, TiO ₂ 0.25, P ₂ O ₅ 0.23, Cl ₂ 0.005, F ₂ 0.001;
aluminosilicate - clay with a moisture content of 20.2 composition: 10.99; SiO ₂ 62.15; Al ₂ O ₃ 14.98; Fe ₂ O ₃ 7.38; CaO 0.89; MgO 0.69; SO ₃ 0.39; R ₂ O 2.21, including Na ₂ O 1.01; K ₂ O 1.82; the sum of 99.68 on the main oxides, n 2.78; p 2.03, small components: Li ₂ O 0.001, BaO 0.002, SrO 0.001, NiO 0.008, CoO 0.001, Mn ₂ O ₃ 0.01, Cr ₂ O ₃ 0.11, MoO 0.01, TiO ₂ 0.136, P ₂ O ₅ 0.03; Cl ₂ 0.01; F ₂ 0.001;
ferrous - pyrite cinder with a moisture content of 12.10% of the composition: SiO ₂ 11.17; Al ₂ O ₃ 0.97; Fe ₂ O ₃ 76.72; CaO 3.55; MgO 1.96; SO ₃ 4.47; R ₂ O 0.63, including Na ₂ O 0.35, K ₂ O 0.43; the sum of 99.47 on the main oxides, n 0.14; p 0.12; small components: Li ₂ O 0.001, BaO 0.08, SrO 0.002, NiO 0.037, CoO 0.03, Mn ₂ O ₃ 0.09, Cr ₂ O ₃ 0.24, MoO 0.06, TiO ₂ 0.02 , P ₂ O ₅ 0, Cl ₂ 0, F ₂ 0;
strontium-containing: CA: strontianitocalcite: limestone mixed with this mineral in the form of a strontianitic interlayer; content in terms of SrO 2.5 - 3% of the mass; SB: strontianite calcareous ore, including strontianite in terms of SrO 15 - 18% of the mass - the product of the enrichment of ingredient A; SV - celestine calcareous ore, including in terms of SrO 22 - 24% of the mass;
barium-containing: VA: barium sulfide - a secondary industrial product, including in terms of BaO 7 - 12% of the mass; BB: viterite ore, including in terms of BaO 2 - 4% of the mass; BC - barite ore, including in terms of BaO 3 - 8% of the mass.

 For a control feed mixture (without additives of strontium and barium-containing minerals), the ratio of the indicated initial ingredients (in parts by weight and in kg / t of clinker) is adjusted to obtain modular characteristics in terms of clinker, shown in table 1.

 For the raw material mixture according to the prototype, the specified lime ingredient and the ingredients CA and BC are taken as lime ingredients in an approximate ratio of 6: 1: 1 by weight, while maintaining an adjustable ratio of the starting ingredients to obtain the same modular characteristics.

 For the raw mixes according to the invention, the ratio of the starting ingredients is adjusted to obtain the various modular characteristics shown in table 1, in terms of clinker. It should be noted that, as can be seen from the background characteristics of the starting ingredients in terms of SrO and BaO, in the ordinary (control) raw material mixture they are significantly lower than those achieved in the raw material mixture according to the invention, and even more so according to the prototype.

 To adjust the composition of the raw mix for strontium and barium, the spectroscopic method is used for the former, and the standard chemical-analytical method according to GOST 5382-91 for the latter.

To obtain clinker and cement from raw mixes - the control, prototype and prepared according to the invention - as a clinker kiln, use a rotary kiln with a diameter of 5.8 and a length of 185 m, heated by natural gas with a calorific value of about 6700 kcal / kg, or about 28000 kJ / kg, with an average clinker productivity from the control raw mix of 70 t / h, from the mixture according to the prototype 72 t / h and from the mixture according to the invention from 72 to 75 t / h depending on the modular characteristics calculated by the formulas
KN = [C (1.65A + 0.35F)] / 2.8S, (1)
silicate module n = S / (A + F), (2)
alumina module p = A / F, (3)
whence for the calculated (potential) mineralogical composition according to V.A. Kindu have
C ₃ S = 3.8 • SiO ₂ (3KH - 2), (4)
C ₂ S = 8.6 • SiO ₂ (l - KH), (5)
C ₃ A = 2.65 (A - 0.64F), (6)
C ₄ AF = 3.04F. (7)
The results of the experiments, shown in table 1, include data on the characteristics of the average clinker samples: the content of two technically most important impurities - SrO and BaO, as well as the characteristics R ₂ O / SO ₃ and Al ₂ O ₃ / Fe ₂ O ₃ essential for the invention = p, CN, and the content in the finished clinker free calcium oxide (CaO _svob) or a free lime and iron monoxide (FeO), or ferrous oxide. The content of SrO and BaO impurities is given according to the spectral and chemical analysis of average samples of raw mixes, the remaining characteristics are according to chemical analysis of average clinker samples obtained by firing these mixtures. Details are given in the notes to table 1.

To test products obtained from raw mixes - clinker and cement - the first is crushed together with a gypsum component in a laboratory bicameral mill of periodic action lined with cast iron armored plates, with the dimensions of each chamber: length 0.28 m, diameter 0.5 m, rotation speed 48 min ^-1 , drive power 1.1 kW, engine speed 930 min ^-1 , grinding load on each chamber (with portland cement about 10 kg in each chamber): tsilpebs with a diameter of 20 mm and a length of L 32 mm 5 kg, duration mixing 15 min. The grinding of cement is carried out with the measurement of its specific surface according to the method of breathability, in this case, using the device according to G.S. Khodakov. Further, the strength characteristics of the obtained Portland cement are determined in a standard cement-sand mortar prepared according to GOST 310.4-81 by testing 4 x 4 x 16 cm beam samples after standard storage: first for 1 day in an air-moist environment, then for 3 and 28 days in water with a temperature of 17-23 ^o C.

To determine the deformative properties (shrinkage and expansion) of the obtained cements, the following methodology is used. A cement-water suspension (cement paste) is prepared manually according to GOST 310.3-76 and filled with prism forms (beams) with dimensions of 2 x 2 x 13 cm as follows. On a steel sheet, which is faced with the surface of the laboratory bench, collect molds for the manufacture of these samples, including each rectangular metal pallet, on which a steel frame is installed, including three slots for forming prisms. At the centers of the end walls (2 x 2 cm) of each nest there are hemispherical recesses that are filled with plasticine. In the latter, steel balls with a diameter of 5 or 6 mm are pressed into a depth of 2–3 mm, thereby fixing them on the walls of the nests in the frame. Then the frame is shaken several times, hitting the edge of the steel table lining to check the strength of the balls. After making sure that the balls hold tight, the prepared frames are mounted on steel pallets. The places of contact between the frames and pallets are carefully walled up with hot grease, consisting of a mixture of paraffin and rosin (3: 1), 4 g for each frame. Then the molds are filled with the indicated materials and compacted in the same way as they are done in the manufacture of samples for strength testing according to GOST 310.4-81, i.e. on a vibrating table with an oscillation frequency of 3000 min ^-1 , previously rigidly fixing the forms on the vibrating table using mechanical clamps.

46-50 hours after mixing of the indicated materials, the prisms with balls installed in their ends are removed from the molds, marked and immediately placed in an air-moist environment with a relative humidity (W) of at least 95% and a temperature of 17-23 ^o С (medium 1) . Next, the linear dimensions of the samples are measured after a specified time and compared with the first measurement made immediately after the formwork.

 To test the samples for compressive strength, a standard hydraulic press with a self-adjusting top plate is used, when bending (tensile when bending), a testing machine for loading the beams according to a three-point scheme, when testing shrinkage deformations, a device according to GOST 11052-74 for measuring linear shrinkage strains / extensions equipped with an hour indicator micrometer with a scale with divisions through 0.01 mm and two hands, of which the larger indicates fractions of a millimeter, and the smaller indicates millimeters, with each millimeter corresponding There is no full revolution of the big arrow. The indicator is equipped with a hemispherical recessed pin for tight contact with the balls fixed on the samples and fixed on the rails in such a way that the distance between the first indication of the indicator arrows and the lower end of the measuring cell into which the prism is mounted remains always constant and then changes as changes in the linear dimensions of prisms.

