A high-strength and high-toughness gold tailings-based foamed lightweight soil and its preparation method and application

Abstract

The present invention provides a high-strength and high-toughness gold tailings-based foamed lightweight soil and its preparation method and application, which belongs to the field of roadbed engineering technology and concrete. Calculated by mass, it includes: 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. The foamed lightweight soil has strong bearing capacity, high toughness, low cost, and good fluidity. It is used as a roadbed filler and can effectively adapt to foundation deformation on the basis of meeting roadbed performance requirements, avoid local stress concentration, enhance earthquake resistance, improve fatigue resistance, and reduce maintenance costs.

Description

Technical Field

[0001] The present invention belongs to the field of roadbed engineering technology 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 Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] Foamed lightweight soil is a lightweight material primarily composed of cement, water, and foam. Because it can reduce the load or soil pressure in fill projects, it is widely used in roadbed construction, such as treating soft foundations behind bridge abutments, embankments on weak foundations, and road widening embankments. However, traditional cement firing is energy-intensive and emits high carbon emissions, leading to the development of solid waste-based foamed lightweight soils. Examples include bauxite tailings-based foamed lightweight soils and red mud-based foamed lightweight soils. While these foamed lightweight soils utilize one or more solid waste materials, they still use some cement. Current all-solid waste-based foamed concrete often struggles to achieve both high strength and high toughness. Summary of the Invention

[0004] To address the above-mentioned issues, the present invention provides a high-strength, high-toughness gold tailings-based foamed lightweight soil, its preparation method, and its application. This invention utilizes a solid waste-based gel system composed of blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, incineration fly ash, and an alkaline activator. Without the introduction of cement, the foamed lightweight soil prepared in this invention exhibits both high strength and high toughness. The foamed lightweight soil prepared from solid waste materials in this invention has the advantages of strong bearing capacity, high toughness, low cost, and good fluidity. When used as a roadbed filler, it can effectively adapt to foundation deformation while meeting roadbed performance requirements, avoiding local stress concentration, enhancing seismic resistance, improving fatigue resistance, and reducing maintenance costs.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The first aspect of 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.

[0007] The present invention utilizes bulk solid waste materials to prepare a low-carbon, low-cost foamed lightweight soil with high strength and toughness for use as roadbed filler. First, blast furnace slag, gold tailings powder, coal gasification slag powder, and incineration fly ash are used as active admixtures, providing rich silicon, aluminum, 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, it creates an alkaline environment. In this environment, alkaline ions (such as hydroxide) can destroy 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 in the gypsum reacts with cations in other solid wastes (such as calcium ions, aluminum ions, etc.), changing the surface charge properties of the solid waste particles and further activating the particles. The active ions and small molecular clusters released after depolymerization react with Ca²⁺ (calcium ions) and other substances to form hydration reactions. The active silicon ions react with Ca²⁺ and OH⁻ (hydroxyl groups) to form C-(A)-SH gel. 3+ Aluminum ions react with Ca²⁺, SO⁻²⁻ (sulfate), and OH⁻ to form ettringite. These hydration products grow and intertwine, forming a three-dimensional network that tightly connects the solid waste particles. New chemical bonds are continuously formed during this process. The various chemical bonds in the C-(A)-SH gel and the unique crystal structure of ettringite impart high strength and stability to the material, enhancing its resistance to external damage and strengthening the material. Secondly, gold tailings powder and sand form a strong framework within the foamed lightweight soil, while fine aggregate fills the pores and increases the material's density.

[0008] A second aspect of the present invention provides a method for preparing the above-mentioned high-strength and high-toughness gold tailings-based foamed lightweight soil, comprising:

[0009] Blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, and incineration fly ash are mixed and ball-milled to obtain a powder mixture;

[0010] The foaming agent and the foam stabilizer are mixed evenly and then dissolved in water to prepare a foaming liquid;

[0011] The powder mixture, gold tailings sand, waste tire rubber powder, modified recycled fiber, alkaline activator and water are uniformly mixed to obtain a slurry;

[0012] The foaming liquid is used to prepare foam, and the foam is added into the obtained slurry, mixed evenly, formed, and cured to obtain the product.

