A high performance self-compacting concrete and a method for preparing the same

Abstract

The application relates to the technical field of concrete preparation, in particular to high-performance self-compacting concrete and a preparation method thereof, which solves the problems existing in the prior art and comprises the following components: cement, fly ash, slag powder, graphene oxide, nano-silica aerogel, water reducing agent and air entraining agent. The application breaks through the interface incompatibility problem of GO and SA through silanization modification and magnetic field induction. The nano interlayer of GO and the mesopore and macropore of SA form a hierarchical mass transfer path. CaCO3 seeds in the pores of SA direct the oriented growth of C-S-H gel, and the early strength development rate is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of concrete preparation, and particularly relates to a high-performance self-compacting concrete and a preparation method thereof. BACKGROUND

[0002] With the continuous development of modern construction technology, the requirements for the performance of concrete materials are also increasing. As a kind of high-performance concrete, self-compacting concrete has a wide application prospect in complex structure construction, tunnel engineering, marine engineering and other fields due to its excellent self-leveling, self-filling and self-compacting properties. However, the traditional self-compacting concrete often faces the problem of difficult to balance the workability, mechanical properties and durability during the preparation process.

[0003] Disadvantages in the prior art:

[0004] The traditional self-compacting concrete often needs to make a compromise between workability and mechanical properties. In order to achieve good self-leveling properties, it is usually necessary to increase the water-cement ratio or use high-efficiency water reducing agent, but this often sacrifices the mechanical strength and durability of the concrete.

[0005] Although the application of nanomaterials in concrete can significantly improve its performance, due to the high surface energy and easy agglomeration characteristics of nanomaterials, the uniform dispersion of nanomaterials in the concrete matrix has always been a technical problem. Uneven dispersion will greatly reduce the enhancement effect of nanomaterials, and even may cause new performance problems.

[0006] The existing self-compacting concrete has very limited self-repairing ability after being damaged externally. This leads to the fact that once the concrete is damaged by micro-cracks and other damages during long-term use, its performance will be difficult to recover, which seriously affects the safety and durability of the structure.

[0007] Therefore, we propose a high-performance self-compacting concrete and a preparation method thereof to solve the above problems. SUMMARY

[0008] The purpose of the present application is to solve the problems existing in the prior art, and to provide a high-performance self-compacting concrete and a preparation method thereof.

[0009] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0010] A high-performance self-compacting concrete comprises the following components by weight: cement 100-120 parts, fly ash 25-35 parts, slag powder 20-30 parts, graphene oxide 0.05-0.15 parts, nano-silica aerogel 0.3-0.8 parts, water reducing agent 0.8-1.5 parts, and air entraining agent 0.005-0.015 parts.

[0011] As a preferred technical solution:

[0012] The high-performance self-compacting concrete also comprises the following components in the weight percentage: 0.02-0.08 parts of a biomimetic enzyme, 2.5-4.0 parts of a magnesium phosphate precursor.

[0013] The high-performance self-compacting concrete also comprises the following components in the weight percentage: 0.02-0.08 parts of a biomimetic enzyme, 2.5-4.0 parts of a magnesium phosphate precursor.

[0014] The high-performance self-compacting concrete also comprises the following components in the weight percentage: 0.02-0.08 parts of a biomimetic enzyme, 2.5-4.0 parts of a magnesium phosphate precursor. 2 / g; the biomimetic enzyme is in the form of a calcium alginate microcapsule carrier with a particle size of 50-100 μm; the magnesium phosphate precursor has a particle size distribution of D50=5±1 μm, D90=15±2 μm, and a specific surface area of 1.2±0.2 m 2 / g; the biomimetic enzyme is in the form of a calcium alginate microcapsule carrier with a particle size of 50-100 μm; the magnesium phosphate precursor has a particle size distribution of D50=5±1 μm, D90=15±2 μm, and a specific surface area of 1.2±0.2 m

[0015] The high-performance self-compacting concrete also comprises the following components in the weight percentage: 0.02-0.08 parts of a biomimetic enzyme, 2.5-4.0 parts of a magnesium phosphate precursor.

[0016] The second aspect of the present application provides a preparation method of the high-performance self-compacting concrete, comprising the following steps:

[0017] S1 functional modification of graphene oxide: graphene oxide is dispersed in a NaOH solution, ultrasonic treatment is performed to expand the interlayer spacing, and then 3-aminopropyl triethoxysilane is added for water bath reaction, so that the surface-Si-O-functional group is grafted through the click reaction of the amino group and the epoxy group, and functionalized graphene is obtained.

[0018] S2 pore activation of S2 nano-aerogel: mesoporous SiO2 aerogel was placed in a vacuum reactor, and hexamethyldisilazane vapor was introduced for surface hydrophobic modification. Then, the modified aerogel was immersed in an ethanol solution containing CaCl2 to pre-deposit nano-CaCO3 seeds on the 20-50 nm mesoporous inner wall by capillary action, thereby obtaining a modified aerogel;

[0019] S3 heterostructure assembly: functionalized graphene was mixed with the modified aerogel, and ethanol solution was added as a medium for directional assembly in a rotating magnetic field to form a three-dimensional wrinkled network. After centrifugal separation and drying, a composite reinforcement with hierarchical mass transfer channels was obtained, which was marked as GO-SA composite;

[0020] S4 preparation of mesoporous SiO2-coated magnesium phosphate: MgO was mixed with NH4H2PO4 and ball milled, and a SiO2 shell layer was deposited by chemical vapor deposition (CVD) in a fluidized bed to obtain a core-shell structure, which was marked as MP@mSiO2;

[0021] S5 loading of enzyme active components: a urease solution was prepared, and droplets were generated by microfluidic technology and dropped into a cross-linking bath containing CaCl2 to form calcium alginate microcapsules. Then, MP@mSiO2 was mixed with the microcapsules, and the mixture was shaken in a phosphate buffer to anchor MP@mSiO2 on the surface of the microcapsules by electrostatic adsorption, thereby obtaining an MP@mSiO2 / enzyme microcapsule system;

[0022] S6 topological optimization of water-reducing agent molecular chains: polycarboxylic acid water-reducing agent was grafted with acrylamide monomers using ammonium persulfate as an initiator to obtain a comb-shaped polymer with a side chain density of 50%. The main chain of the comb-shaped polymer was adsorbed on the surface of cement particles, and the side chains were inserted into the pores of GO-SA to produce a steric hindrance effect, thereby obtaining an optimized water-reducing agent;

[0023] S7 interface activation: blast furnace slag powder was mixed with fly ash, and NaOH solution was added to the planetary ball mill for activation to obtain an activated mixture of slag powder and fly ash;

[0024] S8 preparation of primary paste: the activated mixture of slag powder and fly ash was mixed with cement, and then 60% of the total water amount was added and the optimized water-reducing agent was incorporated. A double-planetary mixer was used for low-speed stirring to form a base paste with thixotropy;

[0025] S9 hierarchical dispersion of nano-enhanced phase: GO-SA composite was dispersed in the remaining 40% water, and a three-stage ultrasonic dispersion process was used for dispersion and shear activation of the base paste to obtain a shear-thinning fluid;

[0026] S10 directional implantation of functional micro-reactors: the MP@mSiO2 / enzyme microcapsule system and an air entraining agent were dispersed in an ethanol solution, and the mixture was sprayed into the stirring shear-thinning fluid through an atomizing nozzle to obtain a mixture.

