Premixed high-strength flow-state solidified soil and preparation method thereof

Abstract

The invention relates to the technical field of building materials, and particularly discloses premixed high-strength flow-state solidified soil and a preparation method thereof. Comprising the following components: 15 to 24 parts of cement, 20 to 35 parts of fly ash, 30 to 42 parts of slag, 5 to 10 parts of an epoxy resin-based fiber reinforced composite material, 0.5 to 1 part of a dispersant, 1 to 2 parts of a water reducing agent, 0.3 to 0.5 part of an auxiliary agent and 100 parts of deionized water. An epoxy resin-based fiber reinforced composite material, a dispersing agent, a water reducing agent and deionized water are added and mixed, a staged stirring and layered pouring technology is adopted, it is ensured that raw materials are evenly distributed and the structure is densified, the premixed flow-state solidified soil is prepared from industrial solid waste, the cost can be effectively reduced, energy consumption and CO2 emission can be reduced, and the environment-friendly effect is achieved. The composite material has the characteristics of high strength and good compatibility, is convenient to transport, and conforms to the development direction of environmental protection and sustainability.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and particularly to a premixed high-strength flowable solidified soil and a preparation method thereof. Background Art

[0002] Premixed flowable solidified soil is a new type of environmentally friendly building material, mainly using waste soil or foundation soil as the base material, and forming a highly fluid multi-functional building material through the addition of a curing agent and water. As a new type of backfill material, premixed flowable solidified soil has the characteristics of rich raw material sources, self-leveling, self-compacting, and rapid curing, and is convenient for construction, low in cost, and green and environmentally friendly. It can be used to replace traditional fillers in scenarios such as subgrade reinforcement and engineering backfill, solving problems such as large demand for natural resources, serious dust pollution, and insufficient compaction degree in narrow spaces by traditional fillers.

[0003] Chinese patent application with publication number CN119528500A discloses a solid waste-based premixed flowable solidified soil and a preparation method thereof. The solid waste-based premixed flowable solidified soil includes soil, water, and a curing agent. The curing agent includes 20-40 parts of fly ash, 30-47 parts of slag, 6-18 parts of silica fume, 10-15 parts of sea sludge, 1-3 parts of water reducing agent, 1-3 parts of sodium hydroxide, 1-3 parts of calcium sulfoaluminate, 3-10 parts of fiber reinforcing material, and 1-3 parts of phosphate. This premixed flowable solidified soil has excellent crack resistance and can avoid problems such as stress concentration and excessive shrinkage. However, this premixed flowable solidified soil has a certain corrosiveness to equipment, the treatment of sea sludge is complex, the cost is relatively high, and the early strength is insufficient, the raw material dispersibility is poor, and the anti-seepage ability is poor. Chinese patent application with publication number CN118993685A discloses a flowable solidified soil and a preparation method and application construction method thereof. The flowable solidified soil includes weathered rock soil and / or bored slag, and a curing agent. The curing agent includes cement, slag micro powder, fly ash, silica powder, water reducing agent, and water glass. Using weathered rock soil or on-site bored slag as the main material of the flowable solidified soil, and curing it through cement, slag micro powder, and fly ash; using slag to replace part of the cement can reduce the carbon emission, and can largely consume the engineering slag generated in urban construction. The strength of the flowable solidified soil after pouring is greater than that of concrete. However, this flowable solidified soil has poor durability, high cost, and the dispersibility among raw materials is average, affecting the fluidity and strength uniformity of the flowable solidified soil.

[0004] Therefore, it is an urgent problem to be solved to develop a premixed flowable solidified soil with high strength, good durability and easy construction. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a premixed high-strength flowable solidified soil and a preparation method thereof, solving the problem of general strength of premixed flowable solidified soil.

[0006] To achieve the above object, the present invention discloses a premixed high-strength fluidized solidified soil, which comprises the following components by mass: 15-24 parts of cement, 20-35 parts of fly ash, 30-42 parts of slag, 5-10 parts of epoxy resin-based fiber reinforced composite material, 0.5-1 part of dispersant, 1-2 parts of water reducing agent, 0.3-0.5 part of auxiliary agent, and 100 parts of deionized water; The preparation method of the epoxy resin-based fiber reinforced composite material comprises the following steps: S1. Ultrasonically disperse nano calcium carbonate in acetone. After uniform dispersion, add acetic acid solution to adjust the pH to 5-5.5, then add γ-glycidyl ether oxypropyl trimethoxysilane, heat, stir and mix to react. After the reaction is completed, filter while it is hot, wash with acetone, and vacuum dry at 60°C for 12 h to obtain epoxy modified calcium carbonate; S2. Mix itaconic acid, acrylic acid and deionized water uniformly, dropwise add sulfuric acid to adjust the pH to 1.5-2. In a nitrogen atmosphere, heat up, add 2-acrylamido-2-methylpropanesulfonic acid, polypropylene fiber, dodecyl acrylate and initiator, stir and mix to react. After the reaction is completed, filter with suction, wash with deionized water and absolute ethanol, and dry at 60°C for 12 h to obtain polypropylene fiber reinforced material; S3. Mix epoxy resin and epoxy modified calcium carbonate uniformly, then add polypropylene fiber reinforced material, methyltetrahydrophthalic anhydride, 2,4,6-tris(dimethylaminomethyl)phenol, stir and mix to react. After the reaction is completed, carry out vacuum degassing to obtain epoxy resin-based fiber reinforced composite material.

