Integrated cementing material special for ultra-high performance concrete and preparation method

Abstract

The invention belongs to the field of cement concrete, and particularly relates to an integrated cementing material special for ultra-high performance concrete and a preparation method of the integrated cementing material. The integrated cementing material comprises fly ash, slag powder, carbide slag, semi-hydrated gypsum, silica fume, a powder reinforcing agent, calcium nitrate and sodium silicate. The production process of the integrated cementing material comprises the following steps: winnowing ultrafine microbeads from fly ash, grinding solid waste powder by a fluidized bed type jet mill, chemically strengthening the powder reinforcing agent, chemically nucleating calcium nitrate and sodium silicate, and mixing the integrated cementing material. The ultra-high performance concrete cementing material is prepared from a high-activity solid waste material, the viscosity of a mixture is reduced by winnowing ultrafine micro-beads, the strength of the cementing material is improved by synergistic reaction of slag powder, carbide slag and semi-hydrated gypsum, and a C-S-H crystal nucleus is formed by chemical reaction of calcium nitrate and sodium silicate to provide active sites, so that the cementing material is prepared. And the cementing material is prepared by combining powder chemical dispersion and integrated mixing, so that the carbon emission and production difficulty of the ultra-high performance concrete are remarkably reduced.

Description

Technical Field

[0001] The present invention belongs to the field of cement concrete, and in particular relates to an integrated cementitious material dedicated to ultra-high performance concrete and a preparation method thereof. Background Art

[0002] Ultra-high performance concrete (UHPCC) is a new type of cement-based composite material with ultra-high strength, ultra-high toughness, and ultra-high durability. It has excellent structural lightness and extremely low life cycle costs. Currently, UHPCC is gradually replacing ordinary concrete in many new construction and maintenance structural projects, such as prefabricated bridge components, cast-in-place bridge decks, joint connections, and outsourced reinforcement, and has fully demonstrated its excellent material properties. However, compared to ordinary concrete, the most prominent feature of UHPCC is the large number of raw materials and the high measurement accuracy requirements. Among them, cementitious materials such as cement, mineral admixtures, silica fume, and functional admixtures are the key to determining the performance of UHPCC materials and are also the decisive factors affecting carbon emission performance. Therefore, how to reduce the types of raw materials, improve the uniformity of cementitious materials, reduce the carbon emissions of cementitious materials, and increase measurement redundancy are key factors in the production of UHPCC.

[0003] To address the above-mentioned issues, patents CN 117466608 B and CN 115849800 B respectively use solid wastes such as fly ash, coal gasification slag, and basalt powder in combination with a certain amount of cement to prepare ultra-high performance concrete cementitious materials to reduce the carbon emissions and material costs of ultra-high performance concrete. However, such treatment methods not only fail to solve the fundamental production problems of a wide variety of cementitious materials and high metering accuracy, but also fail to provide a series of activation and uniformity improvement methods for the raw materials. Therefore, they have no practical application significance. CN 118619606 B and CN118005352B use chemical modification to treat solid waste to obtain ultra-high performance concrete cementitious materials with better and more stable performance. However, the cost of treating solid waste solely by chemical modification is high, so they also have no practical production significance.

[0004] Based on the analysis of existing patent literature, there are many patents related to the preparation of ultra-high performance concrete using solid waste, but the actual application significance is not strong. There are fewer patents for using chemical modification to improve the performance of solid waste in ultra-high performance concrete. There are basically no patents related to ultra-high performance concrete cementitious materials based on graded grinding and integrated mixing to form all-solid waste. Summary of the Invention

[0005] The purpose of the present invention is to provide an integrated cementitious material specifically for ultra-high performance concrete (UHPCC) to address the inherent problems of a wide variety of UHPCC cementitious materials and high carbon emissions. This invention addresses the production difficulties associated with the large variety of UHPCC cementitious materials, high metering precision, high carbon emissions, and poor mixing uniformity. By employing systematic processes such as air separation, grinding, dispersion modification, CSH nucleation preparation, and integrated mixing, the present invention successfully reduces the number of UHPCC cementitious materials to a single type. Furthermore, through a series of physical and chemical reaction designs, a highly effective UHPCC-specific cementitious material is formed.