[0027] S11 low temperature dynamic curing: after the mixture is injected into the mold, pre-curing inhibits the destruction of enzyme activity by early hydration heat release, and the preparation of self-compacting concrete is completed.

[0028] The preparation method of a high-performance self-compacting concrete as described above, wherein the three-stage ultrasonic dispersion process in S9 includes: high-frequency dispersion: 40 kHz ultrasonic treatment for 10 minutes to disassemble graphene stacks; low-frequency infiltration: 28 kHz ultrasonic treatment for 20 minutes to make aerogel pores fully absorb water; shear activation: injecting the matrix slurry under high-speed shearing at 10,000 rpm to form a shear-thinning fluid.

[0029] The preparation method of a high-performance self-compacting concrete as described above, wherein in the S10 step, micro-bubble groups with a pore size of 150±50 μm are formed in the slurry, and the spatial uniform distribution of microcapsules is 300-500 μm apart.

[0030] The preparation method of a high-performance self-compacting concrete as described above, wherein in S11, after the mixture is injected into the mold, pre-curing inhibits the destruction of enzyme activity by early hydration heat release, and then the temperature is raised and an alternating magnetic field is applied to induce Ca 2+ Along the GO-SA network directional migration, oriented growth C-S-H gel is formed, and the preparation of self-compacting concrete is completed.

[0031] Compared with the prior art, the beneficial effects of the present application are:

[0032] Graphene oxide (GO) and nano-silica aerogel (SA) form a covalent grafting heterostructure (GO-SA) to provide mechanical enhancement and water regulation; the cascade reaction design of magnesium phosphate precursor and biomineralization enzyme realizes the dual functions of early strength and crack repair;

[0033] Cement provides early hydration products (C-S-H gel), and the glass body of slag and fly ash contributes to the late strength through the pozzolanic effect; NaOH activation pretreatment exposes the active Si-O - group of slag / fly ash, and forms chemical bonding with cement hydration products to reduce the interface transition zone (ITZ) defects;

[0034] The oxygen-containing functional groups of GO adsorb free water through hydrogen bonding, and the mesoporous of SA stores water to realize self-curing; the two-dimensional confinement effect of GO guides the oriented growth of C-S-H gel along the (002) crystal plane, and the nanopores of SA buffer shrinkage stress;

[0035] Polycarboxylate superplasticizers reduce the water-cement ratio to 0.28-0.32 by inserting side chains into the pores of GO-SA, while stabilizing the rheological properties of the slurry; sodium dialkyl sulfonate air-entraining agent introduces uniform microbubbles, which improves fluidity through the "ball effect" while reducing strength loss.

[0036] Silanized GO and hydrophobically modified SA are assembled through magnetic field induction to form a covalently grafted "hard-soft" network, possessing both conductivity (resistivity monitoring of cracks) and impermeability. Calcium alginate microcapsules load MP@mSiO2 through electrostatic adsorption, achieving spatial isolation and controlled release of repair components. Low-temperature pre-curing inhibits early hydration exothermic reactions and protects urease activity. Alternating magnetic field induces Ca... 2+ Migrating along the GO-SA network, it forms an oriented CSH gel, reducing the weak areas of the ITZ. Attached Figure Description

[0037] Fig. 1 This is a compressive strength test diagram of Embodiment 4 of the present invention;

[0038] Fig. 2 Line graphs showing data from embodiments and comparative examples of the present invention. Detailed Implementation

[0039] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of conflict, the definitions in this specification shall prevail. When a mass, concentration, temperature, time, or other value or parameter is expressed as a range, preferred range, or a series of upper and lower preferred values, this shall be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether such range is disclosed individually. For example, a range of 1-50 should be understood to include selections from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 3 Any number, combination of numbers, or subrange of numbers between the integers 6, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50, and all decimal values ​​between the integers listed above, such as 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, and 1.9. Regarding subranges, specifically consider “nested subranges” extending from any endpoint of the range. For example, nested subranges of the exemplary range 1-50 could include 1-10, 1-20, 1-30, and 1-40 in one direction, or 50-40, 50-30, 50-20, and 50-10 in another direction.

[0040] The application will be further described below in connection with specific embodiments, and the experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0041] A high-performance self-compacting concrete comprises the following components in parts by weight: cement 100-120 parts, fly ash 25-35 parts, slag powder 20-30 parts, graphene oxide 0.05-0.15 parts, nano-silica aerogel 0.3-0.8 parts, water reducing agent 0.8-1.5 parts, air entraining agent 0.005-0.015 parts, biological mineralization enzyme 0.02-0.08 parts, and magnesium phosphate precursor 2.5-4.0 parts.

[0042] In the formula, the biological mineralization enzyme is urease, the magnesium phosphate precursor is MgO / NH4H2PO4 with a molar ratio of 1:1.2, the water reducing agent is polycarboxylic acid water reducing agent, and the air entraining agent is one or more of sodium dialkyl sulfonate air entraining agent and ammonium persulfate.

[0043] Specifically, the glass content of the latent hydration activity of the slag powder is greater than or equal to 85%; the sheet thickness of the graphene oxide is 2-5 nm, and the oxygen-containing functional group accounts for 20-30%, so as to control the oriented growth of C-S-H gel through two-dimensional confinement effect; the nano-silica aerogel has a mesoporous structure, a pore size of 10-50 nm, and a specific surface area of 600-800 m 2 / g, adsorbs free water, and simultaneously improves the plasticity and impermeability; the carrier form of the biological mineralization enzyme is a calcium alginate microcapsule package with a particle size of 50-100 μm; the particle size distribution of the magnesium phosphate precursor is D50=5±1 μm and D90=15±2 μm, and the specific surface area is 1.2±0.2 m 2 / g, and reacts with the cement hydration product to generate struvite (Ksp=10 -13 ), so as to fill microcracks; the molecular weight of the water reducing agent is 20,000-30,000, and the side chain density is 40-60%, so as to cooperatively reduce the water-binder ratio to 0.28-0.32 through steric hindrance and electrostatic repulsion; the air entraining agent controls the proportion of introduced micro-bubbles (pore size 50-200 μm) to be 4-6%, so as to improve the fluidity through the ball effect while maintaining the strength.

