Novel shield muck-based green material and preparation method thereof

Abstract

The invention belongs to the technical field of production of novel green materials for resource recycling, and particularly relates to a novel shield muck-based material and a preparation method thereof. The novel green material comprises the following raw materials in parts by weight: 50-80 parts of micro-nano particle shield muck with the water content of 40%-70%, 1-30 parts of basalt short fiber aggregate with the length of 20-100 mm and 1-30 parts of a biomass curing agent, the preparation method comprises the steps of micro-nano particle shield muck preparation, mixing and stirring, pouring molding and demolding curing, and the technological process is shown in Figure 1. The compressive strength of the product is 4 times higher than the curing strength of cement with the same dosage, the performance is higher than that of a traditional sintered brick, and the product has the advantages of high strength, good stability, high water resistance, simple structure, high production capacity, low cost, wide application scene and the like; in-situ low-cost harmless resource regeneration and cyclic utilization of the building engineering solid waste on the construction site is achieved, the industrial popularization prospect is wide, and the economic, social and ecological benefits are remarkable.

Description

Technical Field

[0001] The present invention belongs to the technical field of resource recycling and green new material production, and specifically relates to a green new material for shield slag base and a preparation method thereof. Background Art

[0002] With the rapid development of urban rail transit and underground space development, shield tunneling has become the mainstream technology for tunnel construction. However, the resulting shield excavation has caused a series of environmental problems. Shield excavation excavation has high moisture content (some exceeding 80%), high porosity, low permeability, high fluidity, and high levels of pollutants. Traditional disposal methods rely primarily on landfilling, which leads to the following environmental risks: 1. Resource waste and land occupation: Shield excavation excavation is rich in resources such as sand, gravel, and clay. Landfilling not only wastes resources but also occupies a large amount of landfill space, exacerbating land resource constraints. 2. Pollutant dispersion: Chemicals, clay minerals, and heavy metals in the excavation can migrate with groundwater, causing chronic toxicity to ecosystems and human health. 3. Geological hazard risks: Large-scale accumulation can easily trigger secondary hazards such as landslides and debris flows, and insufficient landfill processing capacity leads to secondary environmental pressures.

[0003] In response to the above problems, some people have relied on cement-based cementitious materials to solidify shield slag, but there are the following defects: First, low efficiency and high cost: high-moisture slag requires large amounts of curing agents and secondary dehydration, making the process complex and costly. Second, pollution risk: traditional cementitious materials may introduce heavy metal ions, and existing technologies are insufficient to synergistically fix pollutants (such as humic acid and heavy metals), making it difficult to meet environmental standards. Third, insufficient performance: the cured material has low strength and poor freeze-thaw resistance, making it difficult to meet engineering application requirements. For example, the strength of cement-cured soil after 7 days is only approximately 1 MPa, far lower than the effectiveness of new curing agents. For example, Chinese patent publication number CN115093181A discloses a high-strength unburned brick based on shield slag in the loess region and a preparation method thereof. The raw materials of the high-strength unburned brick include, by mass, 85-90.1 parts of slag, 9.8-14.8 parts of cement, and 0.1-0.2 parts of a soil solidifier; the slag is dehydrated shield slag; the components of the soil solidifier include sodium carboxymethyl cellulose, water-based epoxy resin, sodium methyl silicate, nano-silica, potassium chloride, and potassium sulfate, and the mass ratio is sodium carboxymethyl cellulose: water-based epoxy resin: sodium methyl silicate: nano-silica: potassium chloride: potassium sulfate = (60-75): (15-30): (2-4): (2-4): (2-4): (2-4). Although this invention can effectively use subway shield slag to make unfired pressed bricks, and the use of water-based epoxy resin as a curing agent reduces environmental pollution, it still relies on cement, and the process is complicated. The use of water-based epoxy resin further increases the cost investment. For example, Chinese patent publication number CN112777995 A discloses a raw shield slag unburned product and a preparation method thereof. The unburned product is composed of raw materials in the following mass ratios: the mass ratio of active industrial waste slag to the slag content in the raw shield slag is 1.5-4:6-8.5, the mass ratio of sodium silicate powder to active industrial waste slag is 0.01-0.5:1, and the mass ratio of water to the raw shield slag is 0-0.25:1. The preparation method includes the following steps: mixing the sodium silicate powder and the active industrial waste slag in a mass ratio; adding water to the raw shield slag and stirring evenly, then adding the evenly mixed sodium silicate powder and active industrial waste slag, stirring evenly, pouring into a mold, and demolding to obtain the unburned product I; soaking the unburned product I in an alkali metal hydroxide solution to obtain the final unburned product II. Although the invented unburned shield slag product has good mechanical properties and durability, it is soaked in alkaline solution and the unburned shield slag contains pollutants, so the product and process are not environmentally friendly.For example, Chinese patent publication number CN117534350A discloses a curing agent for original shield slag roadbed material, roadbed material and preparation method thereof, wherein the curing agent comprises the following raw materials in the following mass percentages: 60%-92% alkali-activated cementitious material, 1%-12% stone powder, 5%-18% gypsum and 1%-10% admixture; the amount of the curing agent accounts for 1%-15% of the mass of the roadbed material; the present invention also includes a preparation method of the shield slag cured roadbed material, which is prepared by mixing the curing agent with the shield slag and stirring them uniformly, and then spreading and backfilling; the shield slag roadbed material of the present invention has a 3d strength of more than 1.5 MPa and a 7d strength of more than 3.0 MPa after curing, but its strength after curing is not high, its stability is poor, and its water resistance is weak.