[0006] The technical solutions of the present invention are as follows:

[0007] One of the technical solutions of the present invention is to provide an integrated cementitious material dedicated to ultra-high performance concrete, which is composed of the following raw materials in parts by weight:

[0008] 598-602 parts of fly ash, 398-402 parts of slag powder, 99-101 parts of carbide slag, 99-101 parts of hemihydrate gypsum, 148-152 parts of silica fume, 0.19-0.20 parts of powder reinforcing agent, 9.5-10.5 parts of calcium nitrate, and 9.5-10.5 parts of sodium silicate;

[0009] in:

[0010] The fly ash is first-grade fly ash, with a total SiO2 and Al2O3 content greater than 80%, a CaO content less than 10%, and a median particle size less than 20 μm;

[0011] The slag powder is water-quenched slag powder of S95 or above, with a total SiO2 and Al2O3 content greater than 60%, a CaO content greater than 30%, and a median particle size less than 20μm;

[0012] Carbide slag is a dry powder product after the hydrolysis of calcium carbide, with a moisture content of less than 5%, a CaO content of more than 85%, and a median particle size of less than 20 μm;

[0013] Hemihydrate gypsum is a natural β-hemihydrate gypsum powder with a CaSO4 content greater than 80% and a median particle size less than 20μm;

[0014] Silica fume is non-densified silica fume with SiO2 content greater than 90% and median particle size less than 1μm;

[0015] The powder reinforcing agent is a mixture of acrylic acid and γ-methacryloxypropyltrimethoxysilane in a mass ratio of 1:2;

[0016] Calcium nitrate is analytical grade Ca(NO3)2·4H2O with a purity greater than 99%;

[0017] Sodium silicate is analytical grade Na2SiO3·9H2O with a purity greater than 99%.

[0018] As a further option for integrated cementitious materials, the fly ash is subjected to air separation through an air classification mill system, with a crushing disk speed of 4200 r / min, a classification impeller speed of 3000 r / min, a discharge sieve aperture of 2 μm, and an air separation rate greater than 15%, obtaining spherical fly ash microbeads with a median particle size of 1.8 μm and a SiO2 content of 53.8%.

[0019] As a further option for integrated cementitious materials, the slag powder, carbide slag, and hemihydrate gypsum are ground through a fluidized bed airflow mill system with an air pressure of 0.8 MPa, a discharge sieve aperture of 5 μm, and a grinding time of 2-3 hours. The resulting powder can generate calcium silicate gel and ettringite structure in an aqueous environment.

[0020] As a further option for integrated gelling materials, the powder enhancer is mixed with the powder material in a dry and dispersed modified rotor mill with a rotor speed of 4200 r / min, a nozzle pressure of 0.8 MPa, a drying temperature of 120°C, and a shear dispersion time of 2-2.5 hours to form a polyacrylate network structure, encapsulating the silica-alumina mineral material and enhancing its reactivity.

[0021] As a further option for the integrated gelling material, the calcium nitrate reacts with sodium silicate in an alkaline environment to generate CSH crystal nuclei, and the reaction formula is:

[0022] xCa(NO3)2·4H2O+yNa2SiO3·9H2O+zH2O→xCaO·ySiO2·(4x+9y+z)H2O+2(x+y)NaNO3;

[0023] The CSH nuclei serve as initial active sites for the hydration reaction, thereby increasing the hydration rate and strength development of the cementitious material.

[0024] The second technical solution of the present invention is to provide a method for preparing an integrated gelling material, comprising the following steps:

[0025] Step (1), fly ash air separation: placing fly ash in an air classification mill system, adjusting the rotation speed of the crushing disk, the rotation speed of the classification impeller, the discharge sieve hole, and controlling the air separation rate to obtain fly ash microbead powder material 1;

[0026] Step (2), grinding slag powder, carbide slag, and hemihydrate gypsum: placing the slag powder, carbide slag, and hemihydrate gypsum in a fluidized bed jet mill system, adjusting the air pressure and the discharge sieve aperture, and grinding to obtain powder material 2;

[0027] Step (3), powder material modification: placing powder material 1, powder material 2, silica fume and powder reinforcing agent in a dry and dispersed modified rotor mill, adjusting the rotor speed, nozzle pressure, drying temperature, and shearing and dispersing to obtain reinforced powder material 3;

[0028] Step (4), CSH crystal nucleus preparation: calcium nitrate and sodium silicate are mixed evenly to form CSH crystal nucleus material 4;

[0029] Step (5), integrated mixing: placing the reinforcing powder material 3 and the crystal core material 4 in a dispersion vibration mill, adjusting the rotation speed and vibration frequency, and mixing and grinding to obtain an integrated gelling material.

[0030] As a further option for the method of preparing an integrated cementitious material, it is characterized in that the fly ash microbeads after air separation in step (1) have a 2μm particle content of ≥71.1%, a SiO2 content of ≥53.8%, and are regular spherical particles, which are used to reduce the viscosity of the mixture and improve the density.

[0031] As a further option of the method for preparing the integrated cementitious material, it is characterized in that the synergistic reaction of slag powder, carbide slag and hemihydrate gypsum in step (2) includes:

[0032] (a) SiO2 reacts with Ca(OH)2 to form CSH gel:

[0033] SiO2+mCa(OH)2+nH2O→mCaO·SiO2·(n+m)H2O;

[0034] (b) Hemihydrate gypsum reacts with water to form dihydrate gypsum:

[0035]

[0036] (c) Al2O3, Ca(OH)2, and dihydrate gypsum react to form ettringite:

[0037] Al2O3+3Ca(OH)2+3CaSO4·2H2O+27H2O→3CaO·Al2O3·3CaSO4·32H2O.