[0007] Preferably, the cement is composed of ordinary portland cement and sulfoaluminate cement with a mass ratio of 5:1.

[0008] Preferably, the dispersant is hydroxypropyl methyl cellulose.

[0009] Preferably, the water reducing agent is a polycarboxylate water reducing agent.

[0010] Preferably, the auxiliary agent is composed of a retarder and an antifoaming agent with a mass ratio of 1:3, wherein the retarder is sodium pyrophosphate and the antifoaming agent is a polyether modified antifoaming agent.

[0011] Preferably, the mass ratio of nano calcium carbonate, acetone and γ-glycidyl ether oxypropyl trimethoxysilane in S1 is 100:1500-1800:20-30.

[0012] Preferably, the reaction temperature in S1 is 80°C-85°C and the reaction time is 3 h-5 h.

[0013] Preferably, the mass ratio of itaconic acid, acrylic acid, deionized water, 2-acrylamido-2-methylpropanesulfonic acid, polypropylene fiber, dodecyl acrylate, and initiator in S2 is 20-30:10-15:3000-4000:42-60:100:7-10:2.5-4.

[0014] Preferably, the reaction temperature in S2 is 75°C - 85°C, and the reaction time is 2h - 3h.

[0015] Preferably, the initiator in S2 includes any one of azobisisobutyronitrile, ammonium persulfate, and potassium persulfate.

[0016] Preferably, the mass ratio of epoxy resin, epoxy modified calcium carbonate, polypropylene fiber reinforced material, methyltetrahydrophthalic anhydride, and 2,4,6-tris(dimethylaminomethyl)phenol in S3 is 100:3-7:5-10:60-70:1-2.

[0017] Preferably, the reaction temperature in S3 is 60°C - 70°C, and the reaction time is 2h - 3h.

[0018] Preferably, the epoxy resin in S3 is epoxy resin E51.

[0019] A preparation method of the pre-mixed high-strength flowing solidified soil as described above includes the following steps: Dry cement, fly ash, and slag respectively, then grind the dried fly ash and dried slag. After the treatment is completed, stir in a mixer at a stirring rate of 300r / min - 400r / min for 5min - 8min. After mixing evenly, obtain a mixture, then add a dispersant, a water reducer, and an auxiliary agent, stir and mix for 3min - 5min, then add an epoxy resin-based fiber reinforced composite material, stir and mix at a stirring rate of 200r / min - 250r / min for 5min - 8min, add deionized water, stir and mix at a stirring rate of 500r / min - 600r / min for 4min - 6min, and after casting, vibrating, covering, and demolding, obtain the pre-mixed high-strength flowing solidified soil.

[0020] Preferably, during the drying treatment of the cement, fly ash, and slag, dry until the water content ≤ 1%. After grinding, the specific surface area of fly ash ≥ 400m 2 / kg, and the specific surface area of slag ≥ 600m 2 / kg, and the casting is carried out in layers.

[0021] Compared with the prior art, the beneficial effects of the present invention are: In the present invention, γ-glycidoxypropyltrimethoxysilane is used to modify nano calcium carbonate, introducing epoxy groups on the surface of nano calcium carbonate to obtain epoxy-modified calcium carbonate, effectively avoiding the agglomeration of nano calcium carbonate. Using itaconic acid, acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, polypropylene fiber, and dodecyl acrylate as raw materials, polymerization occurs under the action of an initiator to obtain a polypropylene fiber-reinforced material. A large number of carboxyl groups, sulfonic acid groups, and hydrophobic segments are introduced onto the polypropylene fiber-reinforced material, which can effectively improve the dispersibility and prevent agglomeration. The sulfonic acid group can improve the hydrophilicity and suspension stability of the matrix, effectively prevent the sedimentation and stratification of the filler, and can also chelate with metal ions Ca 2+ to inhibit the deterioration of the cement matrix caused by ion erosion. The introduced long-chain alkyl hydrophobic segments can reduce the water absorption rate of the solidified soil, enhancing the water resistance and freeze-thaw resistance. The epoxy groups on the epoxy resin, epoxy-modified calcium carbonate, and polypropylene fiber-reinforced material react with methyltetrahydrophthalic anhydride to obtain an epoxy resin-based fiber-reinforced composite material, effectively enhancing the chemical bonding between the polypropylene fiber and the epoxy resin, improving the fiber-resin interfacial bonding force, and simultaneously enhancing the mechanical anchoring with the cement matrix. Mixing cement, fly ash, slag, epoxy resin-based fiber-reinforced composite material, dispersant, water reducer, additives, and deionized water gives a ready-mixed high-strength flowing solidified soil.

[0022] As mineral admixtures in the flowing solidified soil, fly ash and slag can effectively reduce costs, energy consumption, and CO2 emissions, conforming to the development direction of environmental protection and sustainability. The active alumina, silicate, and other components contained in fly ash can form various hardening products, improving the compressive strength and toughness of the matrix. At the same time, they fill between the aggregates to make the structure more compact, affecting the setting time and hydration reaction of the cement, increasing the late strength of the solidified soil, inhibiting the alkali-aggregate reaction, and improving the durability. As a kind of solid waste, slag contains abundant silicon and aluminum elements. The calcium-aluminum minerals and expanded silicate substances contained in slag can promote the reaction of cement in the matrix to generate hardening products, increasing the strength, durability, and impermeability of the matrix.

