High-performance self-compacting concrete and preparation method thereof

Abstract

The invention relates to the technical field of concrete preparation, in particular to high-performance self-compacting concrete and a preparation method thereof, solves the defects in the prior art, and comprises the following components: cement, fly ash, slag powder, graphene oxide, nano-silica aerogel, a water reducer and an air entraining agent. Through silanization modification and magnetic field induction, the problem of interface incompatibility of GO and SA is solved. Graded mass transfer paths are formed between nano layers of GO and mesopores and macropores of SA. And the CaCO3 seed crystal in the SA hole directionally guides the oriented growth of the C-S-H gel, so that the early strength development rate is increased.

Description

Technical Field

[0001] The invention relates to the technical field of concrete preparation, and in particular to a high-performance self-compacting concrete and a preparation method thereof. Background Art

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

[0003] Deficiencies in the prior art:

[0004] Traditional self-compacting concrete often requires 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 a high-efficiency water reducer, 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, its uniform dispersion in the concrete matrix has always been a technical challenge due to the high surface energy and easy agglomeration of nanomaterials. Uneven dispersion will greatly reduce the reinforcement effect of nanomaterials and may even cause new performance problems.

[0006] Existing self-compacting concrete often has very limited self-repair capabilities after suffering external damage. This means that once microcracks and other damage occur in the concrete during long-term use, its performance will be difficult to recover, seriously affecting the safety and durability of the structure.

[0007] Therefore, we proposed a high-performance self-compacting concrete and its preparation method to solve the above problems. Summary of the invention

[0008] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a high-performance self-compacting concrete and a preparation method thereof.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

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

[0011] As the preferred technical solution:

[0012] The high-performance self-compacting concrete as described above further comprises the following components in parts by weight: 0.02 to 0.08 parts of biomineralization enzyme and 2.5 to 4.0 parts of magnesium phosphate precursor.

[0013] In the high-performance self-compacting concrete as described above, the biomineralization enzyme is urease, the magnesium phosphate precursor is MgO / NH4H2PO4, the molar ratio is 1:1.2, the water reducer is a polycarboxylate water reducer, and the air entraining agent is one or more of a sodium dialkyl sulfonate air entraining agent and ammonium persulfate.

[0014] The high-performance self-compacting concrete as described above, wherein the glass content in the potential hydration activity of the slag powder is ≥85%; the flake thickness of the graphene oxide is 2-5nm, and the oxygen-containing functional groups account for 20-30%; the nano-silica aerogel is a mesoporous structure with a pore size of 10-50nm and a specific surface area of ​​600-800m 2 / g; the carrier form of the biomineralization enzyme is calcium alginate microcapsule encapsulation, 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 reducer is 20000-30000, the side chain density is 40-60%, and the water-binder ratio is synergistically reduced to 0.28-0.32 through steric hindrance and electrostatic repulsion; the air entraining agent controls the introduction of microbubbles to account for 4-6%, and improves fluidity while maintaining strength through the ball effect.

[0015] The high-performance self-compacting concrete as described above constructs a three-dimensional wrinkled graphene network based on the graphene oxide, with an interlayer spacing of 0.8-1.2nm, and forms a covalently grafted heterostructure with nano-silica aerogel through π-π interaction; the magnesium phosphate precursor is coated with mesoporous SiO2, with a shell thickness of 50-100nm, and is loaded with biomineralization enzyme liposomes inside, with a particle size of 30-50nm.

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

[0017] S1 Functionalization modification of graphene oxide: Graphene oxide was dispersed in NaOH solution and ultrasonically treated to expand the interlayer spacing. Then 3-aminopropyltriethoxysilane was added for water bath reaction. Through the click reaction between amino group and epoxy group, surface-SiO-functional group grafting was achieved to obtain functionalized graphene.

[0018] Pore ​​activation of S2 nano-aerogel: The mesoporous SiO2 aerogel was placed in a vacuum reactor, and hexamethyldisilazane vapor was introduced to perform surface hydrophobic modification, and then immersed in an ethanol solution containing CaCl2, and nano-CaCO3 seeds were pre-deposited on the inner wall of the 20-50nm mesopores by capillary action to obtain modified aerogel;

[0019] S3 heterostructure assembly: functionalized graphene was mixed with modified aerogel, ethanol solution was added as a medium, and they were assembled 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 labeled as GO-SA composite.

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

[0021] S5 Loading of enzyme active components: Prepare urease solution, generate droplets by microfluidics technology, and drop them into a cross-linking bath containing CaCl2 to form calcium alginate microcapsules. Then, mix MP@mS iO2 with the microcapsules, oscillate in phosphate buffer, and anchor MP@mS iO2 on the surface of the microcapsules by electrostatic adsorption to obtain the MP@mS iO2 / enzyme microcapsule system;

[0022] Topological optimization of the molecular chain of S6 water reducer: polycarboxylic acid water reducer was grafted and copolymerized with acrylamide monomer, and ammonium persulfate was used as the initiator to obtain a comb-like polymer with a side chain density of 50%. Its main chain 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, thus obtaining an optimized water reducer;

[0023] S7 interface activation: blast furnace slag powder and fly ash are mixed, and NaOH solution is added to activate them in a planetary ball mill to obtain an activated slag powder and fly ash mixture;

[0024] S8 Primary slurry preparation: dry-mix the activated slag powder and fly ash mixture with cement, then add 60% of the total water, add optimized water reducing agent, and stir at low speed with a double planetary mixer to form a thixotropic matrix slurry;

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

[0026] Directed implantation of S10 functional microreactor: The MP@mS iO2 / enzyme microcapsule system and air-entraining agent were co-dispersed in an ethanol solution and sprayed into the stirring shear-thinning fluid through an atomizing nozzle to obtain a mixed material;

[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 completes the preparation of self-compacting concrete.