[0038] As a further option for the method of preparing an integrated gelling material, it is characterized in that in step (3), the powder reinforcing agent generates a polyacrylate structure through a polymerization reaction, forming a chain or network cross-linked coating layer, thereby enhancing the strength and toughness of the silica-alumina mineral material, and optimizing the pore negative pressure by complexing water molecules, thereby improving the volume stability.

[0039] A third technical solution of the present invention is to provide an ultra-high performance concrete, which is prepared using the integrated cementitious material according to any one of claims 1 to 5, comprising the following steps:

[0040] Step (1) Weigh 1000 parts of integrated cementitious material, 1000 parts of quartz sand, 156 parts of steel fiber, 8 parts of polycarboxylate water reducer, and 178 parts of water in parts by weight;

[0041] Step (2) dry-mixing the cementitious material with quartz sand for 2 minutes, adding water and a water-reducing agent and stirring for 5 minutes, sifting in steel fibers and stirring for another 2 minutes to prepare an ultra-high performance concrete mixture;

[0042] After forming in step (3), room temperature curing or steam curing is adopted, and the compressive strength after 1 day is ≥70MPa, the compressive strength after 28 days is ≥150MPa, and the compressive strength after steam curing is ≥160MPa.

[0043] As a further option for ultra-high performance concrete, the quartz sand can be replaced with machine-made sand, and the concrete mixture has a T500 time of ≤5 seconds, an expansion of ≥700 mm, and an expansion loss of ≤5% in 1 hour.

[0044] As a further option for ultra-high performance concrete, the steel fiber is 0.2×13mm low-carbon steel fiber, with a dosage of 156 parts, the concrete fracture toughness is ≥30MPa·√m, and the chloride ion diffusion coefficient is <1×10 -12 m 2 / s.

[0045] The fourth technical solution of the present invention is to provide the use of integrated cementitious materials for bridge prefabricated parts, cast-in-place bridge decks, joint connections or outsourced reinforcement projects, replacing traditional cement-based materials and reducing carbon emissions by ≥40%.

[0046] As a further option for the use of the integrated cementitious material, it is used to prepare ultra-high performance concrete with a compressive strength of ≥160 MPa and a mixture viscosity of ≤30 Pa·s.

[0047] The beneficial effects brought about by the technical solutions provided in the embodiments of the present application include at least the following beneficial effects:

[0048] 1. The present invention takes the production difficulties caused by the large variety of ultra-high performance concrete cementitious materials, high metering precision, large carbon emissions, and poor mixing uniformity as its starting point. It adopts systematic processes such as air separation, grinding, dispersion modification, CSH crystal nucleus preparation, and integrated mixing to apply various solid wastes to ultra-high performance concrete cementitious materials. Based on systematic processing, the ultra-high performance concrete cementitious materials are successfully reduced to one, and through a series of physical and chemical reaction designs, an excellent ultra-high performance concrete-specific cementitious material is formed.

[0049] 2. The present invention proposes a method for preparing fly ash microbeads by air separation of fly ash. The fly ash microbeads after sorting have a 2μm particle content of 71.1% and a SiO2 content of 53.8%, and are all spherical particles. The fly ash microbeads with small particle size, high SiO2 content and spherical shape fully exert the filling effect, secondary hydration effect and ball effect in the low water-binder ratio ultra-high performance concrete system, which can further improve the density of ultra-high performance concrete, produce more calcium silicate gel and achieve a physical viscosity reduction effect.

[0050] 3. The present invention uses slag powder, carbide slag, and semi-hydrated gypsum to replace traditional cement in ultra-high performance concrete cementitious materials. A series of chemical reactions are carried out using highly active SiO2, Al2O3, Ca(OH)2, and CaSO4 in solid waste to generate calcium silicate (CSH) gel and ettringite (AFt), which are consistent with cement hydration products. The CSH crystal nuclei formed by calcium nitrate and sodium silicate in an alkaline solution environment are used as active sites for the hydration reaction. Ultimately, solid waste is effectively used to achieve a good replacement for cement products and significantly reduce carbon emissions.

[0051] 4. The present invention proposes a method for strengthening silica-alumina fine powder, introduces a polyacrylate structure, and through network structure cross-linking / coating, chemical bond strengthening, complexing water molecules and other effects, can provide good coating and strengthening effects before the synergistic reaction of the powdered mineral materials. Chemical bonding greatly improves the strength and toughness of the silica-alumina powder material, and complexing water molecules optimizes the pore negative pressure to improve the volume stability, etc., ultimately achieving the performance enhancement of the integrated cementitious material. DETAILED DESCRIPTION

[0052] The following will be combined with the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0053] Example 1: Preparation of integrated cementitious materials and application of ultra-high performance concrete

[0054] 1. Selection of raw materials used in this embodiment of the integrated cementitious material.

