A preparation method of a curing agent for high liquid limit clayey soil based fluidized solidified soil

Abstract

This invention relates to the field of building materials, specifically disclosing a method for preparing a curing agent for high liquid limit viscous slag-based fluidized solidified soil. The method includes the following steps: using fly ash, blast furnace slag, composite alkali source, solid waste gypsum, modified waste incineration fly ash, slag powder, and nano-suspension as raw materials. First, the fly ash, blast furnace slag, composite alkali source, solid waste gypsum, modified waste incineration fly ash, and slag powder are mixed evenly. Then, the resulting mixed powder undergoes plasma treatment for surface modification. After modification, the nano-suspension is added and mixed with water to form a slurry for grinding. Then, the mixture is spray-dried, and the resulting modified powder is activated by pulsed microwaves to obtain the curing agent for fluidized solidified soil. This method effectively overcomes the shortcomings of traditional ordinary silicate cement curing agents, such as insufficient curing effect on high liquid limit slag soil.

Description

Technical Field

[0001] This invention relates to the field of building materials, and specifically to a method for preparing a curing agent for high liquid limit viscous slag-based fluidized solidified soil. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] With the rapid advancement of urbanization in my country, the scale of underground engineering construction continues to expand. Deep foundation projects such as shield tunnels, pile foundations, and diaphragm walls generate massive amounts of construction waste during construction. Traditional methods of disposing of construction waste primarily involve stockpiling and dumping, which not only occupies a large amount of valuable land resources but also allows fine particles in the waste to easily pollute soil and water bodies through rainwater runoff. Furthermore, transportation and disposal processes incur enormous costs. Therefore, the resource utilization of construction waste has become an urgent problem to be solved in the process of urban development.

[0004] Fluidized solidified soil technology is an effective way to realize the resource utilization of construction waste, and its core lies in the performance of the solidifying agent. Fluidized solidified soil is composed of construction waste, solidifying agent, water, and additives. It initially exists in a fluid state and hardens into a stable solid, combining ease of construction with structural performance. This technology can transform construction waste into a self-compacting, filling fluidized material for applications such as foundation pit backfilling, trench backfilling, and cavity filling, showing broad application prospects.

[0005] Currently, ordinary Portland cement remains the mainstream solidifying agent in the field of fluidized solidified soil. However, cement production is a high-energy-consuming and high-carbon-emission industry, emitting approximately 0.8 to 0.9 tons of carbon dioxide for every ton of ordinary Portland cement produced. More importantly, ordinary Portland cement is not effective in solidifying high-liquid-limit slag soils. This is mainly because high-liquid-limit soils have characteristics such as high water content, difficulty in draining pore water, low natural dry density, difficulty in compaction, and insufficient roadbed bearing capacity. After solidification with ordinary cement, they cannot achieve sufficient strength to meet engineering requirements, and the solidified soil is prone to drying shrinkage cracking. Summary of the Invention

[0006] This invention provides a method for preparing a curing agent for high liquid limit viscous slag-based fluidized solidified soil, effectively overcoming the shortcomings of traditional ordinary silicate cement curing agents, such as insufficient curing effect on high liquid limit slag-based soils. Specifically, the technical solution of this invention is as follows.

[0007] A method for preparing a solidifying agent for high liquid limit viscous slag-based fluidized solidified soil includes the following steps: (1) After mixing carbide slag, steel slag powder and sodium metasilicate, microwave irradiation activation was performed, followed by quenching treatment to obtain a composite alkali source for later use.

[0008] (2) The waste incineration fly ash, dihydrogen phosphate, and water are mixed and stirred under heating conditions. After the mixture is heated, the solid product is separated and calcined to obtain pre-stabilized fly ash. The pre-stabilized fly ash is then mixed with nano-Fe3O4 to obtain modified waste incineration fly ash for later use.

[0009] (3) Mix MgO, ZnO and CaO nanopowders, add polycarboxylate superplasticizer mother liquor and naphthalene sulfonate, then add water for dispersion treatment to obtain nano suspension for later use.

[0010] (4) Mix fly ash, blast furnace slag, solid waste gypsum, slag powder, the composite alkali source, and the modified waste incineration fly ash. Then, perform surface modification of the obtained mixed powder by plasma treatment. After completion, add the nano suspension and mixing water to form a slurry for grinding treatment. Then, spray dry and perform pulsed microwave activation on the obtained modified powder to obtain the curing agent.

[0011] Further, in step (1), the mass ratio of the carbide slag, steel slag powder, and sodium metasilicate is 4~6:2~4:1~3.

[0012] Further, in step (1), the microwave irradiation activation time is 10~15 min. Optionally, the power of the microwave is 800~1000W.

[0013] Further, in step (1), the quenching treatment time is 1~2 minutes. Optionally, the quenching treatment is carried out in liquid nitrogen.

[0014] Further, in step (2), the mass ratio of the waste incineration fly ash, dihydrogen phosphate, and water is 50:1~2.5:10~20. Optionally, the dihydrogen phosphate includes at least one of sodium dihydrogen phosphate, potassium dihydrogen phosphate, and ammonium dihydrogen phosphate.

[0015] Furthermore, in step (2), the heating temperature is 40~50℃, and the stirring time is 0.5~2 hours.

[0016] Furthermore, in step (2), the roasting temperature is 300~400℃ and the time is 20~40min.

[0017] Furthermore, in step (2), the mass ratio of the pre-stabilized fly ash to nano Fe3O4 is 8~12:1.

