High-strength and high-toughness gold tailing-based foam light soil as well as preparation method and application thereof

Abstract

The invention provides high-strength and high-toughness gold tailing-based foam light soil as well as a preparation method and application thereof, and belongs to the field of roadbed engineering technologies and concrete. The thermal insulation material comprises the following components in parts by mass: 20-46 parts of blast furnace slag, 8-15 parts of gold tailing powder, 12-25 parts of coal gasification slag powder, 8-15 parts of carbide slag, 5-10 parts of gypsum, 5-15 parts of incineration fly ash, 1-3 parts of an alkaline activator, 25-40 parts of gold tailing sand, 1-3 parts of waste tire rubber powder, 0.8-1.2 parts of modified recycled fibers, 0.1-0.3 part of a foam stabilizer, 4-7 parts of a foaming agent and 35-76 parts of water. The foam light soil is strong in bearing capacity, high in toughness, low in cost and good in flowability, and can effectively adapt to foundation deformation, avoid local stress concentration, enhance shock resistance, improve fatigue resistance and reduce maintenance cost on the basis of meeting roadbed performance requirements when being used as roadbed filler.

Description

Technical Field

[0001] The present invention belongs to the technical fields of subgrade engineering and concrete, and particularly relates to a high-strength and high-toughness gold tailings-based foamed lightweight soil and a preparation method and application thereof. Background Technique

[0002] Disclosing the information of this background technical part is only intended to increase the understanding of the overall background of the present invention, and is not necessarily regarded as an admission or an implication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] Foamed lightweight soil is a lightweight material mainly composed of cement, water and foam. Because it can reduce the load or soil pressure of filling projects, it is widely used in subgrade construction, such as treating the soft foundation at the back of abutments, soft foundation embankments, and widened road embankments. However, traditional cement production by firing has high energy consumption and high carbon emissions. Therefore, solid waste-based foamed lightweight soil has become a research hotspot. For example: bauxite tailings-based foamed lightweight soil, red mud-based foamed lightweight soil, etc. Although the above-mentioned foamed lightweight soils use one or several solid waste materials, they still use some cement. At present, all-solid waste-based foamed concrete often has difficulty in combining high strength and high toughness. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides a high-strength and high-toughness gold tailings-based foamed lightweight soil and a preparation method and application thereof. The present invention uses blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, incineration fly ash and an alkaline activator to form a solid waste-based gel system. Without introducing cement, the prepared foamed lightweight soil combines high strength and high toughness. The foamed lightweight soil prepared based on solid waste materials of the present invention has the advantages of strong bearing capacity, high toughness, low cost and good fluidity. When used as a subgrade filler, it can effectively adapt to the foundation deformation on the basis of meeting the subgrade performance requirements, avoid local stress concentration, enhance the seismic resistance, improve the fatigue resistance and reduce the maintenance cost.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: In the first aspect of the present invention, there is provided a high-strength and high-toughness gold tailings-based foamed lightweight soil, which is composed of the following raw materials in parts by weight: 20-46 parts of blast furnace slag, 8-15 parts of gold tailings powder, 12-25 parts of coal gasification slag powder, 8-15 parts of carbide slag, 5-10 parts of gypsum, 5-15 parts of incineration fly ash, 1-3 parts of alkaline activator, 25-40 parts of gold tailings sand, 1-3 parts of waste tire rubber powder, 0.8-1.2 parts of modified recycled fiber, 0.1-0.3 parts of foam stabilizer, 4-7 parts of foaming agent, and 35-76 parts of water.

[0006] The present invention uses bulk solid waste materials to prepare a foam lightweight soil with low carbon, low cost, high strength and high toughness, which is used as a subgrade filler. First, blast furnace slag, gold tailings powder, coal gasification slag powder, and incineration fly ash are used as active admixtures to provide rich silicon sources, aluminum sources, and calcium sources (silicon-aluminum ratio of 1.8 - 2.8, silicon-calcium ratio of 2.5 - 3.5). The calcium hydroxide rich in carbide slag is strongly alkaline and, together with gypsum, constructs an alkaline environment. In this environment, alkaline ions (such as hydroxide ions) can break the stable silicon-oxygen tetrahedron and aluminum-oxygen tetrahedron network structures in the above-mentioned active admixtures, causing them to depolymerize and release active silicon, aluminum and other elements. At the same time, the components in the solid waste undergo ion exchange reactions in the alkaline solution. The sulfate radicals in gypsum will react with cations (such as calcium ions, aluminum ions, etc.) in other solid wastes, changing the surface charge properties of the solid waste particles and further activating the particles; the active ions and small molecular groups released after depolymerization undergo hydration reactions with Ca²⁺ (calcium ions), etc. The active silicon ions react with Ca²⁺ and OH⁻ (hydroxide ions) to form C-(A)-S-H gel, and Al 3+ (aluminum ions) react with Ca²⁺, SO4²⁻ (sulfate radicals), OH⁻, etc. to form ettringite. These hydration products grow and intertwine to form a three-dimensional network structure, tightly connecting the solid waste particles; during this process, new chemical bonds are continuously formed. The various chemical bonds in the C-(A)-S-H gel and the special crystal structure of ettringite endow the material with high strength and stability, improving its ability to resist external damage and enhancing the strength of the material. Secondly, the gold tailings powder and gold tailings sand form a firm skeleton in the foam lightweight soil, and the fine-grained aggregates fill the pores, improving the density of the material.