[0055] Fly ash: Use first-grade fly ash with a combined SiO2 and Al2O3 content greater than 80%, a CaO content less than 10%, a median particle size less than 20 μm, and a maximum particle size of 20.7 μm.

[0056] Slag powder: Use S95 or above water-quenched slag powder, with a total SiO2 and Al2O3 content greater than 60%, a CaO content greater than 30%, and a median particle size less than 20μm.

[0057] Carbide slag: It is the dry powder product after the hydrolysis of calcium carbide, with a moisture content of less than 5%, a CaO content greater than 85%, and a median particle size of less than 20μm.

[0058] Hemihydrate gypsum: natural β-hemihydrate gypsum powder, CaSO4 content greater than 80%, median particle size less than 20μm.

[0059] Silica fume: Use non-densified silica fume with SiO2 content greater than 90% and median particle size less than 1μm.

[0060] Powder reinforcement: It is a mixture of acrylic acid and γ-methacryloxypropyltrimethoxysilane in a ratio of 1:2.

[0061] Calcium nitrate: analytical grade Ca(NO3)2·4H2O, content greater than 99%.

[0062] Sodium silicate: analytical grade Na2SiO3·9H2O, content greater than 99%.

[0063] All raw materials are strictly screened and dried to ensure that their physical and chemical properties are stable and meet process requirements.

[0064] 2: Preparation of integrated cementitious materials.

[0065] The preparation steps of the integrated cementitious material include:

[0066] Step 1: Preparation of fly ash air separation microbeads.

[0067] 598 parts of fly ash were placed in an air classifying mill system. The pulverizing disc speed was adjusted to 4200 r / min, the classifying impeller speed was adjusted to 3000 r / min, and the discharge sieve aperture was set to 2 μm, with an air separation rate controlled to be greater than 15%. The impact of the high-speed rotating pulverizing disc and the centrifugal force caused the hollow spherical particles in the fly ash to be separated into the classification zone with the airflow. Further screening was performed by the classifying blade speed and sieve aperture, ultimately obtaining fly ash microbead powder material 1 that met the sphericity and particle size requirements.

[0068] After testing, the fly ash microbeads after air separation have the following characteristics:

[0069] Particles with a size of less than 2 μm account for 71.1%;

[0070] SiO2 content reaches 53.8%;

[0071] It presents regular spherical particle morphology;

[0072] The median particle size is 1.8 μm;

[0073] The above characteristics enable it to play the role of ball effect, filling effect and secondary hydration reaction in the subsequent ultra-high performance concrete system, which helps to reduce the viscosity of the mixture, improve the density and later strength.

[0074] Step 2: Grind slag powder, carbide slag and hemihydrate gypsum together.

[0075] 398 parts of slag powder, 99 parts of carbide slag, and 101 parts of hemihydrate gypsum were fed into a fluidized bed jet mill system. The air pressure was adjusted to 0.8 MPa, the discharge sieve aperture was set to 5 μm, and the powder material 2 was obtained after thorough grinding for 23 hours.

[0076] The principle of this stage is to use high-pressure airflow to form multiple intersecting airflows within the pulverizing chamber. During this process, the material is repeatedly pulverized by collision, friction, and shearing. Subsequently, the fine particles enter the classification zone under the suction force of the fan. The high-speed rotating classification turbine separates the coarse and fine particles. The fine particles that meet the particle size requirements are collected as the finished product.

[0077] After testing, the obtained powder material 2 has the following characteristics:

[0078] The average particle size is less than 5 μm;

[0079] High content of active ingredients SiO2, Al2O3, CaO, and CaSO4;

[0080] In alkaline environment, CSH gel and ettringite structure (AFt) can be generated;

[0081] This stage provides the key basis for the subsequent formation of cement hydration products.

[0082] Step 3: Powder materials 1 and 2 are modified synergistically with silica fume and powder reinforcing agent.

[0083] 150 parts of powder material 1 (fly ash microbeads), 600 parts of powder material 2 (slag powder + carbide slag + semi-hydrated gypsum), and 150 parts of silica fume are added together into a dry and dispersed modified rotor mill. The rotor speed is adjusted to 4200 r / min, and 0.15 parts of powder enhancer is evenly sprayed on the surface of the mixed powder through a special nozzle. The nozzle pressure is adjusted to 0.8 MPa, and the drying temperature is controlled to 120°C. Shear dispersion is continued for 22.5 hours to finally obtain the reinforced powder material 3.

[0084] The core of this stage is:

[0085] Use strong shearing and breaking forces to achieve efficient mixing;

[0086] Introduce powder reinforcement through the nozzle to promote polymerization reaction;

[0087] High temperature drying is used to improve the activity and stability of the powder.

[0088] Acrylic acid and γ-methacryloxypropyltrimethoxysilane in the powder reinforcing agent undergo polymerization reaction under aqueous solution conditions to generate polyacrylate structures and form a network or chain cross-linked coating layer, thereby enhancing the reactivity and mechanical properties of the silica-alumina mineral material.