[0044] A three-dimensional wrinkled graphene network is constructed according to the graphene oxide, the interlayer spacing is 0.8-1.2 nm, a covalent grafting heterostructure (Si-O-C bond) is formed with the nano-silica aerogel through π-π interaction, the wrinkled structure of the graphene improves the flexural strength, and the nano-silica aerogel reduces the drying shrinkage;

[0045] The magnesium phosphate precursor is coated with mesoporous SiO2, the shell thickness is 50-100 nm, the inside is loaded with biomimetic enzyme liposomes, the particle size is 30-50 nm, and when cracks occur, mechanical stress triggers the shell to break, and the enzyme activates the cascade reaction after contacting with the magnesium phosphate.

[0046] In the following method, the rotation magnetic field induced assembly is through the Lorentz force and magnetic vortex effect of the magnetic field on the polar molecules and nanoparticles, which promotes the directional arrangement and grafting of functionalized graphene and aerogel in the medium;

[0047] Example one

[0048] A preparation method of high-performance self-compacting concrete, comprising the following steps:

[0049] S1 Functional modification of graphene oxide: disperse graphene oxide (oxygen-containing functional group 20%) in NaOH solution (solid-liquid ratio 1:200) with pH=10, treat in 20 kHz ultrasonic field for 40 minutes, expand the interlayer spacing to 1.5 nm, then add 3-aminopropyl triethoxysilane (APTES, the amount is 12% of the mass of graphene), react in a 50°C water bath for 3 hours, realize the grafting of surface-Si-O-functional groups through the click reaction of amino and epoxy groups, and obtain functionalized graphene;

[0050] S2 Pore activation of nano-aerogel: place mesoporous SiO2 aerogel (specific surface area 550 m 2 / g) in a vacuum reaction kettle, introduce hexamethyldisilazane (HMDS) vapor, and perform surface hydrophobic modification at 120°C for 10 hours, reduce the hydroxyl density to ≤3 / nm 2 , then immerse in an ethanol solution containing 0.1 mol / L CaCl2, and pre-deposit nano-CaCO3 seeds (particle size 5 nm) in the 20 nm mesoporous inner wall through capillary action, to obtain modified aerogel;

[0051] S3 Heterostructure assembly: mix the functionalized graphene and the modified aerogel according to a mass ratio of 1:5, add an ethanol solution containing 0.5wt% polyethylene glycol as a medium, and directionally assemble in a 0.5T rotating magnetic field for 1 hour, the graphene layers are vertically intercalated in the aerogel pores through Si-O-C covalent bonds, forming a three-dimensional wrinkled network (interlayer spacing 0.8 nm, porosity 93%), after centrifugal separation and drying, a composite reinforcement with hierarchical mass transfer channels is obtained, marked as GO-SA composite;

[0052] Preparation of S4 mesoporous SiO2 coated magnesium phosphate: MgO was mixed with NH4H2PO4 at a molar ratio of 1:1.2, ball-milled to D50=3 μm, and then a SiO2 shell layer was deposited by chemical vapor deposition (CVD) in a fluidized bed, with a tetraethoxysilane (TEOS) vapor partial pressure of 0.1 kPa, a deposition temperature of 350°C, and a deposition time of 20 minutes, to obtain a core-shell structure with a shell thickness of 70 nm, labeled as MP@mSiO2;

[0053] S5 loading of enzyme active component: a urease solution (enzyme activity ≥5000 U / g) containing 1 wt% sodium alginate was prepared, droplets with a particle size of 60 μm were generated by microfluidic technology, and then dropped into a cross-linking bath containing 5 wt% CaCl2 to form calcium alginate microcapsules, then the MP@mSiO2 and the microcapsules were mixed at a mass ratio of 4:1, and oscillated in a phosphate buffer solution at pH=7 for 24 hours, to anchor the MP@mSiO2 on the surface of the microcapsules by electrostatic adsorption (loading rate ≥85%), to obtain a MP@mSiO2 / enzyme microcapsule system;

[0054] S6 topological optimization of water-reducing agent molecular chain: a polycarboxylic acid water-reducing agent (molecular weight 25000) was grafted with acrylamide monomers (molar ratio 1:3) at 60°C, using ammonium persulfate as an initiator, and a comb-shaped polymer with a side chain density of 50% was obtained by controlling the reaction time (1 hour), the main chain of which was adsorbed on the surface of cement particles, and the side chain was inserted into the GO-SA pores to produce a steric hindrance effect, to obtain an optimized water-reducing agent;

[0055] S7 interfacial activation of slag powder / fly ash: blast furnace slag powder (glass content 88%) and fly ash (CaO content 8%) were mixed at a mass ratio of 2:1, 0.1 mol / L NaOH solution (solid-liquid ratio 1:5) was added to a planetary ball mill, and activated at a rotation speed of 300 rpm for 35 minutes, which produced active ≡Si-O - sites on the surface of the glass body, which formed chemical bonds with subsequent cement hydration products, to obtain an activated mixture of slag powder and fly ash;

[0056] S8 preparation of primary paste: the activated mixture of slag powder and fly ash was dry-mixed with cement (P O 52.5) at a mass ratio of 3:7 for 3 minutes, then 60% of the total water (water-binder ratio 0.30) was added, and the optimized water-reducing agent (0.6 parts) was incorporated, and a thixotropic base paste was formed by stirring at a low speed of 60 rpm for 2 minutes using a double-planetary mixer;

[0057] S9 hierarchical dispersion of nano-enhanced phase: the GO-SA complex was dispersed in the remaining 40% water, and a three-stage ultrasonic dispersion process was used:

[0058] High-frequency dispersion: 30 kHz ultrasonic treatment for 8 minutes, disassembling graphene stacks;

[0059] Low-frequency infiltration: 25 kHz ultrasonic treatment for 15 minutes, making the aerogel pores fully absorb water;

[0060] Shear activation: injecting the base paste under high-speed shear at 8000 rpm to form a shear-thinning fluid (apparent viscosity ≤ 50 Pa s);

[0061] S10 Directional implantation of functional microreactors: dispersing the MP@mSiO2 / enzyme microcapsule system and an air entraining agent (sodium dialkyl sulfonate) in an ethanol solution containing 0.05wt% hydroxypropyl methylcellulose, and spraying into the shear-thinning fluid under stirring through an atomizing nozzle at a pressure of 0.1 MPa. This process forms:

[0062] Microbubble groups (pore size 100 μm, volume fraction 5.2%);

[0063] Spatially uniform distribution of microcapsules (spacing 300 μm);

[0064] Obtaining the mixture;

[0065] S11 Low-temperature dynamic curing: immediately after injecting the mixture into the mold, placing it in a 5℃ environment for 1 hour of pre-curing to inhibit the destruction of enzyme activity by early hydration heat release, then increasing the temperature to 25℃ at a rate of 0.5℃ / min, and applying a 0.5T alternating magnetic field for 15 minutes to induce Ca 2+ Along the GO-SA network, the C-S-H gel is oriented and grown (orientation degree ≥ 70%), and the self-compacting concrete is prepared.