[0007] In the second aspect of the present invention, a preparation method of the above-mentioned high-strength and high-toughness gold tailings-based foam lightweight soil is provided, including: Mix blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, and incineration fly ash, and ball mill to obtain a powder mixture; Mix the foaming agent and the foam stabilizer evenly and dissolve them in water to prepare a foaming solution; Mix the powder mixture, gold tailings sand, waste tire rubber powder, modified recycled fiber, alkaline activator, and water evenly to obtain a slurry; Prepare foam using the foaming solution, add the foam to the obtained slurry, mix evenly, mold, and cure to obtain the product.

[0008] In the third aspect of the present invention, the above-mentioned high-strength and high-toughness gold tailings-based foam lightweight soil or the high-strength and high-toughness gold tailings-based foam lightweight soil prepared by the above preparation method is provided for use in the preparation of subgrade fillers.

[0009] Advantages of the present invention (1) Compared with traditional solid waste-based foam concrete, the present invention abandons traditional cement and uses blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, incineration fly ash and alkaline activator as low-carbon cementitious materials. It uses gold tailings sand to replace traditional silty sand, and uses waste tire rubber powder and recycled fibers as toughening agents, combined with a foaming agent and a foam stabilizer to jointly prepare foam lightweight soil, which has low carbon, low cost and combines high strength and high toughness. When used as a subgrade filler, it meets the strength requirements in the current "Technical Specification for the Filling Engineering of Aerated Lightweight Soil" (CJJ / T 177-2012). At the same time, it can effectively adapt to the foundation deformation. When the soft foundation subsides, it deforms moderately by itself without damage, preventing the subgrade from cracking and collapsing; it can disperse the vehicle load stress, avoiding local stress concentration; it enhances the seismic resistance, absorbs energy during an earthquake, reduces the degree of earthquake damage, and ensures post-earthquake traffic; it improves the fatigue resistance and is not easily fatigued and damaged under repeated vehicle loads.

[0010] (2) The present invention uses multi-source solid waste to replace cement, which conforms to the goals of environmental protection development and green highway construction, reduces production costs, and is conducive to promoting the comprehensive utilization of large quantities of solid waste.

[0011] (3) The preparation method of the present invention is simple, highly practical, and easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0013] Figure 1 It is a foam lightweight soil specimen formed by indoor test using the high-strength and high-toughness gold tailings-based foam lightweight soil of Example 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0014] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0015] As described in the background art, as a subgrade material, the toughness performance of foamed lightweight soil is crucial. First of all, it can effectively adapt to the deformation of the foundation. When the soft foundation settles, it can deform moderately by itself without being damaged, preventing the subgrade from cracking and collapsing. Secondly, it can disperse the vehicle load stress, avoid local stress concentration, and extend the service life of the subgrade. Moreover, it enhances the seismic resistance, absorbs energy during an earthquake, reduces the degree of earthquake damage, and ensures post-earthquake traffic. In addition, it improves the fatigue resistance and is not easily damaged by repeated vehicle loads. Finally, it is convenient for construction and later maintenance. It is not easily cracked and segregated during construction, and it is easy to repair even if there is damage, reducing the maintenance cost. In addition, the frost resistance and resistance to dry-wet cycles of foamed lightweight soil are also crucial for the foundation treatment performance. Therefore, it is urgent to develop a low-carbon, low-cost foamed lightweight soil with high strength and high toughness.

[0016] To this end, the present invention provides a high-strength and high-toughness gold tailings-based foamed lightweight soil, which is composed of the following raw materials in parts by weight: 20-46 parts of blast furnace slag, 8-15 parts of gold tailings powder, 12-25 parts of coal gasification slag powder, 8-15 parts of carbide slag, 5-10 parts of gypsum, 5-15 parts of incineration fly ash, 1-3 parts of alkaline activator, 25-40 parts of gold tailings sand, 1-3 parts of waste tire rubber powder, 0.8-1.2 parts of modified recycled fiber, 0.1-0.3 parts of foam stabilizer, 4-7 parts of foaming agent, and 35-76 parts of water.