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

[0029] In the method for preparing a high-performance self-compacting concrete as described above, in the step S10, a microbubble group is formed in the slurry, the pore size is 150±50 μm, and the microcapsules are evenly distributed in space with a spacing of 300-500 μm.

[0030] According to the method for preparing high-performance self-compacting concrete as described above, in S11, after the mixture is injected into the mold, pre-curing is performed to suppress the damage of early hydration heat to enzyme activity, and then the temperature is increased and an alternating magnetic field is applied to induce Ca 2+ It migrates along the GO-SA network to form an oriented growth CSH gel, completing the preparation of self-compacting concrete.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

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

[0033] Cement provides early hydration products (CSH gel), and the glassy bodies of slag and fly ash contribute to the later strength through the pozzolanic effect; NaOH activation pretreatment exposes the active SiO - Groups, forming chemical bonds with cement hydration products, reducing defects in the interfacial transition zone (ITZ);

[0034] The oxygen-containing functional groups of GO adsorb free water through hydrogen bonds, and the mesopores of SA store water to achieve self-maintenance; the two-dimensional confinement effect of GO guides the CSH gel to grow along the (002) crystal plane, and the nanopores of SA buffer the shrinkage stress;

[0035] The polycarboxylate water reducer inserts into the pores of GO-SA through the side chain, reducing the water-binder ratio to 0.28-0.32 and stabilizing the rheological properties of the slurry. The sodium dialkyl sulfonate air entraining agent introduces uniform microbubbles, improves fluidity through the "ball effect", and reduces strength loss.

[0036] Silanized GO and hydrophobically modified SA were assembled by magnetic field induction to form a covalently grafted "hard-soft" network, which has both conductivity (resistivity monitoring cracks) and impermeability. Calcium alginate microcapsules loaded MP@mSiO2 by electrostatic adsorption to achieve spatial isolation and controlled release of repair components. Low-temperature pre-curing inhibited early hydration exotherm and protected urease activity. Alternating magnetic field induced Ca 2+ Migrate along the GO-SA network to form oriented CSH gel and reduce the weak area of ​​ITZ. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a compressive strength test diagram of the fourth embodiment of the present invention;

[0038] Figure 2 It is a data line chart of the embodiments and comparative examples of the present invention. DETAILED DESCRIPTION

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. In the event of a conflict, the definitions in the specification shall prevail. "When mass, concentration, temperature, time, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood to specifically disclose all ranges formed by any pairing of any upper range limit or preferred value with any lower range limit or preferred value, regardless of whether the range is disclosed separately. For example, a range of 1-50 should be understood to include 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, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91 6, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50, any number, combination of numbers, or subrange, and all decimal values ​​between the above integers, for example, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, and 1.9. With respect to subranges, "nested subranges" extending from any endpoint within the range are specifically contemplated. For example, nested subranges of the exemplary range 1-50 may include 1-10, 1-20, 1-30, and 1-40 in one direction, or 50-40, 50-30, 50-20, and 50-10 in the other direction."

[0040] The present invention is further explained below in conjunction with specific examples. The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are all commercially available unless otherwise specified.

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

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

[0043] Specifically, the glass content in the potential hydration activity of slag powder is ≥85%; the thickness of graphene oxide is 2-5nm, and the oxygen-containing functional groups account for 20-30%. The oriented growth of CSH gel is regulated by the two-dimensional confinement effect; the nano-silica aerogel has a mesoporous structure with a pore size of 10-50nm and a specific surface area of ​​600-800m 2 / g, adsorbing free water, and simultaneously improving plasticity and impermeability; the carrier form of the biomineralization enzyme is calcium alginate microcapsule encapsulation, with a particle size of 50-100μm; the particle size distribution of the magnesium phosphate precursor is D50=5±1μm, D90=15±2μm, and the specific surface area is 1.2±0.2m 2 / g, reacts with cement hydration products to form struvite (Ksp = 10 -13 ) to achieve micro-crack filling; the molecular weight of the water reducer is 20000-30000, the side chain density is 40-60%, and the water-binder ratio is synergistically reduced to 0.28-0.32 through steric hindrance and electrostatic repulsion; the air entraining agent controls the introduction of microbubbles (pore size 50-200μm) accounting for 4-6%, and the fluidity is improved while maintaining strength through the ball effect.

[0044] A three-dimensional wrinkled graphene network is constructed based on graphene oxide, with an interlayer spacing of 0.8-1.2nm. Through the π-π interaction, a covalent grafted heterostructure (SiOC bond) is formed with nano-silica aerogel. The graphene wrinkled structure improves the flexural strength, and the nano-silica aerogel reduces drying shrinkage.

[0045] The magnesium phosphate precursor is coated with mesoporous SiO2, with a shell thickness of 50-100nm, and is internally loaded with biomineralization enzyme liposomes with a particle size of 30-50nm. When cracks are generated, mechanical stress triggers the rupture of the shell, and the enzyme activates a cascade reaction after contact with magnesium phosphate.