[0023] Nano calcium carbonate has the characteristics of easy availability of raw materials, low price, and harmlessness to organisms, and is a filler with excellent mechanical properties. Polypropylene fibers have high strength and good toughness, which can improve the crack resistance, bonding force, and durability of the solidified soil, effectively prevent the generation of cracks, resist external impacts and fatigue effects, and improve the durability of the matrix.

[0024] The dispersant hydroxypropyl methylcellulose can stabilize the fiber dispersion through steric hindrance effects and prevent agglomeration. The polycarboxylate water reducer can adsorb on the surface of the gelling particles, release free water, reduce the viscosity, improve the fluidity, reduce the water-cement ratio, and cooperate with the layered pouring process to ensure the fluidity and self-compactness, suitable for the construction of complex structures.

[0025] The nano-calcium carbonate added in the present invention can effectively fill the pores of the cement matrix, reduce permeability, and improve the interfacial bonding. The polypropylene fiber can serve as a skeleton material, enhancing the crack resistance through fiber bridging and stress dispersion. By modifying the polypropylene fiber, the introduced sulfonic acid groups and carboxyl groups hydrophilize the surface of the hydrophobic polypropylene fiber, effectively enhancing the hydrogen bond binding with the cement hydration products and improving the compatibility. The epoxy resin has a high cross-linking density and corrosion resistance, and can wrap the particles of inorganic cementitious materials such as cement and fly ash, significantly enhancing the compressive strength and flexural strength of the solidified soil. The nano-calcium carbonate can improve the compressive strength of the matrix, and the polypropylene fiber and epoxy resin can improve the toughness of the matrix. The three act synergistically to form a three-dimensional network, which can effectively inhibit the propagation of microcracks, improve the crack resistance of the matrix, form a bridging effect with the solidified soil matrix, inhibit the propagation of microcracks, and improve the strength and durability of the solidified soil.

[0026] In the present invention, cement, fly ash, and slag are used as inorganic solidifying agents, and a mixture is obtained by mixing. This mixture serves as a cementitious system. Epoxy resin-based fiber-reinforced composite materials, dispersants, water reducers, and deionized water are added thereto and mixed. The staged stirring and layered pouring process is adopted. The organic solidifying agent and the inorganic solidifying agent act synergistically to ensure uniform distribution of the raw materials and densification of the structure, with good homogeneity, and pre-mixed high-strength flowing solidified soil is obtained. In the pre-mixed high-strength flowing solidified soil, a large amount of industrial solid waste fly ash and slag are added to replace cement, reducing the amount of cement used, which can reduce CO2 emissions and raw material costs, is green and environmentally friendly, and meets the requirements of sustainable development. The added cement is a compound of ordinary Portland cement and sulfoaluminate cement. The sulfoaluminate cement has the characteristics of rapid hardening at low temperature, which can effectively shorten the demolding period and improve the construction efficiency. At the same time, it can quickly generate ettringite and C-S-H gel to provide early strength. The tricalcium silicate contained in the ordinary Portland cement can dominate the later hydration and generate C-S-H gel and Ca(OH)2. By drying and grinding the fly ash and slag, the reaction activity of the materials can be significantly improved. The high activity of the cement combined with the slag and fly ash combines the early strength and the later durability. The slag and fly ash undergo a pozzolanic reaction under the excitation of Ca(OH)2 to generate secondary C-S-H gel, filling the pores of the matrix and improving the density. The pre-mixed flowing solidified soil made from industrial solid waste has the characteristics of high strength, good compatibility, is easy to transport, has low cost, and is green and environmentally friendly. Specific Embodiments

[0027] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below. Preferred embodiments of the present invention are given below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure content of the present invention more thorough and comprehensive.

[0028] Example 1

[0029] A preparation method of premixed high-strength fluidized solidified soil, comprising the following steps: By mass, weigh 15 parts of cement, 20 parts of fly ash, 30 parts of slag, 5 parts of epoxy resin-based fiber-reinforced composite material, 0.5 part of dispersant hydroxypropyl methylcellulose, 1 part of polycarboxylate water reducer, 0.3 part of auxiliary agent, and 100 parts of deionized water. The auxiliary agent is composed of retarder sodium pyrophosphate and defoamer polyether-modified defoamer with a mass ratio of 1:3. Dry the cement, fly ash, and slag respectively until the water content ≤ 1%. Then grind the dried fly ash and dried slag. After grinding, the specific surface area of fly ash ≥ 400 m 2 / kg, and the specific surface area of slag ≥ 600 m 2 / kg. After the treatment is completed, stir in a mixer at a stirring rate of 300 r / min for 8 min. After mixing evenly, a mixture is obtained. Then add the dispersant, water reducer, and auxiliary agent, and stir and mix for 3 min. Then add the epoxy resin-based fiber-reinforced composite material and stir and mix at a stirring rate of 200 r / min for 8 min. Add deionized water and stir and mix at a stirring rate of 500 r / min for 6 min. Adopt layered pouring, and after pouring, forming, vibrating, covering, and demolding, premixed high-strength fluidized solidified soil is obtained.