The initial components of cement, in addition to the mentioned Portland cement clinker:
gypsum component (HA): gypsum stone, including, according to petrographic analysis, 1.5 wt.% clay impurities;
active mineral additives (AMD):
natural, sedimentary origin: flask composition (wt.%): pp 17.36; SiO ₂ 52.03; Al ₂ O ₃ 6.25; Fe ₂ O ₃ 3.54; CaO 17.31; MgO 1.67; SO ₃ 0.05; Na ₂ O 0.25; K ₂ O 1.54;
artificial: slag blast furnace granular composition (wt.%): pp 0.36; SiO ₂ 31.75; Al ₂ O ₃ 10.63; Fe ₂ O ₃ 2.12; MnO 0.30; CaO 50.90; MgO 1.24; S (sulfide ion) 2.09; SO ₃ 0.30;
water-reducing components (VK):
modifier for cement MTs-1 according to TU 5743-026-00369171-01 - a mixture of polymethylene polynaphthalenesulfonates and sodium sulfate - an analogue of S-3 in the form of a powder - microgranules;
a mixture of MC-1 and technical lignosulfonates in wt. ratio 1: 0.3 in powder form;
a modifier based on melamine resin - "Peramin"(imported);
modifier based on calcium nitrate and low molecular weight monosaccharides - own production of the inventors.

When these water-reducing components are introduced into the cement during joint grinding of the cement components, the resulting product is called cement of low water demand and meets the technical conditions developed for this type of cement;
expanding additive (RD): RD1: based on sulfoaluminate clinker, synthetic fatty acids of fraction C ₁₇ - C ₂₀ and sulfobenzoic acid in wt. ratio of 100;
RD2: based on aluminum sulfate, drying oils of phthalic and phthalic acid in wt. ratio of 100: 30: 10; 9 - based on sulfoaluminate clinker, a mixture of technical stearic acid and ceresite (one of the fossil waxes) in wt. 1: 1 ratio and a mixture of sulfobenzoic, maleic and mannuronic (one of the aldonic) acids in wt. the ratio of 1: 1: 1, with a total wt. the ratio of the components of the RD 100: 2.5: 20;
All source materials comply with state standards and other regulatory and technical documentation.

 The expanding additive according to the invention is prepared by mixing the components in a laboratory stirrer LM1 of a cylindrical type with a length of 30 cm and a diameter of 5 cm, filled with steel balls with a diameter of 1.0-1.2 cm at 15 vol. % with powdered components of the additive and 30 vol.% with a mixture of powdered and liquid components of the additive, for 20 minutes

 The test results, as follows from the data shown in table 1, cement raw mixes according to the invention in lines 3 and below, compared with the control raw mix and raw mix according to the prototype, lines 1 and 2, respectively, confirm the significant beneficial effect of the additives according to the invention, and namely, a significant increase in strength indicators and a multiple decrease in shrinkage deformation of cement stone, which corresponds to the above explanation of the invention. At the same time, an active mineral additive in combination with a high alumite clinker obtained using a promoter, as well as a hyperalite clinker (lines 4 and 5 of table 1, respectively) does not increase shrinkage deformations, and in the case of Portland cement based on hyperalite clinker, it does not prevent shrinkage of cement stone. When using strontium- and barium-containing raw mixes according to the invention, the low water demand cement (row 6 of table 1) is non-shrinking in the absence of an expanding additive, in contrast to the published data on this cement. According to the data in row 7 of table 1, when using strontium- and barium-containing feed mixtures according to the invention, Portland cement becomes expandable when only 0.5% by weight of the expanding agent is added. This result is a record: the cost of expanding Portland cement is almost the same as the cost of ordinary Portland cement, if you do not take into account the preliminary costs, in this case, to establish the optimal dispersion of the specified Sr-Ba-containing Portland cement by successively changing the content of the expanding additive and the level of dispersion ; when using the methods of mathematical design of the experiment, the number of experiments to achieve optimum variables — the RD content and the specific surface area of cement — is reduced to six trials that take approximately 30 days, although these costs are one-time; with further production, only a slight adjustment is required. As for cement of low water demand, the required content of expanding additive to achieve the expansion of cement stone is also low (1-4 wt.%, Lines 8 and 9 of table 1), and the excess content of the specified additives in Portland cement (see line 7 of this table) due to the lower specific surface area of the latter compared to cements of low water demand (see lines 8 and 9 of table 1). At the same time, regular dependences of the properties of these materials with an expanding additive on its composition are observed: sulfoaluminate compositions of the additive are always more effective compared to those containing aluminum sulfate.

It should be noted that both the compositions of the water-lowering component presented in Table 1, as well as the others mentioned above and including the condensation products of melamine-containing resins, as well as compositions based on monosaccharides and their combinations, and mixtures of these substances, as well as their mixtures with electrolytes, can be obtained the results are almost similar to those shown in table 1. The differences relate only to the consumption of the water-reducing component in the manufacture of cement of low water demand, as well as to the relationship of the specified consumption with the size of alkaline m modulus. Salts of derivatives of naphthalene sulfonic acid and technical lignosulfonates can be used at any value of the alkaline module within the specified range, but with its increase, the consumption of the water-reducing component should be increased from about 0.8 - 1.2 to 1.5 - 2 wt. hours for 100 wt. including clinker component. Salts of derivatives of melamine-containing resins should be used only in combination with a clinker component, characterized by an alkaline modulus of 0.7 - 1 and a content of alkali metal compounds in terms of R ₂ O of not more than 0.8 wt.%, At a flow rate of from about 0.7 to 1.6 wt.h. at 100 max. clinker ingredient. Finally, complex salts of alkaline earth metals with monosaccharides should also be used in combination with low alkaline clinkers, and their flow rate should be kept at about one third lower than that indicated for salts of derivatives of melamine-containing resins.

Tests of the numerous compositions of the expanding additives mentioned above with the use of film formers of all four of the listed groups, as well as etching agents of all 11 of the listed groups, also allow to obtain results in optimal combinations that are almost similar to those shown in table 1, taking into account the following features:
1) the mass of film-forming substances in the expanding additive increases within the specified range with respect to the mass of sulfoaluminate clinker or aluminum sulfate in the following series: technical stearic acid is no more than a mixture of technical stearic and oleic acids no more than synthetic fatty acids of fraction C ₂₁ - ₂₂ C less than synthetic fatty acid fraction C ₁₇ - C ₂₀ less than technical arachidic acid less than technical oleic acid less than fossil waxes no more than the mixture and digging waxes with any of the above acids in this series is less than synthetic waxes less than a mixture of synthetic waxes with any of the above acids in this series is less than flax wax less than a mixture of flax wax with any of the above acids in this series is less than than prepared fatty oils (castor oil, its acid derivatives, peanut, soybean) are approximately the same as mixtures of these oils with any of the substances listed above in this series are less than natural quick drying oil imerno same as mixtures of said drying oil with any of the above substances in a given row is not more than linseed natural polymerized about the same as the mixture of said drying oil with any of the above substances in a given row less than linseed oil semisynthetic combination classes K ₃ - K _{5 is} about the same as a mixture of the specified drying oil with any of the above substances in this series of phthalic drying oil is about the same as a mixture of the specified drying oil with any of the above substances in this series is no more than a semi-synthetic drying oil polymerization is approximately the same as a mixture of the indicated drying oil with any of the above substances in this series is less than an emulsion drying oil with CaO emulsifier is approximately the same as a mixture of the specified drying oil with any of the above substances in this series is less than solutions of any of the above higher substances in this row in mineral oil. The minimum values of the mass of the film former in the expanding additive relate mainly to the first members of the above series, and the maximum values mainly to the last members of the above series;
2) the mass of etching agents in the expanding additive increases within the specified range with respect to the mass of sulfoaluminate clinker or aluminum sulfate in the following series: technical sulfobenzoic acid is about the same as benzoic acid, no more than hydroxymethylbenzoic acid, about the same as phthalic acid less than hippuric acid less than propiolic acid no more than sulfosalicylic acid about the same as salicylic acid no more than pyruvic acid m than maleic acid is about the same as methylmaleic acid is about the same as fumaric acid no more than the anhydrides of the above acids in about the same order no more than glycolic acid no more than glyoxalic acid no more than mesoxalic acid no more than glyoxylic acid no more than sorbic acid no more than ricinoleic acid no more than acrylic acid no more than aldonic acids less than crotonic aldehyde about the same as mannitol no more than ethylene glycol less than adipic acid is approximately the same as the anhydrides of the above acids to glycolic in approximately the same order is approximately the same as methylethylcarbinol no more than adipole no more than levulinic acid ≤ phenylglycine less than crotonaldehyde less than cycloheptanol less than resin acids in paired mixtures with the above substances in this series are approximately the same as mixtures of any of the above substances. In addition, it is possible to use as components of the latter also by-products and industrial wastes including these substances from this series as crude components, as well as acidic by-products and wastes of various chemical and pharmaceutical industries, for example formic acid, acetic acid, citric acid, ascorbic acid, pure acidic chemicals, production of synthetic resins with a volatility of not more than 5 mg / m ^{3 of} air of the working area. The minimum values of the mass of the etching agent in the expanding additive relate mainly to the first members of the above series, and the maximum values mainly to the last members of the above series. It should be noted that salicylic and sulfosalicylic acids, as well as their anhydrides, are especially effective for cements based on raw mixtures with an alumina module in the range of 0.5 - 1, since they form not only aluminum but also organo-iron compounds.

