SK288420B6 - Method for cement production and concrete mixture made by the method - Google Patents

Abstract

Method for production of cement mixture comprising combining of complex admixture formed by mineral component and by water solution of surface agent with the component of Portland cement by mixing or grinding, wherein the particular components of the complex admixture and Portland cement are individually dosed into a standard mill for cement grinding and consequently altogether grinded, wherein the mineral component of the complex admixture is reactive powder on the basis of SiO2 and the surface agent is superplasticizer on the basis of modified polycarboxylate polymers.

Description

The present invention relates to a process for the production of a cementitious compound and a cementitious compound produced by this method.

BACKGROUND OF THE INVENTION

A new type of cement ground with complex admixtures has been developed that has a very high strength and can be produced with a very low clinker content (Sobolev, K. and Podmore, C., VICON: The Next Big Thing, Global Cement Magazine, June 2001, 14-15, 2001). Production techniques use a special admixture in the cement grinding process, which significantly improves the properties of the cement. This approach resulted in the development of a new high performance cement.

According to the proposed technology, the addition of reactive silicate complex admixture is realized during the grinding of Portland cement. Thus, the clinker is ground in a ball mill together with a mineral complex admixture, grinding ingredients, gypsum and a newly invented admixture. As a result, high performance cement can achieve a high early 1 day compressive strength up to 44 MPa and a high 28 day compressive strength up to 95 MPa. The resulting high performance cement is then available to produce high performance concrete.

In such cement, the amount of clinker can be significantly reduced. Up to 70% of the cement can be replaced by cheaper local additives: sand, limestone, natural pozzolanic or volcanic materials, ash, granulated blast furnace slag, and also waste ceramics or glass. All of this can be used as a cheap local natural mineral additive. In addition, the use of granulated blast furnace slag, in addition to high strength and sulphate resistance, provides excellent chemical resistance and high temperature resistance.

A previous patent by Sobolev et al. US 2003/0188669 A1 discloses a family of complex admixtures, their production and method of their use in cement and concrete technology. This method makes it possible to produce high-strength and extremely resistant cement systems as well as cement systems with specially designed properties, as well as cheaper ecological cements with high mineral admixtures. The use of complex admixtures provides an increase in the compressive strength of cementitious materials up to 145-180 MPa and / or allows the introduction of large amounts, up to 70%, of mineral local natural admixtures into the cementitious composition. The dry and / or semi-dry admixture and the manufacturing process take advantage of a favorable combination of sorbents with active silica and water reduction / broad range water reduction (HWR) additives. The main criterion for the selection of sorbents is their compatibility with the cement system, especially for the long-term effect. The favorable combination of sorbent - a water-reducing additive - enables the creation of a wide range of versatile and super-efficient complex admixture modifiers for the cement system. The use of complex admixtures in cement and concrete technology makes it possible to produce high-strength and high-strength cement systems as well as cement systems with specially designed properties. Selection of special mineral impurities such as high density, chemical, thermal or abrasive resistance, thermal expansion, electrical conductivity, etc. enables the production of cement systems with specially designed and unique properties.

There is known information on dry or semi-dry complex admixtures for cementitious systems containing surfactants, e.g. a water reducing agent or a broad spectrum water reducing agent, in aqueous solution, and an active silica sorbent. In this complex admixture, such a sorbent is selected from materials with fine alkaline reactive non-crystalline silica such as fly ash, bran ash, zeolite, silica fume, bentonite, activated kaolin, montmorillonite, diatomite, and such sorbent is selected from melamine, sulfide, melamine sulfonate, polyacrylate admixtures or mixtures thereof (including other admixtures) are used as a surfactant. Other chemical or mineral admixtures may be used for the complex admixture mixture, such as high porosity light sand, inorganic or organic salts or hydroxides, grinding additives, etc.

The manufacturing process of the dry or semi-dry complex admixture involves mixing the components in a normal or high speed spindle or planetary mixer, in a vibratory mixer or mill, as well as air jet mixers and mills. Additional granulation, drying, pressing, extrusion, crushing, calendering is used to finish the blend mixture.

US 2004/0089203 A1, Ronina V. discloses a method of producing mixed cement, wherein the cement comprises Portland cement mixed with a micro-filler and an additive for reducing water content to a dry cement mix and fine complementary cement materials selected from materials such as blast furnace slag, ash, quartz, silica, amorphous silica, limestone and recycled concrete.