[0046] Embodiment 1

[0047] A method for preparing high-performance self-compacting concrete comprises the following steps:

[0048] S1 Functionalization modification of graphene oxide: Graphene oxide (containing 20% ​​oxygen functional groups) was dispersed in a NaOH solution with a pH of 10 (solid-liquid ratio of 1:200), and treated in a 20kHz ultrasonic field for 40 minutes to expand the interlayer spacing to 1.5nm. Subsequently, 3-aminopropyltriethoxysilane (APTES, 12% of the mass of graphene) was added and reacted in a 50°C water bath for 3 hours. Through the click reaction between the amino group and the epoxy group, the surface-Si-O-functional group was grafted to obtain functionalized graphene;

[0049] Pore ​​activation of S2 nano-aerogel: mesoporous SiO2 aerogel (specific surface area 550m 2 / g) was placed in a vacuum reactor, and hexamethyldisilazane (HMDS) vapor was introduced to perform surface hydrophobic modification at 120°C for 10 hours to reduce the hydroxyl density to ≤3 / nm 2 , then immersed in an ethanol solution containing 0.1 mol / LCaCl2, and pre-deposited nano-CaCO3 seeds (particle size 5 nm) on the inner wall of the 20 nm mesopores by capillary action to obtain a modified aerogel;

[0050] S3 heterostructure assembly: Functionalized graphene and modified aerogel were mixed in a mass ratio of 1:5, and an ethanol solution containing 0.5wt% polyethylene glycol was added as a medium. The mixture was assembled in a 0.5T rotating magnetic field for 1 hour. The graphene sheets were vertically intercalated into the aerogel pores through SiOC covalent bonds to form a three-dimensional wrinkled network (interlayer spacing 0.8nm, porosity 93%). After centrifugal separation and drying, a composite reinforcement with graded mass transfer channels was obtained, which was labeled as GO-SA composite.

[0051] Preparation of S4 mesoporous SiO2-coated magnesium phosphate: MgO and NH4H2PO4 were mixed in a molar ratio of 1:1.2, ball-milled to D50 = 3 μm, and then the SiO2 shell was deposited by chemical vapor deposition (CVD) in a fluidized bed. The vapor partial pressure of tetraethoxysilane (TEOS) was controlled to 0.1 kPa, the deposition temperature was 350 °C, and the time was 20 minutes. A core-shell structure with a shell thickness of 70 nm was obtained, which was marked as MP@mSiO2;

[0052] S5 Loading of enzyme active components: Prepare a urease solution containing 1wt% sodium alginate (enzyme activity ≥5000U / g), generate droplets with a particle size of 60μm by microfluidic technology, and drop them into a cross-linking bath containing 5wt% CaCl2 to form calcium alginate microcapsules, then mix MP@mSiO2 and microcapsules in a mass ratio of 4:1, oscillate in a phosphate buffer at pH=7 for 24 hours, and anchor MP@mSiO2 to the surface of the microcapsules by electrostatic adsorption (loading rate ≥85%) to obtain a MP@mSiO2 / enzyme microcapsule system;

[0053] Topological optimization of the molecular chain of S6 water reducer: polycarboxylic acid water reducer (molecular weight 25000) and acrylamide monomer (molar ratio 1:3) were grafted copolymerized at 60°C, and ammonium persulfate was used as the initiator. By adjusting the reaction time (1 hour), a comb-like polymer with a side chain density of 50% was obtained. Its main chain 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, thus obtaining an optimized water reducer;

[0054] S7 slag powder / fly ash interface activation: 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 to a planetary ball mill and activated at 300 rpm for 35 minutes. This process produces active ≡Si-O - sites, forming chemical bonds with subsequent cement hydration products to obtain an activated mixture of slag powder and fly ash;

[0055] S8 Primary slurry preparation: The activated slag powder and fly ash mixture was dry-mixed with cement (P·O52.5) ​​at a mass ratio of 3:7 for 3 minutes, and then 60% of the total water (water-cement ratio 0.30) was added, and an optimized water reducer (0.6 parts) was added, and a double planetary mixer was used to stir at a low speed of 60 rpm for 2 minutes to form a thixotropic matrix slurry;

[0056] S9 Gradual dispersion of nano-enhanced phase: GO-SA complex was dispersed in the remaining 40% water using a three-stage ultrasonic dispersion process:

[0057] High-frequency dispersion: 30kHz ultrasonic treatment for 8 minutes to disassemble the graphene stack;

[0058] Low-frequency infiltration: 25kHz ultrasonic treatment for 15 minutes to allow the aerogel pores to fully absorb water;

[0059] Shear activation: Inject the matrix slurry under high-speed shear at 8000 rpm to form a shear-thinning fluid (apparent viscosity ≤ 50 Pa·s);

[0060] Directional implantation of S10 functional microreactor: The MP@mSiO2 / enzyme microcapsule system and the air entraining agent (sodium dialkyl sulfonate) are co-dispersed in an ethanol solution containing 0.05wt% hydroxypropyl methylcellulose and sprayed into the stirring shear-thinning fluid at a pressure of 0.1MPa through an atomizing nozzle. This process forms the following in the slurry:

[0061] Microbubble cluster (pore size 100 μm, volume share 5.2%);

[0062] Spatial uniform distribution of microcapsules (spacing 300 μm);

[0063] Obtaining a mixed material;

[0064] S11 Low temperature dynamic curing: After the mixture is injected into the mold, it is immediately placed in a 5℃ environment for pre-curing for 1 hour to inhibit the damage of early hydration heat to enzyme activity. Then the temperature is raised to 25℃ at a rate of 0.5℃ / min, and a 0.5T alternating magnetic field is applied for 15 minutes to induce Ca 2+ It migrates along the GO-SA network to form an oriented CSH gel (orientation degree ≥ 70%), completing the preparation of self-compacting concrete.