[0030] The preparation method of the epoxy resin-based fiber-reinforced composite material includes the following steps: S1. Ultrasonically disperse nano calcium carbonate in acetone. After dispersing evenly, add acetic acid solution to adjust the pH to 5, and then add γ-glycidyl ether oxypropyltrimethoxysilane. The mass ratio of nano calcium carbonate, acetone, and γ-glycidyl ether oxypropyltrimethoxysilane is 100:1500:20. Heat, stir and mix, react at 80 °C for 5 h. After the reaction is completed, filter while it is hot, wash with acetone, and vacuum dry at 60 °C for 12 h to obtain epoxy-modified calcium carbonate; S2. Mix itaconic acid, acrylic acid and deionized water evenly, add sulfuric acid dropwise to adjust the pH to 1.5. Under a nitrogen atmosphere, heat up, and add 2-acrylamido-2-methylpropanesulfonic acid, polypropylene fiber, dodecyl acrylate and initiator azobisisobutyronitrile. The mass ratio of itaconic acid, acrylic acid, deionized water, 2-acrylamido-2-methylpropanesulfonic acid, polypropylene fiber, dodecyl acrylate and initiator azobisisobutyronitrile is 20:10:3000:42:100:7:2.5. Stir and mix to make a reaction occur. The reaction temperature is 75 °C and the reaction time is 3 h. After the reaction is completed, perform suction filtration, wash with deionized water and absolute ethanol, and dry at 60 °C for 12 h to obtain a polypropylene fiber reinforced material; S3. Mix epoxy resin E51 and epoxy modified calcium carbonate evenly, then add polypropylene fiber reinforced material, methyltetrahydrophthalic anhydride, 2,4,6-tris(dimethylaminomethyl)phenol. The mass ratio of epoxy resin E51, epoxy modified calcium carbonate, polypropylene fiber reinforced material, methyltetrahydrophthalic anhydride, 2,4,6-tris(dimethylaminomethyl)phenol is 100:3:5:60:1. Stir and mix, and react at 60 °C. The reaction time is 3 h. After the reaction is completed, perform vacuum degassing to obtain an epoxy resin-based fiber reinforced composite material.

[0031] Example 2

[0032] A preparation method of premixed high-strength flowing solidified soil includes the following steps: By mass, weigh 18 parts of cement, 28 parts of fly ash, 35 parts of slag, 7 parts of epoxy resin-based fiber reinforced composite material, 0.6 part of dispersant hydroxypropyl methylcellulose, 1.4 parts of polycarboxylate water reducer, 0.4 part of additive, and 100 parts of deionized water. The additive consists of retarder sodium pyrophosphate and defoamer polyether modified defoamer with a mass ratio of 1:3. Perform drying treatment on cement, fly ash, and slag respectively until the water content ≤ 1%. Then perform grinding treatment on the dried fly ash and dried slag. After the grinding treatment, the specific surface area of fly ash ≥ 400 m 2 / kg, the specific surface area of slag ≥ 600 m 2 / kg. After the treatment is completed, perform stirring in a mixer at a stirring rate of 350 r / min for 6 min to obtain a mixture. Then add the dispersant, water reducer and additive, stir and mix for 4 min, then add the epoxy resin-based fiber reinforced composite material, stir and mix at a stirring rate of 220 r / min for 6 min, add deionized water, stir and mix at a stirring rate of 520 r / min for 5 min, and adopt layered pouring. After pouring, forming, vibrating, covering, and demolding, obtain the premixed high-strength flowing solidified soil.

[0033] The preparation method of the epoxy resin-based fiber reinforced composite material comprises the following steps: S1. Ultrasonically disperse nano calcium carbonate in acetone. After uniform dispersion, add acetic acid solution to adjust the pH to 5.2, and then add γ-glycidoxypropyltrimethoxysilane. The mass ratio of nano calcium carbonate, acetone, and γ-glycidoxypropyltrimethoxysilane is 100:1600:24. Heat and stir to mix, react at 82 °C for 4 h. After the reaction, filter while it is hot, wash with acetone, and dry in vacuum at 60 °C for 12 h to obtain epoxy-modified calcium carbonate; S2. Mix itaconic acid, acrylic acid, and deionized water evenly, add sulfuric acid dropwise to adjust the pH to 1.8. In a nitrogen atmosphere, raise the temperature, and add 2-acrylamido-2-methylpropanesulfonic acid, polypropylene fiber, dodecyl acrylate, and initiator azobisisobutyronitrile. The mass ratio of itaconic acid, acrylic acid, deionized water, 2-acrylamido-2-methylpropanesulfonic acid, polypropylene fiber, dodecyl acrylate, and initiator azobisisobutyronitrile is 24:12:3500:48:100:8:3. Stir and mix to react at a reaction temperature of 80 °C for 2.5 h. After the reaction, filter by suction, wash with deionized water and absolute ethanol, and dry at 60 °C for 12 h to obtain polypropylene fiber reinforced material; S3. Mix epoxy resin E51 and epoxy-modified calcium carbonate evenly, and then add polypropylene fiber reinforced material, methyltetrahydrophthalic anhydride, and 2,4,6-tris(dimethylaminomethyl)phenol. The mass ratio of epoxy resin E51, epoxy-modified calcium carbonate, polypropylene fiber reinforced material, methyltetrahydrophthalic anhydride, and 2,4,6-tris(dimethylaminomethyl)phenol is 100:5:7:64:1.4. Stir and mix, react at 65 °C for 2.5 h. After the reaction, remove bubbles in vacuum to obtain epoxy resin-based fiber reinforced composite material.