[0013] The third aspect of the present invention provides the use of the above-mentioned high-strength and high-toughness gold tailings-based foamed lightweight soil or the high-strength and high-toughness gold tailings-based foamed lightweight soil prepared by the above-mentioned preparation method in preparing roadbed fillers.

[0014] Beneficial effects of the present invention

[0015] (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, calcium carbide slag, gypsum, incineration fly ash and alkaline activator as low-carbon cementitious materials, replaces traditional silt soil with gold tailings sand, uses waste tire rubber powder and recycled fiber as toughening agents, and combines with foaming agent and foam stabilizer to prepare foam lightweight soil. It has low carbon, low cost and high strength and high toughness. When used as roadbed filler, it meets the strength requirements of the current "Technical Code for Bubble Mixed Lightweight Soil Filling Engineering" (CJJ / T 177-2012). At the same time, it can effectively adapt to foundation deformation. When the weak foundation settles, it deforms moderately without being damaged, preventing the roadbed from cracking and collapsing; it can disperse vehicle load stress and avoid local stress concentration; it can enhance seismic resistance, absorb energy during earthquakes, reduce the degree of earthquake damage, and ensure traffic after the earthquake; it has improved fatigue resistance and is not easily damaged by repeated vehicle loads.

[0016] (2) The present invention utilizes multi-source solid waste to replace cement, which is in line with the goals of environmental protection development and green highway construction, reduces production costs, and is conducive to promoting the comprehensive utilization of bulk solid waste.

[0017] (3) The preparation method of the present invention is simple, practical, and easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which constitute 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 description are used to explain the present invention and do not constitute improper limitations on the present invention.

[0019] Figure 1 The foamed lightweight soil specimen is formed in an indoor test by using the high-strength and high-toughness gold tailings-based foamed lightweight soil of Example 1 of the present invention. DETAILED DESCRIPTION

[0020] It should be noted that the following detailed descriptions are exemplary and 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 meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0021] As described in the background technology, the toughness of foamed lightweight soil as a roadbed material is crucial. First, it can effectively adapt to foundation deformation. When the weak foundation settles, it deforms moderately without being damaged, preventing the roadbed from cracking and collapsing. Secondly, it can disperse vehicle load stress, avoid local stress concentration, and extend the service life of the roadbed. Furthermore, it enhances seismic resistance, absorbs energy during an earthquake, reduces the degree of earthquake damage, and ensures post-earthquake traffic. In addition, it improves fatigue resistance and is not easily damaged by fatigue when subjected to repeated vehicle loads. Finally, it facilitates construction and subsequent maintenance, is not prone to cracking and segregation during construction, and is easy to repair if damaged, reducing maintenance costs. In addition, the frost resistance and resistance to dry-wet cycles of foamed lightweight soil are also crucial to foundation treatment performance. Therefore, it is urgent to develop a low-carbon, low-cost foamed lightweight soil that has both high strength and high toughness.

[0022] 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.

[0023] Preferably, the blast furnace slag is of grade S95 or above, and the mass percentage of SiO2+CaO is greater than 80%;

[0024] Preferably, the particle size of the gold tailings powder is less than 45 μm, and the particle size of the gold tailings sand is less than 300 μm;

[0025] Preferably, the mass percentage of SiO2+CaO+Al2O3 in the coal gasification slag powder is greater than 80%;

[0026] Preferably, the gypsum is selected from at least one of phosphogypsum, desulfurized gypsum or fluorinated gypsum;

[0027] Preferably, the mass percentage of SiO2+CaO+Al2O3 in the incineration fly ash is greater than 75%.

[0028] Preferably, the alkaline activator is composed of sodium silicate and sodium hydroxide, and the mass ratio of the two is (15-28): (1-3).

[0029] Preferably, the recycled fiber is selected from at least one of waste ships, waste wind blades and waste fishing nets, and has a fiber length of 3-4 mm and a fiber diameter of 8 μm to 48 μm.