[0089] The experimental results show that after the completion of this stage, the specific surface area of ​​the powder material 3 increases significantly, the activity index increases by about 30%, and it exhibits good fluidity and dispersibility.

[0090] (4) Preparation of CSH core materials

[0091] 9.5 parts of calcium nitrate and 10.5 parts of sodium silicate were fully mixed in a stirrer to obtain the desired CSH crystal nucleus material 4.

[0092] In an alkaline environment, calcium nitrate and sodium silicate undergo a copolymerization precipitation reaction to generate CSH crystal nuclei:

[0093] xCa(NO3)2·4H2O+yNa2SiO3·9H2O+zH2O→xCaO·ySiO2·(4x+9y+z)H2O+2(x+y)NaNO3;

[0094] The CSH nuclei formed by this reaction can serve as active sites for subsequent hydration reactions, greatly increasing the hydration rate and degree without affecting the subsequent strength development.

[0095] XRD analysis confirmed that the obtained material 4 had a typical CSH structure peak, indicating that the crystal nucleus was successfully formed.

[0096] Step 5: Final mixing of the integrated cementitious material.

[0097] The reinforcing powder material 3 and the crystal core material 4 are placed together in a dispersion vibration mill, the rotation speed is adjusted to 1500 r / min, the vibration frequency is adjusted to 2000 Hz, and the mixture is mixed and ground for 30 minutes to obtain an integrated cementitious material specially used for ultra-high performance concrete.

[0098] This step ensures highly uniform mixing between the components, avoids local enrichment or segregation, and thus ensures the consistency and stability of the overall performance of the cementitious material.

[0099] The final integrated cementitious material has the following characteristics:

[0100] Density: 2.85g / cm 3 ;

[0101] Specific surface area: ≥500m 2 / kg;

[0102] Fluidity: ≥300mm (standard consistency);

[0103] Early activity: 1-day activity index ≥80%;

[0104] The strength develops well in the later stage, and the compressive strength after 28 days can reach more than 150MPa.

[0105] 3: Preparation and construction of ultra-high performance concrete containing integrated cementitious materials.

[0106] (1) Concrete mix design.

[0107] Weigh the raw materials according to the following formula:

[0108] Components Weight (parts) Integrated cementitious materials 1000 Quartz sand (0.1-0.5mm) 200 Quartz sand (0.5-1mm) 300 Quartz sand (1-2mm) 500 Steel fiber (0.2×13mm) 156 Polycarboxylate water reducer 8 water 178

[0109] (2) Concrete mixing process.

[0110] Use planetary or horizontal shaft mixer for mixing operation:

[0111] 1. First add the integrated cementitious material, quartz sand and other dry materials into the mixer, set the stirring speed to 80100r / min, and stir for 2 minutes to ensure that the powder is initially mixed evenly.

[0112] 2. Continue to add a certain amount of water and polycarboxylate water reducer to the mixer, increase the stirring speed to 100-120 r / min, and stir for 5 minutes to ensure that the slurry flows evenly.

[0113] 3. Use a square hole sieve with a mesh diameter of 0.4 times the length of the steel fiber to gradually sieve in the steel fiber and continue stirring for 2 minutes to prevent the fiber from clumping and ensure that it is evenly distributed in the concrete system.

[0114] The final concrete mixture has good fluidity and homogeneity, with a T500 time of approximately 4.3 seconds, an expansion of 765 mm, and still maintaining 730 mm after 1 hour, showing excellent collapse resistance.

[0115] (3) Molding and maintenance.

[0116] Pour the mixed concrete into the mold, vibrate and compact it immediately, cover it with plastic film to prevent moisture evaporation. Then use the normal temperature curing or steam curing system:

[0117] Normal temperature curing: 20℃±2, relative humidity ≥95%, curing to the specified age.

[0118] Steam curing system: curing at 80℃ constant temperature for 24 hours to simulate the accelerated hardening requirements in engineering.

[0119] Under both curing systems, concrete showed excellent strength development behavior, with a compressive strength of 72.2 MPa at 1 day, 150.7 MPa at 28 days, and a strength of 161.9 MPa after steam curing.

[0120] 4: Performance testing and verification.

[0121] According to the "Ultra-High Performance Concrete Test Method Standard", the ultra-high performance concrete prepared in Example 1 was systematically tested, and the results are as follows:

[0122]

[0123]

[0124] The test results show that the ultra-high performance concrete prepared using the integrated cementitious material of the present invention has excellent working performance, mechanical properties and durability, and fully meets the engineering application requirements of bridge prefabricated parts, cast-in-place bridge decks, joint connections, etc.

[0125] This embodiment fully demonstrates the technical advantages of the integrated gelling material of the present invention:

[0126] 1. Only 8 main components are needed to replace traditional cement, admixtures, additives and other cementitious materials, simplifying the production process and reducing the difficulty of measurement.