[0066] Example Two

[0067] A method for preparing a high-performance self-compacting concrete, comprising the following steps:

[0068] S1 Functional modification of graphene oxide: dispersing graphene oxide (oxygen-containing functional groups 25%) in a NaOH solution with pH = 10 (solid-liquid ratio 1:200), treating in a 35 kHz ultrasonic field for 55 minutes to expand the interlayer spacing to 1.7 nm, then adding 3-aminopropyl triethoxysilane (APTES, amount 15% of the mass of graphene), and reacting in a 80℃ water bath for 3 hours. Through the click reaction of amino and epoxy groups, the surface -Si-O- functional groups are grafted to obtain functionalized graphene;

[0069] S2 Activation of nanometer aerogel channels: mesoporous SiO2 aerogel (specific surface area 650 m 2(g) Placed in a vacuum reactor, the surface was hydrophobically modified by introducing hexamethyldisilazane (HMDS) vapor at 120°C for 11 hours to reduce the hydroxyl density to ≤3 / nm 2 Subsequently, the modified aerogel was immersed in an ethanol solution containing 0.1 mol / L CaCl2, and nano-CaCO3 seeds (7 nm in size) were pre-deposited on the 30 nm mesoporous inner wall by capillary action to obtain the modified aerogel;

[0070] S3 Heterostructure assembly: The functionalized graphene and the modified aerogel were mixed at a mass ratio of 1:5, and an ethanol solution containing 0.5 wt% polyethylene glycol was added as a medium. The mixture was directionally assembled in a 0.8T rotating magnetic field for 2 hours. The graphene layers were vertically intercalated into the pores of the aerogel through Si-O-C covalent bonds, forming a three-dimensional wrinkled network (interlayer spacing of 0.9 nm and porosity of 93%). After centrifugal separation and drying, a composite reinforcement with hierarchical mass transfer channels was obtained, labeled as GO-SA composite.

[0071] S4 Preparation of mesoporous SiO2-coated magnesium phosphate: MgO and NH4H2PO4 were mixed at a molar ratio of 1:1.2, ball milled to D50=5μm, and then a SiO2 shell layer was deposited by chemical vapor deposition (CVD) in a fluidized bed. The partial pressure of tetraethoxysilane (TEOS) vapor was controlled at 0.3kPa, the deposition temperature was 400°C, and the deposition time was 25 minutes. A core-shell structure with a shell thickness of 80nm was obtained, labeled as MP@mSiO2.

[0072] S5 Loading of enzyme active components: A urease solution containing 1wt% sodium alginate (enzyme activity ≥5000U / g) was prepared, and droplets with a particle size of 70μm were generated by microfluidic technology and dropped into a crosslinking bath containing 5wt% CaCl2 to form calcium alginate microcapsules. Then, MP@mSiO2 and microcapsules were mixed at a mass ratio of 4:1, and oscillated in a phosphate buffer solution at pH=7 for 24 hours. MP@mSiO2 was anchored on the surface of the microcapsules by electrostatic adsorption (loading rate ≥85%), and a MP@mSiO2 / enzyme microcapsule system was obtained.

[0073] S6 Topological optimization of water-reducing agent molecular chains: Polycarboxylic acid water-reducing agent (molecular weight 25000) and acrylamide monomer (molar ratio 1:3) were grafted and copolymerized at 60°C using ammonium persulfate as an initiator. By adjusting the reaction time (2 hours), a comb-shaped polymer with a side chain density of 50% was obtained. The main chain was adsorbed on the surface of the cement particles, and the side chain was inserted into the GO-SA pores to produce a steric hindrance effect, resulting in an optimized water-reducing agent.

[0074] S7 Interfacial activation of slag powder / fly ash: Blast furnace slag powder (glass content 88%) and fly ash (CaO content 8%) were mixed in a mass ratio of 2:1, and 0.1 mol / L NaOH solution (solid-liquid ratio 1:5) was added in a planetary ball mill at a speed of 350 rpm for 40 minutes. This process produced active ≡Si-O - sites on the surface of the glass body, which formed chemical bonds with subsequent cement hydration products, to obtain an activated slag powder and fly ash mixture;

[0075] S8 Primary paste preparation: The activated slag powder and fly ash mixture was dry mixed with cement (P O 52.5) in a mass ratio of 3:7 for 5 minutes, then 60% of the total water (water-binder ratio 0.30) was added, and an optimized water reducer (0.8 parts) was incorporated, and a thixotropic base paste was formed by stirring at a low speed of 70 rpm for 3 minutes using a double planetary mixer;

[0076] S9 Hierarchical dispersion of nano-enhanced phase: The GO-SA complex was dispersed in the remaining 40% water using a three-stage ultrasonic dispersion process:

[0077] High-frequency dispersion: 40 kHz ultrasonic treatment for 10 minutes to disassemble the graphene stack;

[0078] Low-frequency infiltration: 28 kHz ultrasonic treatment for 20 minutes to fully absorb water in the aerogel pores;

[0079] Shear activation: Inject the base paste under high-speed shear at 10,000 rpm to form a shear-thinning fluid (apparent viscosity ≤ 50 Pa s);

[0080] S10 Directional implantation of functional micro-reactors: The MP@mSiO2 / enzyme microcapsule system was dispersed in an ethanol solution containing 0.05wt% hydroxypropyl methyl cellulose with an air entraining agent (sodium dialkyl sulfonate), and was sprayed into the shear-thinning fluid being stirred through an atomizing nozzle at a pressure of 0.2 MPa. This process formed:

[0081] a micro-bubble group (pore size 150 μm, volume fraction 5.2%);

[0082] a spatially uniform distribution of microcapsules (spacing 400 μm);

[0083] to obtain a mixture;

[0084] S11 Low-temperature dynamic curing: After the mixture was injected into the mold, it was immediately placed in a 5°C environment for 2 hours of pre-curing to inhibit the destruction of enzyme activity by early hydration heat release, then heated to 25°C at a rate of 0.5°C / min, and an alternating magnetic field of 0.5T was applied for 20 minutes to induce Ca 2+Along the GO-SA network orientation migration, form the orientation growth of C-S-H gel (orientation ≥ 70%), complete the preparation of self-compacting concrete.