[0017] Preferably, the blast furnace slag is above S95 grade, and the mass percentage of SiO2 + CaO is greater than 80%; Preferably, the particle size of the gold tailings powder is less than 45μm, and the particle size of the gold tailings sand is less than 300μm; Preferably, in the coal gasification slag powder, the mass percentage of SiO2 + CaO + Al2O3 is greater than 80%; Preferably, the gypsum is selected from at least one of phosphogypsum, desulfurized gypsum or fluorogypsum; Preferably, in the incineration fly ash, the mass percentage of SiO2 + CaO + Al2O3 is greater than 75%.

[0018] Preferably, the alkaline activator is composed of sodium silicate and sodium hydroxide, and the mass ratio of the two is (15-28):(1-3).

[0019] Preferably, the recycled fiber is selected from at least one of waste ships, waste wind turbine blades and waste fishing nets, the fiber length is 3-4mm, and the fiber diameter is 8μm-48μm.

[0020] Preferably, the modified recycled fiber is obtained by sequentially modifying the recycled fiber with a silane coupling agent and nano-silica. After the recycled fiber is modified with the silane coupling agent, one end of the silane coupling agent molecule forms a chemical bond on the fiber surface, and the other end undergoes physical or chemical reactions with the cement hydration products in the foamed lightweight soil, forming a transition layer between the two to enhance the interfacial bonding force, enabling the modified recycled fiber to effectively transfer stress; when the foamed lightweight soil generates micro-cracks under external force, the modified recycled fiber withstands and disperses the stress at the crack tip by virtue of its good bonding force, changes the crack propagation direction, consumes energy, and hinders the further development of the crack; moreover, due to the action of the silane coupling agent, the modified recycled fiber can be evenly dispersed in the matrix, dispersing the concentrated stress to the surrounding matrix to avoid local stress concentration; in addition, the modified recycled fiber increases the internal friction in the foamed lightweight soil mixture, reduces the fluidity loss, prevents segregation and bleeding, and improves the workability. At the same time, the modification with nano-silica can improve the strength and durability of the foamed lightweight soil.

[0021] More preferably, the silane coupling agent is selected from at least one of KH550, KH570, and KH792.

[0022] Preferably, the fluidity of the high-strength and high-toughness gold tailings-based foamed lightweight soil is 200 - 250 mm.

[0023] Preferably, the foam stabilizer is selected from at least one of dodecyldimethylamine oxide, polyvinyl alcohol, and diethanolamide.

[0024] Preferably, the foaming agent is selected from at least one of protein foaming agent, sodium dodecyl sulfate, and lignosulfonate.

[0025] The present invention also provides a preparation method of the above-mentioned high-strength and high-toughness gold tailings-based foamed lightweight soil, including: Mixing blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, and incineration fly ash, and ball milling to obtain a powder mixture; Mixing the foaming agent and the foam stabilizer evenly and dissolving them in water to prepare a foaming solution; Mixing the powder mixture, gold tailings sand, waste tire rubber powder, modified recycled fiber, alkaline activator, and water evenly to obtain a slurry; Preparing foam using the foaming solution, adding the foam to the obtained slurry, mixing evenly, forming, and curing to obtain the product.

[0026] Preferably, the dilution ratio of the foaming solution is 30 - 50 times.

[0027] More specifically, it includes: (1)Proportionally ball-mill blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, and incineration fly ash for 2 - 3 min at a rotation speed of 400 - 500 r / min to obtain a uniform powder mixture for standby. (2)Immerse the recycled fibers in deionized water for ultrasonic cleaning for 2 - 3 min, and place them in an oven to dry at 60°C for 24 h. Mix absolute ethanol and deionized water in proportion to prepare a 95% ethanol aqueous solution, and add a silane coupling agent (the mass concentration of the silane coupling agent is 5% - 10%) to obtain Solution A. Mix nano-silica and deionized water (the mass concentration of nano-silica is 2% - 5%), and ultrasonically disperse the nano-silica dispersion B to obtain the nano-silica dispersion B. Immerse the recycled fibers in Solution A in proportion, set the water bath temperature of the constant temperature water bath to 60°C, take out the recycled fibers after 120 - 180 min of water bath, and repeatedly rinse them with deionized water until clean. Then immerse the recycled fibers treated with Solution A in the nano-silica dispersion B, stir with a magnetic stirrer for 10 - 20 min, take out the fibers, rinse them with deionized water until clean, and then place them in an oven to dry at 60°C for 24 h to obtain modified recycled fibers.