[0018] Further, in step (3), the mass ratio of MgO, ZnO and CaO is 1.5~2.5:0.5~1.3:0.4~1.5.

[0019] Further, in step (3), the polycarboxylate superplasticizer mother liquor and naphthalene sulfonate are 8-12% and 1.5-2.5% of the total mass of MgO, ZnO, and CaO nanopowders, respectively. Optionally, the naphthalene sulfonate includes at least one of sodium naphthalene sulfonate, sodium methylene bisnaphthalene sulfonate (FDN), and naphthalene sulfonic acid formaldehyde condensate.

[0020] Further, in step (3), water is added in a ratio of 30~50 wt.% of the solid content of the nano suspension.

[0021] Further, in step (3), the stirring rate of the dispersion treatment is 3000~5000 r / min, and the time is 20~40 min.

[0022] Further, in step (4), the proportions of each component are as follows: 18-22 parts by weight of fly ash, 35-40 parts by weight of blast furnace slag, 8-10 parts by weight of solid waste gypsum, 3-5 parts by weight of slag powder, 12-18 parts by weight of composite alkali source, 4-6 parts by weight of modified waste incineration fly ash, and 2-3 parts by weight of nano suspension.

[0023] Further, in step (4), the plasma treatment time is 10-20 min, and the power is 150-250 W. Optionally, the working gas for the plasma treatment includes argon, etc. The plasma treatment causes active functional groups to form on the surface of the mixed powder particles, which chemically bond or strongly physically adsorb with the polycarboxylate superplasticizer and naphthalene sulfonate in the subsequently added nano-suspension, thereby significantly enhancing the density of the interface region between the nanoparticles and the fluidized solidified soil matrix. Simultaneously, the active functional groups also promote the uniform nucleation and growth of hydration products in the slurry, improving the overall gelling activity of the curing agent and the mechanical properties of the fluidized solidified soil.

[0024] Furthermore, in step (4), the solid content of the slurry is 55~65 wt.%.

[0025] Furthermore, in step (4), the grinding process takes 1.5 to 2.5 hours and the linear velocity is 10 to 15 m / s.

[0026] Furthermore, in step (4), the power of the pulsed microwave activation is 400~600W, the on-time is 3~8s, the off-time is 8~15s, and the number of cycles is 15~25.

[0027] Compared with the prior art, the present invention has at least the following beneficial technical effects: (1) This invention uses carbide slag, steel slag powder, and sodium metasilicate as raw materials. The materials are first activated by microwave irradiation, and then quenched to form a composite alkali source. In this process, the selective bulk heating effect of microwaves is used to rapidly raise the temperature of the components. Due to the different thermal expansion coefficients of the components, thermal stress is generated at the multiphase interface, inducing lattice distortion, dislocation entanglement, and submicron-level microcracks within the crystal. Simultaneously, the crystal water of sodium metasilicate is strongly polarized in the microwave field, causing its layered structure to break down and transforming into highly active amorphous sodium metasilicate. Subsequently, the components at high temperature are rapidly quenched, causing the lattice distortion, dislocation entanglement, microcracks, and metastable phases to be "frozen" inside the crystal before they can recover. The sudden shrinkage of the unit cell volume further induces a change in the non-uniformity of the lattice constant, resulting in nanoscale steps, twists, and active bond breaks on the crystal surface. This composite alkali source, rich in defects and surface reconstruction, readily permeates water along defect channels upon contact with water, significantly increasing the Ca-O bond breaking rate. Simultaneously, the hydration and dissolution of amorphous sodium metasilicate are also markedly accelerated. These two factors synergistically promote the breakdown of OH-... - Rapid release causes the pH of the slurry to rise rapidly, thus providing a strongly alkaline environment for the depolymerization of inert glass in blast furnace slag and the ultra-rapid nucleation of ettringite (AFt), significantly improving the early strength of the fluidized solidified soil.

[0028] (2) This invention uses a nano-suspension prepared from MgO, ZnO, CaO nanoparticles, polycarboxylate superplasticizer mother liquor, and naphthalene sulfonate to modify the surface of the mixed powder formed by fly ash, blast furnace slag, composite alkali source, solid waste gypsum, modified waste incineration fly ash, and slag powder. This effectively overcomes the problems of low strength, poor impermeability, and easy cracking caused by large drying shrinkage, coarse hydration products, and high porosity when using traditional silicate cement as a curing agent to solidify high liquid limit slag. Among them: the magnesium hydroxide generated by the hydration of the MgO nanoparticles expands with volume, which can compensate for the drying shrinkage caused by water evaporation in high liquid limit slag, effectively inhibiting drying shrinkage cracks and improving volume stability. The ZnO nanoparticles, as a lattice regulator, can refine the crystal size of the hydration products, reduce microcrack sources, and improve crack resistance and mechanical strength. The CaO nanoparticles increase the pH value of the system and accelerate the hydration reaction rate, improving early strength. The three form a synergistic effect of "compensation-refinement-activation". The polycarboxylate superplasticizer and naphthalene sulfonate form a protective shell containing PEG long chains and naphthalene rings on the surface of the nanoparticles, thereby adsorbing Ca in the fluidized solidified soil. 2+The induced AFt and CSH gels undergo directional nucleation and growth on the surface of nanoparticles, forming a whisker-like interlocking structure. This significantly improves the density of the interface region between the nanoparticles and the fluidized solidified soil matrix, thereby enhancing the mechanical properties of the fluidized solidified soil. Furthermore, the nano-suspension can regulate the hydration heat release rate of the fluidized solidified soil, preventing early cracking. Through these modifications, the drying shrinkage coefficient, compressive strength, impermeability grade, and porosity of the fluidized solidified soil are significantly improved, effectively overcoming the shortcomings of traditional cement in solidifying high-liquid-limit slag soils.