[0085] Example three

[0086] A preparation method of high-performance self-compacting concrete, comprising the following steps:

[0087] S1 Functional modification of graphene oxide: disperse graphene oxide (oxygen-containing functional group 25%) in NaOH solution (pH=10, solid-liquid ratio 1:200), treat in 40 kHz ultrasonic field for 65 minutes, expand the interlayer spacing to 1.8 nm, then add 3-aminopropyl triethoxysilane (APTES, the amount is 15% of the mass of graphene), react in 80°C water bath for 4 hours, realize the grafting of surface-Si-O-functional group through the click reaction of amino and epoxy group, and obtain functionalized graphene;

[0088] S2 Pore activation of nano-aerogel: place mesoporous SiO2 aerogel (specific surface area 750 m 2 / g) in a vacuum reaction kettle, introduce hexamethyldisilazane (HMDS) vapor, and perform surface hydrophobic modification at 120°C for 12 hours, so that the hydroxyl density is reduced to ≤3 / nm 2 , then immerse in an ethanol solution containing 0.1 mol / L CaCl2, and pre-deposit nano-CaCO3 seeds (particle size 8 nm) in the 35 nm mesoporous inner wall through capillary action, to obtain a modified aerogel;

[0089] S3 Heterostructure assembly: mix the functionalized graphene and the modified aerogel according to a mass ratio of 1:5, add an ethanol solution containing 0.5wt% polyethylene glycol as a medium, and perform directional assembly in a 0.8T rotating magnetic field for 2 hours, so that the graphene layers are vertically intercalated in the aerogel pores through Si-O-C covalent bonds, forming a three-dimensional wrinkled network (interlayer spacing 0.95 nm, porosity 93%), and then the composite reinforcement with hierarchical mass transfer channels is obtained through centrifugal separation and drying, and is marked as GO-SA composite;

[0090] S4 Preparation of mesoporous SiO2 coated magnesium phosphate: mix MgO and NH4H2PO4 according to a molar ratio of 1:1.2, ball mill to D50=5μm, and then deposit a SiO2 shell layer in a fluidized bed through chemical vapor deposition (CVD), control the partial pressure of tetraethoxysilane (TEOS) vapor to be 0.3kPa, the deposition temperature is 450°C, and the time is 35 minutes, to obtain a core-shell structure with a shell layer thickness of 85nm, which is marked as MP@mSiO2;

[0091] S5 Loading of enzyme active component: urease solution (enzyme activity > 5000 U / g) containing 1 wt% sodium alginate was prepared, droplets with a diameter of 75 μm were generated by microfluidic technology and dropped into a cross-linking bath containing 5 wt% CaCl2 to form calcium alginate microcapsules, then MP@mSiO2 was mixed with the microcapsules at a mass ratio of 4:1, and the mixture was oscillated in a phosphate buffer solution at pH = 7 for 24 hours to anchor MP@mSiO2 on the surface of the microcapsules by electrostatic adsorption (loading rate > 85%), thereby obtaining an MP@mSiO2 / enzyme microcapsule system;

[0092] S6 Topological optimization of water-reducing agent molecular chain: graft copolymerization of polycarboxylic acid water-reducing agent (molecular weight 25000) and acrylamide monomer (molar ratio 1:3) was carried out at 65°C using ammonium persulfate as an initiator, and a comb-shaped polymer with a side chain density of 50% was obtained by controlling the reaction time (2 hours), the main chain of which was adsorbed on the surface of cement particles, and the side chain was inserted into the pores of GO-SA to produce a steric hindrance effect, thereby obtaining an optimized water-reducing agent;

[0093] S7 Interfacial activation of slag powder / fly ash: blast furnace slag powder (glass content 88%) and fly ash (CaO content 8%) were mixed at a mass ratio of 2:1, 0.1 mol / L NaOH solution (solid-liquid ratio 1:5) was added to a planetary ball mill, and the mixture was activated at a rotation speed of 450 rpm for 55 minutes, which produced active ≡Si-O - sites on the surface of the glass body, and formed chemical bonds with subsequent cement hydration products, thereby obtaining an activated mixture of slag powder and fly ash;

[0094] S8 Preparation of primary paste: the activated mixture of slag powder and fly ash was dry-mixed with cement (P O 52.5) at a mass ratio of 3:7 for 6 minutes, then 60% of the total water (water-binder ratio 0.30) was added, and the optimized water-reducing agent (0.9 parts) was incorporated, and the mixture was stirred at a low speed of 80 rpm for 4 minutes using a double-planetary mixer to form a base paste with thixotropy;

[0095] S9 Hierarchical dispersion of nano-enhanced phase: the GO-SA complex was dispersed in the remaining 40% water, and a three-stage ultrasonic dispersion process was adopted:

[0096] High-frequency dispersion: 40 kHz ultrasonic treatment for 12 minutes to disassemble the graphene stack;

[0097] Low-frequency infiltration: 30 kHz ultrasonic treatment for 20 minutes to fully absorb water in the pores of the aerogel;

[0098] Shear activation: the base paste was injected under high-speed shear at 10000 rpm to form a shear-thinning fluid (apparent viscosity < 50 Pa s);

[0099] S10 Directional implantation of functional microreactors: Disperse the MP@mSiO2 / enzyme microcapsule system and air entraining agent (sodium dialkyl sulfonate) in an ethanol solution containing 0.05wt% hydroxypropyl methyl cellulose, spray into the shear-thinning fluid being stirred through an atomizing nozzle at a pressure of 0.3MPa, and in the process, form:

[0100] Microbubble groups (pore size 170μm, volume ratio 5.2%);

[0101] Spatially uniform distribution of microcapsules (spacing 400μm);

[0102] Obtain the mixture;

[0103] S11 Low-temperature dynamic curing: After injecting the mixture into the mold, immediately place it in a 5℃ environment for 2 hours of pre-curing to inhibit the destruction of enzyme activity by early hydration heat release, then increase the temperature to 25℃ at a rate of 0.5℃ / min, and apply a 0.8T alternating magnetic field for 25 minutes to induce Ca 2+ Migrate along the GO-SA network to form oriented C-S-H gel (orientation ≥70%), completing the preparation of self-compacting concrete.