[0028] (3)Weigh sodium silicate solution and sodium hydroxide in proportion. Prepare a sodium silicate solution with a mass concentration of 5%, dissolve sodium hydroxide in the sodium silicate solution, mix and stir evenly, and let it stand and cool to room temperature to prepare an alkaline activator for standby. (4)Weigh the foaming agent, foam stabilizer, and water in proportion. Mix the foaming agent and foam stabilizer evenly and dissolve them in water to prepare a foaming solution for standby. (5)Proportionally mix the powder mixture, gold tailings sand, waste tire rubber powder, recycled fibers / modified recycled fibers, alkaline activator, and water evenly, and stir to obtain a slurry. (6)Prepare foam using a foaming solution with a dilution ratio of 30 - 50 times, add the foam to the obtained slurry, stir at a stirring speed of 300 - 400 r / min for 2 - 3 min, form, and cure to obtain high-strength and high-toughness gold tailings-based foam lightweight soil.

[0029] The following will further elaborate on the present invention in conjunction with specific embodiments. It should be noted that the specific embodiments are interpretations rather than limitations of the present invention.

[0030] In the following examples and comparative examples, all reagents are commercially available products. The length of the recycled fibers is 3 - 4 mm.

[0031] Table 1 Material Mix Ratio (by Mass Ratio)

[0032] Example 1 The mix proportion of the high-strength and high-toughness gold tailings-based foamed lightweight soil in this embodiment is shown in Table 1. Among them, the gypsum is fluorogypsum; the recycled fiber is waste fishing net; the foam stabilizer is dodecyldimethylamine oxide; the foaming agent is protein foaming agent.

[0033] The preparation method of using the high-strength and high-toughness gold tailings-based foamed lightweight soil in this embodiment as subgrade filler includes the following steps: (1) Grind blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, and incineration fly ash according to the proportions in Table 1 for 2 minutes at a rotation speed of 400 r / min to obtain a uniform powder mixture, which is reserved for later use; (2) Immerse the recycled fiber in deionized water for ultrasonic cleaning for 2 minutes and dry it at 60 °C for 24 hours; Mix absolute ethanol and deionized water in proportion to prepare an ethanol aqueous solution with a volume concentration of 95%, and add silane coupling agent KH550 (mass concentration of 5%) to obtain Solution A; Mix nano-silica and deionized water evenly (mass concentration of nano-silica is 2%) and perform ultrasonic dispersion to obtain nano-silica dispersion liquid B; Immerse the recycled fiber in Solution A at a ratio of 1:10, set the water bath temperature at 60 °C, take out the recycled fiber after 120 minutes of water bath, and repeatedly rinse it with deionized water until clean; Immerse the recycled fiber treated with Solution A in nano-silica dispersion liquid B, stir for 10 minutes and then take out the recycled fiber, rinse it with deionized water until clean, and then dry it at 60 °C for 24 hours to obtain modified recycled fiber for later use.

[0034] (3) Weigh sodium silicate and sodium hydroxide according to a mass ratio of 15:1, prepare a sodium silicate solution with a mass concentration of 5% for sodium silicate, dissolve sodium hydroxide in the sodium silicate solution, mix evenly, let it stand, and naturally cool to room temperature to prepare an alkaline activator, which is reserved for later use; (4) Weigh the foaming agent, foam stabilizer, and water according to a ratio of foaming agent: water = 1:30 (volume ratio), mix the foaming agent and foam stabilizer evenly and dissolve them in water to prepare a foaming solution, which is reserved for later use; (5) Mix the powder mixture, gold tailings sand, waste tire rubber powder, modified recycled fiber, alkaline activator, and water evenly according to the proportion and stir to obtain a slurry; (6) Prepare foam using a foaming solution with a dilution ratio of 30 times, add the foam to the obtained slurry, stir at a speed of 300 r / min for 2 minutes, form, and cure to obtain high-strength and high-toughness gold tailings-based foamed lightweight soil.

[0035] Example 2 The mix proportion of the high-strength and high-toughness gold tailings-based foamed lightweight soil in this embodiment is shown in Table 1: Among them, the gypsum is fluorogypsum; the recycled fiber is waste ships (glass fiber reinforced plastics from the hull deck part); the foam stabilizer is dodecyldimethylamine oxide; and the foaming agent is protein foaming agent.