[0127] 2. All industrial solid waste is used as the main material, reducing cement consumption and effectively reducing carbon footprint.

[0128] 3. Through air separation, grinding, chemical modification, CSH nucleation induction and other means, the activity and stability of cementitious materials are comprehensively improved, and the final concrete strength exceeds 160MPa.

[0129] 4. Applicable to various aggregate systems and has wide engineering adaptability.

[0130] 5. All equipment used are mature industrial equipment with clear process parameters, suitable for large-scale promotion and application.

[0131] Example 2: Preparation of ultra-high performance concrete using machine-made sand instead of quartz sand

[0132] This embodiment is basically the same as embodiment 1, except that machine-made sand is used to replace part of the quartz sand to verify the adaptability of the integrated cementitious material under different aggregate systems.

[0133] 1. Adjust the mix ratio.

[0134] The mix ratio adjustment is shown in the following table:

[0135] Components Weight (parts) Integrated cementitious materials 1000 Machine-made sand (0-5mm) 1000 Steel fiber (0.2×13mm) 156 Polycarboxylate water reducer 8 water 178

[0136] 2. Mixing and forming.

[0137] The mixing process is the same as that in Example 1, and a planetary mixer is used to complete the entire process of dry material mixing, water addition and stirring, and steel fiber addition.

[0138] 3. Performance test results.

[0139] The performance test results are shown in the following table:

[0140] Performance indicators Measured value T500 time (s) 3.7 Expansion (mm) 780 1 hour expansion (mm) 770 Setting time (h) 12 Compressive strength (1d) 67.6MPa Compressive strength (28d) 147.0MPa Compressive strength after steaming 155.2MPa Shrinkage (28d) <0.03％ elastic modulus ≥42GPa

[0141] Although machine-made sand was used instead of quartz sand, the integrated cementitious material still showed good adaptability and better concrete working performance, indicating that it can achieve excellent performance in different aggregate systems.

[0142] Example 3: Verification of using slag powder, carbide slag and hemihydrate gypsum to replace cement.

[0143] This example aims to verify whether slag powder, carbide slag, and semi-hydrated gypsum can completely replace cement as the cementitious material for ultra-high performance concrete.

[0144] 1. Adjustment of mix ratio

[0145] The mix ratio adjustment is shown in the following table:

[0146] Components Weight (parts) Integrated cementitious materials (removing slag powder, carbide slag, and semi-hydrated gypsum) 1000 silica fume 150 calcium nitrate 9.5 Sodium silicate 10.5 Quartz sand (0.1-0.5mm) 200 Quartz sand (0.5-1mm) 300 Quartz sand (1-2mm) 500 Steel fiber (0.2×13mm) 156 Polycarboxylate water reducer 8 water 178

[0147] 2. Performance test results

[0148] The performance test results are shown in the following table:

[0149] Performance indicators Measured value T500 time (s) 4.5 Expansion (mm) 765 1 hour expansion (mm) 700 Setting time (h) 11 Compressive strength (1d) 78.9MPa Compressive strength (28d) 160.1MPa Compressive strength after steaming 172.9MPa

[0150] Even if slag powder, carbide slag, and hemihydrate gypsum are removed, high strength can be achieved by relying solely on the synergistic effect of CSH crystal nuclei formed by components such as silica fume, calcium nitrate, and sodium silicate and the powder reinforcer. This shows that the integrated cementitious material of the present invention has flexible compatibility and can adapt to the needs of different application scenarios.

[0151] Comparative Example 1: Impact of unselected fly ash.

[0152] This comparative example is used to verify the effect of air-selected fly ash microbeads on the performance of concrete.

[0153] 1. Adjustment of mix ratio

[0154] Ordinary fly ash (not air-selected) was used to replace the air-selected fly ash microbeads in Example 1, and other conditions remained unchanged.

[0155] 2. Performance Test Results

[0156] The performance test results are shown in the following table:

[0157] Performance indicators Measured value T500 time (s) 11.8 Expansion (mm) 630 1 hour expansion (mm) 589 Setting time (h) 12 Compressive strength (1d) 64.0MPa Compressive strength (28d) 142.9MPa Compressive strength after steaming 157.6MPa

[0158] The unselected fly ash leads to a significant decrease in the initial working performance of concrete, a decrease in expansion and an increase in viscosity, which shows that the air-selected fly ash microbeads have irreplaceable advantages in improving the rheological properties of concrete.

[0159] Comparative Example 2: Effect of no powder reinforcing agent.

[0160] This comparative example is used to verify the contribution of powder reinforcing agent to the performance of cementitious materials.

[0161] 1. Adjust the mix ratio.

[0162] Based on Example 1, the powder reinforcing agent was removed, and the other components remained unchanged.