 From the results shown in table 1, it follows that the first objective of the invention - the creation of a cement raw material mixture, which allows after firing Portland cement clinker based on it to obtain the minimum shrinkage deformation of cement stone made from Portland cement based on the specified clinker, is solved.

 The specified cement raw mix does not allow to obtain the maximum technical effect without using the method of manufacturing Portland cement with reduced shrinkage obtained from clinker based on the specified mixture.

The prior art proposed A.E. The Sheikin method of manufacturing Portland cement with reduced shrinkage, characterized by a mineralogical composition comprising four components: tricalcium silicate (alite, C ₃ S), dicalcium silicate (C ₂ S), tricalcium aluminate (C ₃ A), aluminoferrite phase (usually tetracalcium aluminoferrite, C ₄ AF), which consists in limiting the content of C ₃ A and C ₂ S to 5 and 15% of the mass of cement, respectively, that is, reducing the content of clinker phases, which, after mixing the specified cement with water, increase the composition compared to other They contain a fraction of the content of hydrated phases in the form of gels, which undergo a greater shrinkage during cement hardening as compared with hydrated phases with an increased fraction of crystals formed from С ₃ S and C ₄ AF [15]. Although this explanation, first expressed by the author of this technical solution back in 1943, currently does not find support, the method itself was later confirmed by the most authoritative sources [16, 17] and is taken into account by the current SNiP: restriction of the content of tricalcium aluminate and belite in Portland cement with reduced shrinkage is considered appropriate at the present time. The disadvantage of this technical solution is that in this way it is not possible to obtain non-shrink Portland cement: the minimum shrinkage in the best samples from a cement paste of normal density under the indicated limitations of the mineralogical composition of clinker is approximately 1.2 - 1.4 mm / m at 28 days of age when stored in an air-humid environment with a relative humidity of more than 95%.

Also known is Portland cement with reduced shrinkage, produced in Sweden and characterized by the following contents of the indicated minerals: C ₃ S 81, C ₂ S 1, C ₃ A 5, C ₄ AF 7, impurities - the rest, characterized by an alumina module of about 1.4, KN 0.996, the joint grinding of which with a gypsum component, taken in an amount of 3.5% of the mass of cement, is carried out to a specific surface of 4500 m ² / kg, with a value of shrinkage strain measured under these conditions, about 1 mm / m [18]. This result is superior to that obtained according to the previous technical solution and is a logical conclusion to the main idea of A.E. Sheikin stated above about the maximum restriction of the content of C ₃ A and C ₂ S in Portland cement clinker to obtain Portland cement with reduced shrinkage. Tests of this Swedish Portland cement were carried out in Poland, and the results were transferred to NIICement under a cooperation agreement with the Polish Institute of Cementing Materials (Opole) and, in addition to the publication, are also contained in the NIICement report on joint work. However, according to Swedish researchers, the production of such a clinker requires high energy costs for exceptionally fine grinding of the raw material mixture and high fuel costs for its firing, and the resulting product is characterized by insufficiently stable quality, including inconstancy of shrinkage, therefore, to date, the production of cement by the method according to this technical solution in Sweden discontinued. Thus, the indicated idea of Sheikin in a logically complete form turned out to be industrially impracticable, although the result obtained by limiting the shrinkage of cement paste without introducing expanding additives remains the best known in the art.

 Closest to the invention, the technical solution (prototype) is a method of manufacturing Portland cement with reduced shrinkage from Portland cement clinker, obtained by firing before sintering a cement raw material mixture containing lime, silicate and ferrous ingredients, as well as strontium compounds in terms of oxide in the amount of 0.03 - 0.5% of the mass, and subsequent joint grinding of the specified clinker with a gypsum component [19]. In the presence of this impurity, but in quantities increased up to 3% of the mass, the strength properties of cements significantly increased, including in the early stages of hardening, with the exception of high-alumina ones (p. 311 of this work). In the presence of barium impurities, similar in mechanism of action, to barium impurities, belite and low aluminate cements are also most effective (pp. 308–311 of the mentioned source). As indicated above, the increase in the strength of cements, ceteris paribus, is antibacterial to shrinkage deformations, therefore, these impurities contribute to the reduction of shrinkage deformations of cement from clinker obtained by firing the specified raw material mixture, without undesirable consequences in the form of an increase in energy consumption for firing clinker and grinding cement, in contrast to the previous technical solution; on the contrary, in [19] a decrease in the energy consumption for cement grinding in the presence of the indicated impurities in the clinker is mentioned. But the disadvantage of this technical solution is similar to the previous one: the experiments of the authors of the present invention indicate that the minimum shrinkage achieved with cement made according to this method is approximately 1-1.2 mm / m.

 The objective of the present invention in terms of a method of manufacturing Portland cement with reduced shrinkage is to drastically reduce the shrinkage deformations of the obtained cement compared to the prior art, up to zero values when measured under the above conditions without the use of an expanding additive, and also to reduce the content of this additive to a minimum level, down to up to 0.5 - 2% of the mass of cement. This decrease allows to decisively increase the volume of implementation of the specified cement in the construction complex.

This problem is solved by the fact that in the method of manufacturing Portland cement with reduced shrinkage from Portland cement clinker, obtained by firing before sintering a cement raw material mixture containing lime, silicate and ferrous ingredients, as well as strontium compounds in terms of strontium oxide in an amount of 0.03-0 , 5% of the mass, alkali metal oxides and sulfur trioxide, and subsequent joint grinding of the specified clinker with a gypsum component, the cement raw material mixture contains strontium compounds in the lime ingredient in ide of natural minerals from the group of calcitostrontianite and / or strontianite, and / or celestin with an alumina module of the specified mixture of 0.5-1.25 and wt. the ratio of alkali metal oxides in terms of sodium oxide Na ₂ O and sulfur trioxide 0.7-1.5, while firing is carried out in an oxidizing atmosphere until the content in clinker, wt. %: free calcium oxide 0.05-0.8 and iron monoxide 0.01-0.3, and joint grinding is carried out at a mass ratio of the specified clinker and gypsum component in terms of sulfur trioxide 100: (0.3-6) to specific surface area in the range of 250-700 m ² / kg and taking into account the criterion of minimum shrinkage in the air-moist environment of samples from cement paste.

 In an embodiment of the invention, said raw material mixture further comprises barium compounds in the form of sulfide and / or witherite and / or barite in terms of barium oxide in an amount of 0.15-0.5%.

 In another embodiment of the invention, the coefficient of saturation of lime is taken in the range of 0.9-1.15 in terms of Portland cement clinker.

 In the third embodiment of the invention, calcium sulfate is taken as a gypsum component in the form of a natural gypsum stone, comprising 0.01-1.5 wt.% Clay impurities.