[0029] (3) This invention uses dihydrogen phosphate to pre-stabilize waste incineration fly ash before roasting to obtain pre-stabilized fly ash. Modified waste incineration fly ash is then prepared by loading nano-Fe3O4 onto its surface, effectively overcoming the problem of soluble salts and organic matter inhibiting hydration in high liquid limit slag. The pre-stabilization treatment generates a calcium phosphate passivation film on the fly ash surface. This film can encapsulate and block harmful ions such as chloride ions and sulfates, as well as some organic matter, within the fly ash, inhibiting their dissolution. Further roasting not only removes the organic matter in the fly ash, completely eliminating its adsorption and inhibition effect on blast furnace slag hydration, but also promotes the dehydration and condensation of the calcium phosphate passivation film, significantly improving the long-term barrier performance of the film. Simultaneously, during the subsequent pulsed microwave activation of the modified powder, the nano-Fe3O4 on the surface of the modified waste incineration fly ash undergoes efficient thermal conversion under microwave irradiation, causing a rapid increase in the surface temperature of the powder particles. This results in a thermal cycle effect of "rapid heating-brief heat preservation-natural cooling," accelerating the formation and diffusion of lattice defects within the particles, thereby enhancing the surface activity and gelling reaction activity of the powder, and obtaining a highly active solidifying agent for fluidized solidified soil. Thus, fly ash, which originally easily deteriorates the chemical environment of high liquid limit soil, is transformed into a functional component that fills and densifies, and promotes gelling, effectively overcoming the defects of low early strength and high porosity when using traditional silicate cement to solidify high liquid limit soil. Attached Figure Description

[0030] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Hereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings, wherein: Figure 1 The image shows a sample of the curing agent for the fluidized solidified soil prepared in Example 1 below.

[0031] Figure 2 The image shows a sample of the curing agent for the fluidized solidified soil prepared in Example 2 below.

[0032] Figure 3 The image shows a sample of the curing agent for the fluidized solidified soil prepared in Example 3 below.

[0033] Figure 4The image shows a sample of the curing agent for the fluidized solidified soil prepared in Example 4 below.

[0034] Figure 5 The image shows a sample of the curing agent for the fluidized solidified soil prepared in Example 5 below.

[0035] Figure 6 The image shows a sample of the curing agent for the fluidized solidified soil prepared in Example 6 below.

[0036] Figure 7 The image shows a sample of the curing agent for the fluidized solidified soil prepared in Example 7 below.

[0037] Figure 8 The image shows a sample of the curing agent for the fluidized solidified soil prepared in Example 8 below.

[0038] Figure 9 The image shows a sample of the curing agent for the fluidized solidified soil prepared in Example 9 below.

[0039] Figure 10 The image shows a sample of the curing agent for the fluidized solidified soil prepared in Example 10 below. Detailed Implementation

[0040] The present invention is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of skill in the art. The reagents and raw materials used in this invention are readily available through conventional means, and unless otherwise specified, they shall be used in accordance with conventional methods in the art or as per the product instructions. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention.

[0042] Example 1 A method for preparing a solidifying agent for high liquid limit viscous slag-based fluidized solidified soil includes the following steps: (1) Mix calcium carbide slag, steel slag powder and sodium metasilicate in a mass ratio of 5:3:2 and stir evenly. Then, activate with microwave irradiation at a power of 1000W for 10 minutes. After completion, quench the obtained solid product with liquid nitrogen for 2 minutes to obtain a composite alkali source for later use.

[0043] (2) The waste incineration fly ash, potassium dihydrogen phosphate, and water were mixed at a mass ratio of 50:1.5:16 and heated to 45°C with stirring for 1 hour. After the mixture was heated, the solid product was filtered out and calcined at 350°C for 30 minutes at a heating rate of 10°C / min to obtain pre-stabilized fly ash. The pre-stabilized fly ash was then dispersed and mixed with nano-Fe3O4 at a mass ratio of 10:1 with stirring for 30 minutes to obtain modified waste incineration fly ash for later use.

[0044] (3) Mix MgO, ZnO and CaO nanopowders in a mass ratio of 2:1:1 and stir until homogeneous. Then add 10% of the mass of polycarboxylate superplasticizer mother liquor and 2% of sodium α-naphthalenesulfonate to the mixed nanopowder. Add water and stir at a rate of 4500 r / min for 30 min to obtain a nano suspension with a solid content of 45 wt.% for later use.

[0045] (4) Take the following raw materials in the following proportions: 18 parts by weight of fly ash, 35 parts by weight of granulated blast furnace slag powder, 8 parts by weight of solid waste gypsum (desulfurized gypsum powder), 3 parts by weight of slag powder, 12 parts by weight of the composite alkali source of this embodiment, 4 parts by weight of modified waste incineration fly ash of this embodiment, and 2.5 parts by weight of nano-suspension of this embodiment. First, mix the fly ash, granulated blast furnace slag powder, solid waste gypsum, slag powder, composite alkali source, and modified waste incineration fly ash evenly. Then, use argon as the working gas to treat the resulting mixed powder with plasma for 15 minutes at a power of 200W. After completion, add the nano-suspension and mixing water to form a slurry with a solid content of 60wt.% and grind it for 1.5 hours at a grinding linear speed of 15m / s. After completion, the resulting mixture is spray-dried, and the modified powder is then subjected to pulsed microwave activation: the microwave power is 500W, and the activation is repeated 20 times in a cycle of 5 seconds on and 10 seconds off. This yields a curing agent for fluidized solidified soil (e.g., ...). Figure 1 (As shown).