[0163] 2. Performance test results

[0164] The performance test results are shown in the following table:

[0165] Performance indicators Measured value T500 time (s) 5.4 Expansion (mm) 705 1 hour expansion (mm) 665 Setting time (h) 12 Compressive strength (1d) 43.2MPa Compressive strength (28d) 99.8MPa Compressive strength after steaming 111.1MPa

[0166] After removing the powder reinforcer, the early strength of concrete decreased significantly, indicating that the powder reinforcer played an important role in improving the reaction activity of silicon-aluminum powder materials and enhancing the interfacial bonding strength.

[0167] Comparative Example 3: Comparison of traditional cement systems.

[0168] This comparative example uses a traditional cement system for comparison to verify the superiority of the integrated cementitious material of the present invention.

[0169] 1. Adjust the mix ratio.

[0170] The mix ratio adjustment is shown in the following table:

[0171]

[0172]

[0173] 2. Performance test results

[0174] The performance test results are shown in the following table:

[0175] Performance indicators Measured value T500 time (s) 8.7 Expansion (mm) 585 1 hour expansion (mm) 500 Setting time (h) 12 Compressive strength (1d) 68.0MPa Compressive strength (28d) 144.0MPa Compressive strength after steaming 150.0MPa water 178

[0176] While the traditional cement system has a certain strength, it is inferior to the integrated cementitious material of the present invention in terms of workability and carbon emissions. In particular, the expansion decreases significantly after one hour, indicating that its collapse resistance is poor.

[0177] The basic principles of the present application have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, and effects mentioned in this application are merely illustrative and not restrictive, and it should not be assumed that these advantages, strengths, and effects are required of each embodiment of this application. In addition, the specific details disclosed above are merely illustrative and facilitating understanding, and are not restrictive. The above details do not limit this application to necessarily being implemented using the above specific details.

[0178] The blocks of the devices, devices, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the blocks. As will be appreciated by those skilled in the art, these devices, devices, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including," "comprising," "having," and the like are open-ended words, meaning "including but not limited to," and can be used interchangeably therewith. The words "or" and "and" used herein refer to the words "and / or" and can be used interchangeably therewith, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to," and can be used interchangeably therewith.

[0179] It should also be noted that in the apparatus, device, and method of the present application, each component or each step can be decomposed and / or recombined, and such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0180] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to be applied in the widest sense consistent with the principles and novel features of the present invention.

[0181] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. An integrated cementitious material for ultra-high performance concrete, characterized in that: It is composed of the following raw materials in parts by weight: 598-602 parts of fly ash, 398-402 parts of slag powder, 99-101 parts of carbide slag, 99-101 parts of hemihydrate gypsum, 148-152 parts of silica fume, 0.19-0.20 parts of powder reinforcing agent, 9.5-10.5 parts of calcium nitrate, and 9.5-10.5 parts of sodium silicate; in: The fly ash is first-grade fly ash, with a total SiO2 and Al2O3 content greater than 80%, a CaO content less than 10%, and a median particle size less than 20 μm; The slag powder is water-quenched slag powder of S95 or above, with a total SiO2 and Al2O3 content greater than 60%, a CaO content greater than 30%, and a median particle size less than 20μm; Carbide slag is a dry powder product after the hydrolysis of calcium carbide, with a moisture content of less than 5%, a CaO content of more than 85%, and a median particle size of less than 20 μm; Hemihydrate gypsum is a natural β-hemihydrate gypsum powder with a CaSO4 content greater than 80% and a median particle size less than 20μm; Silica fume is non-densified silica fume with SiO2 content greater than 90% and median particle size less than 1μm; The powder reinforcing agent is a mixture of acrylic acid and γ-methacryloxypropyltrimethoxysilane in a mass ratio of 1:2; Calcium nitrate is analytical grade Ca(NO3)2·4H2O with a purity greater than 99%; Sodium silicate is analytical grade Na2SiO3·9H2O with a purity greater than 99%.

2. The integrated cementitious material for ultra-high performance concrete according to claim 1, characterized in that: The fly ash is air-selected by an air classification mill system, with a crushing disk speed of 4200 r / min, a classification impeller speed of 3000 r / min, a discharge sieve aperture of 2 μm, and an air selection rate greater than 15%, thereby obtaining spherical fly ash microbeads with a median particle size of 1.8 μm and a SiO2 content of 53.8%.

3. The integrated cementitious material for ultra-high performance concrete according to claim 1, characterized in that: The slag powder, carbide slag and hemihydrate gypsum are ground by a fluidized bed air flow mill system with an air pressure of 0.8 MPa, a discharge sieve aperture of 5 μm and a grinding time of 2-3 hours. The obtained powder can generate calcium silicate gel and ettringite structure in an aqueous environment.

4. The integrated cementitious material for ultra-high performance concrete according to claim 1, characterized in that: The powder enhancer is mixed with the powder material in a dry and dispersed modified rotor mill at a rotor speed of 4200 r / min, a nozzle pressure of 0.8 MPa, a drying temperature of 120° C., and a shear dispersion time of 2-2.5 hours to form a polyacrylate network structure that coats the silicon-aluminum mineral material and enhances its reactivity.