[0036] The preparation method of the high-strength and high-toughness gold tailings-based foamed lightweight soil used as subgrade filler in this embodiment includes the following steps: (1) Proportionally ball-mill blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, and incineration fly ash for 2 min at a rotation speed of 500 r / min to obtain a uniform powder mixture, which is reserved for later use; (2) Immerse the recycled fiber in deionized water for ultrasonic cleaning for 3 min, and place it in an oven to dry at 60 °C for 24 h; Mix absolute ethanol and deionized water in proportion to prepare a 95% ethanol aqueous solution, and add silane coupling agent KH570 (mass concentration of 7%) to obtain solution A; Mix nano-silica and deionized water (mass concentration of nano-silica is 5%) and disperse them ultrasonically to obtain nano-silica dispersion B; Immerse the recycled fiber in solution A at a ratio of 1:10, set the water bath temperature of the constant temperature water bath to 60 °C, take out the recycled fiber after 160 min of water bath, and repeatedly rinse it with deionized water until clean; Immerse the recycled fiber treated with solution A in nano-silica dispersion B, stir it with a magnetic stirrer for 15 min, take out the recycled fiber, rinse it with deionized water until clean, and then place it in an oven to dry at 60 °C for 24 h for later use.

[0037] (3) Weigh sodium silicate and sodium hydroxide at a mass ratio of 28:1, prepare a sodium silicate solution with a mass concentration of 5% from sodium silicate, dissolve sodium hydroxide in the sodium silicate solution, mix and stir evenly, and let it stand and cool to room temperature to prepare an alkaline activator, which is reserved for later use; (4) Weigh the foaming agent, foam stabilizer, and water in proportion, mix the foaming agent and the foam stabilizer evenly and dissolve them in water to prepare a foaming solution, which is reserved for later use; (5) Mix the powder mixture, gold tailings sand, waste tire rubber powder, recycled fiber, alkaline activator, and water in proportion, and stir to obtain a slurry; (6) Prepare foam using a foaming solution with a dilution ratio of 50 times, add the foam to the obtained slurry, stir at a stirring speed of 350 r / min for 3 min, form, and cure to obtain the high-strength and high-toughness gold tailings-based foamed lightweight soil.

[0038] Example 3 The mix proportion of the high-strength and high-toughness gold tailings-based foamed lightweight soil in this embodiment is shown in Table 1: The above-mentioned gypsum is fluorogypsum; the recycled fiber is waste fishing net; the foam stabilizer is dodecyldimethylamine oxide; the foaming agent is protein foaming agent.

[0039] The preparation method of the high-strength and high-toughness gold tailings-based foamed lightweight soil used as subgrade filler in this embodiment includes the following steps: (1) Grind blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, and incineration fly ash proportionally for 3 minutes at a rotation speed of 500 r / min to obtain a uniform powder mixture, which is reserved for later use; (2) Immerse the recycled fiber in deionized water for ultrasonic cleaning for 3 minutes, and place it in an oven to dry at 60 °C for 24 hours; Mix absolute ethanol and deionized water proportionally to prepare a 95% ethanol aqueous solution, and add silane coupling agent KH792 (mass concentration of 10%) to obtain solution A; Mix nano-silica and deionized water (mass concentration of nano-silica is 5%), and perform ultrasonic dispersion to obtain nano-silica dispersion B; Immerse the recycled fiber in solution A at a ratio of 1:10, set the water bath temperature of the constant temperature water bath to 60 °C, take out the recycled fiber after 120 minutes of water bath, and repeatedly rinse it with deionized water until clean; Immerse the recycled fiber treated with solution A in nano-silica dispersion B, stir it with a magnetic stirrer for 10 minutes, then take out the recycled fiber, rinse it with deionized water, and then place it in an oven to dry at 60 °C for 24 hours for later use.

[0040] (3) Weigh sodium silicate and sodium hydroxide according to a mass ratio of 28:3, prepare a sodium silicate solution with a mass concentration of 5% for sodium silicate, dissolve sodium hydroxide in the sodium silicate solution, mix and stir evenly, and let it stand and cool to room temperature to prepare an alkaline activator, which is reserved for later use; (4) Weigh the foaming agent, foam stabilizer and water proportionally, mix the foaming agent and foam stabilizer evenly and dissolve them in water to prepare a foaming solution, which is reserved for later use; (5) Mix the powder mixture, gold tailings sand, waste tire rubber powder, recycled fiber, alkaline activator and water proportionally, and stir to obtain a slurry; (6) Prepare foam with a foaming solution with a dilution ratio of 40 times, add the foam to the obtained slurry, stir at a stirring speed of 400 r / min for 2 minutes, mold and cure to obtain high-strength and high-toughness gold tailings-based foamed lightweight soil.

[0041] Example 4 The mix proportion of the high-strength and high-toughness gold tailings-based foamed lightweight soil in this example is shown in Table 1: The above-mentioned gypsum is fluorogypsum; the recycled fiber is waste wind turbine blade; the foam stabilizer is dodecyldimethylamine oxide; the foaming agent is protein foaming agent.