[0034] Example 3

[0035] A preparation method of premixed high-strength flowing solidified soil comprises the following steps: By mass, weigh 18 parts of cement, 28 parts of fly ash, 35 parts of slag, 7 parts of epoxy resin-based fiber reinforced composite material, 0.6 part of dispersant hydroxypropyl methylcellulose, 1.4 parts of polycarboxylate water reducer, 0.4 part of additive, and 100 parts of deionized water. The additive consists of retarder sodium pyrophosphate and defoamer polyether-modified defoamer with a mass ratio of 1:3. Respectively conduct drying treatment on cement, fly ash, and slag until the water content ≤ 1%. Then conduct grinding treatment on the dried fly ash and dried slag. After the grinding treatment, the specific surface area of fly ash ≥ 400 m 2 / kg, and the specific surface area of slag ≥ 600 m 2 / kg. After the treatment is completed, it is stirred in a blender at a stirring rate of 350 r / min for 6 min. After being evenly mixed, a mixed material is obtained. Then, a dispersant, a water reducer and an auxiliary agent are added, and stirred and mixed for 4 min. Then, an epoxy resin-based fiber-reinforced composite material is added and stirred and mixed at a stirring rate of 220 r / min for 6 min. Deionized water is added and stirred and mixed at a stirring rate of 520 r / min for 5 min. Stratified casting is adopted, and after casting, vibrating, covering and demolding, a premixed high-strength flowing solidified soil is obtained.

[0036] The preparation method of the epoxy resin-based fiber-reinforced composite material includes the following steps: S1. Ultrasonically disperse nano calcium carbonate in acetone. After being evenly dispersed, add acetic acid solution to adjust the pH to 5.2, and then add γ-glycidoxypropyltrimethoxysilane. The mass ratio of nano calcium carbonate, acetone and γ-glycidoxypropyltrimethoxysilane is 100:1600:28. Heat, stir and mix, react at 82 °C for 4 h. After the reaction is completed, filter while it is hot, wash with acetone, and vacuum dry at 60 °C for 12 h to obtain epoxy-modified calcium carbonate; S2. Mix itaconic acid, acrylic acid and deionized water evenly, dropwise add sulfuric acid to adjust the pH to 1.8. In a nitrogen atmosphere, heat up, and add 2-acrylamido-2-methylpropanesulfonic acid, polypropylene fiber, dodecyl acrylate and initiator azodiisobutyronitrile. The mass ratio of itaconic acid, acrylic acid, deionized water, 2-acrylamido-2-methylpropanesulfonic acid, polypropylene fiber, dodecyl acrylate and initiator azodiisobutyronitrile is 28:12:3500:55:100:9:3.5. Stir and mix to react at a reaction temperature of 80 °C for 2.5 h. After the reaction is completed, filter by suction, wash with deionized water and absolute ethanol, and dry at 60 °C for 12 h to obtain a polypropylene fiber-reinforced material; S3. Mix epoxy resin E51 and epoxy-modified calcium carbonate evenly, and then add polypropylene fiber-reinforced material, methyltetrahydrophthalic anhydride, 2,4,6-tris(dimethylaminomethyl)phenol. The mass ratio of epoxy resin E51, epoxy-modified calcium carbonate, polypropylene fiber-reinforced material, methyltetrahydrophthalic anhydride and 2,4,6-tris(dimethylaminomethyl)phenol is 100:6:9:68:1.6. Stir and mix, react at 65 °C for 2.5 h. After the reaction is completed, vacuum degas to obtain an epoxy resin-based fiber-reinforced composite material.

[0037] Example 4

[0038] A preparation method of a premixed high-strength flowing solidified soil includes the following steps: By mass fraction, weigh 21 parts of cement, 32 parts of fly ash, 40 parts of slag, 9 parts of epoxy resin-based fiber-reinforced composite material, 0.8 part of dispersant hydroxypropyl methylcellulose, 1.8 parts of polycarboxylate water reducer, 0.4 part of auxiliary agent, and 100 parts of deionized water. The auxiliary agent is composed of retarder sodium pyrophosphate and defoamer polyether-modified defoamer with a mass ratio of 1:3. Dry the cement, fly ash, and slag respectively until the water content ≤ 1%. Then grind the dried fly ash and dried slag. After grinding, the specific surface area of the fly ash ≥ 400 m 2 / kg, and the specific surface area of the slag ≥ 600 m 2 / kg. After the treatment is completed, stir in a mixer at a stirring rate of 350 r / min for 6 min. After mixing evenly, a mixture is obtained. Then add the dispersant, water reducer, and auxiliary agent and stir and mix for 4 min. Then add the epoxy resin-based fiber-reinforced composite material and stir and mix at a stirring rate of 220 r / min for 6 min. Add deionized water and stir and mix at a stirring rate of 520 r / min for 5 min. Adopt layered pouring, and after pouring, vibrating, covering, and demolding, a ready-mixed high-strength flowing solidified soil is obtained.

[0039] The preparation method of the epoxy resin-based fiber-reinforced composite material is the same as that of the epoxy resin-based fiber-reinforced composite material in Example 3.