[0004] Based on the above problems, there is an urgent need to develop an efficient solidification process for shield slag, which takes into account both lightweight and high strength, promotes the transformation of shield slag into green building materials, reduces processing costs and meets engineering application needs. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a new green material for shield slag foundation and a preparation method thereof.

[0006] The object of the present invention is achieved through the following technical scheme: a new green material based on shield slag, comprising the following raw materials in parts by weight: 50 to 80 parts of micro-nano-particle shield slag with a moisture content of 40% to 70%, 1 to 30 parts of basalt short fiber aggregate with a length of 20 to 100 mm, and 1 to 30 parts of a biomass curing agent.

[0007] As a preferred technical solution, the raw materials also include basalt short fiber aggregate or other fiber aggregate.

[0008] As a preferred technical solution, the micro-nano particle shield slag can also be prepared using various construction waste soil, sand and gravel slag, tailings or general industrial solid waste as raw materials.

[0009] The above-mentioned method for preparing a new green shield slag-based material comprises the following steps: S1. Preparation of shield tunneling soil micro- and nano-particles: Through shear mixing of shield tunneling mud and water, uniform distribution and density, and harmless treatment, the shield tunneling soil micro- and nano-particles are produced with a particle size of ≤5mm and a moisture content of 40% to 70%. S2 mixing: 1 to 30 parts by weight of basalt short fiber aggregate and 50 to 80 parts by weight of micro-nano particle shield slag prepared in step S1 are mixed and stirred, while spraying 1 to 30 parts by weight of a biomass curing agent, mixing and stirring to obtain a building material raw material; S3 curing molding: The building material raw materials are poured into the molding mold at a pressure of 0.5-10MPa and cured to obtain the initial product; S4. Demolding and curing: The initial product is demolded and left to dry for more than 12 hours to produce a new type of green building material product that does not require sintering.

[0010] Among them, the shield tunneling mud and water wall breaking, uniform mixing and efficient thickening system is an existing device, and the inventor has applied for a patent with the publication number CN116589163B.

[0011] The biomass curing agent of this invention is a highly efficient, independently developed curing agent. Upon contact with soil, its long copolymer chains form a durable, waterproof, semi-flexible solid matrix structure, permanently curing the soil. The curing agent contains the following raw materials in parts by weight: 0.2 parts rosin acid, 5 parts acrylic acid, 0.5 parts acrylamide, 3 parts N,N′-methylenebisacrylamide, 0.1 part ammonium persulfate, and 1 part tetramethylethylenediamine.

[0012] In the present invention: 1. Shield tunneling debris is processed using micro-nano particle technology and then added with the rosin acid-based biomass soil solidifier disclosed in this invention to create a "green building material." This method eliminates the need for pressing, sintering, or cement, directly producing a new green material and enabling the cost-effective, harmless recycling of construction waste on-site.

[0013] 2. According to the application scenario requirements or economic value considerations, one is to directly shape it into structural materials (such as floor tiles, wall tiles, panels), powder raw materials or pouring slurries and other new green building materials, roadbed materials, which can be widely used in prefabricated buildings, urban road paving, rural revitalization roadbed construction and paving materials, traffic road enclosure isolation, river embankment and seaport construction and other scenarios; the second is to use molds to make special handicrafts; the third is to use it for high-standard farmland reclamation after repair, that is, after treatment with soil conditioners, the high-salinity and alkaline slag with a pH of 8.5-9.0 is repaired to a full-plant soil with a pH of 6.0-7.5 suitable for plant growth for reclamation.

[0014] 3. The curing agent disclosed in this invention is an environmentally friendly biomass curing agent. Traditional curing agents, such as epoxy resin curing agents, while performing well, are high in volatile organic compounds (VOCs), posing potential risks to the environment and health. The curing agent of this invention is a low-cost, environmentally friendly biomass curing agent, primarily composed of rosin acid and acrylamide. It exhibits lower toxicity and improved biocompatibility. This novel biomass curing agent maintains product performance while minimizing environmental impact.