[0046] Performance testing: The curing agent prepared in this embodiment was mixed with high liquid limit viscous slag (liquid limit ω) taken from a subway shield tunnel section. L =52.3%, Plastic Limit ω P=24.6%, natural moisture content 38.5%) were mixed at a mass ratio of 1:9, and mixing water was added according to the design flow spread of 160±20mm. After stirring evenly, the resulting fluidized solidified soil was poured into a triple mold of 70.7mm×70.7mm×70.7mm. It was cured under standard curing conditions (temperature 20±2℃, relative humidity ≥95%) until the specified age. Then, various performance tests were performed on the obtained specimens: (1) The compressive strength test was conducted in accordance with the "Standard for Test Methods of Physical and Mechanical Properties of Concrete" (GB / T50081-2019); (2) The water penetration test and drying shrinkage test were conducted in accordance with the "Standard for Test Methods of Long-Term Performance and Durability of Concrete" (GB / T50082-2024); (3) The porosity test used the mercury intrusion porosimetry (MIP) method to determine the total pore volume and then convert the porosity. The test results of each performance index are shown in Table 1 below.

[0047] Table 1 3D unconfined compressive strength / MPa 1.62 7d unconfined compressive strength / MPa 2.58 28-day unconfined compressive strength / MPa 4.35 <![CDATA[28d drying shrinkage value / ×10 -6 > 285 <![CDATA[Coefficient of permeability of 28d / cm·s -1 > <![CDATA[3.2×10 -8 ]]> 28d porosity / % 24.7 Example 2 A method for preparing a solidifying agent for high liquid limit viscous slag-based fluidized solidified soil includes the following steps: (1) Mix calcium carbide slag, steel slag powder and sodium metasilicate in a mass ratio of 4:2:1 and stir evenly. Then, activate by microwave irradiation with a power of 900W for 15 minutes. After completion, quench the obtained solid product with liquid nitrogen for 1.5 minutes to obtain a composite alkali source for later use.

[0048] (2) The waste incineration fly ash, sodium dihydrogen phosphate, and water were mixed at a mass ratio of 50:1:10 and heated to 40°C and stirred for 2 hours. After the mixture was heated, the solid product was filtered out and calcined at 300°C for 40 minutes at a heating rate of 10°C / min to obtain pre-stabilized fly ash. The pre-stabilized fly ash was then dispersed and mixed with nano Fe3O4 at a mass ratio of 8:1 and stirred for 25 minutes to obtain modified waste incineration fly ash for later use.

[0049] (3) Mix MgO, ZnO and CaO nanopowders in a mass ratio of 1.5:0.5:0.4 and stir until homogeneous. Then add 12% of the mass of polycarboxylate superplasticizer mother liquor and 2.5% of sodium methylene bisnaphthalene sulfonate to the mixed nanopowder. Add water and stir at a rate of 3000 r / min for 40 min to obtain a nano suspension with a solid content of 50 wt.% for later use.

[0050] (4) Take the following raw materials in the following proportions: 21 parts by weight of fly ash, 37 parts by weight of granulated blast furnace slag powder, 9 parts by weight of solid waste gypsum (phosphogypsum powder), 4.5 parts by weight of slag powder, 15 parts by weight of the composite alkali source of this embodiment, 5 parts by weight of the modified waste incineration fly ash of this embodiment, and 2 parts by weight of the nano suspension of this embodiment. First, mix the fly ash, granulated blast furnace slag powder, solid waste gypsum, slag powder, composite alkali source, and modified waste incineration fly ash evenly. Then, use argon as the working gas to treat the resulting mixed powder with plasma for 10 minutes at a power of 250W. After completion, add the nano suspension and mixing water to form a slurry with a solid content of 55wt.% and grind it for 2 hours at a grinding linear speed of 15m / s. After completion, the resulting mixture is spray-dried, and the modified powder is then subjected to pulsed microwave activation: the microwave power is 600W, and the pulsed microwave activation is repeated 25 times in a manner that is 3 seconds on and 8 seconds off. Upon completion, a curing agent for fluidized solidified soil (such as...) is obtained. Figure 2 (As shown).

[0051] Performance testing: The performance indicators of the fluidized solidified soil formed by the curing agent prepared in this embodiment were tested using the same method as in Example 1 above. The results are shown in Table 2 below.

[0052] Table 2 3D unconfined compressive strength / MPa 1.55 7d unconfined compressive strength / MPa 2.49 28-day unconfined compressive strength / MPa 4.21 <![CDATA[28d drying shrinkage value / × 10 -6 > 298 <![CDATA[Permeability coefficient of 28d / cm·s -1 > <![CDATA[3.8×10 -8 ]]> 28d porosity / % 25.8 Example 3 A method for preparing a solidifying agent for high liquid limit viscous slag-based fluidized solidified soil includes the following steps: (1) Mix calcium carbide slag, steel slag powder and sodium metasilicate in a mass ratio of 6:4:3 and stir evenly. Then, activate by microwave irradiation with a power of 800W for 15 minutes. After completion, quench the obtained solid product with liquid nitrogen for 1 minute to obtain a composite alkali source for later use.