In the first step, the additive materials are dry milled to a specific surface area of at least 1000 cm ² / g (Blaine) and in the second step the additive milled materials are exposed to dry milled together with at least 20 wt. a high-reactive cementitious compound to achieve a specific surface area of at least 3000 cm ² / g (Blaine). In this composition, the high reactive cementitious composition comprises cement, at least one of the SiO 2 containing micro-filler components, and a water-reducing agent in powder form; said mixture was previously ground using a vibrating grinding means so that the cement particles are subjected to a large amount of impact resulting in an increase in the surface energy and chemical reactivity of the cement. Thus, the mixed cement contains from 20% to 80% by weight. such a highly reactive cementitious compound. The method for producing a concrete mixture from the mixed cement comprises as first steps the preparation of the mixed cement and as the second step the mixing of the mixed cement with water, coarse aggregate and / or sand and optionally with a water reducing agent and an aeration additive.

Compressive strength classes for conventional normal and heavy concrete according to EN 206-1: 2000 are from C 8/10 to C 100/115 with a minimum characteristic cubic strength fck, cube of 10 N / mm2 (MPa) to 115 N / mm2. Compressive strength classes for lightweight concrete according to EN 206-1: 2000 are from LC 8/9 to LC 80/88, with a minimum characteristic cubic strength fck, cube of 9 N / mm ² to 88 N / mm ² . Lightweight concrete requires lightweight porous aggregates that can be selected from natural processed materials (e.g., expanded clay, expanded slate or expanded clay slate), by-products (e.g. foam slag or sintered powdered ash) or unprocessed materials (e.g. pumice).

There is no exact dividing line between conventional concrete of normal strength and high-strength concrete, but the usual boundary is set at approximately 50 MPa (Table 1).

Table 1 Strength classification and concrete parameters

parameter conventional concrete High-strength concrete Very high-strength concrete Ultra high strength concrete Strength, MPa <50 50 to 100 100 to 150 > 150 Water to cement ratio > 0.45 0.45 to 0.30 0.30 to 0.25 <0.25 chemical admixtures Not required, plasticizers may be used plasticizers, superplasticizers superplasticizerConcrete superplasticizerConcrete Mineral admixtures Not required, pozzolans, ash, slag can be used Fly ash, siliceous drift Siliceous drift Silica drift, nanosilicon

For the production of ultra-high strength concrete having a compressive strength of 100 N / mm ² or higher, it is necessary to reduce the water / cement ratio (V / C) to below 0.25, ensuring that the workability is maintained by the addition of superplasticizers.

Ultra High Performance Concrete (UHPC), also known as Reactive Powder Concrete (RPC), is a high-strength, flexible material made by combining high-performance steel or organic fibers with a Portland cement cement matrix, silica drift, nanosilicon, quartz flour, broad spectrum water (superplasticizer), water and fine quartz sand. After heat treatment, ultra high performance concrete provides compressive strengths of up to 200 MPa (typically 120 to 150 MPa) and flexural strengths up to 50 MPa (typically 15 to 25 MPa), a modulus of elasticity of 45 to 50 GPa. The bending behavior of this material is a key parameter providing deformability and ability to withstand bending and tensile loads even after initial cracking. The use of UHPC / RPC for construction is attractive due to the self-compacting ability of the material and the elimination of the need for secondary steel reinforcement.

SUMMARY OF THE INVENTION

The method of making a cementitious composition of the present invention comprises (a) combining a mineral component with an aqueous surfactant solution (a surfactant component) to form a complex additive; (b) combining said admixture with a Portland cement component at a cement-to-admixture ratio of about 10,000: 1 to 1:10, to form a cementitious composition, wherein step (b) comprises combining said complex admixture with said cementitious component by mixing or grinding.

The essence of the method of making a cementitious composition according to the invention is that the individual components of the complex admixture the individual components of the Portland cement are dosed separately into a standard cement grinding mill and subsequently co-milled, the mineral component of the complex admixture being a reactive SiO2 powder. liquid superplasticizer based on modified polycarboxylate polymers.

Most preferably, a standard grinding cement mill is an industrial grinding unit consisting of two ball mills, one for pre-grinding and one for fine grinding, a reactive powder based

S1O2 is a siliceous drift, wherein the siliceous drift is metered directly into the inlet of the fine grinding mill and the liquid superplasticizer based on modified polycarboxylate polymers is dosed on top of the raw materials into the inlet mill.

Portland cement comprises at least one of the following ingredients: (i) Portland clinker comprising one or more combinations of calcium silicates and / or calcium aluminates and / or one or more kinds of calcium sulfate; (ii) Portland cement; (iii) cement with moderate heat generation at solidification; (iv) high early strength cement; (v) low hydration heat cement; (vi) sulphate resistant cement; (vii) white Portland cement; (viii) mixed cement; (ix) Portland slag cement; (x) Portland pozzolanic cement; (xi) expansion cements (e.g., type K cement); (xii) high aluminous cement; and (xiii) oil well cements.