[0042] In this embodiment, the preparation method of high-strength and high-toughness gold tailings-based foamed lightweight soil used as subgrade filler includes the following steps: (1) Grind blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, and incineration fly ash proportionally for 3 minutes at a rotation speed of 450 r / min to obtain a uniform powder mixture for later use; (2) Immerse the recycled fiber in deionized water for ultrasonic cleaning for 2 minutes, and dry it in an oven at 60 °C for 24 hours; Mix absolute ethanol and deionized water proportionally to prepare a 95% ethanol aqueous solution, and add silane coupling agent KH550 (mass concentration of 8%) to obtain solution A; Mix nano-silica and deionized water (mass concentration of nano-silica is 3%) and disperse them ultrasonically to obtain nano-silica dispersion B; Immerse the recycled fiber in solution A at a ratio of 1:10, set the water bath temperature of the constant temperature water bath to 60 °C, take out the recycled fiber after 150 minutes of water bath, and rinse it repeatedly with deionized water until clean; Immerse the recycled fiber treated with solution A in nano-silica dispersion B, stir it with a magnetic stirrer for 15 minutes, take out the recycled fiber, rinse it with deionized water until clean, and then place it in an oven and dry it at 60 °C for 24 hours for later use.

[0043] (3) Weigh sodium silicate and sodium hydroxide at a mass ratio of 15:3, prepare a 5% sodium silicate solution with sodium silicate, dissolve sodium hydroxide in the sodium silicate solution, mix and stir evenly, and let it stand and cool to room temperature to prepare an alkaline activator for later use; (4) Weigh the foaming agent, foam stabilizer, and water proportionally, mix the foaming agent and foam stabilizer evenly and dissolve them in water to prepare a foaming solution for later use; (5) Mix the powder mixture, gold tailings sand, waste tire rubber powder, recycled fiber, alkaline activator, and water proportionally and stir to obtain a slurry; (6) Prepare foam with a foaming solution with a dilution ratio of 40 times, add the foam to the obtained slurry, stir at a stirring speed of 380 r / min for 3 minutes, form, and cure to obtain high-strength and high-toughness gold tailings-based foamed lightweight soil.

[0044] Example 5 The mix proportion of the high-strength and high-toughness gold tailings-based foamed lightweight soil in this embodiment is shown in Table 1: The above-mentioned gypsum is fluorogypsum; the recycled fiber is waste fishing net; the foam stabilizer is dodecyldimethylamine oxide; the foaming agent is protein foaming agent.

[0045] In this embodiment, the preparation method of high-strength and high-toughness gold tailings-based foamed lightweight soil used as subgrade filler includes the following steps: (1)Proportionally ball-mill blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, and incineration fly ash for 2 minutes at a rotation speed of 500 r / min to obtain a uniform powder mixture for later use; (2)Soak the recycled fibers in deionized water for ultrasonic cleaning for 2 minutes, and dry them in an oven at 60 °C for 24 hours; Mix absolute ethanol and deionized water in proportion to prepare a 95% ethanol aqueous solution, and add silane coupling agent KH550 (mass concentration of 6%) to obtain solution A; Mix nano-silica and deionized water (mass concentration of nano-silica is 4%) and disperse them ultrasonically to obtain nano-silica dispersion B; Soak the recycled fibers in solution A at a ratio of 1:10, set the water bath temperature of the constant temperature water bath to 60 °C, take out the recycled fibers after 120 minutes of water bath, and rinse them repeatedly with deionized water until clean; Soak the recycled fibers treated with solution A in nano-silica dispersion B, stir with a magnetic stirrer for 12 minutes, take out the recycled fibers, rinse them with deionized water until clean, and then place them in an oven and dry at 60 °C for 24 hours for later use.

[0046] (3)Weigh sodium silicate and sodium hydroxide according to a mass ratio of 20:3, prepare a sodium silicate solution with a mass concentration of 5% for sodium silicate, dissolve sodium hydroxide in the sodium silicate solution, mix and stir evenly, and let it stand and cool to room temperature to prepare an alkaline activator for later use; (4)Weigh the foaming agent, foam stabilizer and water in proportion, mix the foaming agent and the foam stabilizer evenly and dissolve them in water to prepare a foaming solution for later use; (5)Mix the powder mixture, gold tailings sand, waste tire rubber powder, recycled fibers, alkaline activator and water in proportion and stir to obtain a slurry; (6)Prepare foam using a foaming solution with a dilution ratio of 35 times, add the foam to the obtained slurry, stir at a stirring speed of 360 r / min for 2 minutes, mold and cure to obtain high-strength and high-toughness gold tailings-based foam lightweight soil.

[0047] Example 6 The mix proportion of the high-strength and high-toughness gold tailings-based foam lightweight soil in this example is shown in Table 1: The above-mentioned gypsum is fluorogypsum; the recycled fibers are waste fishing nets; the foam stabilizer is dodecyldimethylamine oxide; the foaming agent is protein foaming agent.