[0053] (2) The waste incineration fly ash, ammonium dihydrogen phosphate, and water were mixed at a mass ratio of 50:2.5:20 and heated to 50°C and stirred for 0.5 hours. After the mixture was heated, the solid product was filtered out and calcined at 400°C for 20 minutes at a heating rate of 10°C / min to obtain pre-stabilized fly ash. The pre-stabilized fly ash was then dispersed and mixed with nano-Fe3O4 at a mass ratio of 12:1 and stirred for 30 minutes to obtain modified waste incineration fly ash for later use.

[0054] (3) Mix MgO, ZnO and CaO nanopowders in a mass ratio of 2.5:1.3:1.5 and stir until homogeneous. Then add 8% of the mass of polycarboxylate superplasticizer mother liquor and 1.5% of sodium β-naphthalenesulfonate to the mixed nanopowder. Add water and stir at a rate of 5000 r / min for 20 min to obtain a nano suspension with a solid content of 30 wt.% for later use.

[0055] (4) Take the following raw materials in the following proportions: 22 parts by weight of fly ash, 40 parts by weight of granulated blast furnace slag powder, 10 parts by weight of solid waste gypsum (fluorogypsum powder), 5 parts by weight of slag powder, 18 parts by weight of the composite alkali source of this embodiment, 6 parts by weight of the modified waste incineration fly ash of this embodiment, and 3 parts by weight of the nano suspension of this embodiment. First, mix the fly ash, granulated blast furnace slag powder, solid waste gypsum, slag powder, composite alkali source, and modified waste incineration fly ash evenly. Then, use argon as the working gas to treat the resulting mixed powder with plasma for 20 minutes at a power of 150W. After completion, add the nano suspension and mixing water to form a slurry with a solid content of 65wt.% and grind it for 2.5 hours at a grinding linear speed of 10m / s. After completion, the resulting mixture is spray-dried, and the modified powder is then subjected to pulsed microwave activation: the microwave power is 400W, and the pulsed microwave activation is repeated 15 times, with each pulse lasting 8 seconds and then stopping for 15 seconds. This process yields a curing agent for fluidized solidified soil (such as...). Figure 3 (As shown).

[0056] Performance testing: The performance indicators of the fluidized solidified soil formed by the curing agent prepared in this embodiment were tested using the same method as in Example 1 above. The results are shown in Table 3 below.

[0057] Table 3 3D unconfined compressive strength / MPa 1.52 7d unconfined compressive strength / MPa 2.45 28-day unconfined compressive strength / MPa 4.18 <![CDATA[28d drying shrinkage value / × 10 -6 > 302 <![CDATA[Permeability coefficient of 28d / cm·s -1 > <![CDATA[4.1×10 -8 ]]> 28d porosity / % 26.0 Example 4 A method for preparing a solidifying agent for high liquid limit viscous slag-based fluidized solidified soil includes the following steps: (1) Mix carbide slag, steel slag powder and sodium metasilicate in a mass ratio of 5:3:2 and stir evenly to obtain a composite alkali source for later use.

[0058] (2) Take the following raw materials in the following proportions: 18 parts by weight of fly ash, 35 parts by weight of granulated blast furnace slag powder, 8 parts by weight of solid waste gypsum (desulfurized gypsum powder), 3 parts by weight of slag powder, 12 parts by weight of the composite alkali source of this embodiment, 4 parts by weight of the modified waste incineration fly ash of the above embodiment 1, and 2.5 parts by weight of the nano suspension of the above embodiment 1. First, mix the fly ash, granulated blast furnace slag powder, solid waste gypsum, slag powder, composite alkali source, and modified waste incineration fly ash evenly. Then, use argon as the working gas to treat the resulting mixed powder with plasma for 15 minutes at a power of 200W. After completion, add the nano suspension and mixing water to form a slurry with a solid content of 60wt.% and grind it for 1.5 hours at a grinding linear speed of 15m / s. After completion, the resulting mixture is spray-dried, and the modified powder is then subjected to pulsed microwave activation: the microwave power is 500W, and the activation is repeated 20 times in a cycle of 5 seconds on and 10 seconds off. This yields a curing agent for fluidized solidified soil (e.g., ...). Figure 4 (As shown).

[0059] Performance testing: The performance indicators of the fluidized solidified soil formed by the curing agent prepared in this embodiment were tested using the same method as in Example 1 above. The results are shown in Table 4 below.

[0060] Table 4 3D unconfined compressive strength / MPa 0.84 7d unconfined compressive strength / MPa 1.42 28-day unconfined compressive strength / MPa 2.65 <![CDATA[28d drying shrinkage value / × 10 -6 > 387 <![CDATA[Permeability coefficient of 28d / cm·s -1 > <![CDATA[8.7×10 -7 ]]> 28d porosity / % 32.4 Example 5 A method for preparing a solidifying agent for high liquid limit viscous slag-based fluidized solidified soil includes the following steps: (1) Take the following proportions of raw materials: 18 parts by weight of fly ash, 35 parts by weight of granulated blast furnace slag powder, 8 parts by weight of solid waste gypsum (desulfurized gypsum powder), 3 parts by weight of slag powder, 12 parts by weight of the composite alkali source of Example 1 above, 4 parts by weight of waste incineration fly ash without any modification treatment, and 2.5 parts by weight of the nano suspension of Example 1 above.