[0015] Biomass rosin acid is used in conjunction with acrylic acid to form a dense three-dimensional network structure through a chemical reaction, endowing handicrafts with excellent physical and chemical properties such as high strength, high hardness, and good wear resistance. In addition, its low shrinkage and rapid curing properties allow the handicraft to accurately replicate the shape of the mold, making it suitable for the creation of exquisite sculptures and decorative items.

[0016] The present invention has the following advantages: The present invention discloses a method for preparing a new green material from shield tunneling debris. The shield tunneling debris is treated using micro-nano particle technology, and then the rosin acid-based biomass soil solidifier disclosed in the present invention is added. The green new material is directly prepared without pressing, sintering, or cement. The solidifier disclosed in the present invention forms a dense three-dimensional network structure through a chemical reaction. Upon contact with the soil, its long copolymer chains form a durable, waterproof, semi-flexible solid matrix structure, permanently solidifying the shield tunneling soil. The product performance of the present invention has the advantages of high strength, good stability, strong water resistance, simple structure, high production capacity and low cost, and a wide range of applications. The finished product has a compact structure and excellent thermal insulation. Preliminary tests show that the compressive strength is greater than 30MPa and the softening coefficient after 30 days of soaking in water is greater than 0.93. The compressive strength is more than four times the solidification strength of the same cement content, and the performance is superior to that of traditional fired bricks. This method realizes the low-cost, harmless resource recycling and recycling of construction project solid waste on the construction site. The industrialization and application prospects are broad, and the economic, social, and ecological benefits are significant. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a process flow chart of the present invention; Figure 2 This is a comparison diagram before and after the shield slag treatment of the present invention; Figure 3 This is a schematic diagram of a sample of shield slag after solidification according to the present invention; Figure 4 This is a schematic diagram of the green new material of the present invention after being struck by a hammer. DETAILED DESCRIPTION

[0018] The present invention is further described below with reference to the embodiments, and the protection scope of the present invention is not limited to the following: Example 1: A new green material based on shield slag, comprising the following raw materials in parts by weight: 60 parts of micro-nano-granular shield slag with a moisture content of 50%, 20 parts of basalt short fiber aggregate 20 to 100 mm long, and 10 parts of a biomass curing agent. The biomass curing agent comprises the following raw materials in parts by weight: 0.2 parts of rosin acid, 5 parts of acrylic acid, 0.5 parts of acrylamide, 3 parts of N,N′-methylenebisacrylamide, 0.1 parts of ammonium persulfate, and 1 part of tetramethylethylenediamine.

[0019] Example 2: A new green material based on shield slag, comprising the following raw materials in parts by weight: 70 parts of micro-nano-granular shield slag with a moisture content of 60%, 10 parts of basalt short fiber aggregate 20 to 100 mm long, and 20 parts of a biomass curing agent. The biomass curing agent comprises the following raw materials in parts by weight: 0.2 parts of rosin acid, 5 parts of acrylic acid, 0.5 parts of acrylamide, 3 parts of N,N′-methylenebisacrylamide, 0.1 parts of ammonium persulfate, and 1 part of tetramethylethylenediamine.

[0020] Example 3: A new green material based on shield slag, comprising the following raw materials in parts by weight: 60 parts of micro-nano-granular shield slag with a moisture content of 55%, 15 parts of basalt short fiber aggregate 20-100 mm long, and 15 parts of a biomass curing agent. The biomass curing agent comprises the following raw materials in parts by weight: 0.2 parts of rosin acid, 5 parts of acrylic acid, 0.5 parts of acrylamide, 3 parts of N,N′-methylenebisacrylamide, 0.1 parts of ammonium persulfate, and 1 part of tetramethylethylenediamine.

[0021] Example 4: A method for preparing a new green material based on shield slag soil, such as Figures 1 to 4 As shown, the following steps are included: S1. Preparation of shield tunneling soil micro- and nano-particles: Shield tunneling soil, made from construction waste, is subjected to shield mud and water wall-breaking, shear mixing, uniform distribution, and harmless treatment to produce micro- and nano-particles with a moisture content of 50% and a particle size of ≤5mm. S2 mixing: 20 parts by weight of basalt short fiber aggregate and 60 parts by weight of micro-nano particles shield slag prepared in step S1 were mixed and stirred, while spraying 10 parts by weight of a biomass curing agent, mixing and stirring to obtain a raw building material; The biomass solidifying agent was prepared by the following method: taking the raw materials of the biomass solidifying agent formula ratio of Example 1, rosin acid and acrylic acid were mixed, and reacted at room temperature for 2.5 hours to produce ABA-Aac; ABA-Aac was mixed with acrylamide, shaken, and then N,N′-methylenebisacrylamide, ammonium persulfate and tetramethylethylenediamine were added, mixed evenly, and reacted for 60 minutes to produce a rosin acid-based biomass soil solidifying agent.