 In a further embodiment of the invention, when co-milling, an active mineral supplement is additionally added in an amount of 0.5-40 wt.%.

 In an embodiment of the invention, the moisture content of the active mineral additive before co-grinding is 6-12 wt.%.

 In another embodiment of the invention, when co-milling, a water-reducing component is additionally introduced at a mass ratio of said clinker and water-reducing component 100: (0.3-2.5).

In another embodiment of the invention, materials from the group are used as a water-lowering component of said Portland cement: a salt of an alkaline earth and / or alkali metal product of the condensation of naphthalene sulfonic acid with formaldehyde, a salt of an alkaline earth and / or alkali metal product of the condensation of melamine-containing resins with formaldehyde, a technical alkaline earth lignosulfonate and / or alkaline metals, ordinary or modified phenol-formaldehyde resin, a complex salt of an alkaline earth metal and sulfuric and / or otnoy and / or formic and / or acetic acid with low molecular monosaccharides C ₃ -C _5, the paired mixture of these materials in a weight ratio of from 4: 1 to 1: 4.

 In another embodiment of the invention, joint grinding is carried out in a ventilated grinder with a degree of aspiration of the latter corresponding to the sanitary minimum, controlled by the absence of dusting from the inlet neck of the grinder.

 In a further embodiment of the invention, co-grinding is carried out with the additional introduction of an expanding additive, comprising as components sulfoaluminate clinker or aluminum sulfate, a film former and etching agent, with a weight ratio of said clinker and said additive of 100: (0.5-4).

In an embodiment of the invention, a prefabricated mixture of sulfoaluminate clinker or aluminum sulfate, a film former and an etching agent is used as the additive, and hydrophobizing substances from the groups are used as a film former: higher fatty acids — synthetic fatty acids of the C ₁₇ -C ₂₂ fraction, technical stearic, arachinic , oleic acid, paired mixtures of these substances, drying oils - natural - polymerized and quick-drying, semi-synthetic - polymerized, combined class K ₃ -K ₅ , phthalic, emulsion with emulsifier calcium oxide CaO, paired mixtures of these substances, waxes - flax, fossil, synthetic - the product of esterification of oxidized paraffins, vegetable oils
- fatty preparations, their paired mixtures with substances of the previous groups and / or secondary products and wastes containing them, solutions of substances of any of the above groups in mineral oil, and substances that selectively activate aluminates, calcium sulfoaluminates of calcium and aluminum salts are used as an etching agent the specified additive, from the groups: pyruvic acid, aldonic acids, levulinic acid, mesoxalic acid, aromatic acids - industrial benzoic acid, sulfobenzoic acid, hydroxymethylbenzoic acid, phthalic acid, hippuric acid, their acid derivatives, anhydrides of the indicated acids, unsaturated carboxylic acids - acrylic acid, propiol acid, sorbic acid, ricinoleic acid, hydroxy acids - glycolic acid, glyoxal acid, their acid derivatives, salicylic acid, sulfosalicylic acid their derivatives, carbocyclic compounds - adipic acid, its anhydride, phenylglycine, cycloheptanol, dicarboxylic compounds - maleic acid, methylmaleic acid, fumaric acid, and nhydrides of these acids, resin acids in paired mixtures with substances from the previous groups, alcohols - adipole, mannitol, ethylene glycol, methylethylcarbinol, aldehydes - glyoxylic acid, crotonic aldehyde, paired and ternary mixtures of these substances and / or secondary products and wastes containing them, with the mass ratio of the components in the specified additive 100: (2.5-30) :( 2-20), respectively.

 The essence of the invention in terms of a method of manufacturing Portland cement with reduced shrinkage during the firing process of strontium and strontium-barium-containing clinker is that the oxidizing medium is strictly maintained throughout the sintering zone. The reason is the probability of the formation of a common clinker liquid phase in the eutectic composition in the local zones of the rotary kiln with the reducing medium of strontium ferrite. One of the factors that ensure the appearance of the latter is equal deviations from the relative basicity of the indicated eutectic clinker melt (hereinafter abbreviated ECR) equal to 1, the values of the relative basicity of SrO (+0.09) and FeO (-0.09). The presence of strontium ferrite in clinker, calcined in a reducing medium, was actually experimentally recorded during its burning and, as experience shows, completely eliminates the positive effect of strontium compounds on the technical properties of cement due to the fact that strontium ferrite, which occurs during crystallization of clinker minerals during clinker cooling in aluminoferrite phase, virtually eliminates strontium from the hydrated phases involved in the formation of the matrix of cement stone in hardening cement due to being too slow constant rate of hydration alyumoferritnoy phase comprising said ferrite. This also applies to barium.

 Due to the presence of technologically important small constituents of the cement raw material mixture and the clinker obtained from it according to the invention, which are strontium and barium in this method, and their deactivation even with slight deviations from the firing regime in an oxidizing environment, acceptable for high quality clinker at a known level techniques, activities carried out to maintain the specified mode of firing, also go beyond known from the prior art. In this case, there can be no talk of either burning or burning of the indicated clinker, which are equally unacceptable: in the first case, due to the presence of unbroken clinker along with free lime mayenite [20], which accumulates strontium due to excess vacancies; this distracts a significant part of strontium from the useful function of incorporation after mixing cement with water into the main matrix of cement stone. In the second case, in burnt clinker, mayenite arises as a secondary phase after a long stay of the clinker in the sintering zone of the furnace; he again collects strontium from the remaining phases, concentrates it and, dissolving when the clinker is cooled in the aluminoferrite phase, transfers strontium into it. The aluminoferrite phase in burnt clinkers fired in an oxidizing atmosphere is also hydraulically relatively passive, although to a lesser extent than in a reducing atmosphere, but ultimately with a similar adverse effect on the activity of strontium and / or barium impurities. Therefore, it is not sufficient to practically burn clinker by the method according to the invention according to the two above criteria: the content of free lime and the content of iron monoxide, trying to minimize their content within the indicated ranges, since both of these phases are determined in time samples of the finished clinker, between instants of selection of which the instability of the regime firing is not fixed. To stabilize the clinker firing mode according to the method according to the invention, the dust content of the sintering zone of the furnace, determined by the difference in the light absorption of visible and infrared light in the sintering zone of the furnace by two corresponding pyrometers, is used as a sensor for free lime. The readings of the pyrometers are continuously recorded, and the moment of their difference, corresponding to a fraction of more than about 10% of the luminous flux intensity, is considered a criterion for increasing the vacuum in the furnace by partially opening the diaphragm of the baking smoke exhauster and / or partially closing the diaphragm of the fan of the general blast of the clinker cooler, if any, and the primary air flow of the refrigerator is separately regulated in this furnace unit. The rationale for the relationship between clinker spraying and the burning or burning of clinker and, accordingly, the content in the last free lime, is the work [20], which has received worldwide recognition. As a sensor for iron monoxide, the value of the average frequency of the emission spectrum of the sintering zone, analyzed by a spectrometer from light fluxes in these pyrometers, is used. Red or blue shifts of the average frequency of the spectrum from the average level, recorded during normal operation of the furnace in both visible and infrared light, by about 10%, correspond to an increase in the likelihood of occurrence of underburning or burnout, respectively, and, therefore, an increase in the likelihood of zones with recovery conditions and FeO impurities in clinker, accompanied by deactivation of these small components. It is important that, unlike the previous method, the results of the frequency analysis of the emission spectra do not depend on the degree of dustiness of the furnace atmosphere and better “feel” the mode of the firing process in the firing zones remote from the furnace head, which is more important for the appearance of FeO impurity in comparison with an admixture of free lime.