[0065] Embodiment 2

[0066] A method for preparing high-performance self-compacting concrete comprises the following steps:

[0067] S1 Functionalization modification of graphene oxide: Graphene oxide (containing 25% oxygen functional groups) was dispersed in a NaOH solution with a pH of 10 (solid-liquid ratio of 1:200), and treated in a 35kHz ultrasonic field for 55 minutes to expand the interlayer spacing to 1.7nm. Subsequently, 3-aminopropyltriethoxysilane (APTES, 15% of the mass of graphene) was added and reacted in a water bath at 80°C for 3 hours. Through the click reaction between amino groups and epoxy groups, surface-Si-O-functional group grafting was achieved to obtain functionalized graphene;

[0068] Pore ​​activation of S2 nano-aerogel: mesoporous SiO2 aerogel (specific surface area 650m 2 / g) was placed in a vacuum reactor, and hexamethyldisilazane (HMDS) vapor was introduced to perform surface hydrophobic modification at 120°C for 11 hours to reduce the hydroxyl density to ≤3 / nm 2 , then immersed in an ethanol solution containing 0.1 mol / LCaCl2, and pre-deposited nano-CaCO3 seeds (particle size 7 nm) on the inner wall of the 30 nm mesopores by capillary action to obtain a modified aerogel;

[0069] S3 heterostructure assembly: Functionalized graphene and modified aerogel were mixed in a mass ratio of 1:5, and an ethanol solution containing 0.5wt% polyethylene glycol was added as a medium. The mixture was assembled in a 0.8T rotating magnetic field for 2 hours. The graphene sheets were vertically intercalated into the aerogel pores through SiOC covalent bonds to form a three-dimensional wrinkled network (interlayer spacing 0.9nm, porosity 93%). After centrifugal separation and drying, a composite reinforcement with graded mass transfer channels was obtained, which was labeled as GO-SA composite.

[0070] Preparation of S4 mesoporous SiO2-coated magnesium phosphate: MgO and NH4H2PO4 were mixed in a molar ratio of 1:1.2, ball-milled to D50 = 5 μm, and then the SiO2 shell was deposited by chemical vapor deposition (CVD) in a fluidized bed. The vapor partial pressure of tetraethoxysilane (TEOS) was controlled to 0.3 kPa, the deposition temperature was 400 °C, and the time was 25 minutes. A core-shell structure with a shell thickness of 80 nm was obtained, which was marked as MP@mSiO2;

[0071] S5 Loading of enzyme active components: Prepare a urease solution containing 1wt% sodium alginate (enzyme activity ≥5000U / g), generate droplets with a particle size of 70μm by microfluidic technology, and drop them into a cross-linking bath containing 5wt% CaCl2 to form calcium alginate microcapsules, then mix MP@mSiO2 and microcapsules in a mass ratio of 4:1, oscillate in a phosphate buffer at pH=7 for 24 hours, and anchor MP@mSiO2 to the surface of the microcapsules by electrostatic adsorption (loading rate ≥85%) to obtain a MP@mSiO2 / enzyme microcapsule system;

[0072] Topological optimization of the molecular chain of S6 water reducer: polycarboxylic acid water reducer (molecular weight 25000) and acrylamide monomer (molar ratio 1:3) were grafted copolymerized at 60°C, and ammonium persulfate was used as the initiator. By adjusting the reaction time (2 hours), a comb-like polymer with a side chain density of 50% was obtained. Its main chain 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, thus obtaining an optimized water reducer;

[0073] S7 slag powder / fly ash interface activation: blast furnace slag powder (88% glass content) and fly ash (8% CaO content) were mixed in a mass ratio of 2:1, and 0.1 mol / L NaOH solution (solid-liquid ratio 1:5) was added to a planetary ball mill and activated at 350 rpm for 40 minutes. This process produces active ≡ SiO on the glass surface. - sites, forming chemical bonds with subsequent cement hydration products to obtain an activated mixture of slag powder and fly ash;

[0074] S8 Primary slurry preparation: The activated slag powder and fly ash mixture was dry-mixed with cement (P·O52.5) ​​at a mass ratio of 3:7 for 5 minutes, and then 60% of the total water (water-cement ratio 0.30) was added, and an optimized water reducer (0.8 parts) was added, and a double planetary mixer was used to stir at a low speed of 70 rpm for 3 minutes to form a thixotropic matrix slurry;

[0075] S9 Gradual dispersion of nano-enhanced phase: GO-SA complex was dispersed in the remaining 40% water using a three-stage ultrasonic dispersion process:

[0076] High-frequency dispersion: 40kHz ultrasonic treatment for 10 minutes to disassemble the graphene stack;

[0077] Low-frequency infiltration: 28kHz ultrasonic treatment for 20 minutes to allow the aerogel pores to fully absorb water;

[0078] Shear activation: Inject the matrix slurry under high-speed shear at 10,000 rpm to form a shear-thinning fluid (apparent viscosity ≤ 50 Pa·s);

[0079] Directional implantation of S10 functional microreactor: The MP@mSiO2 / enzyme microcapsule system and the air entraining agent (sodium dialkyl sulfonate) were co-dispersed in an ethanol solution containing 0.05wt% hydroxypropyl methylcellulose and sprayed into the stirring shear-thinning fluid at a pressure of 0.2MPa through an atomizing nozzle. This process formed in the slurry:

[0080] Microbubble cluster (pore size 150 μm, volume share 5.2%);

[0081] Spatial uniform distribution of microcapsules (spacing 400 μm);

[0082] Obtaining a mixed material;

[0083] S11 Low temperature dynamic curing: After the mixture is injected into the mold, it is immediately placed in a 5℃ environment for pre-curing for 2 hours to inhibit the damage of early hydration heat to enzyme activity. Then the temperature is raised to 25℃ at a rate of 0.5℃ / min, and a 0.5T alternating magnetic field is applied for 20 minutes to induce Ca 2+ It migrates along the GO-SA network to form an oriented CSH gel (orientation degree ≥ 70%), completing the preparation of self-compacting concrete.