[0061] (2) First, mix the fly ash, granulated blast furnace slag powder, solid waste gypsum, slag powder, composite alkali source, and unmodified waste incineration fly ash. Then, using argon as the working gas, treat the resulting mixed powder with plasma for 15 minutes at a power of 200W. After completion, add the nano suspension and mixing water to form a slurry with a solid content of 60wt.% and grind it for 1.5 hours at a grinding linear speed of 15m / s. After completion, spray dry the resulting mixture and perform pulsed microwave activation on the obtained modified powder: the microwave power is 500W, and the pulsed microwave activation is repeated 20 times according to the method of turning on for 5 seconds and stopping for 10 seconds as one pulsed microwave activation. After completion, the solidifying agent for fluidized solidified soil (such as...) is obtained. Figure 5 (As shown).

[0062] Performance testing: The performance indicators of the fluidized solidified soil formed by the curing agent prepared in this embodiment were tested using the same method as in Example 1 above. The results are shown in Table 5 below.

[0063] Table 5 3D unconfined compressive strength / MPa 0.52 7d unconfined compressive strength / MPa 0.98 28-day unconfined compressive strength / MPa 1.85 <![CDATA[28d drying shrinkage value / × 10 -6 > 468 <![CDATA[Coefficient of permeability of 28d / cm·s -1 > <![CDATA[3.2×10 -6 ]]> 28d porosity / % 36.5 Example 6 A method for preparing a solidifying agent for high liquid limit viscous slag-based fluidized solidified soil includes the following steps: (1) Mix MgO, ZnO and CaO nanopowders in a mass ratio of 1.5:0.5:0.4 and stir until homogeneous. Then add 2.5% sodium methylene bisnaphthalene sulfonate to the mixed nanopowders. Add water and stir at 3000 r / min for 40 min to obtain a nano suspension with a solid content of 50 wt.% for later use.

[0064] (2) Take the following raw materials in the following proportions: 21 parts by weight of fly ash, 37 parts by weight of granulated blast furnace slag powder, 9 parts by weight of solid waste gypsum (phosphogypsum powder), 4.5 parts by weight of slag powder, 15 parts by weight of the composite alkali source of Example 2 above, 5 parts by weight of the modified waste incineration fly ash of Example 2 above, and 2 parts by weight of the nano suspension of this example. First, mix the fly ash, granulated blast furnace slag powder, solid waste gypsum, slag powder, composite alkali source, and modified waste incineration fly ash evenly. Then, use argon as the working gas to treat the resulting mixed powder with plasma for 10 minutes at a power of 250W. After completion, add the nano suspension and mixing water to form a slurry with a solid content of 55wt.% and grind it for 2 hours at a grinding linear speed of 15m / s. After completion, the resulting mixture is spray-dried, and the modified powder is then subjected to pulsed microwave activation: the microwave power is 600W, and the pulsed microwave activation is repeated 25 times in a manner that is 3 seconds on and 8 seconds off. Upon completion, a curing agent for fluidized solidified soil (such as...) is obtained. Figure 6 (As shown).

[0065] Performance testing: The performance indicators of the fluidized solidified soil formed by the curing agent prepared in this embodiment were tested using the same method as in Example 1 above. The results are shown in Table 6 below.

[0066] Table 6 3D unconfined compressive strength / MPa 0.96 7d unconfined compressive strength / MPa 1.67 28-day unconfined compressive strength / MPa 2.92 <![CDATA[28d drying shrinkage value / × 10 -6 > 358 <![CDATA[Permeability coefficient of 28d / cm·s -1 > <![CDATA[1.5×10 -7 ]]> 28d porosity / % 29.8 Example 7 A method for preparing a solidifying agent for high liquid limit viscous slag-based fluidized solidified soil includes the following steps: (1) Mix MgO, ZnO and CaO nanopowders in a mass ratio of 1.5:0.5:0.4 and stir until homogeneous. Then add 12% of the mass of polycarboxylate superplasticizer mother liquor to the mixed nanopowder, add water and stir and disperse at a rate of 3000 r / min for 40 min to obtain a nano suspension with a solid content of 50 wt.% for later use.

[0067] (2) Take the following raw materials in the following proportions: 21 parts by weight of fly ash, 37 parts by weight of granulated blast furnace slag powder, 9 parts by weight of solid waste gypsum (phosphogypsum powder), 4.5 parts by weight of slag powder, 15 parts by weight of the composite alkali source of Example 2 above, 5 parts by weight of the modified waste incineration fly ash of Example 2 above, and 2 parts by weight of the nano suspension of this example. First, mix the fly ash, granulated blast furnace slag powder, solid waste gypsum, slag powder, composite alkali source, and modified waste incineration fly ash evenly. Then, use argon as the working gas to treat the resulting mixed powder with plasma for 10 minutes at a power of 250W. After completion, add the nano suspension and mixing water to form a slurry with a solid content of 55wt.% and grind it for 2 hours at a grinding linear speed of 15m / s. After completion, the resulting mixture is spray-dried, and the modified powder is then subjected to pulsed microwave activation: the microwave power is 600W, and the pulsed microwave activation is repeated 25 times in a manner that is 3 seconds on and 8 seconds off. Upon completion, a curing agent for fluidized solidified soil (such as...) is obtained. Figure 7 (As shown).

[0068] Performance testing: The performance indicators of the fluidized solidified soil formed by the curing agent prepared in this embodiment were tested using the same method as in Example 1 above. The results are shown in Table 7 below.