Said mineral component is selected from the group consisting of: (i) Portland cement or clinker (similar to the above vi to xiii); (ii) one or more combinations of calcium silicates and / or calcium aluminates; (iii) one or more calcium sulfate species; (iv) nanomaterials and / or ceramics based on or containing metals, carbon, carbonates, oxides; and (v) reactive powders based on SiO ₂ .

Said nanomaterial component is selected from, but not limited to: (i) nano SiO ₂ , nano TiO ₂ , nano SnO ₂ , nano Fe ₂ O ₃ , nano Zr ₂ O ₃ , nano ZrO ₂ , nano A1 ₂ O ₃ , nano CaCO ₃ , nano MgCO ₃ , nano CaMg (CO ₃ ) ₂ , nano FeCO ₃ , nano BaSO ₄ ; (ii) nano clay; carbon or aluminosilicate nanotubes / nanofiber; (iv) nanocement / nano CSH; and / or (v) mixtures thereof and / or compounds thereof.

Said reactive powders based on SiO ₂ are fine alkaline reacting non-crystalline silica containing materials selected from the group consisting of fly ash (e.g. silica or calcium), fluid fly ash, sludge fly ash, pulp fly ash, rice bran ash, zeolite , silica fume, bentonite, activated kaolin, metakaolin, clay, thermally activated clay, alfalfa, montmorillonite and diatomite and other natural / manufactured materials containing at least 1% amorphous SiO ₂ .

Grinding provides particle size reduction, homogenization and / or mechanical-chemical activation. During the grinding, gypsum and / or anhydride and / or calcium sulfate hemihydrate is added to the cementitious mixture. The cement particles can be reduced to micron, submicron and nanosize; the mixture can be further modified here by adding nanoparticles and nanotubes of different composition / origin.

The grinding ingredients can be used as a component of the complex admixture or can be used for grinding, superfine grinding and mechanical-chemical activation. The effect of accelerating the grinding with grinding additives is achieved to reduce agglomeration and surface tension, since the particles easily agglomerate during fine grinding or after the addition of a fine powder. Grinding aids are usually liquid products commonly manufactured as aqueous solutions of high charge density organic compounds such as glycols, glycol esters (glycol compounds are e.g. ethylene glycol, diethylene glycol), amines, alkanoamines (aliphatic amines such as triethylenetetramine, tetraethylene ethylamine, tetraethylene ethylamine such as diethanolamine, triethanolamine, tri-isopropanolamine, more complex compounds such as aminoethylethanolamine and hydroxyethyldiethylenetriamine), aminoacetate salts and / or carboxylates of alkanoamines, phenols and phenol derivatives, fatty acid salts, etc. The grinding ingredients may be added as a component of the master mix. The grinding ingredients are composed of polar organic compounds that arrange their dipoles, so that they saturate charges on the newly formed particle surface while reducing re-agglomeration. These polar compounds interact with cement grains, either by irreversible physical absorption or by chemical reaction with cement salts, promoting high temperatures above 100 ° C that are achieved inside the mill during the milling process. Because of their polar nature, such compounds are preferably absorbed at the reactive centers of the cementitious surfaces formed by the decay of the electrovalent bonds, thereby reducing the surface energy forces that cause the aggregation of the newly formed cementitious particles. The subsequent reduction in surface energy forces causes a dry dispersion of cement, which in turn increases the fluidity of the cement and significantly reduces the retention time of the mill and is very useful in mechanical-chemical activation.

The grinding additives according to the invention have an auxiliary function for superfine grinding and mechanical-chemical activation of the complex admixture and cement mixture.

Intensive grinding can activate multi-component systems mechanically-chemically, through particle size reduction, surface defects and electrostatic charges. This results in a material with increased surface free energy and thus increased reactivity. Mechanical energy is transmitted by normal and slip stresses acting on the surfaces of the solid material. The effect of this externally applied stress field is an increase in the stress field in the solid mass. The voltage field is manifested through various manifestations, such as atomic transitions from equilibrium steady states in crystal lattice nodes, changes in bond lengths and angles, and sometimes, excitation of the electron subsystem. This, in turn, requires the formation of metastable structures that must release some of the accumulated energy in order to get into a more stable thermodynamic state. There is a multi-stage model of energy dissipation so that phase transitions and mechanical-chemical reactions can continue. Part of the mechanical energy provided is retained by the solid material in the form of excess energy. Essentially, this energy is bound to sustained metastable states that are retained in the activated material after mechanical processing. This excess energy can be released very slowly, following the progression of irreversible processes reaching thermodynamic equilibrium. From the macroscopic point of view, energy release occurs according to three mechanisms, heat, plastic deformation and breaking of chemical bonds (mechanical-chemical reaction). The relative speed of the energy release processes and the application of the voltage field plays an important role in determining the final properties of the milled product.