[0084] Embodiment 3

[0085] A method for preparing high-performance self-compacting concrete comprises the following steps:

[0086] S1 Functionalization modification of graphene oxide: Graphene oxide (containing 25% oxygen functional groups) was dispersed in a NaOH solution with a pH of 10 (solid-liquid ratio of 1:200), and treated in a 40kHz ultrasonic field for 65 minutes to expand the interlayer spacing to 1.8nm. Subsequently, 3-aminopropyltriethoxysilane (APTES, 15% of the mass of graphene) was added and reacted in a water bath at 80°C for 4 hours. The surface-Si-O-functional group was grafted through a click reaction between the amino group and the epoxy group to obtain functionalized graphene.

[0087] Pore ​​activation of S2 nano-aerogel: mesoporous SiO2 aerogel (specific surface area 750m 2 / g) was placed in a vacuum reactor, and hexamethyldisilazane (HMDS) vapor was introduced to perform surface hydrophobic modification at 120°C for 12 hours to reduce the hydroxyl density to ≤3 / nm 2 , then immersed in an ethanol solution containing 0.1 mol / LCaCl2, and pre-deposited nano-CaCO3 seeds (particle size 8 nm) on the inner wall of the 35 nm mesopores by capillary action to obtain a modified aerogel;

[0088] S3 heterostructure assembly: Functionalized graphene and modified aerogel were mixed in a mass ratio of 1:5, and an ethanol solution containing 0.5wt% polyethylene glycol was added as a medium. The mixture was assembled in a 0.8T rotating magnetic field for 2 hours. The graphene sheets were vertically intercalated into the aerogel pores through SiOC covalent bonds to form a three-dimensional wrinkled network (interlayer spacing 0.95nm, porosity 93%). After centrifugal separation and drying, a composite reinforcement with graded mass transfer channels was obtained, which was labeled as GO-SA composite.

[0089] Preparation of S4 mesoporous SiO2-coated magnesium phosphate: MgO and NH4H2PO4 were mixed in a molar ratio of 1:1.2, ball-milled to D50 = 5 μm, and then the SiO2 shell was deposited by chemical vapor deposition (CVD) in a fluidized bed. The tetraethoxysilane (TEOS) vapor partial pressure was controlled to 0.3 kPa, the deposition temperature was 450 ° C, and the time was 35 minutes. A core-shell structure with a shell thickness of 85 nm was obtained, which was marked as MP@mSiO2;

[0090] S5 Loading of enzyme active components: Prepare a urease solution containing 1wt% sodium alginate (enzyme activity ≥5000U / g), generate droplets with a particle size of 75μm by microfluidic technology, and drop them into a cross-linking bath containing 5wt% CaCl2 to form calcium alginate microcapsules, then mix MP@mSiO2 and microcapsules in a mass ratio of 4:1, oscillate in a phosphate buffer at pH=7 for 24 hours, and anchor MP@mSiO2 to the surface of the microcapsules by electrostatic adsorption (loading rate ≥85%) to obtain a MP@mSiO2 / enzyme microcapsule system;

[0091] Topological optimization of the molecular chain of S6 water reducer: polycarboxylic acid water reducer (molecular weight 25000) and acrylamide monomer (molar ratio 1:3) were grafted copolymerized at 65°C, and ammonium persulfate was used as the initiator. By adjusting the reaction time (2 hours), a comb-like polymer with a side chain density of 50% was obtained. Its main chain 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, thus obtaining an optimized water reducer;

[0092] S7 slag powder / fly ash interface activation: blast furnace slag powder (88% glass content) and fly ash (8% CaO content) were mixed in a mass ratio of 2:1, and 0.1 mol / L NaOH solution (solid-liquid ratio 1:5) was added to a planetary ball mill and activated at 450 rpm for 55 minutes. This process produces active ≡ SiO on the glass surface. - sites, forming chemical bonds with subsequent cement hydration products to obtain an activated mixture of slag powder and fly ash;

[0093] S8 Primary slurry preparation: The activated slag powder and fly ash mixture was dry-mixed with cement (P·O52.5) ​​at a mass ratio of 3:7 for 6 minutes, and then 60% of the total water (water-cement ratio 0.30) was added, and an optimized water reducer (0.9 parts) was added, and a double planetary mixer was used to stir at a low speed of 80 rpm for 4 minutes to form a thixotropic matrix slurry;

[0094] S9 Gradual dispersion of nano-enhanced phase: GO-SA complex was dispersed in the remaining 40% water using a three-stage ultrasonic dispersion process:

[0095] High-frequency dispersion: 40kHz ultrasonic treatment for 12 minutes to disassemble the graphene stack;

[0096] Low-frequency infiltration: 30kHz ultrasonic treatment for 20 minutes to allow the aerogel pores to fully absorb water;

[0097] Shear activation: Inject the matrix slurry under high-speed shear at 10,000 rpm to form a shear-thinning fluid (apparent viscosity ≤ 50 Pa·s);

[0098] Directional implantation of S10 functional microreactor: The MP@mSiO2 / enzyme microcapsule system and the air entraining agent (sodium dialkyl sulfonate) were co-dispersed in an ethanol solution containing 0.05wt% hydroxypropyl methylcellulose and sprayed into the stirring shear-thinning fluid at a pressure of 0.3MPa through an atomizing nozzle. This process formed in the slurry:

[0099] Microbubble cluster (pore size 170 μm, volume share 5.2%);

[0100] Spatial uniform distribution of microcapsules (spacing 400 μm);

[0101] Obtaining a mixed material;

[0102] S11 Low temperature dynamic curing: After the mixture is injected into the mold, it is immediately placed in a 5℃ environment for pre-curing for 2 hours to inhibit the damage of early hydration heat to enzyme activity. Then the temperature is raised to 25℃ at a rate of 0.5℃ / min, and an alternating magnetic field of 0.8T is applied for 25 minutes to induce Ca 2+ It migrates along the GO-SA network to form an oriented CSH gel (orientation degree ≥ 70%), completing the preparation of self-compacting concrete.