[0048] The preparation method of the high-strength and high-toughness gold tailings-based foam lightweight soil used as subgrade filler in this example includes the following steps: (1)Proportionally ball-mill blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, and incineration fly ash for 3 minutes at a rotation speed of 480 r / min to obtain a uniform powder mixture for later use; (2) Immerse the recycled fibers in deionized water and perform ultrasonic cleaning for 2 min, then place them in an oven and dry at 60 °C for 24 h; Mix anhydrous ethanol and deionized water in proportion to prepare a 95% ethanol aqueous solution, and add silane coupling agent KH570 (mass concentration of 9%) to obtain solution A; Mix nano-silica and deionized water (mass concentration of nano-silica is 4%), and perform ultrasonic dispersion to obtain nano-silica dispersion B; Immerse the recycled fibers in solution A at a ratio of 1:10, set the water bath temperature of the constant temperature water bath to 60 °C, take out the recycled fibers after 170 min of water bath, and repeatedly rinse them clean with deionized water; Immerse the recycled fibers treated with solution A in nano-silica dispersion B, take out the recycled fibers after stirring with a magnetic stirrer for 18 min, and rinse them clean with deionized water, then place them in an oven and dry at 60 °C for 24 h for standby.

[0049] (3) Weigh sodium silicate and sodium hydroxide according to a mass ratio of 25:3, prepare a 5% sodium silicate solution from sodium silicate, dissolve sodium hydroxide in the sodium silicate solution, mix and stir evenly, and let it stand and cool to room temperature to prepare an alkaline activator for standby. (4) Weigh the foaming agent, foam stabilizer and water according to the proportion, mix the foaming agent and foam stabilizer evenly and dissolve them in water to prepare a foaming solution for standby. (5) Mix the powder mixture, gold tailings sand, waste tire rubber powder, recycled fibers, alkaline activator and water in proportion and stir to obtain a slurry. (6) Prepare foam using a foaming solution with a dilution ratio of 30 times, add the foam to the obtained slurry, stir at a stirring speed of 340 r / min for 2 min, form and cure to obtain high-strength and high-toughness gold tailings-based foam lightweight soil.

[0050] Comparative Example 1 The difference between this comparative example and Example 1 is that an equal amount of ordinary Portland cement PO42.5 is used to replace "blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, incineration fly ash and alkaline activator".

[0051] The raw material ratio of this comparative example is: 81 parts of ordinary Portland cement PO42.5, 30 parts of gold tailings sand, 1.2 parts of recycled fibers, 0.3 parts of foam stabilizer, 6 parts of foaming agent, and 76 parts of water. Other methods and steps are the same as those in Example 1 and will not be elaborated here.

[0052] Comparative Example 2 The difference between this comparative example and Example 1 is that all the gold tailings sand in the raw materials is replaced with an equal amount of traditional silty soil. Other methods and steps are the same as those in Example 1 and will not be elaborated here.

[0053] Comparative Example 3 The difference between this comparative example and Example 1 is that ordinary recycled fibers are used to replace the modified recycled fibers.

[0054] Comparative Example 4 The difference between this comparative example and Example 1 is that the raw materials do not contain recycled fibers.

[0055] Comparative Example 5 The difference between this comparative example and Example 1 is that no gold tailings powder is added, and the dosage of coal gasification slag powder is adjusted to 27 parts.

[0056] Comparative Example 6 The difference between this comparative example and Example 1 is that no coal gasification slag powder is added, and the dosage of gold tailings powder is adjusted to 27 parts.

[0057] Performance verification According to the "Technical Specification for Filling Engineering of Foamed Lightweight Soil" (CJJ / T 177-2012) and the "Test Methods for Properties of Autoclaved Aerated Concrete" (GB / T 11969-2020), combined with the on-site use environment, compressive strength tests, flexural strength tests, dry-wet cycle tests, and freeze-thaw cycle tests were carried out on the foamed lightweight soil specimens at 3d, 7d, and 28d for Examples 1-6 and Comparative Examples 1-6. The test results are shown in Table 2.

[0058] Table 2 Test results of performance tests

[0059] Figure 1 The foamed lightweight soil specimen for indoor test molding was prepared with the high-strength and high-toughness gold tailings-based foamed lightweight soil of Example 1. It can be seen from Table 2 that the compressive strengths of Examples 1-6 at 3d, 7d, 28d, and 90d are higher than those of Comparative Examples 1-6, and the flexural toughness and dry-wet strength coefficients are higher than those of Comparative Examples 1-6. This indicates that the compressive strength and water stability of the high-strength and high-toughness gold tailings-based foamed lightweight soil prepared in Examples 1-6 are superior to those of Comparative Examples 1-6. The freeze-thaw strength losses of Examples 1-6 are lower than those of Comparative Examples 1-6, which indicates that the frost resistance of the high-strength and high-toughness gold tailings-based foamed lightweight soil prepared in Examples 1-6 is superior to that of Comparative Examples 1-6.