[0069] Table 7 3D unconfined compressive strength / MPa 1.12 7d unconfined compressive strength / MPa 1.94 28-day unconfined compressive strength / MPa 3.28 <![CDATA[28d drying shrinkage value / × 10 -6 > 335 <![CDATA[Permeability coefficient of 28d / cm·s -1 > <![CDATA[8.6×10 -8 ]]> 28d porosity / % 28.2 Example 8 A method for preparing a solidifying agent for high liquid limit viscous slag-based fluidized solidified soil includes the following steps: (1) Take the following proportions of raw materials: 22 parts by weight of fly ash, 40 parts by weight of granulated blast furnace slag powder, 10 parts by weight of solid waste gypsum (fluorogypsum powder), 5 parts by weight of slag powder, 18 parts by weight of the composite alkali source of the above Example 3, 6 parts by weight of the modified waste incineration fly ash of the above Example 3, and 3 parts by weight of the nano suspension of the above Example 3.

[0070] (2) First, mix the fly ash, granulated blast furnace slag powder, solid waste gypsum, slag powder, composite alkali source, and modified waste incineration fly ash evenly. Then, using argon as the working gas, treat the resulting mixed powder with plasma for 20 minutes at a power of 150W. After completion, add the nano-suspension and mixing water to form a slurry with a solid content of 65wt.% and grind it for 2.5 hours at a grinding linear speed of 10m / s. After completion, spray dry the resulting mixture to obtain a solidifying agent for fluidized solidified soil (such as...). Figure 8 (As shown).

[0071] Performance testing: The performance indicators of the fluidized solidified soil formed by the curing agent prepared in this embodiment were tested using the same method as in Example 1 above. The results are shown in Table 8 below.

[0072] Table 8 3D unconfined compressive strength / MPa 1.01 7d unconfined compressive strength / MPa 1.76 28-day unconfined compressive strength / MPa 3.06 <![CDATA[28d drying shrinkage value / × 10 -6 > 368 <![CDATA[Permeability coefficient of 28d / cm·s -1 > <![CDATA[1.9×10 -7 ]]> 28d porosity / % 30.5 Example 9 A method for preparing a solidifying agent for high liquid limit viscous slag-based fluidized solidified soil includes the following steps: (1) Take the following proportions of raw materials: 22 parts by weight of fly ash, 40 parts by weight of granulated blast furnace slag powder, 10 parts by weight of solid waste gypsum (fluorogypsum powder), 5 parts by weight of slag powder, 18 parts by weight of the composite alkali source of the above Example 3, 6 parts by weight of the modified waste incineration fly ash of the above Example 3, and 3 parts by weight of the nano suspension of the above Example 3.

[0073] (2) First, mix the fly ash, granulated blast furnace slag powder, solid waste gypsum, slag powder, composite alkali source, and modified waste incineration fly ash evenly. Then, add the nano-suspension and mixing water to form a slurry with a solid content of 65 wt.% and grind it for 2.5 hours at a grinding linear speed of 10 m / s. After completion, spray dry the resulting mixture and perform pulsed microwave activation on the obtained modified powder: the microwave power is 400W, and the pulsed microwave activation is repeated 15 times according to the method of turning on for 8 seconds and stopping for 15 seconds as one pulsed microwave activation. After completion, the solidifying agent for fluidized solidified soil (such as...) is obtained. Figure 9 (As shown).

[0074] Performance testing: The performance indicators of the fluidized solidified soil formed by the curing agent prepared in this embodiment were tested using the same method as in Example 1 above. The results are shown in Table 9 below.

[0075] Table 9 3D unconfined compressive strength / MPa 1.18 7d unconfined compressive strength / MPa 1.92 28-day unconfined compressive strength / MPa 3.35 <![CDATA[28d drying shrinkage value / × 10 -6 > 346 <![CDATA[Permeability coefficient of 28d / cm·s -1 > <![CDATA[1.6×10 -7 ]]> 28d porosity / % 29.6 Example 10 A method for preparing a solidifying agent for high liquid limit viscous slag-based fluidized solidified soil includes the following steps: (1) Mix the waste incineration fly ash, sodium dihydrogen phosphate and water in a mass ratio of 50:1:10 and heat to 40°C and stir for 2 hours. After completion, filter out the solid product and heat it to 300°C for 40 minutes at a heating rate of 10°C / min to obtain modified waste incineration fly ash for later use.

[0076] (2) Take the following raw materials in the following proportions: 21 parts by weight of fly ash, 37 parts by weight of granulated blast furnace slag powder, 9 parts by weight of solid waste gypsum (phosphogypsum powder), 4.5 parts by weight of slag powder, 15 parts by weight of the composite alkali source of Example 2 above, 5 parts by weight of the modified waste incineration fly ash of this example, and 2 parts by weight of the nano suspension of Example 2 above. First, mix the fly ash, granulated blast furnace slag powder, solid waste gypsum, slag powder, composite alkali source, and modified waste incineration fly ash evenly. Then, use argon as the working gas to treat the resulting mixed powder with plasma for 10 minutes at a power of 250W. After completion, add the nano suspension and mixing water to form a slurry with a solid content of 55wt.% and grind it for 2 hours at a grinding linear speed of 15m / s. After completion, the resulting mixture is spray-dried, and the modified powder is then subjected to pulsed microwave activation: the microwave power is 600W, and the pulsed microwave activation is repeated 25 times in a manner that is 3 seconds on and 8 seconds off. Upon completion, a curing agent for fluidized solidified soil (such as...) is obtained. Figure 10 (As shown).