[0103] Embodiment 4

[0104] A method for preparing high-performance self-compacting concrete comprises the following steps:

[0105] S1 Functionalization modification of graphene oxide: Graphene oxide (containing 25% oxygen functional groups) was dispersed in a NaOH solution with a pH of 10 (solid-liquid ratio of 1:200), and treated in a 40kHz ultrasonic field for 70 minutes to expand the interlayer spacing to 2nm. Subsequently, 3-aminopropyltriethoxysilane (APTES, 15% of the mass of graphene) was added and reacted in a water bath at 80°C for 5 hours. The surface-Si-O-functional group was grafted through a click reaction between the amino group and the epoxy group to obtain functionalized graphene.

[0106] Pore ​​activation of S2 nano-aerogel: mesoporous SiO2 aerogel (specific surface area 750m 2 / g) was placed in a vacuum reactor, and hexamethyldisilazane (HMDS) vapor was introduced to perform surface hydrophobic modification at 120°C for 12 hours to reduce the hydroxyl density to ≤3 / nm 2 , then immersed in an ethanol solution containing 0.1 mol / LCaCl2, and pre-deposited nano-CaCO3 seeds (particle size 10 nm) on the inner wall of the 50 nm mesopores by capillary action to obtain a modified aerogel;

[0107] S3 heterostructure assembly: Functionalized graphene and modified aerogel were mixed in a mass ratio of 1:5, and an ethanol solution containing 0.5wt% polyethylene glycol was added as a medium. The mixture was assembled in a 1.2T rotating magnetic field for 2 hours. The graphene sheets were vertically intercalated into the aerogel pores through SiOC covalent bonds to form a three-dimensional wrinkled network (interlayer spacing 1.1nm, porosity 93%). After centrifugal separation and drying, a composite reinforcement with graded mass transfer channels was obtained, which was labeled as GO-SA composite.

[0108] Preparation of S4 mesoporous SiO2-coated magnesium phosphate: MgO and NH4H2PO4 were mixed in a molar ratio of 1:1.2, ball-milled to D50 = 5 μm, and then the SiO2 shell was deposited by chemical vapor deposition (CVD) in a fluidized bed. The vapor partial pressure of tetraethoxysilane (TEOS) was controlled to 0.5 kPa, the deposition temperature was 500 °C, and the time was 35 minutes. A core-shell structure with a shell thickness of 90 nm was obtained, which was marked as MP@mSiO2;

[0109] S5 Loading of enzyme active components: Prepare a urease solution containing 1wt% sodium alginate (enzyme activity ≥5000U / g), generate droplets with a particle size of 80μm by microfluidic technology, and drop them into a cross-linking bath containing 5wt% CaCl2 to form calcium alginate microcapsules, then mix MP@mSiO2 and microcapsules in a mass ratio of 4:1, oscillate in a phosphate buffer at pH=7 for 24 hours, and anchor MP@mSiO2 to the surface of the microcapsules by electrostatic adsorption (loading rate ≥85%) to obtain a MP@mSiO2 / enzyme microcapsule system;

[0110] Topological optimization of the molecular chain of S6 water reducer: polycarboxylic acid water reducer (molecular weight 25000) and acrylamide monomer (molar ratio 1:3) were grafted copolymerized at 60°C, and ammonium persulfate was used as the initiator. By adjusting the reaction time (2 hours), a comb-like polymer with a side chain density of 50% was obtained. Its main chain 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, thus obtaining an optimized water reducer;

[0111] S7 slag powder / fly ash interface activation: 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 to a planetary ball mill and activated at 500 rpm for 50 minutes. This process produces active ≡Si-O - sites, forming chemical bonds with subsequent cement hydration products to obtain an activated mixture of slag powder and fly ash;

[0112] S8 Primary slurry preparation: The activated slag powder and fly ash mixture was dry-mixed with cement (P·O52.5) ​​at a mass ratio of 3:7 for 5 minutes, and then 60% of the total water (water-cement ratio 0.30) was added, and an optimized water reducer (1.1 parts) was added, and a double planetary mixer was used to stir at a low speed of 80 rpm for 5 minutes to form a thixotropic matrix slurry;

[0113] S9 Gradual dispersion of nano-enhanced phase: GO-SA complex was dispersed in the remaining 40% water using a three-stage ultrasonic dispersion process:

[0114] High-frequency dispersion: 45kHz ultrasonic treatment for 15 minutes to disassemble the graphene stack;

[0115] Low-frequency infiltration: 30kHz ultrasonic treatment for 25 minutes to allow the aerogel pores to fully absorb water;

[0116] Shear activation: Inject the matrix slurry under high-speed shear at 12,000 rpm to form a shear-thinning fluid (apparent viscosity ≤ 50 Pa·s);

[0117] Directional implantation of S10 functional microreactor: The MP@mSiO2 / enzyme microcapsule system and the air entraining agent (sodium dialkyl sulfonate) are co-dispersed in an ethanol solution containing 0.05wt% hydroxypropyl methylcellulose and sprayed into the stirring shear-thinning fluid at a pressure of 0.2MPa through an atomizing nozzle. This process forms the following in the slurry:

[0118] Microbubble cluster (pore size 200 μm, volume percentage 5.2%);

[0119] Spatial uniform distribution of microcapsules (spacing 500 μm);

[0120] Obtaining a mixed material;

[0121] S11 Low temperature dynamic curing: After the mixture is injected into the mold, it is immediately placed in a 5℃ environment for pre-curing for 2 hours to inhibit the damage of early hydration heat to enzyme activity. Then the temperature is raised to 25℃ at a rate of 0.5℃ / min, and an alternating magnetic field of 0.8T is applied for 30 minutes to induce Ca 2+ It migrates along the GO-SA network to form an oriented CSH gel (orientation degree ≥ 70%), completing the preparation of self-compacting concrete.