[0060] It can be seen that the present invention uses multi-source solid wastes to replace traditional cement, adds waste tire rubber powder and modified recycled fibers, through the mutual excitation of various solid wastes, and adds an alkaline activator to promote the depolymerization reaction of the silicon-aluminum active components in the solid wastes to release [SiO4] 4- and [AlO4] 5-The plasma forms chemical bonds with the elastic sulfide network of the rubber powder and the polar groups grafted on the fiber surface, and is finally reconstructed into a multi-scale composite structure with C-(A)-S-H gel as the main phase, interspersed with elastic micro-regions and fiber-reinforced interfaces, thereby enhancing the strength, flexural toughness, water stability and frost resistance of the material.

[0061] From the comparison between Example 1 and Comparative Examples 5 and 6, it can be seen that, compared with using gold tailings powder or coal gasification slag powder alone, adding both of them can better improve the strength, flexural toughness, water stability and frost resistance of the material.

[0062] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A high-strength and high-toughness gold tailings-based foamed lightweight soil, characterized in that, It is composed of the following raw materials in parts by weight: 20 - 46 parts of blast furnace slag, 8 - 15 parts of gold tailings powder, 12 - 25 parts of coal gasification slag powder, 8 - 15 parts of carbide slag, 5 - 10 parts of gypsum, 5 - 15 parts of incineration fly ash, 1 - 3 parts of alkaline activator, 25 - 40 parts of gold tailings sand, 1 - 3 parts of waste tire rubber powder, 0.8 - 1.2 parts of modified recycled fiber, 0.1 - 0.3 parts of foam stabilizer, 4 - 7 parts of foaming agent, and 35 - 76 parts of water.

2. The high-strength and high-toughness gold tailings-based foamed lightweight soil according to claim 1, wherein The blast furnace slag is above S95 grade, and the mass percentage of SiO2 + CaO is greater than 80%; Or, the particle size of the gold tailings powder is less than 45μm, and the particle size of the gold tailings sand is less than 300μm; Or, in the coal gasification slag powder, the mass percentage of SiO2 + CaO + Al2O3 is greater than 80%; Or, the gypsum is selected from at least one of phosphogypsum, desulfurized gypsum, or fluorogypsum; Or, in the incineration fly ash, the mass percentage of SiO2 + CaO + Al2O3 is greater than 75%.

3. The high-strength and high-toughness gold tailings-based foamed lightweight soil according to claim 1, characterized in that, The alkaline activator is composed of sodium silicate and sodium hydroxide, and the mass ratio of the two is (15 - 28):(1 - 3).

4. The high-strength and high-toughness gold tailings-based foamed lightweight soil according to claim 1, characterized in that, The recycled fiber is selected from at least one of waste ships, waste wind turbine blades, and waste fishing nets, and the fiber length is 3 - 4mm.

5. The high-strength and high-toughness gold tailings-based foamed lightweight soil according to claim 1, wherein The modified recycled fiber is obtained by sequentially modifying the recycled fiber with a silane coupling agent and nano - silica.

6. The high-strength and high-toughness gold tailings-based foamed lightweight soil according to claim 1, characterized in that, The foam stabilizer is selected from at least one of dodecyldimethylamine oxide, polyvinyl alcohol, and diethanolamide.

7. The high-strength and high-toughness gold tailings-based foamed lightweight soil according to claim 1, wherein, The foaming agent is selected from at least one of protein foaming agent, sodium dodecyl sulfate, and lignosulfonate.

8. A method for preparing the high-strength and high-toughness gold tailings-based foamed lightweight soil according to any one of claims 1-7, characterized in that, It includes: Mix blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, and incineration fly ash, and ball - mill to obtain a powder mixture; Mix the foaming agent and the foam stabilizer evenly and dissolve them in water to prepare a foaming liquid; Mix the powder mixture, gold tailings sand, waste tire rubber powder, modified recycled fiber, alkaline activator, and water evenly to obtain a slurry; Prepare foam using the foaming liquid, add the foam to the obtained slurry, mix evenly, form, and cure to obtain the product.

9. The preparation method of the high-strength and high-toughness gold tailings-based foamed light soil according to claim 8, wherein, The dilution ratio of the foaming liquid is 30 - 50 times.

10. Application of the high - strength and high - toughness gold tailings - based foam lightweight soil according to any one of claims 1 - 7 or the high - strength and high - toughness gold tailings - based foam lightweight soil prepared by the preparation method according to any one of claims 8 and 9 in the preparation of subgrade fillers.

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