The major part of the energy supplied is converted into heat. Concentration of the voltage field at certain locations in the crystal can lead to the crystal being crushed, thereby creating a new surface. Repetition of this phenomenon causes a decrease in crystal size (particle size reduction) to certain critical values. Further energy supply leads to the accumulation of failures inside or on the crystal surface, ultimately leading to complete amortization. Transformation of the crystal into the amorphous phase leads to mechanical and thermodynamic destabilization and collapse of the crystal lattice. Mechanical energy continually increases the concentration of crystal disorders to a critical value beyond which the amorphous phase is thermodynamically more stable than crystalline. The amortization process involves the generation of disorders such as point disorders (e.g. interstitials and vacancies), line disorders (e.g. edge and screw dislocations), surface disorders (e.g. grain edges and crystal surfaces), and anomalous distribution of point disorders. The amortization of the crystal begins on a thin surface layer and then proceeds inward and a metastable polymorphic structure occurs. When the chemical bonds break, this can lead to a mechanical-chemical reaction. Thus, mechanical-chemical activation is characterized by the accumulation of disorders (amortization process), the formation of polymorphic structures and the occurrence of solid state chemical reactions. The supplied mechanical energy makes the material metastable and allows the formation of activated material.

According to the invention, mechanical-chemical activation provides the formation of activated material with most active centers maintained for hydration and interaction with nanomaterials, chemical and mineral admixtures, resulting in the formation of a favorable cement mix. Active centers are suitable for the absorption of superplasticizers, water reducing agents, solidification retarders, solidification accelerators, air and nanoparticle binding admixtures and the formation of active nanolayers. Active centers are responsible for accelerated hydration of cement particles, to promote enhanced internal bonding between hydration products.

Chemical impurities are different compounds with different effects and uses. Plasticizers and superplasticizers are designed and added to concrete to control processability and flowability and reduce water content to a large extent. Plasticizers and superplasticizers are generally lignosulfonates, sulfonated melamine-formaldehyde condensate, sulfonated naphthalene-formaldehyde condensate, polycarboxylate ether copolymers, polyacrylates, polystyrene sulfonates, polymers and oligomers; accelerators are usually inorganic salts such as calcium nitrate, calcium chloride; the retarders are based on sugars, hydrocarbons and polysaccharides; the air binding admixtures are based on surfactants such as wood resin salts, synthetic detergents, petroleum acid salts, and fatty and resin acids and their salts.

Mechanics of action of basic plasticizing admixtures in concrete are electrostatic for melamine and naphthaline sulfonates, electrostatic and steric for polycarboxylate ethers, electrostatic, steric and tribological for polycarboxylate ethers in combination with stabilizers.

The advantage of using polycarboxylate ether superplasticizers is due to electrostatic repulsion by transfer of positively charged surfaces (due to sorption of dissociated polymer backbones) with steric repulsion added by additional side chains. By adding a stabilizer, it is possible to achieve a further increase in flowability, since the sliding surfaces are formed on the contact surfaces between the individual solid particles, which further reduce the internal friction of the suspension (tribological effect). The first hydration products may grow in the space between the two sterically distributed cement grains without this substantially affecting the slurry flow. The time of strong initial plasticization and extended workability of fresh concrete can be adjusted by changing the ratio of the length of the main chains to the side chains.

Complex admixture with superplasticizers may have a similar effect in concrete. The use of superplasticizers in complex admixtures increases the active particle surface, improves the dispersion of particles including nanoparticles and nano tubes in the cementitious composition.

When the cement comes into contact with water, a gel is formed on the grain surface. This complex sulfoaluminate hydrate gel creates a barrier effect and controls the dissolution and mass flow between the interior of the cement grain and the water between the grains, thereby controlling the hydration of the silicate phases. This gel develops over time, acquires a structure and forms colloidal crystals that connect cement grains (Figure 1). The additives and admixtures used in the cement paste interact with this gel and modify its structure in terms of quantity and quality; these modifications also depend on the chemical composition of the cement. After the initial phase, the gel is transformed into calcium silicate hydrate (C-S-H) and ettringite forms. These structures contribute to the mechanical properties of the cement.