The invention in terms of a method of manufacturing Portland cement with reduced shrinkage by the process of co-grinding the components of the specified strontium and / or strontium-barium-containing cement is that the specific surface area of the finished product is selected within the specified range for minimum shrinkage of the grinding product. The dependence of shrinkage on the specific surface of cement, known from the prior art, namely, “shrinkage is proportional to the specific surface of cement” [21] for strontium-containing clinkers at the indicated values of aluminous and alkaline modules differs from the known one due to the fact that strontium-containing calcium hydrosilicates are much larger degrees increase the elastic modulus of the cement stone, than the strength indicators, and the number of these hydrosilicates is greater, the higher the specific surface of the cement and speed, and akzhe its degree of hydration. Therefore, the dependence of shrinkage on the specific surface for strontium-containing, as well as strontium- and barium-containing cements is extreme. The position of the indicated extrema corresponding to minimal shrinkage on the specific surface scale in this case depends on the gypsum content in the cement. Moreover, a feature compared with the prior art is that the content of the gypsum component in terms of sulfur trioxide is kept close to the minimum (0.3 - 0.5% by weight), which is much lower compared to the generally accepted minimum known from the level technology (1.5% of the mass), at close to the minimum values of the alumina module (0.5 - 0.7) of the clinker ingredient and close to the minimum values of the "alkaline" module (0.7 - 0.8). Only in this case, when selecting the specific surface of strontium-containing and / or strontium-and barium-containing cement, the optimum specific surface area corresponding to the minimum shrinkage (0.5 - 0.7 mm / m) is wide and is in the range of 320 - 450 m ² / kg. At close to the maximum values of the alumina module within the specified range, equal to 1 - 1.25, and maximum values of the "alkaline" module, equal to 1 - 1.5, it is necessary to maintain close to the maximum within the specified ranges of the content of strontium and / or strontium compounds and barium, and the specific surface area of cement corresponding to the minimum shrinkage (about 0.7 - 0.8 mm / m) is also reduced compared to the above extremum, the latter tapering and is in the range of about 280 - 380 m ² / kg . The average values of alumina and alkaline modules located near the centers of the ranges indicated for them correspond to the average values of the content of strontium and strontium-barium compounds near the centers of the ranges indicated for them, as well as the average values of the gypsum component in cement and correspond to the average values of the extrema of the specific surface cement (about 300 - 400 m ² / kg), which corresponds to shrinkage indicators in the range of about 0.6 - 0.7 mm / m. In practice, the selection of the optimal specific surface for cement with a given level of content of these small components takes a long time. For this purpose, a set of cements of various specific surfaces within the specified range is made from the corresponding clinker and the shrinkage deformations of the cement stone made from them according to the specified procedure are determined, considering, as already mentioned, the specific surface area of cement with the minimum shrinkage stone as optimal. It was in this way that the optimum values of the specific surface and the minimum values of shrinkage were obtained, which are presented in Table 1 for various cement raw mixes, clinkers obtained from them and milled cement based on these clinkers.

Moreover, an increase in KH values within the range of 0.9 - 1 leads to a narrowing of the indicated optimums of the specific surface and a decrease in shrinkage by about 0.1 mm / m for approximately every 0.03 increase in the KH value. With an increase in KH values in excess of 1 in cement, in contrast to the centuries-old experience of cement technology (indicating an increase in shrinkage with the introduction of an active mineral additive [22]), an active mineral additive should be introduced to reduce shrinkage. The decrease in shrinkage is achieved due to the unusually fast start of the pozzolanic reaction, even during the grinding process, which is facilitated by the increased moisture content of the indicated mineral additive, which contributes to the grinding process at its empirically established level of not more than 12 wt.%, And the presence of the ultrafast hydrated above in the clinker according to the invention hyperalitis corresponding to KH above 1; both of these factors facilitate grinding and increase the proportion of strontium-containing and strontium-barium-containing hydrosilicates in the matrix of cement stone, which leads to a particularly low shrinkage of Portland cement obtained by the method according to the invention - from close to zero values to 0.3 mm / m - with specific surface area in terms of clinker component 320 - 380 m ² / kg. This result in a situation when during the summer season practically no energy is required to dry the mineral additive introduced into the cement, and during the winter season they are approximately halved compared to those known from the prior art, is the first major surprise of the invention compared to the level technicians. In the prior art, such a low level of shrinkage deformations is known either when Portland cement contains at least 14% expanding admixture, or as a result of autoclaving concrete. In this case, it was obtained from Portland cement without expanding additives under normal hardening, which is the second major surprise of the invention.

When a water-reducing component is introduced into the cement during joint grinding and transition of cement, respectively, from a Portland cement discharge to a low water demand cement discharge in accordance with current TUs [23] due to a decrease in water demand by about 20–30% compared to control cements of a similar specific surface without a water-reducing component, the specific surface extrema corresponding to the minimum shrinkage increase, and the values of shrinkage are significantly reduced. So, for the first time it is possible to achieve zero shrinkage values at 7-, 28- and 90-day-olds with a specific surface area of cement of low water demand in the range of 420 - 460 m ² / kg and KN in the range of 0.9 - 1. This result is the third major surprise inventions, since it is known from the prior art that, on the contrary, shrinkage deformations of cements of low water demand are higher than that of control Portland cement [24]. The reason for the lack of shrinkage in low water demand cement is that, as indicated in the last cited work, in low water demand cement, the matrix is monolithic in the sense that all the components of cement stone are fused together. Thus, the positive effect of strontium- and strontium-barium-containing compounds in the composition of the hydrated phases extends to the cement stone as a whole, which leads to the seemingly unexpected result.

With the additional introduction of a complex expanding additive based on sulfoaluminate clinker, or aluminum sulfate, film former and etching agent, the last two components are organic substances; they respectively represent:
substances from the groups are used in the film former: 1) higher fatty acids; 2) drying oils; 3) waxes; 4) vegetable oils; 5) mixtures of these substances. All of these substances form oxygen, water, and carbon dioxide protective colloidal shells (films) on the surface of the particles of the expanding additive, and then the matrix components;
substances from the groups are used in the etching agent: 1) aromatic acids; 2) their aldehydes; 3) unsaturated carboxylic acids; 4) hydroxy acids; 5) carbocyclic compounds; 6) dicarboxylic compounds; 7) alcohols: adipole, mannitol, ethylene glycol, methylethylcarbinol; 8) aldehydes; 9) ketones; 10) resin acids; 11) mixtures of these substances. All of these substances selectively interact with the aluminate and sulfoaluminate phases of the sulfoaluminate clinker, aluminum sulfate, as well as the aluminate phase of the Portland cement clinker with almost instant formation of organometallic, in this case organoaluminium complex compounds. They cannot form in the presence of atmospheric oxygen, moisture, and carbon dioxide, but they form under the protective film.

 At the same time, during joint grinding or when mixing with an expanding additive of both Portland cement and low water demand cement, a cell texture of the location of the expanding agent in the form of a mesh mesh surrounding all particles of cement, unknown from the prior art, is formed. The internal phase of the network, which forms on the surface of the particles of the expanding phase and matrix ingredients, is represented by the indicated organoaluminum compounds, and if strontium and / or strontium-barium-containing compounds are present in the Portland cement clinker due to the activation of the crystal lattice of the phases, by other organometallic compounds, including organo-calcium; these compounds are protected from atmospheric agents by the external phase of the network with the indicated protective colloids. After mixing with water the cement obtained by the method according to the invention, the colloidal protective film is destroyed by water according to the mechanism described in detail in [25]. After that, organometallic compounds play a catalytic role in the formation of aluminates and then calcium sulfoaluminates, which are actually expanding agents, and, in addition, ensure the inclusion of strontium and strontium-barium compounds in the hydrosilicate matrix. Such a matrix is more durable and even more elastic, which significantly reduces shrinkage. And in the low water demand cement obtained according to the invention, all elements of the matrix structure, including calcium hydrosilicates, hydroaluminates and calcium hydrosulfoaluminates, are combined, and thereby form even more durable matrices with minimal shrinkage or with a zero level of shrinkage. In this case, the need for an expanding agent is minimal compared with the prior art and in the manufacture of cement of low water demand reaches a minimum of 0.5 wt. % expanding additives necessary to achieve expansion deformation of the cement matrix. This result is the fourth major surprise of the invention as a whole compared to the prior art and a new step in the development of expanding cement technology. Until now, as mentioned above, it was considered necessary to introduce at least 14% of the expanding additive into the cement composition to reliably achieve the expansion effect [26].

 The essence of the alleged invention in terms of a method of manufacturing Portland cement with reduced shrinkage becomes clearer from an example of its implementation.