[0104] Example Four

[0105] A method for preparing a high-performance self-compacting concrete, comprising the following steps:

[0106] S1 Functional modification of graphene oxide: Disperse graphene oxide (oxygen-containing functional groups 25%) in a NaOH solution with pH=10 (solid-liquid ratio 1:200), treat in an ultrasonic field at 40kHz for 70 minutes to expand the interlayer spacing to 2nm, then add 3-aminopropyl triethoxysilane (APTES, amount 15% of the mass of graphene), and react in a water bath at 80℃ for 5 hours to realize the grafting of -Si-O- functional groups on the surface through the click reaction of amino and epoxy groups, obtaining functionalized graphene;

[0107] S2 Activation of nanoporous aerogel channels: Place mesoporous SiO2 aerogel (specific surface area 750m 2 / g) in a vacuum reaction kettle, introduce hexamethyldisilazane (HMDS) vapor, and perform surface hydrophobic modification at 120℃ for 12 hours to reduce the hydroxyl density to ≤3 / nm 2 , then immerse in an ethanol solution containing 0.1mol / L CaCl2 to pre-deposit nano-CaCO3 seeds (particle size 10nm) in the 50nm mesoporous inner wall through capillary action, obtaining modified aerogel;

[0108] S3 Heterostructure assembly: functionalized graphene and modified aerogel were mixed with a mass ratio of 1:5, and 0.5wt% polyethylene glycol in ethanol solution was added as a medium. The mixture was oriented and assembled in a 1.2T rotating magnetic field for 2 hours. Graphene sheets were vertically intercalated into the pores of the aerogel through Si-O-C covalent bonds, forming a three-dimensional wrinkled network (interlayer spacing 1.1 nm, porosity 93%). After centrifugal separation and drying, a composite reinforcement with hierarchical mass transfer channels was obtained, labeled as GO-SA composite;

[0109] S4 Preparation of mesoporous SiO2-coated magnesium phosphate: MgO and NH4H2PO4 were mixed in a molar ratio of 1:1.2, ball milled to D50=5μm, and then a SiO2 shell layer was deposited by chemical vapor deposition (CVD) in a fluidized bed. The partial pressure of tetraethyl silane (TEOS) vapor was controlled at 0.5kPa, the deposition temperature was 500℃, and the deposition time was 35 minutes. A core-shell structure with a shell thickness of 90nm was obtained, labeled as MP@mSiO2;

[0110] S5 Loading of enzyme active components: a urease solution containing 1wt% sodium alginate (enzyme activity ≥5000U / g) was prepared, and droplets with a particle size of 80μm were generated by microfluidic technology and dropped into a crosslinking bath containing 5wt% CaCl2 to form calcium alginate microcapsules. Then, MP@mSiO2 and microcapsules were mixed in a mass ratio of 4:1, and oscillated in a phosphate buffer solution at pH=7 for 24 hours. MP@mSiO2 was anchored on the surface of the microcapsules by electrostatic adsorption (loading rate ≥85%), and a MP@mSiO2 / enzyme microcapsule system was obtained;

[0111] S6 Topological optimization of water reducing agent molecular chain: polycarboxylic acid water reducing agent (molecular weight 25000) and acrylamide monomer (molar ratio 1:3) were grafted and copolymerized at 60℃, using ammonium persulfate as initiator. By adjusting the reaction time (2 hours), a comb-shaped polymer with a side chain density of 50% was obtained. The main chain was adsorbed on the surface of cement particles, and the side chain was inserted into the GO-SA pores to produce a steric hindrance effect, resulting in an optimized water reducing agent;

[0112] S7 Interfacial activation of slag powder / fly ash: blast furnace slag powder (glass content 88%) and fly ash (CaO content 8%) were mixed in a mass ratio of 2:1, and 0.1mol / L NaOH solution (solid-liquid ratio 1:5) was added to a planetary ball mill and activated at 500rpm for 50 minutes. This process produced active ≡Si-O - sites on the surface of the glass body, which formed chemical bonds with subsequent cement hydration products, resulting in an activated mixture of slag powder and fly ash;

[0113] S8 Preparation of primary slurry: the activated mixture of slag powder and fly ash was mixed with cement (P O52.5) Dry mixing for 5 minutes at a mass ratio of 3:7, followed by the addition of 60% of the total water amount (water binder ratio 0.30) and the incorporation of an optimized water reducing agent (1.1 parts), using a double planetary mixer at a low speed of 80 rpm for 5 minutes, to form a matrix slurry with thixotropy;

[0114] S9 Hierarchical dispersion of nano-enhancing phase: Disperse GO-SA complex in the remaining 40% water using a three-stage ultrasonic dispersion process:

[0115] High-frequency dispersion: 45 kHz ultrasonic treatment for 15 minutes to disassemble the graphene stacks;

[0116] Low-frequency infiltration: 30 kHz ultrasonic treatment for 25 minutes to fully hydrate the aerogel pores;

[0117] Shear activation: Inject the matrix slurry under high-speed shear at 12000 rpm to form a shear-thinning fluid (apparent viscosity ≤ 50 Pa s);

[0118] S10 Directional implantation of functional micro-reactors: Disperse the MP@mSiO2 / enzyme microcapsule system together with an air entraining agent (sodium dialkyl sulfonate) in an ethanol solution containing 0.05 wt% hydroxypropyl methylcellulose, and spray it into the shear-thinning fluid being stirred through an atomizing nozzle at a pressure of 0.2 MPa. This process forms:

[0119] Micro-bubble groups (pore size 200 μm, volume fraction 5.2%);

[0120] Spatially uniform distribution of microcapsules (spacing 500 μm);

[0121] Get the mixture;

[0122] S11 Low-temperature dynamic curing: After the mixture is injected into the mold, it is immediately placed in a 5°C environment for 2 hours of pre-curing to inhibit the destruction of enzyme activity by early hydration heat release, then heated to 25°C at a rate of 0.5°C / min, and an alternating magnetic field of 0.8T is applied for 30 minutes to induce Ca 2+ Directional migration along the GO-SA network, forming oriented growth of C-S-H gel (orientation degree ≥ 70%), completing the preparation of self-compacting concrete.

[0123] Comparative Example One

[0124] A high-performance self-compacting concrete and its preparation method, basically the same as Example Four, the only difference being that there is no GO-SA complex.

[0125] Comparative Example Two

[0126] A high-performance self-compacting concrete and a preparation method thereof, which are basically the same as those in Example Four, except that no MP@mSiO2 / enzyme microcapsule is used.