Well-dispersed nanoparticles act as centers of crystallization of cement hydrates, thereby accelerating hydration. Xano-SiC 'is more effective than silica drift in improving the strength of mortars and concrete. Xano-SiC1 particles fill the pores and also reduce the Ca (OH) ₂ content of the hydration products. These effects are responsible for improving the mechanical properties of the nanoparticle mortar and reduce microcracks. Nanoparticles contribute to the formation of small uniform clusters of CSH gels and small crystals of Ca (OH) ₂ and etringite. Nano-SiO ₂ is involved in pozzolanic reactions, resulting in the consumption of Ca (OH) ₂ and formation of another CSH gel. Nanoparticles improve the structure of the aggregate contact zone, resulting in a better bond between the aggregate and the cement paste. Stopping cracks and bonding between the sliding planes formed by nanoparticles improve resistance, shear strength, tensile strength and flexural strength of cementitious materials. The combination of nano-SiO ₂ and micro-SiO ₂ ensures the best possible compaction of Portland cement.

The combination of chemical admixtures and Portland cement particles with nano- and micro-size ensures good flowability of high-strength and ultra-high-strength concrete, which can be achieved at very low water binder ratios. The flowability of high-strength concrete and ultra-high strength concrete at a low water to cement ratio is significantly influenced by the composition, structure and morphology of organo-mineral nanolayers and nano-grids (when functional groups are only attached to active centers).

The formation of CSH gels and the consumption of Ca (OH) ₂ results in an improvement of the hydration process and further strength development can be achieved by the use of calcium materials such as fired clay, ladle slag, calcium ash, fluid fly ash. The calcareous materials may be mechanically-chemically activated in dry or liquid (aqueous) form using grinding aids and / or chemical impurities with nano- and / or microparticles such as SiO ₂ to deposit active CSH gels on the particle surface; thus activated calcium materials can be further processed to a hydrated product containing CSH gels and Ca (OH) _{2 by} autoclaving.

The Portland cement blend of the present invention is a binder with increased internal bond between hydrated products controlled and adapted at the nanometer scale, as well as a binder modified with nano-sized polymer particles, their solutions / emulsions and / or polymer nanolayers.

The developed cement mix exhibits high early strength and very high final strength, excellent durability and corrosion resistance, improved toughness and deformation properties; in addition, resistance, no / low shrinkage, low thermal expansion and reduced formation of micro-cracks can be improved.

The proposed cementitious compound and complex admixtures are suitable for application in conventional and heavy concrete with compressive strength classes starting from C30 / 37, and are more effective in concrete class from C45 / 55. The proposed cementitious compound is very suitable for application in high-strength concrete and ultra-high strength concrete according to Table 1.

The proposed cementitious compound is also suitable for application in lightweight concrete with compressive strength classes starting from LC30 / 33, and are more effective in concrete class from LC45 / 50.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

The example shows the effect of complex admixtures, the cement mix and the qualitative properties of the developed cement.

Table 2 Chemical composition of cementitious materials

Mixture (wt.%) clinker GBFS FA FBFA SF MK CaO 66,12 40,24 3.25 26.77 0.41 0.50 SiO ₂ 21.70 39,13 51,53 32,26 96.40 52,48 A1 ₂ O ₃ 5.20 7.17 26.81 17.64 0.08 40.58 Fe ₂ O ₃ 2.94 0.29 7.39 6.85 0.06 1.23 MgO 1.22 10.04 2.07 1.32 0.35 0.31 Na ₂ O 0.26 0.32 0.20 1.03 0.19 0.56

GBFS - granulated blast furnace slag; FA - fly ash (silica); FBFA - fluid fly ash; SF - Silica drift; MK- metakaolin; L.O.I. - loss on ignition

The complex admixture was prepared by premixing and granulating the silica drift and melamine resin superplasticizer in a laboratory mixer for 15 minutes. Cement mixture no. 1 was prepared by co-milling Portland clinker, gypsum and complex admixtures in a standard ball mill for 2 hours; the cement proportions are given in Table 3. The mean particle size (D ₅₀ ) of the ground cement, the normal consistency and the initial and final setting times are shown in Tables 3 and 1-, 2-, 7-, 28 and 90 ductile compressive strengths, and The bending of the mortars tested at the v / c ratio of 0.4 (v / c - water / cement ratio) are given in Table 4.

Table 3 Proportions of cementitious materials and fineness (D ₅₀ ), normal consistency, initial and final setting times of developed cement.

clinker gypsum SF SMF D50 NC GO FST % wt. % wt. % wt. % wt. μιη % min. min. Ref. 93.60 6,40 - - 10.13 30.5 190 265 no. 1 84.92 6.84 6.38 1.86 12.69 18.9 114 189

NC - normal consistency; IST - initial setting time and FST - final setting time; Ref. - reference mixture; SMF - superplasticizer based on sodium salt of melamine resin

Table 4 Compressive and flexural strength after 1-, 2-, 7-, 28- and 90-days.

strength, MPa 1 day 2 days 7 days 28 days 90 days Flex. Compr. Flex. Compr. Flex. Compr. Flex. Compr. Flex. Compr. Ref. 5.4 30.2 7.5 41.9 9.6 57.9 9.4 70.4 8.7 73.8 no. 1 6.0 50.4 8.9 59.8 13.4 67.0 12.6 82.7 13.8 91.6

Flex. - flexural strength; Compr. - compressive strength

Example 2

The example shows the effect of complex admixture, the cement mix and the qualitative properties of the developed cement.