[0040] Example 5

[0041] A preparation method of a ready-mixed high-strength flowing solidified soil, comprising the following steps: By mass fraction, weigh 24 parts of cement, 35 parts of fly ash, 42 parts of slag, 10 parts of epoxy resin-based fiber-reinforced composite material, 1 part of dispersant hydroxypropyl methylcellulose, 2 parts of polycarboxylate water reducer, 0.5 part of auxiliary agent, and 100 parts of deionized water. The auxiliary agent is composed of retarder sodium pyrophosphate and defoamer polyether-modified defoamer with a mass ratio of 1:3. Dry the cement, fly ash, and slag respectively until the water content ≤ 1%. Then grind the dried fly ash and dried slag. After grinding, the specific surface area of the fly ash ≥ 400 m 2 / kg, and the specific surface area of the slag ≥ 600 m 2 / kg. After processing, stir in a blender at a rate of 400 r / min for 5 min. After uniform mixing, a mixed material is obtained. Then, a dispersant, a water reducer, and an auxiliary agent are added, and stirred and mixed for 5 min. Then, an epoxy resin-based fiber-reinforced composite material is added and stirred and mixed at a rate of 250 r / min for 5 min. Deionized water is added and stirred and mixed at a rate of 600 r / min for 4 min. Adopt layered pouring, and after pouring, vibrating, covering, and demolding, a premixed high-strength flowing solidified soil is obtained.

[0042] The preparation method of the epoxy resin-based fiber-reinforced composite material includes the following steps: S1. Ultrasonically disperse nano calcium carbonate in acetone. After uniform dispersion, add acetic acid solution to adjust the pH to 5.5, and then add γ-glycidoxypropyltrimethoxysilane. The mass ratio of nano calcium carbonate, acetone, and γ-glycidoxypropyltrimethoxysilane is 100:1800:30. Heat, stir and mix, react at 85 °C for 3 h. After the reaction ends, filter while it is hot, wash with acetone, and vacuum dry at 60 °C for 12 h to obtain epoxy-modified calcium carbonate. S2. Mix itaconic acid, acrylic acid, and deionized water evenly, dropwise add sulfuric acid to adjust the pH to 2. In a nitrogen atmosphere, heat up, and add 2-acrylamido-2-methylpropanesulfonic acid, polypropylene fiber, dodecyl acrylate, and initiator azobisisobutyronitrile. The mass ratio of itaconic acid, acrylic acid, deionized water, 2-acrylamido-2-methylpropanesulfonic acid, polypropylene fiber, dodecyl acrylate, and initiator azobisisobutyronitrile is 30:15:4000:60:100:10:4. Stir and mix to react at a reaction temperature of 85 °C for 2 h. After the reaction ends, filter by suction, wash with deionized water and absolute ethanol, and dry at 60 °C for 12 h to obtain a polypropylene fiber-reinforced material. S3. Mix epoxy resin E51 and epoxy-modified calcium carbonate evenly, and then add polypropylene fiber-reinforced material, methyltetrahydrophthalic anhydride, and 2,4,6-tris(dimethylaminomethyl)phenol. The mass ratio of epoxy resin E51, epoxy-modified calcium carbonate, polypropylene fiber-reinforced material, methyltetrahydrophthalic anhydride, and 2,4,6-tris(dimethylaminomethyl)phenol is 100:7:10:70:2. Stir and mix, react at 70 °C for 2 h. After the reaction ends, carry out vacuum degassing to obtain an epoxy resin-based fiber-reinforced composite material.

[0043] Comparative Example 1 A preparation method of premixed flowing solidified soil includes the following steps: By mass, weigh 21 parts of cement, 32 parts of fly ash, 40 parts of slag, 7.8 parts of epoxy resin E51, 0.7 part of polypropylene fiber reinforcing material, 0.5 part of epoxy-modified calcium carbonate, 0.8 part of dispersant hydroxypropyl methylcellulose, 1.8 parts of polycarboxylate water reducer, 0.4 part of auxiliary agent, and 100 parts of deionized water. The auxiliary agent consists of retarder sodium pyrophosphate and polyether-modified defoamer in a mass ratio of 1:3. Dry the cement, fly ash, and slag respectively until the water content ≤ 1%. Then grind the dried fly ash and dried slag. After grinding, the specific surface area of fly ash ≥ 400m 2 / kg, and the specific surface area of slag ≥ 600m 2 / kg. After the treatment is completed, stir in a mixer at a stirring rate of 350 r / min for 6 min. After mixing evenly, a mixture is obtained. Then add the dispersant, water reducer, and auxiliary agent, and stir and mix for 4 min. Then add epoxy resin E51, polypropylene fiber reinforcing material, and epoxy-modified calcium carbonate, and stir and mix at a stirring rate of 220 r / min for 6 min. Add deionized water and stir and mix at a stirring rate of 520 r / min for 5 min. Adopt layered pouring, and after pouring, forming, vibrating, covering, and demolding, pre-mixed flowing solidified soil is obtained.

[0044] The preparation method of the epoxy-modified calcium carbonate includes the following steps: Ultrasonically disperse nano-calcium carbonate in acetone. After dispersing evenly, add acetic acid solution to adjust the pH to 5.2, and then add γ-glycidoxypropyltrimethoxysilane. The mass ratio of nano-calcium carbonate, acetone, and γ-glycidoxypropyltrimethoxysilane is 100:1600:28. Heat, stir and mix, react at 82 °C for 4 h. After the reaction is completed, filter while it is hot, wash with acetone, and vacuum dry at 60 °C for 12 h to obtain epoxy-modified calcium carbonate.