 Example 2. The conditions for the implementation of the method according to example 1. A method of manufacturing cement in the furnace described in the above example is associated with controlling the absence of a reducing atmosphere in the furnace. Special measures taken for this when firing the cement raw material mixture according to the invention are, as indicated above, in the selection of the optimum draft mode with the regulation of the vacuum in the dusty chamber of the furnace according to the readings of two pyrometers. For this furnace, it was previously established that the frequency of occurrence of iron monoxide in clinker samples in “exorbitant” amounts, that is, exceeding the maximum of the range indicated above, is antibatic to the amount of rarefaction in a dusty chamber. So, with a vacuum level in the specified dust chamber in excess of about 160 mm of water. century, or more than about 1570 Pa, the frequency of occurrence of such clinker samples is on average one in eight hours of operation, whereas when the vacuum level is lower than one in eight hours of operation, whereas when the vacuum level is below 120 mm of water. Art., or less than about 1180 Pa, the frequency of occurrence of such samples exceeds seven. Therefore, when firing the clinker according to the invention, in order to meet the criterion for the content of iron monoxide in it, vacuum is maintained in the dust chamber at a level of at least 180 mm of water. Art., for which it was necessary to reconstruct the smoke exhauster. To comply with the criterion for the content of free lime in the clinker, along with the pyrometric criterion for the measured dust content of the sintering zone, sound control of the noise of clinker falling into the grate cooler is used and, when the noise intensity is reduced to the limit characteristic of underburning, they increase fuel consumption, and when increasing noise intensities to the limit characteristic of burnout, reduce the consumption of process fuel. This is a faster way of regulation compared to the regulation of the draft mode, but it, in contrast to the latter, generates waves of calcined material in the furnace, which is permissible only for the case of a direct prevention of going beyond the rejection limits of technological parameters.

 The data obtained indicate that Portland cement with reduced shrinkage according to the invention and, moreover, expandable can really be manufactured at such low expenditures of the expanding agent (0.5-2.8%), not known either from the prior art or from the modern theory of expansion cements. Moreover, the cost of the specified Portland cement according to the invention for the first time only slightly exceeds the cost of the control Portland cement, and from a unit mass of the expanding agent in this case, it is possible to produce from 20 to 40 or more units of the mass of the specified Portland cement according to the invention, which will increase the achievable production and use of cement according to the invention about five times compared to achievable with the prior art. This is the fifth major surprise of the invention compared to the prior art.

 The technical and economic effect of using the invention significantly increases when implementing in parallel with the method of manufacturing Portland cement with reduced shrinkage a method of preparing a cementitious material for concrete repair and soil reinforcement from a fine fraction of said cement.

 It is known from the prior art that the cementitious material used for the repair of concrete and reinforced concrete and soil reinforcement must meet at least three requirements: 1) have astringent properties in relation to old concrete and adhesive properties in relation to reinforced soils; 2) to be able to penetrate into the pores of the reinforced soil and corroded concrete to create a transition zone of the gear structure, which provides strong contacts of the cementing material with the repaired concrete and soil; 3) characterized by high strength and the ability to maintain established connections and contacts with repaired concrete and reinforced soils, respectively, be little or non-shrink [27]. These requirements, as indicated in the cited work, do not completely satisfy cementitious materials known from the prior art. The need to sharply improve their quality seems to the authors of the cited work no less than a historical challenge that must be answered.

 A known method of preparation of cementing material, which can be used to repair concrete and reinforced concrete and strengthen soils, by means of especially fine grinding of Portland cement with microfillings [28], however, this method significantly reduces the productivity of the mill and increases the specific energy consumption for grinding, and the cement obtained is only due to microfillings characterized by shrinkage, approximately equal to the shrinkage of ordinary Portland cement. But such a shrinkage for this application is unacceptable. Therefore, the widespread introduction of this method and the corresponding material is difficult.

 There is also a method of preparing a cementing material for repairing concrete and reinforced concrete and strengthening soils by isolating from Portland cement the usual dispersion of its fine fractions of less than 10 or 20 microns in size, characterized by high penetration into these substrates, which have high adhesive properties with respect to the latter [29]. The disadvantages of this material are its short setting time and increased shrinkage deformation. The combination of such major product flaws precluded the widespread introduction of this method, known since the mid-60s, and even for the first time provided in the cited technical solution, the introduction of a water-reducing component in the composition of this material does not lead to a radical improvement in its properties.

Closest to the invention, the technical solution (prototype) is a method of preparing a cementitious material for concrete repair and soil strengthening - a fine fraction of Portland cement with reduced shrinkage from Portland cement clinker, obtained by firing before sintering of the cement raw material mixture, which includes lime, silicate and ferrous ingredients, and the subsequent co-grinding the specified clinker with a gypsum component in a ventilated grinder during selection from the initial cement as the specified mate iala fraction with particle sizes in the range of about (0.3 - 20) • 10 ^-6 m and the specific surface area of about 400-2500 m ² / kg by pyleosaditelnyh devices of suction air of said chopper, and separating said fraction of the original high-performance cement used dynamic separator [30]. The introduction of micro-fillers and the use of a special clinker for the manufacture of initial cement with reduced shrinkage, namely aluminoferrite, are also envisaged. The disadvantage of the method according to the prototype is the high shrinkage of the prepared material: it, according to the authors of the present invention, significantly exceeds 1 mm / m when tested under the above conditions for any content of microfiller (silica fume) within up to 15% of the mass of the specified fraction and when using clinker Ferrari type with KN about 1 at p about 0.5 for the manufacture of the original Portland cement.

 The objective of the present invention in terms of the method of preparation of cementing material for concrete repair and soil stabilization is a radical reduction of shrinkage deformation of the prepared material compared to the prior art, up to zero when measured under the above conditions without the use of expansion additives, as well as reducing the content of the latter to a minimum level, up to 1.5 - 4% of the mass of the specified fraction. Such a decrease allows to decisively increase the volume of implementation of the specified method and material prepared by this method in the construction complex, primarily in geotechnical construction and restoration work.

This problem is solved by the fact that in the method of preparing cementing material for concrete repair and soil consolidation - a fine fraction of Portland cement with reduced shrinkage from Portland cement clinker, obtained by firing before sintering of the cement raw material mixture, comprising lime, silicate and ferrous ingredients containing strontium compounds in terms of on oxide in an amount of 0.03-0.5% of the mass, and subsequent joint grinding of the specified clinker with a gypsum component in a ventilated grinder during dust sampling fra particles with a particle size of (0.3-20) • 10 ^-6 m with a specific surface of 400-2500 m ² / kg by means of dust precipitation devices from the suction air of the specified grinder, the composition of the specified dust fraction is controlled by changing the ratio of components in the specified Portland cement and mechanical conditions grinder operation until the content of strontium and barium compounds in the specified dust fraction is 0.2-0.6 wt.%.

 In an embodiment of the invention, when co-milling, a water-reducing component is additionally added to obtain its content of 1-6 wt.% Of the specified dust fraction.

 In another embodiment of the invention, when co-grinding with co-grinding, an expanding additive is additionally added to obtain its content of 0.7-8 wt.% From the specified dust fraction.

 In a further embodiment of the invention, when co-milling, a water-reducing component or expanding additive is additionally added to obtain the contents of the water-reducing component and expanding additives 1.2-5 and 1-8 wt.% Of the specified dust fraction.

 The essence of the invention in terms of the method of preparation of cementitious material is to concentrate in the specified fine fraction of cement during its grinding a significant amount of compounds of strontium or strontium and barium, in order to reduce shrinkage of the product penetrating into the pores or voids of the concrete being repaired or strengthened according to the above-described action scheme these compounds. As the experiments of the authors show, at least two thirds of the total amount of the latter are concentrated in the specified fraction, which allows them to show their shrinkage-reducing effect due to the rapid hydration of these fractions. In embodiments of the invention, to reduce the shrinkage of the specified fraction, used as a cementitious material, easily penetrating into the repaired old concrete and reinforced soil, the water-lowering component of cement, also concentrated by two-thirds in the specified fraction, and the expanding additive, directed to that, make their additional contributions. the same fraction in an amount of about three quarters of the total cement content. On average, this allows for the first time to bring the shrinkage of this fraction to zero values, which previously could not be done in such a simple way, without additional, very difficult to mix it with additionally introduced water-reducing and expanding components. The last operation, due to the high degree of aggregation of particles of this fraction, is not completed until the end, and this, noted by independent experts, the lack of genuine homogeneity significantly reduces the quality of well-known cementitious materials of well-known foreign brands on the domestic market. This served as the basis for this technical solution.