The complex admixture was prepared by pre-mixing the fly ash, silica drift, and naphthalene polymer sodium condensate superplasticizer in a laboratory mixer for 15 minutes. Cement mixture no. 2 was prepared by co-grinding Portland clinker, gypsum and complex admixture in a standard ball mill for 2 hours in proportions listed in Table 5. The mean particle size (D ₅₀ ) of ground cement, normal consistency and initial and final solidification times are shown in Table 5; The 1-, 2-, 7-, 28- and 90-day compressive and flexural strengths of the mortars tested at the v / c ratio of 0.4 (v / c - water / cement ratio) are shown in Table 6.

Table 5 Proportions of cementitious materials and fineness (D ₅₀ ), normal consistency, initial and final setting times of developed cement.

clinker gypsum SF FA SNF D50 NC GO FST % wt. % wt. % wt. % wt. % wt. μιη % min. min. Ref. 93.60 6,40 - - - 10.13 30.5 190 265 no. 2 81.18 6.20 6.00 5.00 1.62 10.69 20.40 125 230

NC - normal consistency and IST - initial setting time and FST final setting time; Ref. - reference mixture for comparison; SNF - naphthalene polymer condensate superplasticizer.

Table 6 Compressive and flexural strength after 1-, 2-, 7-, 28- and 90-days.

MPa strength 1 day 2 days 7 days 28 days 90 days Flex. Compr. Flex. Compr. Flex. Compr. Flex. Compr. Flex. Compr. Ref. 5.4 30.2 7.5 41.9 9.6 57.9 9.4 70.4 8.7 73.8 no. 2 7.0 57.5 9.5 64.8 12.8 81.9 14.2 86.9 16.6 96.5

Flex. - flexural strength; Compr. - compressive strength

Example 3

The example shows the effect of complex admixture, the cement mix and the qualitative properties of the developed cement.

The complex admixture was prepared by premixing and granulating the metakaolin, silica drift and the melamine resin sodium superplasticizer in a laboratory mixer for 15 minutes. Cement mixture # 3 was prepared by co-grinding Portland clinker, gypsum and complex admixture in a standard ball mill for 2 hours in proportions listed in Table 7. The mean particle size (D ₅₀ ) of ground cement, normal consistency and initial and final solidification times are given. in Table 7 and the 1-, 2-, 7-, 28- and 90-day compressive and flexural strengths of the mortars tested at the v / c ratio of 0.4 (v / c - water / cement ratio) are shown in Table 8.

Table 7 Proportions of cementitious materials and fineness (D ₅₀ ), normal consistency, initial and final setting times of developed cement

clinker gypsum SF MK SMF D50 NC GO FS % wt. % wt. % wt. % wt. % wt. μιη % min. min. Ref. 93.60 6,40 - - - 10.13 30.5 190 265 no. 3 81.10 6.10 4.00 7.00 1.80 9.52 19.60 100 170

NC - normal consistency and IST - initial setting time and FST final setting time; Ref. - reference mixture for comparison; SMF - superplasticizer based on sodium salt of melamine resin

Table 8 Compressive and flexural strength after 1-, 2-, 7-, 28- and 90-days.

MPa strength 1 day 2 days 7 days 28 days 90 days Flex. Compr. Flex. Compr. Flex. Compr. Flex. Compr. Flex. Compr. Ref. 5.4 30.2 7.5 41.9 9.6 57.9 9.4 70.4 8.7 73.8 no. 3 8.4 64.4 11.6 76.7 13.2 88.7 16.6 102.8 20.7 105.2

Flex. - flexural strength; Compr. - compressive strength

Example 4

The example shows the effect of complex admixture, the cement mix and the qualitative properties of the developed cement. The complex admixture was prepared by premixing and granulating the fluidized-bed fly ash and silica flux and modified polycarboxylate polymer (PCE) superplasticizer in a laboratory mixer for 10 minutes. Cement mixture no. 4 was prepared by co-milling Portland clinker. Gypsum and complex admixture in a standard ball mill for 2 or 3 hours in proportions listed in Table 9. The mean particle size (D ₅₀ ) of ground cement, normal consistency and initial and final setting times are shown in Tables 9 and 1-, 2-, The 7-, 28- and 90-day compressive and flexural strengths of the mortars tested at the v / c ratio of 0.4 (v / c - water / cement ratio) are shown in Table 10.