[0045] The preparation method of the polypropylene fiber reinforcing material includes the following steps: Mix itaconic acid, acrylic acid, and deionized water evenly, add sulfuric acid dropwise to adjust the pH to 1.8. In a nitrogen atmosphere, heat up, and add 2-acrylamido-2-methylpropanesulfonic acid, polypropylene fiber, dodecyl acrylate, and initiator azobisisobutyronitrile. The mass ratio of itaconic acid, acrylic acid, deionized water, 2-acrylamido-2-methylpropanesulfonic acid, polypropylene fiber, dodecyl acrylate, and initiator azobisisobutyronitrile is 28:12:3500:55:100:9:3.5. Stir and mix to react at a reaction temperature of 80 °C for 2.5 h. After the reaction is completed, filter by suction, wash with deionized water and absolute ethanol, and dry at 60 °C for 12 h to obtain the polypropylene fiber reinforcing material.

[0046] Comparative Example 2 A preparation method of premixed flowing solidified soil comprises the following steps: By mass, weigh 21 parts of ordinary Portland cement, 72 parts of slag, 9 parts of epoxy resin-based fiber reinforced composite material, 0.8 part of dispersant hydroxypropyl methylcellulose, 1.8 parts of polycarboxylate water reducer, 0.4 part of auxiliary agent, and 100 parts of deionized water. The auxiliary agent is composed of retarder sodium pyrophosphate and defoamer polyether modified defoamer with a mass ratio of 1:3. Dry the ordinary Portland cement and slag respectively until the water content ≤ 1%, and then grind the dried slag. After grinding, the specific surface area of the slag ≥ 600m 2 / kg. After the treatment is completed, stir in a mixer at a stirring rate of 350 r / min for 6 min to obtain a mixture. Then add the dispersant, water reducer and auxiliary agent, and stir and mix for 4 min. Then add the epoxy resin-based fiber reinforced composite material and stir and mix at a stirring rate of 220 r / min for 6 min. Add deionized water and stir and mix at a stirring rate of 520 r / min for 5 min. Adopt layered pouring, and after pouring, vibrating, covering and demolding, premixed flowing solidified soil is obtained.

[0047] The preparation method of the epoxy resin-based fiber reinforced composite material is the same as that of the epoxy resin-based fiber reinforced composite material in Example 4.

[0048] In the present invention, the cement used in Examples 1-5 and Comparative Example 1 is composed of ordinary Portland cement and sulfoaluminate cement with a mass ratio of 5:1.

[0049] The ordinary Portland cement used in the examples and comparative examples of the present invention is purchased from Jiangnan Xioda Tian Cement Co., Ltd., P·Ⅱ52.5 cement, with a density of 3.17 g / cm 3 , and the specific surface area is 388m 2 / kg; the sulfoaluminate cement is purchased from Tangshan Polar Bear Building Materials Co., Ltd., grade 42.5, and the specific surface area is 334m 2 / kg; the fly ash is purchased from Shenyang Power Plant Fly Ash Factory, which is grade II fly ash; the slag is purchased from Ninghai Hongji New Materials Co., Ltd., which is S95 grade; the nano calcium carbonate is purchased from Guangxi Warner Technology Co., Ltd., with an average particle size of 20 nm and a purity ≥ 99.99%; the polypropylene fiber is purchased from Beijing Wantuming Technology Co., Ltd., with a diameter of 20 μm and the product number 20200405; the epoxy resin E51 is purchased from Sinopec Corporation, with an epoxy value of 0.51 mol / 100 g; the polycarboxylate water reducer is purchased from Shanghai Chenqi Chemical Technology Co., Ltd., with the model CQJ-JSSQ2; other raw materials and reagents not specified are commercially available.

[0050] The prepared ready-mixed flowing solidified soil of Examples 1-5 and Comparative Examples 1-2 was subjected to relevant tests as follows: (1) Mechanical property test: Examples 1-5 and Comparative Examples 1-2 were respectively subjected to 7-day standard curing and 28-day standard curing. After curing, the 3-day compressive strength, 28-day compressive strength, and 28-day flexural strength were tested. The test standards were referred to T / BGEA001—2019 "Technical Standard for Ready-mixed Flowing Solidified Soil Filling Project" for testing; (2) Cracking property test: Referring to JCT951-2005 "Test Method for Crack Resistance of Cement Mortar", the cracking age of the concrete within 360 days was measured under the environment of constant temperature (20±1)°C and constant humidity (43±2)%; The above test results are shown in Table 1: Table 1 Test items 7-day compressive strength (MPa) 28-day compressive strength (MPa) 28-day flexural strength (MPa) Cracking age (d) Example 1 21.6 41.3 5.4 No cracking Example 2 24.9 47.2 6.2 No cracking Example 3 26.1 49.8 6.5 No cracking Example 4 27.8 52.7 7.1 No cracking Example 5 27.4 51.9 6.9 No cracking Comparative example 1 17.5 35.1 4.3 291 Comparative example 2 20.3 40.0 5.5 347 It can be seen from the test results in Table 1 that the flowing solidified soil corresponding to Samples 1-5 in the present invention has the characteristics of high strength, not easy to crack, and good durability, and has excellent compressive strength and flexural strength. In Comparative Example 1, epoxy resin E51, polypropylene fiber reinforcement, and epoxy-modified calcium carbonate were used to replace the epoxy resin-based fiber reinforcement composite material. The dispersibility of the raw materials became poor, agglomeration was easy to occur, the compatibility between the raw materials was greatly reduced, the comprehensive performance of the matrix was greatly reduced, the strength was greatly reduced, and cracking was easy to occur. In Comparative Example 2, only ordinary Portland cement was added, and slag was used to replace fly ash, resulting in a reduction in comprehensive performance, poor strength, and cracking within 360 days.