As for the quality of the rest of Portland cement produced simultaneously with cementing material according to the method according to the invention, this grinding scheme with the simultaneous release of two finished products, previously known, was once thoroughly analyzed in [31], where it was used for the simultaneous release of quick-setting and ordinary Portland cement, and it was shown that it is enough to conduct quality control of both products on the rougher of them, leaving the grinder (in the cited work - from the pipe mills), then the quality of the fine fraction taken from the suction air will also be guaranteed. Under the conditions of the implementation of the methods according to the invention, this position is fully confirmed and means that in order to achieve the results guaranteed above in terms of strength and deformation properties, it is necessary and sufficient that the specific surface of the main product of the grinder - non-shrink Portland cement - is not lower than about 320 m ² / kg. In this case, the design values of the content of strontium and / or strontium and barium compounds in the cement raw material mixture and Portland cement clinker based on it should be in the range from centers to the upper limits of these ranges, the values of alumina and "alkaline" modules - in the range from centers to lower limits the indicated ranges, the KN value is not lower than 0.95, the values of free CaO and iron monoxide in Portland cement clinker are within the specified ranges, and sulfur trioxide in the total cement sample obtained by proportionally by mixing the product of the grinder and the selected fine fraction for the purpose of chemical analysis, ranging from the center to the lower limit of the specified range. When these requirements are met, the quality of both non-shrinking Portland cement and cementitious material - a fine fraction of the specified cement exceeds the indicators known for the specified products from the prior art, and the setting time of cementing material falls within the limits imposed by the application practice - at least 30 minutes.

 The invention in terms of the method of preparation of the specified cementitious material becomes clearer from an example of its implementation.

 Example 3. The conditions for the implementation of the method of preparation of cementing material for concrete repair and soil strengthening according to the invention, according to examples 1 and 2 and the following additional.

For joint grinding of cement components, a production cement mill 2.4 x 10.6 m in size, a two-chamber, working in a closed cycle with centrifugal separators, is used as a grinder. The grinding load of both chambers is spherical; in the first chamber, the filling factor of the working volume (φ) with grinding bodies is taken to be 0.22, in the second chamber, φ is taken to be 0.26, with an average diameter of balls in the first chamber of 62 mm, in the second 25 mm, the average the vacuum level in the suction chamber is 60 mm in the absence, 20 mm in the presence of a water-reducing component in the grinding mixture. Two separators with a diameter of 2.4 and 3.2 m each are equipped with a cyclone and a bag filter each, and the suction path for the second one at the outlet of the bag filter is also equipped with a common screw for cement dust collected in both filters, as well as a packaging unit for packing the specified dust into paper bags, while cement dust from cyclones is returned, like fine separator products, to the overall mill product. Coarse products of separators (grains) are fed to the mill: the first separator - into the first chamber through the inlet pin, the second separator - into the second chamber of the mill according to the Doppelrotator system described in the book [32] in the modification for cement grinding. In this case, the average values of the difference between the specific surface area of the mill product and dust from cyclones and filters are equal to approximately 70-100 and 150-200 m ² / kg, respectively, and tend to decrease as the specific surface area of the mill product increases from about 250 to 450 m ² / kg To separate the fractions of the above sizes, only dust separated from the suction air by the air duct filter from the second separator is taken, while dust separated from the suction air by the air duct filter from the first separator is returned to the overall mill product, and the mechanical particle size is changed to adjust the particle size the operation mode of the second separator and / or the suction operation of the mill and / or the operation mode of the first separator, which together is combined by the concept: change the "mechanical mode mill work. "

 Due to the concentration of Sr and Ba impurities at the boundaries of clinker minerals and an increase in clinker grindability, in the separated fraction, the greater these small components are, the higher the specific surface of this fraction. In the latter, other cement components are also concentrated with reduced grinding resistance compared to Portland cement clinker - gypsum stone, an expanding additive. A significant part of the water-reducing component falls into the same fraction.

 In this regard, this cement fraction, characterized in the prior art by increased shrinkage deformations, in said cementitious material obtained by the method according to the invention, is characterized by relatively reduced shrinkage deformations, and even shrinkage and expansion, but at large compared to Portland cement with reduced shrinkage, obtained by the method according to the invention, the quantities of expanding additives. The latter can be added to the specified fraction by additional mixing in the appropriate mixer, but this is significantly less economical than obtaining the necessary content of the expanding additive in the specified fraction directly in the process of its selection from aspiration air.

The test results of the fractions obtained by this method, which are a cementing material according to the invention, as well as a control fraction selected during grinding from a control cement, and a similar fraction selected from cement made on the basis of a cement raw material mixture according to the prototype by firing the corresponding clinker, are given in table 2. The main indicator for comparison, along with indicators of strength and shrinkage / expansion, is the penetration depth of the cementitious material L in the concrete being repaired It is strengthened by the ground. The determination method used in the practice of the authors of the present invention is as follows. First, a reference foam concrete is prepared with the following characteristics: dry density grade 450 ± 30 kg / m ³ , strength not less than 0.5 MPa, age not less than 28 days. The remaining indicators correspond to GOST 25485-89. The porosity of this material is approximately 75 ± 5 vol. % The average size of the pore entrances, determined by the optical microscopic method, is from 100 to 300 microns, or 0.1 - 0.3 mm. Prism samples 4 x 4 x 16 cm in size, made from this material by pouring, after 28 to 40 days of hardening in air-wet conditions, dried at 50 -70 ^o C to constant weight and vacuum under forward pressure (residual pressure of about 150 - 280 torr), after which they are immersed in a vessel with freshly prepared dough from cementing material and water at a W / C of 0.5 - 0.6 and the absence of visible delamination, incubated for 1 day in an air-moist environment at a temperature of 20 ± 3 ^o С after which the resulting conglomerates of foam concrete samples and cement they are taken out of the vessel and cracked so that the kinks go through the foam concrete body. The depth of impregnation of the reference foam concrete with cementitious material is measured normal to the initial surface of the foam concrete. The averaged results of these measurements are presented in the last, 23rd column of table 2.

 The results obtained indicate that: 1) the concentration of technologically important small components in the specified fraction was recorded (compare the data given in rows 1 - the control fraction and rows 3 and below of table 2; 2) the water demand of the cementing material according to the invention is significantly lower, and the penetrating ability in reference foam concrete is at least an order of magnitude higher than known from the prior art, which is of great technical importance; 3) the strength characteristics of the cementing material according to the invention are significantly higher, and shrinkage deformation is lower than that of the control; 4) the depth of impregnation of the cementitious material according to the invention.

 Thus, the objective of the invention in terms of creating a cementing material for concrete repair and soil strengthening, characterized by increased strength and reduced shrinkage, up to non-shrink, is solved. The non-shrinkage of this material, achieved without the use of aggregates that reduce penetration by an order of magnitude, is essential to increase the durability of repaired structures, buildings and structures made of concrete and reinforced concrete, as well as to strengthen soils and other works in geotechnical and hydraulic engineering construction.

 These features of the cement raw material mixture, the method of manufacturing Portland cement with reduced shrinkage from Portland cement clinker obtained by firing before the sintering of the specified raw material mixture, and the method of preparation of cementing material for concrete repair and soil strengthening - a fine fraction of the specified Portland cement according to the invention contribute to the wide industrial implementation of the latter.

 Thus, the present invention is fully prepared for industrial implementation.

Literature
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 5. Timashev V.V. et al. Acid-base interaction in a clinker melt. 12th Conference of Silicate Industry and Silicate Science. Budapest: Siliconf, 1977, v. 1, p. 25 to 47.