Table 9 Proportions of cementitious materials and fineness (D ₅₀ ), normal consistency, initial and final setting times of developed cement.

clinker gypsum SF FBFA PLE DSO NC GO FS % wt. % wt. % wt. % wt. % wt. ipm % min. min. Ref. 93.60 6,40 - - - 10.13 30.5 190 265 no. 4 78.30 5.90 8.00 6,40 1.40 13,10 18.8 180 245

NC - normal consistency and IST - initial setting time and FST final setting time; Ref. - reference mixture for comparison; PLE - superplasticizer based on modified polycarboxylate polymers

Table 10 Compressive and flexural strength after 1-, 2-, 7-, 28- and 90-days.

MPa strength 1 day 2 days 7 days 28 days 90 days Flex. Compr. Flex. Compr. Flex. Compr. Flex. Compr. Flex. Compr. Ref. 5.4 30.2 7.5 41.9 9.6 57.9 9.4 70.4 8.7 73.8 no. 4 6.2 44.2 8.2 51.7 12.4 70.5 13.2 78.2 12.7 86.9

Flex. - flexural strength; Compr. - compressive strength

Example 5

The example shows the effect of complex admixture, the cement mix and the qualitative properties of the developed cement. The complex admixture was prepared by pre-mixing the silica drift and modified polycarboxylate polymers (PCE) superplasticizer in a laboratory mixer for 10 minutes. Cement mixture no. 5 was prepared by co-milling Portland clinker, gypsum, slag sand and complex additives in a standard ball mill for 2 hours, using the proportions indicated in Table 11. The mean particle size _(D50) of the ground cement, and the normal consistency of the initial and final setting times are shown in Table 11 and the 1-, 2-, 7-, 28- and 90-day compressive and flexural strengths of the mortars tested at the v / c ratio of 0.4 (v / c - water / cement ratio) are shown in Table 12 .

Table 11 Proportions of cementitious materials and fineness (D ₅₀ ), normal consistency, initial and final setting times of developed cement

clinker gypsum SF GBFS PLE D50 NC GO FST % wt. % wt. % wt. % wt. % wt. μιη % min. min. Ref. 93.60 6,40 - - - 10.13 30.5 190 265 no. 5 35.00 6.70 7.00 50.00 1.30 12.55 20,10 210 295

NC - normal consistency and IST - initial setting time and FST final setting time; Ref. - reference mixture for comparison; PFE - superplasticizer based on modified polycarboxylate polymers

Table 12 Compressive and flexural strength after 1-, 2-, 7-, 28- and 90-days.

MPa strength 1 day 2 days 7 days 28 days 90 days Flex. Compr. Flex. Compr. Flex. Compr. Flex. Compr. Flex. Compr. Ref. 5.4 30.2 7.5 41.9 9.6 57.9 9.4 70.4 8.7 73.8 no. 5 5.3 45.8 8.6 53.7 12.1 70.1 14.3 89.9 15.6 99.9

Flex. - flexural strength; Compr. - compressive strength

Example 6

The example shows the effect of complex admixture, the cement mix and the qualitative properties of the developed cement.

The individual components of the complex admixture, the individual components of the Portland cement were dosed separately into the mill and subsequently ground together. Separate dosing and co-milling were performed using an industrial grinding unit consisting of two ball mills (pre-grinding and fine grinding) and a separator. In this case, the complex admixture was not premixed; so that all components were dosed separately: the silica drift was delivered directly to the mill inlet for final grinding, and the liquid PCE superplasticizer was dosed on top of the raw materials into the inlet mill mill inlet. Other materials were supplied using existing dispensing and delivery systems. To perform mechanical-chemical activation, a silica fume and PCE admixture were added and ground together with the other ingredients (added in the range of 6.4 to 8.4% for SF and 1.4 to 1.9% for PCE) at the target doses of 1.5 and 6.4% for SF, respectively. PCE. Cement mixture no. 6 was prepared by co-milling Portland clinker, gypsum, slag sand and complex additives in a standard ball mill for 2 hours in the proportions listed in Table 13. The mean particle size _(D50) of the ground cement composition, and the normal consistency of the initial and final setting times are shown in Tables 13 and the 1-, 2-, 7-, 28- and 90-day compressive and flexural strengths of mortars tested at the v / c ratio of 0.4 (v / c - water / cement ratio) are shown in Table 14 .