[0051] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirits of the present invention. All equivalent changes and improvements made within the scope of the application of the present invention shall still fall within the scope covered by the present invention.

Claims

1. A premixed high-strength flowing solidified soil, characterized in that: By mass fraction, it includes the following components: 15 - 24 parts of cement, 20 - 35 parts of fly ash, 30 - 42 parts of slag, 5 - 10 parts of epoxy resin - based fiber - reinforced composite material, 0.5 - 1 part of dispersant, 1 - 2 parts of water - reducing agent, 0.3 - 0.5 part of auxiliary agent, and 100 parts of deionized water; The preparation method of the epoxy resin - based fiber - reinforced composite material includes the following steps: S1. Ultrasonically disperse nano - calcium carbonate in acetone. After uniform dispersion, add acetic acid solution to adjust the pH to 5 - 5.5, then add γ - glycidoxypropyltrimethoxysilane, heat, stir and mix to react. After the reaction is completed, filter, wash, and vacuum - dry at 60 °C for 12 h to obtain epoxy - modified calcium carbonate; S2. Mix itaconic acid, acrylic acid and deionized water evenly, dropwise add sulfuric acid to adjust the pH to 1.5 - 2. In a nitrogen atmosphere, raise the temperature, add 2 - acrylamido - 2 - methylpropanesulfonic acid, polypropylene fiber, dodecyl acrylate and initiator, stir and mix to react. After the reaction is completed, filter with suction, wash, and dry at 60 °C for 12 h to obtain polypropylene fiber - reinforced material; S3. Mix epoxy resin and epoxy - modified calcium carbonate evenly, then add polypropylene fiber - reinforced material, methyltetrahydrophthalic anhydride, 2,4,6 - tris(dimethylaminomethyl)phenol, stir and mix to react. After the reaction is completed, carry out vacuum degassing to obtain epoxy resin - based fiber - reinforced composite material.

2. A kind of premixed high-strength flowable solidified soil according to claim 1, characterized in that: The dispersant is hydroxypropyl methyl cellulose.

3. A kind of pre-mixed high-strength flowing solidified soil according to claim 1, characterized in that: The water - reducing agent is polycarboxylate water - reducing agent.

4. A kind of premixed high-strength flowing solidified soil according to claim 1, characterized in that: The auxiliary agent is composed of a retarder and an antifoaming agent with a mass ratio of 1:

3. Among them, the retarder is sodium pyrophosphate, and the antifoaming agent is polyether - modified antifoaming agent.

5. A kind of premixed high-strength flowing solidified soil according to claim 1, characterized in that: In S1, the mass ratio of nano - calcium carbonate, acetone, and γ - glycidoxypropyltrimethoxysilane is 100:1500 - 1800:20 - 30, the reaction temperature is 80 °C - 85 °C, and the reaction time is 3 h - 5 h.

6. The ready-mixed high-strength flowing solidified soil according to claim 1, wherein: In S2, the mass ratio of itaconic acid, acrylic acid, deionized water, 2 - acrylamido - 2 - methylpropanesulfonic acid, polypropylene fiber, dodecyl acrylate, and initiator is 20 - 30:10 - 15:3000 - 4000:42 - 60:100:7 - 10:2.5 - 4, the reaction temperature is 75 °C - 85 °C, and the reaction time is 2 h - 3 h.

7. A kind of premixed high-strength flowing solidified soil according to claim 1, characterized in that: The initiator in S2 includes any one of azobisisobutyronitrile, ammonium persulfate, and potassium persulfate.

8. A kind of premixed high-strength flowing solidified soil according to claim 1, characterized in that: In S3, the mass ratio of epoxy resin, epoxy - modified calcium carbonate, polypropylene fiber - reinforced material, methyltetrahydrophthalic anhydride, and 2,4,6 - tris(dimethylaminomethyl)phenol is 100:3 - 7:5 - 10:60 - 70:1 - 2, the reaction temperature is 60 °C - 70 °C, and the reaction time is 2 h - 3 h.

9. A method for preparing the ready-mixed high-strength flowing solidified soil according to any one of claims 1-8, characterized in that: It includes the following steps: Dry cement, fly ash, and slag respectively, then grind the dried fly ash and dried slag. After the treatment is completed, stir in a mixer at a stirring rate of 300 r / min - 400 r / min for a stirring time of 5 min - 8 min. After mixing evenly, a mixture is obtained. Then add a dispersant, a water reducer, and an auxiliary agent, and stir and mix for 3 min - 5 min. Then add an epoxy resin-based fiber-reinforced composite material and stir and mix at a stirring rate of 200 r / min - 250 r / min for 5 min - 8 min. Add deionized water and stir and mix at a stirring rate of 500 r / min - 600 r / min for 4 min - 6 min. After casting, vibrating, covering, and demolding, pre-mixed high-strength flowable solidified soil is obtained.

10. The preparation method of a kind of premixed high-strength flowing solidified soil according to claim 9, characterized in that: During the drying process of the cement, fly ash, and slag, they are dried to a water content of ≤ 1%. After grinding, the specific surface area of the fly ash is ≥ 400 m 2 / kg, and the specific surface area of the slag is ≥ 600 m 2 / kg. The pouring is carried out in layers.