[0127] Comparative Example Three

[0128] A high-performance self-compacting concrete and a preparation method thereof, which are basically the same as those in Example Four, except that a common water reducing agent is used.

[0129] Comparative Example Four

[0130] A high-performance self-compacting concrete and a preparation method thereof, which are basically the same as those in Example Four, except that a conventional curing is used without a low-temperature magnetic field.

[0131] The concrete prepared in the above-mentioned Example One to Example Four and Comparative Example One to Comparative Example Four is detected:

[0132] Slump flow

[0133] Standard: GB / T 50080-2016 “Standard Test Methods for Properties of Fresh Ordinary Concrete”

[0134] Detection method:

[0135] A slump cone (300 mm high, 100 mm in diameter at the top, and 200 mm in diameter at the bottom) is used to fill the concrete into the cone in three layers and tamp it, and then the slump flow diameter (unit: mm) is measured after the slump cone is vertically lifted, and the T500 time (time required for expansion to 500 mm) is recorded.

[0136] Compressive strength

[0137] Standard: GB / T 50081-2019 “Standard Test Methods for Physical and Mechanical Properties of Concrete”

[0138] Detection method:

[0139] A 150 mm x 150 mm x 150 mm cube specimen is prepared, and standard curing (temperature 20±2℃, humidity ≥95%) is performed until the specified age (3 days, 28 days), and then a pressure testing machine is used to load at a rate of 0.5 MPa / s until failure, and the compressive strength (unit: MPa) is calculated.

[0140] Crack healing rate

[0141] Reference standard: JGJ / T 283-2012 “Technical Specification for Application of Self-compacting Concrete” (Appendix A Self-repairing Performance Test)

[0142] Detection method:

[0143] Pre-crack (width 0.2mm) on the surface of the specimen, standard curing for 28 days, then immersed in water for 7 days, measure the crack width change.

[0144] Healing rate calculation formula:

[0145] Chloride diffusion coefficient

[0146] Standard: GB / T 50476-2017 "Code for Durability Design of Concrete Structures" (Appendix BRCM method)

[0147] Test method:

[0148] Cut Φ100mm x 50mm specimens, vacuum saturated with salt, then placed in RCM test device, apply 60V DC voltage, record the depth of chloride ion migration, calculate the chloride ion diffusion coefficient (unit: x10 -12 m 2 / s).

[0149] The results are as follows in Table 1:

[0150] Table 1

[0151]

[0152] From the above Table 1, it can be directly obtained that in Examples 1 to 4, through multi-component synergy (GO-SA enhancement, microcapsule repair, and optimized water reducing agent) and process innovation (low-temperature magnetic field curing), the following advantages are achieved: Self-compacting: slump spread 773-785mm, meeting the super-high pumping requirements. High strength: 28-day compressive strength 82.9-83.6MPa, reaching the super-high strength concrete standard. Self-repairing ability: crack healing rate 91%-92%, significantly extending the service life of the structure. High durability: chloride diffusion coefficient only about 1.2x10 -12 m 2 / s, suitable for marine environments.

[0153] Referring Figs. 1-2 , in the Examples 4 and Comparative Examples where all other conditions are the same:

[0154] Slump spread

[0155] The slump spread of the Examples meets the self-compacting requirements (standard value ≥750mm, T500≤3s). Comparative Example 1 (without GO-SA) has a significant decrease in flowability due to the lack of GO-SA's nanometer lubrication and aerogel water retention. Comparative Example 3 (ordinary water reducing agent): the water reducing agent is not optimized, and the steric hindrance is insufficient, resulting in a decrease in fluidity.

[0156] Conclusion: GO-SA complex and optimized water reducing agent synergistically improve flowability and self-compacting.

[0157] 28-day compressive strength

[0158] Example Four 28-day strength 83.6 MPa, far exceeding the comparative example. Comparative Example 1 (no GO-SA): lack of nano-reinforced network, strength reduced. Comparative Example 2 (no microcapsule): absence of magnesium phosphate early strength, strength decreased 1. Comparative Example 4 (conventional curing): no magnetic field-induced C-S-H oriented growth, 28-day strength low.

[0159] Conclusion: GO-SA skeleton, magnesium phosphate early strength, and magnetic field curing synergistically improve mechanical properties.

[0160] Crack healing rate

[0161] Example significantly higher than comparative example. Comparative Example 2 (no microcapsule): only rely on cement self-healing, healing rate only 35%. Comparative Example 4 (conventional curing): enzyme activity is impaired, healing rate decreased to 55%.

[0162] Conclusion: Microcapsule cascade repair and low-temperature curing protect enzyme activity are the key to self-repair.

[0163] Chloride ion diffusion coefficient

[0164] Comparative Example 1 (no GO-SA): high porosity due to absence of aerogel, chloride ion diffusion coefficient increased to 5.8 x 10 - 12 m 2 / s. Comparative Example 3 (ordinary water reducing agent): high water-binder ratio, increased permeability.

[0165] Conclusion: GO-SA network dense structure and optimized water-binder ratio synergistically improve impermeability.

[0166] The above description is only the preferred specific implementation of the present application, but the protection scope of the present application is not limited to this. Any skilled person in the art, according to the technical solution and the inventive concept of the present application, makes equivalent replacement or change within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A high performance self-compacting concrete, characterized in that, The cement 100-120 parts by weight, fly ash 25-35 parts by weight, slag powder 20-30 parts by weight, graphene oxide 0.05-0.15 parts by weight, nano-silica aerogel 0.3-0.8 parts by weight, water reducing agent 0.8-1.5 parts by weight, air entraining agent 0.005-0.015 parts by weight; The graphene oxide and nano-silica aerogel are used to form a GO-SA composite, and the GO-SA composite is prepared by the following method: The graphene oxide is dispersed in a NaOH solution, ultrasonic treatment is performed to expand the interlayer spacing, then 3-aminopropyl triethoxysilane is added for water bath reaction, nucleophilic ring-opening reaction of the amino group and the epoxy group is performed to realize grafting of the surface-Si-O-functional group, and functionalized graphene is obtained; The mesoporous SiO2 aerogel is placed in a vacuum reaction kettle, hexamethyldisilazane vapor is introduced for surface hydrophobic modification, then the modified aerogel is immersed in an ethanol solution containing CaCl2, and nano-CaCO3 seeds are pre-deposited on the 20-50 nm mesoporous inner wall through capillary action, and the modified aerogel is obtained; The functionalized graphene and the modified aerogel are mixed, ethanol solution is added as a medium, directional assembly is performed in a rotating magnetic field, a three-dimensional wrinkled network is formed, and after centrifugal separation and drying, a composite reinforcement with hierarchical mass transfer channels is obtained, which is marked as a GO-SA composite.