Table 13 Proportions of cementitious materials and fineness (D ₅₀ ), normal consistency, initial and final setting times of developed cement.

clinker gypsum SF PLE D50 NC GO FST % wt. % wt. % wt. % wt. μιη % min. min. Ref. 93.60 6,40 - - 10.13 30.5 190 265 no. 6 83.13 6.91 8.33 1.62 9.85 19.6 114 189

NC - normal consistency and IST - initial setting time and FST final setting time; Ref. - reference 30 mixture for comparison; RLE - superplasticizer based on modified polycarboxylate polymers

Table 14 Compressive and flexural strength after 1-, 2-, 7-, 28- and 90-days.

MPa strength 1 day 2 days 7 days 28 days 90 days Flex. Compr. Flex. Compr. Flex. Compr. Flex. Compr. Flex. Compr. Ref. 5.4 30.2 7.5 41.9 9.6 57.9 9.4 70.4 8.7 73.8 no. 6 6.5 36.0 8.8 48.1 11.3 68.6 10.4 84.6 12.8 89.2

Flex. - flexural strength; Compr. - compressive strength

Example 7

The example shows the effect of complex admixture, the cement mix and the qualitative properties of the developed cement. The complex admixture was prepared by premixing and granulating the silica particulate and grinding ingredients based on modified polyacrylate polymers (PAP) in a laboratory mixer for 10 minutes. Cement mixture # 7 was prepared by co-grinding Portland clinker, gypsum, granulated blast furnace and complex admixture in a standard ball mill for 2 hours in proportions listed in Table 15. Mean particle size (D ₅₀ ) of ground cement, normal consistency and initial and the final setting times are given in Tables 15 and 1-, 2-, 7-, 28- and 90-day compressive and flexural strengths of the mortars tested at the v / c ratio of 0.4 (v / c - water / cement ratio) are shown in Table 16.

Table 15 Proportions of cementitious materials and fineness (D ₅₀ ), normal consistency, initial and final setting times of developed cement.

clinker gypsum SF PCE D50 NC GO FST % wt. % wt. % wt. % wt. pm % min. min. Ref. 93.60 6,40 - - 10.13 30.5 190 265 no. 7 88,00 6.00 5.84 0.16 12.26 22.9 110 186

NC - normal consistency and IST - initial setting time and FST final setting time; Ref. - reference mixture for comparison; PCE - superplasticizer based on modified polyacrylate polymers

Table 16 Compressive and flexural strength after 1-, 2-, 7-, 28- and 90-days.

MPa strength 1 day 2 days 7 days 28 days 90 days Flex. Compr. Flex. Compr. Flex. Compr. Flex. Compr. Flex. Compr. Ref. 5.4 30.2 7.5 41.9 9.6 57.9 9.4 70.4 8.7 73.8 no. 7 6.0 34.8 8.6 45.3 11.4 65.0 12.6 82.7 13.8 91.6

Flex. - flexural strength; Compr. - compressive strength

The examples given are illustrative only and do not include all possible types of complex admixtures, cement and concrete mixtures and the qualities of the materials developed.

Industrial usability

The developed cement mixtures exhibit high early strengths and very high final strengths, excellent durability and corrosion resistance, improved toughness and deformation properties; in addition, resistance, no / low shrinkage, low thermal expansion, and reduced cracks formation can be improved.

The proposed cementitious compound and complex admixtures are suitable for use in conventional and heavy concrete in compression strength classes starting from C30 / 37, and are more effective in concrete classes from C45 / 55. The proposed cementitious compound is very suitable for use in high strength concrete and ultra high strength concrete according to Table 1 as well as a wide range of fiber reinforced composites.

The proposed cementitious compound is also suitable for use in lightweight concrete in compression strength classes starting from LC 30/33, and is more effective in concrete classes from LC 45/50.

High-performance concrete made from high-performance cement can be used on high-rise buildings, prefabricated reinforced concrete elements, airport runways, bridges, water and ground construction, tunnels, parking floors, sprayed concrete and construction repairs, underwater concrete and special floors and many other special applications, such as earthquake constructions, nuclear and hazardous waste containers.

PATENT CLAIMS

Claims (3)

CLAIMS 1. A process for the production of a cementitious composition comprising combining a complex additive consisting of a mineral component and an aqueous surfactant solution with a Portland cement component by mixing or grinding, characterized in that the individual components of the complex additive are individually dosed into the cement grinding mill and subsequently together ground, wherein the mineral component of the complex admixture is a reactive powder based on SiO ₂ and the surfactant is a liquid superplasticizer based on modified polycarboxylate polymers. Method according to claim 1, characterized in that an industrial grinding unit consisting of two ball mills for pre-grinding and fine grinding is used as the cement grinding mill. Method according to claim 2, characterized in that the reactive SiO ₂ -based powder is a siliceous drift, wherein the siliceous drift is metered directly into the finely ground mill inlet and the liquid superplasticizer based on modified polycarboxylate polymers is dosed on top of the raw materials into the premix mill inlet. . End of document