 6. US patent 2706942, 1977.

 7. Volkonsky B.V. Mineralizers in the cement industry. M. - L .: Stroyizdat, 1964, 198 p., See p. 9 and below.

 8. Boykova A. I. et al. Distribution of strontium and barium over clinker phases. II International meeting on the chemistry and technology of cement. Poster presentations. M .: ROS. Chem. about - in them. DI. Mendeleev et al., 2000, v. 3, p. 31 - 32.

 9. Fedner L.A. The influence of construction and technical properties of cements on the properties of concrete mixtures and concrete. II International meeting on the chemistry and technology of cement. Review reports. M .: ROS. Chem. about - in them. DI. Mendeleev et al., 2000, v. 2, p. 106 - 118.

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Claims (18)

1. Cement raw mix containing lime, silicate and glandular ingredients, as well as strontium compounds in terms of strontium oxide in an amount of 0.03-0.5% by weight, alkali metal oxides and sulfur trioxide, characterized in that it contains strontium compounds in the calcareous ingredient in the form of natural minerals from the group of calcitostrontianite and / or strontianite and / or celestin with an alumina module of the mixture of 0.5 - 1.25 and a weight ratio of alkali metal oxides in terms of sodium oxide Na ₂ O and sulfur trioxide 0, 7-1.5.  2. The mixture according to p. 1, characterized in that it further comprises barium compounds in the form of sulfide and / or witherite and / or barite in terms of barium oxide in an amount of 0.15-0.5 wt. %  3. The mixture according to claim 1 or 2, characterized in that the lime saturation coefficient in terms of Portland cement clinker is taken in the range of 0.9-1.15. 4. A method of manufacturing Portland cement with reduced shrinkage from Portland cement clinker, obtained by firing before sintering a cement raw material mixture containing lime, silicate and glandular ingredients, as well as strontium compounds in terms of strontium oxide in an amount of 0.03-0.5% by weight, alkali metal oxides and sulfur trioxide, and subsequent joint grinding of the specified clinker with a gypsum component, characterized in that the calcined cement raw material mixture contains strontium compounds in a calcareous ingredient in the form Natural minerals from the group kaltsitostrontsianita and / or strontianite, and / or alumina at celestite module and said mixture of 0.5-1.25 weight ratio of alkali metal oxides, based on sodium oxide Na ₂ O and sulfur trioxide 0.7-1, 5, while firing is carried out in an oxidizing atmosphere until it is contained in clinker, wt. %: free calcium oxide 0.05-0.8 and iron monoxide 0.01-0.3, and joint grinding is carried out at a mass ratio of the specified clinker and gypsum component in terms of sulfur trioxide 100: (0.3-6) to specific surface area of 250-700 m ² / kg and taking into account the criterion of minimum shrinkage in the air-moist environment of samples from cement paste.  5. The method according to p. 4, characterized in that said raw material mixture further comprises barium compounds in the form of sulfide and / or witherite and / or barite in terms of barium oxide in an amount of 0.15-0.5%.  6. The method according to p. 4 or 5, characterized in that the lime saturation coefficient in terms of Portland cement clinker is taken in the range of 0.9-1.15.  7. The method according to any one of paragraphs. 4-6, characterized in that as the gypsum component take calcium sulfate in the form of natural gypsum stone, including 0.01-1.5 wt. % clay impurities.  8. The method according to any one of paragraphs. 4-7, characterized in that when co-grinding is additionally introduced 0.5-40 wt. % active mineral supplement.  9. The method according to p. 8, characterized in that the humidity of the active mineral additives before joint grinding of 6-12 wt. %  10. The method according to any one of paragraphs. 4-9, characterized in that when co-milling, a water-reducing component is additionally introduced with a mass ratio of said clinker and water-reducing component 100: (0.3-2.5). 11. The method according to p. 10, characterized in that as a water-reducing component of said Portland cement, materials from the group are used: a salt of an alkaline earth and / or alkali metal product of the condensation of naphthalene sulfonic acid with formaldehyde, a salt of an alkaline earth and / or alkali metal product of the condensation product of melamine-containing resins with formaldehyde, technical lignosulfonate of alkaline earth and / or alkali metals, conventional or modified phenol-formaldehyde resin, complex salt of alkaline earth metal and sulfur, and / or nitric and / or formic and / or acetic acids with low molecular weight C ₃ -C ₅ monosaccharides, paired mixtures of these materials in a mass ratio of from 4: 1 to 1: 4.  12. The method according to p. 10 or 11, characterized in that the joint grinding is carried out in a ventilated grinder with a degree of aspiration of the latter, corresponding to the sanitary minimum, controlled by the absence of dusting from the inlet neck of the grinder.  13. The method according to any one of paragraphs. 4-12, characterized in that the joint grinding is carried out with the additional introduction of an expanding additive, including as components sulfoaluminate clinker or aluminum sulfate, film former and etching agent, with a mass ratio of said clinker and said additive of 100: (0.5-4). 14. The method according to p. 13, characterized in that, as the specified additive, a pre-made mixture of sulfoaluminate clinker or aluminum sulfate, a film former and etching agent is used, hydrophobizing substances from the groups are used as a film former: higher fatty acids - synthetic fatty acids of fraction C _{17 -} С ₂₂ , technical stearic, arachinic, oleic acids, paired mixtures of these substances, drying oils - natural - polymerized and quick-drying, semi-synthetic - polymerized, combine grade K ₃ -K ₅ phthalic, emulsion with emulsifier calcium oxide CaO, paired mixtures of these substances, wax - flax, fossil, synthetic - the product of esterification of oxidized paraffins, vegetable oils - fatty preparations, their paired mixtures with substances of the previous groups and / or secondary products and wastes containing them, solutions of substances of any of the above groups in mineral oil, and substances that selectively activate aluminates, calcium sulfoaluminates and aluminum salts are used as an etching agent in the specified additive, from the groups: pyruvic acid, aldonic acids, levulinic acid, mesoxalic acid aromatic acids - industrial benzoic acid, sulfobenzoic acid, hydroxymethylbenzoic acid, phthalic acid, hippuric acid, their acid derivatives, anhydrides of the indicated acids, unsaturated carboxylic acids - acrylic acid, propiol acid, sorbic acid, ricinoleic acid, hydroxy acids - glycolic acid, glyoxalic acid, their acid derivatives, salicylic acid, sulfos its acid, their derivatives, carbocyclic compounds - adipic acid, its anhydride, phenylglycine, cycloheptanol, dicarboxylic compounds - maleic acid, methyl maleic acid, fumaric acid, anhydrides of the indicated acids, resin acids in paired mixtures with substances from the previous groups, alcohols - adipole, mannitol, ethylene glycol, methylethylcarbinol, aldehydes - glyoxylic acid, crotonic aldehyde, paired and ternary mixtures of these substances and / or secondary products and waste containing them, in a mass ratio leaving in said additive 100: (2.5-30): (2-20), respectively. 15. A method of preparing a cementitious material for concrete repair and soil consolidation - a fine fraction of Portland cement with reduced shrinkage from Portland cement clinker obtained by calcination before sintering of a cement raw material mixture containing lime, silicate and ferrous ingredients containing strontium compounds in terms of strontium oxide in amount 0.03-0.5% of the mass, and subsequent joint grinding of the specified clinker with a gypsum component in a ventilated grinder during the selection of dust fractions with particle sizes (0.3 -20) • 10 ^-6 m with a specific surface of 400-2500 m ² / kg by means of dust precipitation devices from the suction air of the specified grinder, characterized in that the composition of the specified dust fraction is controlled by changing the ratio of components in the specified Portland cement and the mechanical operating conditions of the grinder to obtain in the specified dust fraction of the content of strontium and barium compounds 0.2-0.6 wt. %  16. The method according to p. 15, characterized in that when co-milling, a water-reducing component is additionally introduced to obtain its content of 1-6 wt. % of the specified dust fraction.  17. The method according to p. 15, characterized in that when co-grinding an additional expanding additive is added to obtain its content of 0.7-8 wt. % of the specified dust fraction.  18. The method according to p. 16 or 17, characterized in that when co-milling, a water-reducing component or an expanding additive is additionally added to obtain the contents of a water-reducing component and an expanding additive of 1.2-5 and 1-8 wt. % of the specified dust fraction.

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