2. The high performance self-compacting concrete according to claim 1, characterized in that The bio-mineralization enzyme 0.02-0.08 parts by weight, and the magnesium phosphate precursor 2.5-4.0 parts by weight.

3. The high performance self-compacting concrete according to claim 2, wherein The bio-mineralization enzyme is urease, the magnesium phosphate precursor is MgO / NH4H2PO4 with a molar ratio of 1:1.2, the water reducing agent is polycarboxylic acid water reducing agent, and the air entraining agent is one or more of sodium dialkyl sulfonate air entraining agent and ammonium persulfate.

4. The high performance self-compacting concrete according to claim 2, wherein The potential hydration activity of the slag powder is ≥85%, the sheet thickness of the graphene oxide is 2-5 nm, the oxygen-containing functional group accounts for 20-30%, the nano-silica aerogel is a mesoporous structure with a pore size of 10-50 nm and a specific surface area of 600-800 m 2 / g; the carrier form of the biological mineralization enzyme is a calcium alginate microcapsule package with a particle size of 50-100 μm; the particle size distribution of the magnesium phosphate precursor is D50=5±1 μm, D90=15±2 μm, and the specific surface area is 1.2±0.2 m 2 / g; the molecular weight of the water reducing agent is 20,000-30,000, the side chain density is 40-60%, and the water-binder ratio is reduced to 0.28-0.32 by synergistic effect of steric hindrance and electrostatic repulsion; the air entraining agent controls the proportion of introduced micro-bubbles to be 4-6%, and the flowability is improved by the ball effect while the strength is maintained.

5. The high performance self-compacting concrete according to claim 2, wherein The magnesium phosphate precursor is coated with mesoporous SiO2, the shell layer has a thickness of 50-100 nm, and the inside is loaded with bio-mineralization enzyme liposomes with a particle size of 30-50 nm.

6. A method of preparing high performance self-compacting concrete according to any one of claims 1 to 5, characterized in that, The following steps are included: S1 functionalization and modification of graphene oxide: the graphene oxide is dispersed in a NaOH solution, ultrasonic treatment is performed to expand the interlayer spacing, then 3-aminopropyl triethoxysilane is added for water bath reaction, nucleophilic ring-opening reaction of the amino group and the epoxy group is performed to realize grafting of the surface-Si-O-functional group, and functionalized graphene is obtained; S2 activation of the pore channel of the nano-aerogel: the mesoporous SiO2 aerogel is placed in a vacuum reaction kettle, hexamethyldisilazane vapor is introduced for surface hydrophobic modification, then the modified aerogel is immersed in an ethanol solution containing CaCl2, and nano-CaCO3 seeds are pre-deposited on the 20-50 nm mesoporous inner wall through capillary action, and the modified aerogel is obtained; S3 assembly of a heterostructure: the functionalized graphene and the modified aerogel are mixed, ethanol solution is added as a medium, directional assembly is performed in a rotating magnetic field, a three-dimensional wrinkled network is formed, and after centrifugal separation and drying, a composite reinforcement with hierarchical mass transfer channels is obtained, which is marked as a GO-SA composite; Preparation of mesoporous SiO2 coated magnesium phosphate: MgO and NH4H2PO4 were mixed and ball milled, and a SiO2 shell layer was deposited by chemical vapor deposition (CVD) in a fluidized bed to obtain a core-shell structure, marked as MP@mSiO2; S5 Loading of the enzyme active component: A urease solution containing sodium alginate was prepared, droplets were generated by microfluidics and dropped into a cross-linking bath containing CaCl2, where the sodium alginate cross-linked with Ca 2+ Calcium alginate microcapsules were formed, then MP@mSiO2 was mixed with the microcapsules, which were oscillated in phosphate buffer, and MP@mSiO2 was anchored on the surface of the microcapsules by electrostatic adsorption, to obtain a MP@mSiO2 / enzyme microcapsule system; Topology optimization of molecular chains of water-reducing agent: polycarboxylic acid water-reducing agent was grafted with acrylamide monomers by graft copolymerization, and ammonium persulfate was used as an initiator to obtain a comb-shaped polymer with a side chain density of 50%, the main chain of which is adsorbed on the surface of cement particles, and the side chain is inserted into the GO-SA pores to produce a steric hindrance effect, thereby obtaining an optimized water-reducing agent; Interface activation: mixing blast furnace slag powder with fly ash, adding NaOH solution in a planetary ball mill to activate, obtaining an activated mixture of slag powder and fly ash; Preparation of primary paste: mixing the activated mixture of slag powder and fly ash with cement, then adding 60% of the total water amount and incorporating the optimized water-reducing agent, using a double-planetary mixer to stir at low speed to form a base paste with thixotropy; Hierarchical dispersion of nano-enhanced phase: dispersing the GO-SA complex in the remaining 40% water, using a three-stage ultrasonic dispersion process: High-frequency dispersion: ultrasonic treatment to disassemble graphene stacks; Low-frequency infiltration: ultrasonic treatment to fully water the aerogel pores; Shear activation: injecting the base paste under shear conditions to form a shear-thinning fluid; Directional implantation of functional micro-reactors: dispersing the MP@mSiO2 / enzyme microcapsule system and air entraining agent in an ethanol solution, spraying into the shear-thinning fluid in the mixer through an atomizing nozzle to obtain a mixture; Low-temperature dynamic curing: after injecting the mixture into a mold, pre-curing is used to inhibit the damage to enzyme activity caused by early hydration heat release, and the preparation of self-compacting concrete is completed.

7. The method of claim 6, wherein the high performance self-compacting concrete is prepared by mixing the cement, the fine aggregate, the coarse aggregate, the superplasticizer, the water reducing agent, the water, and the water, and then stirring the mixture. In the S9, the three-stage ultrasonic dispersion process includes: High-frequency dispersion: 40 kHz ultrasonic treatment for 10 minutes to disassemble graphene stacks; Low-frequency infiltration: 28 kHz ultrasonic treatment for 20 minutes to fully water the aerogel pores; Shear activation: injecting the base paste under high-speed shear of 10,000 rpm to form a shear-thinning fluid.

8. The method of claim 6, wherein the high performance self-compacting concrete is prepared by mixing the cement, the fine aggregate, the coarse aggregate, the superplasticizer, the water reducing agent, the water, and the water, and then stirring the mixture. In the S10 step, a group of micro-bubbles with a pore size of 150±50 μm is formed in the paste, and the spatial uniform distribution of the microcapsules is 300-500 μm apart.

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