[0122] Comparative Example 1

[0123] A high-performance self-compacting concrete and a preparation method thereof are basically the same as the fourth embodiment, except that there is no GO-SA composite.

[0124] Comparative Example 2

[0125] A high-performance self-compacting concrete and a preparation method thereof are basically the same as those of Example 4, except that there is no MP@mSiO2 / enzyme microcapsule.

[0126] Comparative Example 3

[0127] A high-performance self-compacting concrete and a preparation method thereof are basically the same as those of the fourth embodiment, except that a common water reducing agent is used.

[0128] Comparative Example 4

[0129] A high-performance self-compacting concrete and a preparation method thereof are basically the same as those of the fourth embodiment, except that conventional curing is used without a low-temperature magnetic field.

[0130] The concrete prepared in the above-mentioned Examples 1 to 4 and Comparative Examples 1 to 4 was tested:

[0131] Slump spread

[0132] Standard: GB / T 50080-2016 "Standard for test methods of performance of ordinary concrete mixtures"

[0133] Detection method:

[0134] Use a slump cone (300mm high, 100mm upper diameter, 200mm lower diameter), load the concrete into the cone in three layers and tamp it down, lift the slump cone vertically and measure the slump expansion diameter (unit: mm), and record the T500 time (the time required to expand to 500mm).

[0135] Compressive strength

[0136] Standard: GB / T 50081-2019 "Standard for Test Methods for Physical and Mechanical Properties of Concrete"

[0137] Detection method:

[0138] Prepare 150mm×150mm×150mm cubic specimens and carry out standard curing (temperature 20±2℃, humidity ≥95%) to the specified age (3 days, 28 days). Use a pressure testing machine to load until failure at a rate of 0.5MPa / s, and calculate the compressive strength (unit: MPa).

[0139] Crack healing rate

[0140] Reference standard: JGJ / T 283-2012 "Technical Specifications for Application of Self-compacting Concrete" (Appendix A Self-repairing Performance Test)

[0141] Detection method:

[0142] Prefabricated cracks (width 0.2 mm) were made on the surface of the specimens. After standard curing for 28 days, the specimens were immersed in water for 7 days and the change in crack width was measured.

[0143] Healing rate calculation formula:

[0144] Chloride ion diffusion coefficient

[0145] Standard: GB / T 50476-2017 "Specification for Durability Design of Concrete Structures" (Appendix BRCM Method)

[0146] Detection method:

[0147] Cut the Φ100mm×50mm specimen, place it in the RCM test device after vacuum saturation, apply 60V DC voltage, record the migration depth of chloride ions, and calculate the chloride ion diffusion coefficient (unit: ×10-12 m 2 / s).

[0148] The results are shown in Table 1:

[0149] Table 1

[0150]

[0151]

[0152] From Table 1 above, it can be directly obtained that in Examples 1 to 4, through multi-component synergy (GO-SA enhancement, microcapsule repair, optimized water reducer) and process innovation (low-temperature magnetic field maintenance), the examples achieve the following advantages: Self-compactness: slump expansion 773-785mm, meeting ultra-high pumping requirements. High strength: 28-day compressive strength 82.9-83.6MPa, reaching the ultra-high strength concrete standard. Self-repair ability: crack healing rate is 91%-92%, significantly extending the life of the structure. High durability: chloride ion diffusion coefficient is only 1.2×10 -12 m 2 / s, suitable for marine environment.

[0153] Reference Figure 1-2 , in Example 4 and Comparative Example where other conditions are the same:

[0154] Slump spread

[0155] The slump expansion example meets the self-compacting requirements (standard value ≥ 750mm, T500 ≤ 3s). Comparative Example 1 (no GO-SA) has a significant decrease in fluidity due to the lack of GO-SA's nano-lubrication and aerogel water retention. Comparative Example 3 (ordinary water reducer): The water reducer is not optimized, and the steric hindrance is insufficient, resulting in reduced fluidity.

[0156] Conclusion: GO-SA composite and optimized water reducer synergistically improve fluidity and self-compacting properties.

[0157] 28 days compressive strength

[0158] Example 4 has a 28-day strength of 83.6 MPa, far exceeding the comparative example. Comparative Example 1 (without GO-SA): lacks a nano-enhanced network, and the strength is reduced. Comparative Example 2 (without microcapsules): lacks the early strength effect of magnesium phosphate, and the strength decreases by 1. Comparative Example 4 (conventional curing): no magnetic field is used to induce CSH oriented growth, and the strength is low after 28 days.

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

[0160] Crack healing rate

[0161] The examples are significantly higher than the comparative examples. Comparative example 2 (no microcapsules): relying solely on cement self-healing, the healing rate is only 35%. Comparative example 4 (conventional maintenance): enzyme activity is impaired, and the healing rate drops to 55%.

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

[0163] Chloride ion diffusion coefficient

[0164] Comparative Example 1 (without GO-SA): The lack of aerogel leads to high porosity and the chloride ion diffusion coefficient increases to 5.8×10 - 12 m 2 / s. Comparative Example 3 (ordinary water reducing agent): The water-cement ratio is high and the permeability is increased.

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

[0166] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A high performance self-compacting concrete, characterized in that: The invention comprises the following components in parts by weight: 100-120 parts of cement, 25-35 parts of fly ash, 20-30 parts of slag powder, 0.05-0.15 parts of graphene oxide, 0.3-0.8 parts of nano-silicon dioxide aerogel, 0.8-1.5 parts of water reducing agent and 0.005-0.015 parts of air entraining agent.