[0077] Performance testing: The performance indicators of the fluidized solidified soil formed by the curing agent prepared in this embodiment were tested using the same method as in Example 1 above. The results are shown in Table 10 below.

[0078] Table 10 3D unconfined compressive strength / MPa 1.20 7d unconfined compressive strength / MPa 1.98 28-day unconfined compressive strength / MPa 3.42 <![CDATA[28d drying shrinkage value / × 10 -6 > 340 <![CDATA[Permeability coefficient of 28d / cm·s -1 > <![CDATA[1.2×10 -7 ]]> 28d porosity / % 29.1 The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a solidifying agent for high liquid limit viscous slag-based fluidized solidified soil, characterized in that, Includes the following steps: (1) After mixing carbide slag, steel slag powder and sodium metasilicate, microwave irradiation activation was carried out, followed by quenching treatment to obtain a composite alkali source for later use. (2) After mixing the waste incineration fly ash, dihydrogen phosphate and water, stir the mixture under heating conditions. After the mixture is completed, separate the solid product and calcine it to obtain pre-stabilized fly ash. Then mix the pre-stabilized fly ash with nano Fe3O4 to obtain modified waste incineration fly ash for later use. (3) Mix MgO, ZnO and CaO nanopowders, add polycarboxylate superplasticizer mother liquor and naphthalene sulfonate, then add water for dispersion treatment to obtain nano suspension for later use; (4) Take the following components in the following proportions: 18-22 parts by weight of fly ash, 35-40 parts by weight of blast furnace slag, 8-10 parts by weight of solid waste gypsum, 3-5 parts by weight of slag powder, 12-18 parts by weight of the composite alkali source, 4-6 parts by weight of the modified waste incineration fly ash, and 2-3 parts by weight of nano suspension; mix the fly ash, blast furnace slag, solid waste gypsum, slag powder, composite alkali source, and modified waste incineration fly ash evenly, then perform surface modification of the obtained mixed powder by plasma treatment, after which the nano suspension and mixing water are added to form a slurry for grinding treatment, then spray drying, and pulse microwave activation of the obtained modified powder to obtain the curing agent.

2. The method for preparing a solidifying agent for high liquid limit viscous slag-based fluidized solidified soil according to claim 1, characterized in that, In step (1), the mass ratio of carbide slag, steel slag powder, and sodium metasilicate is 4~6:2~4:1~3.

3. The method for preparing a solidifying agent for high liquid limit viscous slag-based fluidized solidified soil according to claim 1, characterized in that, In step (1), the microwave irradiation activation time is 10-15 min, and the microwave power is 800-1000W; Alternatively, in step (1), the quenching process is carried out in liquid nitrogen; Alternatively, in step (1), the quenching treatment time is 1~2 minutes.

4. The method for preparing a solidifying agent for high liquid limit viscous slag-based fluidized solidified soil according to claim 1, characterized in that, In step (2), the mass ratio of the waste incineration fly ash, dihydrogen phosphate, and water is 50:1~2.5:10~20.

5. The method for preparing a solidifying agent for high liquid limit viscous slag-based fluidized solidified soil according to claim 1, characterized in that, In step (2), the dihydrogen phosphate salt includes at least one of sodium dihydrogen phosphate, potassium dihydrogen phosphate, and ammonium dihydrogen phosphate; Alternatively, in step (2), the heating temperature is 40~50℃, and the stirring time is 0.5~2 hours; Alternatively, in step (2), the roasting temperature is 300~400℃ and the time is 20~40min.

6. The method for preparing a solidifying agent for high liquid limit viscous slag-based fluidized solidified soil according to claim 1, characterized in that, In step (2), the mass ratio of the pre-stabilized fly ash to nano Fe3O4 is 8~12:

1.

7. The method for preparing a solidifying agent for high liquid limit viscous slag-based fluidized solidified soil according to claim 1, characterized in that, In step (3), the mass ratio of MgO, ZnO, and CaO is 1.5~2.5:0.5~1.3:0.4~1.5; Alternatively, in step (3), the naphthalene sulfonate includes at least one of sodium naphthalene sulfonate, sodium methylene bisnaphthalene sulfonate, and naphthalene sulfonate formaldehyde condensate.

8. The method for preparing a solidifying agent for high liquid limit viscous slag-based fluidized solidified soil according to claim 1, characterized in that, In step (3), the polycarboxylate superplasticizer mother liquor and naphthalene sulfonate are 8-12% and 1.5-2.5% of the total mass of MgO, ZnO, and CaO nanopowder, respectively; Alternatively, in step (3), water is added according to the solid content of the nano suspension being 30~50 wt.%; Alternatively, in step (3), the stirring rate of the dispersion treatment is 3000~5000 r / min, and the time is 20~40 min.

9. The method for preparing a solidifying agent for high liquid limit viscous slag-based fluidized solidified soil according to any one of claims 1-8, characterized in that, In step (4), the plasma treatment time is 10-20 min and the power is 150-250 W; Alternatively, in step (4), the working gas for the plasma treatment includes argon. Alternatively, in step (4), the solid content of the slurry is 55~65 wt.%; Alternatively, in step (4), the grinding process takes 1.5 to 2.5 hours and the linear velocity is 10 to 15 m / s.

10. The method for preparing a solidifying agent for high liquid limit viscous slag-based fluidized solidified soil according to any one of claims 1-8, characterized in that, In step (4), the power of the pulsed microwave activation is 400~600W, the on-time is 3~8s, the off-time is 8~15s, and the number of cycles is 15~25.

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