[0022] S3 curing molding: The building material raw materials are poured into the molding mold at a pressure of 5MPa and cured to obtain a primary product; S4. Demolding and curing: The initial product is demolded and left to dry for 24 hours to produce a new type of green building material product that does not require sintering.

[0023] Example 5: A method for preparing a new green material based on shield slag soil, such as Figure 1 As shown, the following steps are included: S1. Preparation of shield soil micro- and nano-particles: Using sand and gravel as the raw material, shield soil is subjected to shear mixing, uniform distribution, and harmless treatment to produce micro- and nano-particles with a moisture content of 60% and a particle size of ≤5mm. S2 mixing: 10 parts by weight of basalt short fiber aggregate and 70 parts by weight of micro-nano particles shield slag prepared in step S1 were mixed and stirred, while spraying 20 parts by weight of a biomass curing agent, mixing and stirring to obtain a building material raw material; The biomass solidifying agent was prepared by the following method: taking the raw materials of the biomass solidifying agent formula ratio of Example 2, rosin acid and acrylic acid were mixed, and reacted at room temperature for 2.5 hours to produce ABA-Aac; ABA-Aac was mixed with acrylamide, shaken, and then N,N′-methylenebisacrylamide, ammonium persulfate and tetramethylethylenediamine were added, mixed evenly, and reacted for 60 minutes to produce a rosin acid-based biomass soil solidifying agent.

[0024] S3. Curing and molding: The building material raw materials are poured into the molding mold at a pressure of 3MPa and cured to obtain the initial product. A bubble discharge port should be provided during the pouring process. S4. Demolding and curing: The initial product is demolded and left to dry for 60 hours to produce a new type of green building material product that does not require sintering.

[0025] Example 6: A method for preparing a new green material based on shield slag soil, such as Figure 1 As shown, the following steps are included: S1. Preparation of shield tunneling soil micro- and nano-particles: Shield tunneling soil, made from tailings, is subjected to shear mixing, uniform distribution, and harmless treatment. The resulting micro- and nano-particles have a moisture content of 55% and a particle size ≤5mm. S2 mixing: 15 parts by weight of basalt short fiber aggregate and 60 parts by weight of micro-nano particles shield soil prepared in step S1 were mixed and stirred, while spraying 15 parts by weight of a biomass curing agent, mixing and stirring to obtain a building material raw material; The biomass solidifying agent was prepared by the following method: taking the raw materials of the biomass solidifying agent formula ratio of Example 3, rosin acid and acrylic acid were mixed, and reacted at room temperature for 2.5 hours to produce ABA-Aac; ABA-Aac was mixed with acrylamide, shaken, and then N,N′-methylenebisacrylamide, ammonium persulfate and tetramethylethylenediamine were added, mixed evenly, and reacted for 60 minutes to produce a rosin acid-based biomass soil solidifying agent.

[0026] S3 curing molding: The building material raw materials are poured into the molding mold at a pressure of 5MPa and cured to obtain a primary product; S4. Demolding and curing: The initial product is demolded and left to dry for 48 hours to produce a new type of green building material product that does not require sintering.

[0027] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, and they are all covered by the scope of protection of the present invention.

Claims

1. A new green material for shield slag foundation, characterized by: The method comprises the following raw materials in parts by weight: 50-80 parts of micro-nano-particle shield slag with a moisture content of 40%-70%, 1-30 parts of basalt short fiber aggregate with a length of 20-100 mm, and 1-30 parts of a biomass curing agent.

2. A new green material for shield slag base according to claim 1, characterized in that: The raw materials also include basalt short fiber aggregate or other fiber aggregates.

3. The shield slag-based green new material according to claim 1 is characterized in that: The micro-nano particle shield slag can also be prepared using various construction waste soil, sand and gravel slag, tailings or general industrial solid waste as raw materials.

4. The new green material for shield slag base according to claim 1, characterized in that: The raw materials also include biological curing agents or other curing agents and soil-fixing agents.

5. The method for preparing a new green material for shield slag base according to claim 1, characterized in that: It includes the following steps: S1. Preparation of Micro-Nano Shield Mine Soil: This is produced through shear mixing of shield slurry and water, uniform distribution and densification, and harmless treatment. The particle size is ≤5mm and the moisture content is 40% to 70%. S2 mixing: 1 to 30 parts by weight of basalt short fiber aggregate and 50 to 80 parts by weight of micro-nano particle shield slag prepared in step S1 are mixed and stirred, while spraying 1 to 30 parts by weight of a biomass curing agent, mixing and stirring to obtain a building material raw material; S3 curing molding: The building material raw materials are poured into the molding mold at a pressure of 0.5-10MPa and cured to obtain the initial product; S4. Demolding and curing: The initial product is demolded and left to dry for more than 12 hours to produce a new type of green building material product that does not require sintering.

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