2. A high performance self-compacting concrete according to claim 1, characterized in that The invention also comprises the following components in parts by weight: 0.02 to 0.08 parts of biomineralization enzyme and 2.5 to 4.0 parts of magnesium phosphate precursor.

3. A high performance self-compacting concrete according to claim 2, characterized in that: The biomineralization enzyme is urease, the magnesium phosphate precursor is MgO / NH4H2PO4, the molar ratio is 1:1.2, the water reducer is a polycarboxylate water reducer, and the air entraining agent is one or more of a sodium dialkyl sulfonate air entraining agent and ammonium persulfate.

4. A high performance self-compacting concrete according to claim 2, characterized in that: The glass content in the potential hydration activity of the slag powder is ≥85%; the sheet thickness of the graphene oxide is 2-5nm, and the oxygen-containing functional groups account for 20-30%; the nano-silicon dioxide aerogel is a mesoporous structure with a pore size of 10-50nm and a specific surface area of ​​600-800m 2 / g; the carrier form of the biomineralization enzyme is calcium alginate microcapsule encapsulation, 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 reducer is 20000-30000, the side chain density is 40-60%, and the water-binder ratio is synergistically reduced to 0.28-0.32 through steric hindrance and electrostatic repulsion; the air entraining agent controls the introduction of microbubbles to account for 4-6%, and improves fluidity while maintaining strength through the ball effect.

5. The high performance self-compacting concrete according to claim 2, characterized in that: A three-dimensional wrinkled graphene network is constructed based on the graphene oxide, with an interlayer spacing of 0.8-1.2 nm, and a covalently grafted heterostructure is formed with the nano-silica aerogel through π-π interaction; The magnesium phosphate precursor is coated with mesoporous SiO2, the shell thickness is 50-100nm, and the biomineralization enzyme liposome is loaded inside, and the particle size is 30-50nm.

6. A method for preparing high performance self-compacting concrete according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1 Functionalization modification of graphene oxide: Graphene oxide was dispersed in NaOH solution and ultrasonically treated to expand the interlayer spacing. Then 3-aminopropyltriethoxysilane was added for water bath reaction. The surface -Si-O-functional group was grafted through the click reaction between amino group and epoxy group to obtain functionalized graphene. Pore ​​activation of S2 nano-aerogel: The mesoporous SiO2 aerogel was placed in a vacuum reactor, and hexamethyldisilazane vapor was introduced to perform surface hydrophobic modification, and then immersed in an ethanol solution containing CaCl2, and nano-CaCO3 seeds were pre-deposited on the inner wall of the 20-50nm mesopores by capillary action to obtain modified aerogel; S3 heterostructure assembly: functionalized graphene was mixed with modified aerogel, ethanol solution was added as a medium, and they were assembled 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 labeled as GO-SA composite. Preparation of S4 mesoporous SiO2-coated magnesium phosphate: MgO and NH4H2PO4 were mixed and ball-milled, and the SiO2 shell was deposited by chemical vapor deposition (CVD) in a fluidized bed to obtain a core-shell structure, which was labeled MP@mSiO2; S5 Loading of enzyme active components: Prepare urease solution, generate droplets by microfluidics technology, and drop them into a cross-linking bath containing CaCl2 to form calcium alginate microcapsules. Then, mix MP@mSiO2 with the microcapsules, oscillate in phosphate buffer, and anchor MP@mSiO2 on the surface of the microcapsules by electrostatic adsorption to obtain the MP@mSiO2 / enzyme microcapsule system. Topological optimization of the molecular chain of S6 water reducer: polycarboxylic acid water reducer was grafted and copolymerized with acrylamide monomer, and ammonium persulfate was used as the initiator to obtain a comb-like polymer with a side chain density of 50%. Its main chain 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, thus obtaining an optimized water reducer; S7 interface activation: blast furnace slag powder and fly ash are mixed, and NaOH solution is added to activate the mixture in a planetary ball mill to obtain an activated slag powder and fly ash mixture; S8 Primary slurry preparation: dry-mix the activated slag powder and fly ash mixture with cement, then add 60% of the total water, add optimized water reducing agent, and stir at low speed with a double planetary mixer to form a thixotropic matrix slurry; S9 graded dispersion of nano-reinforced phase: GO-SA composite was dispersed in the remaining 40% of water, and a three-stage ultrasonic dispersion process was used for dispersion and shear activation of the matrix slurry to obtain a shear-thinning fluid; Directed implantation of S10 functional microreactor: The MP@mSiO2 / enzyme microcapsule system and air-entraining agent were co-dispersed in an ethanol solution and sprayed into the stirring shear-thinning fluid through an atomizing nozzle to obtain a mixed material; 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 completes the preparation of self-compacting concrete.

7. The method for preparing a high performance self-compacting concrete according to claim 6, characterized in that: In S9, the three-stage ultrasonic dispersion process includes: High-frequency dispersion: 40kHz ultrasonic treatment for 10 minutes to disassemble the graphene stack; Low-frequency infiltration: 28kHz ultrasonic treatment for 20 minutes to allow the aerogel pores to fully absorb water; Shear activation: Inject the matrix slurry under high-speed shear at 10,000 rpm to form a shear-thinning fluid.

8. The method for preparing a high performance self-compacting concrete according to claim 6, characterized in that: In the step S10, a microbubble group is formed in the slurry with a pore size of 150±50 μm, and the microcapsules are evenly distributed in space with a spacing of 300-500 μm.

9. The method for preparing a high performance self-compacting concrete according to claim 6, characterized in that: In S11, after the mixture is injected into the mold, pre-curing is performed to suppress the damage of early hydration heat to enzyme activity, and then the temperature is raised and an alternating magnetic field is applied to induce Ca 2+ It migrates along the GO-SA network to form an oriented growth CSH gel, completing the preparation of self-compacting concrete.

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