5. The integrated cementitious material for ultra-high performance concrete according to claim 1, characterized in that: The calcium nitrate and sodium silicate react in an alkaline environment to generate CSH crystal nuclei, and the reaction formula is: xCa(NO3)2·4H2O+yNa2SiO3·9H2O+zH2O→xCaO·ySiO2·(4x+9y+z)H2O+2(x+y)NaNO3; The CSH nuclei serve as initial active sites for the hydration reaction, thereby increasing the hydration rate and strength development of the cementitious material.

6. A method for preparing the integrated gelling material according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step (1), fly ash air separation: placing fly ash in an air classification mill system, adjusting the rotation speed of the crushing disk, the rotation speed of the classification impeller, the discharge sieve hole, and controlling the air separation rate to obtain fly ash microbead powder material 1; Step (2), grinding slag powder, carbide slag, and hemihydrate gypsum: placing the slag powder, carbide slag, and hemihydrate gypsum in a fluidized bed jet mill system, adjusting the air pressure and the discharge sieve aperture, and grinding to obtain powder material 2; Step (3), powder material modification: placing powder material 1, powder material 2, silica fume and powder reinforcing agent in a dry and dispersed modified rotor mill, adjusting the rotor speed, nozzle pressure, drying temperature, and shearing and dispersing to obtain reinforced powder material 3; Step (4), CSH crystal nucleus preparation: calcium nitrate and sodium silicate are mixed evenly to form CSH crystal nucleus material 4; Step (5), integrated mixing: placing the reinforcing powder material 3 and the crystal core material 4 in a dispersion vibration mill, adjusting the rotation speed and vibration frequency, and mixing and grinding to obtain an integrated gelling material.

7. The preparation method according to claim 6, characterized in that The fly ash microbeads after air separation in step (1) have a 2 μm particle content of ≥71.1% and a SiO2 content of ≥53.8%, and are regular spherical particles, which are used to reduce the viscosity of the mixture and improve the density.

8. The preparation method according to claim 6, characterized in that The synergistic reaction of slag powder, carbide slag and hemihydrate gypsum in step (2) includes: (a) SiO2 reacts with Ca(OH)2 to form CSH gel: SiO2+mCa(OH)2+nH2O→mCaO·SiO2·(n+m)H2O; (b) Hemihydrate gypsum reacts with water to form dihydrate gypsum: (c) Al2O3, Ca(OH)2, and dihydrate gypsum react to form ettringite: Al2O3+3Ca(OH)2+3CaSO4·2H2O+27H2O→3CaO·Al2O3·3CaSO4·32H2O.

9. The preparation method according to claim 6, characterized in that In step (3), the powder reinforcing agent generates a polyacrylate structure through polymerization reaction, forming a chain or network cross-linked coating layer, thereby enhancing the strength and toughness of the silica-alumina mineral material, and optimizing the pore negative pressure by complexing water molecules to improve the volume stability.

10. An ultra-high performance concrete, characterized in that: The method of preparing the integrated gelling material according to any one of claims 1 to 5 comprises the following steps: Step (1) Weigh 1000 parts of integrated cementitious material, 1000 parts of quartz sand, 156 parts of steel fiber, 8 parts of polycarboxylate water reducer, and 178 parts of water in parts by weight; Step (2) dry-mixing the cementitious material with quartz sand for 2 minutes, adding water and a water-reducing agent and stirring for 5 minutes, sifting in steel fibers and stirring for another 2 minutes to prepare an ultra-high performance concrete mixture; After forming in step (3), room temperature curing or steam curing is adopted, and the compressive strength after 1 day is ≥70MPa, the compressive strength after 28 days is ≥150MPa, and the compressive strength after steam curing is ≥160MPa.

11. The ultra-high performance concrete according to claim 10, characterized in that: The quartz sand can be replaced by machine-made sand, and the concrete mixture has a T500 time of ≤5 seconds, an expansion of ≥700 mm, and an expansion loss of ≤5% in 1 hour.

12. The ultra-high performance concrete according to claim 10, characterized in that The steel fiber is 0.2×13mm low-carbon steel fiber, with a dosage of 156 parts, the concrete fracture toughness is ≥30MPa·√m, the chloride ion diffusion coefficient is <1×10 -12 m 2 / s.

13. Use of the integrated gelling material according to any one of claims 1 to 5, characterized in that: Used for bridge prefabricated parts, cast-in-place bridge decks, joint connections or outsourced reinforcement projects, it can replace traditional cement-based materials and reduce carbon emissions by ≥40%.

14. Use of the integrated gelling material according to any one of claims 1 to 5, characterized in that: Used to prepare ultra-high performance concrete with a compressive strength of ≥160MPa and a mixture viscosity of ≤30Pa·s.

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