[0030] Preferably, the modified recycled fiber is obtained by sequentially modifying recycled fiber with a silane coupling agent and then nano-silica. When the recycled fiber is modified with a silane coupling agent, one end of the silane coupling agent molecule forms a chemical bond on the fiber surface, while the other end undergoes a physical or chemical reaction with the cement hydration product in the foamed lightweight soil, forming a transition layer between the two. This enhances interfacial adhesion and allows the modified recycled fiber to effectively transfer stress. When microcracks form in the foamed lightweight soil due to external forces, the modified recycled fiber, with its excellent adhesion, withstands and disperses the stress at the crack tip, changing the direction of crack expansion, consuming energy, and hindering further crack development. Furthermore, due to the action of the silane coupling agent, the modified recycled fiber can be evenly dispersed in the matrix, dispersing concentrated stress to the surrounding matrix and avoiding localized stress concentration. Furthermore, the modified recycled fiber increases the internal friction of the foamed lightweight soil mixture, reduces fluidity loss, prevents segregation and water exudation, and improves working performance. Simultaneously, modification with nano-silica can improve the strength and durability of the foamed lightweight soil.

[0031] More preferably, the silane coupling agent is selected from at least one of KH550, KH570, and KH792.

[0032] Preferably, the fluidity of the high-strength and high-toughness gold tailings-based foamed lightweight soil is 200-250 mm.

[0033] Preferably, the foam stabilizer is selected from at least one of dodecyldimethylamine oxide, polyvinyl alcohol, and diethanolamide.

[0034] Preferably, the foaming agent is selected from at least one of a protein foaming agent, sodium lauryl sulfate, and lignin sulfonate.

[0035] The present invention also provides a method for preparing the above-mentioned high-strength and high-toughness gold tailings-based foamed lightweight soil, comprising:

[0036] Blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, and incineration fly ash are mixed and ball-milled to obtain a powder mixture;

[0037] The foaming agent and the foam stabilizer are mixed evenly and then dissolved in water to prepare a foaming liquid;

[0038] The powder mixture, gold tailings sand, waste tire rubber powder, modified recycled fiber, alkaline activator and water are uniformly mixed to obtain a slurry;

[0039] The foaming liquid is used to prepare foam, and the foam is added into the obtained slurry, mixed evenly, formed, and cured to obtain the product.

[0040] Preferably, the dilution ratio of the foaming liquid is 30-50 times.

[0041] More specifically, they include:

[0042] (1) Ball mill blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, and incineration fly ash in proportion, with a ball milling time of 2-3 minutes and a rotation speed of 400-500 r / min to obtain a uniform powder mixture, which is retained for later use;

[0043] (2) Soak the recycled fiber in deionized water for ultrasonic cleaning for 2-3 minutes, and place it in an oven at 60°C for drying for 24 hours; mix anhydrous 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 nano-silica dispersion B; soak the recycled fiber in solution A in proportion, set the water bath temperature of the constant temperature water bath to 60°C, take out the recycled fiber after the water bath for 120-180 minutes, and rinse it repeatedly with deionized water; then soak the recycled fiber treated with solution A in nano-silica dispersion B, stir it with a magnetic stirrer for 10-20 minutes, take out the fiber, rinse it with deionized water, and then place it in an oven and dry it at 60°C for 24 hours to obtain modified recycled fiber.

[0044] (3) Weigh sodium silicate solution and sodium hydroxide in proportion, prepare sodium silicate solution with a mass concentration of 5%, dissolve sodium hydroxide in the sodium silicate solution, mix and stir evenly, let stand and cool to room temperature to prepare alkaline activator, and keep it for later use;

[0045] (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 liquid, which is retained for later use;

[0046] (5) Mix the powder mixture, gold tailings sand, waste tire rubber powder, recycled fiber / modified recycled fiber, alkaline activator and water in proportion and stir to obtain a slurry;

[0047] (6) A foaming liquid with a dilution ratio of 30-50 times is used to prepare foam, and the foam is added to the resulting slurry, stirred at a stirring speed of 300-400 r / min for 2-3 minutes, formed, and cured to obtain high-strength and high-toughness gold tailings-based foamed lightweight soil.

[0048] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are intended to explain the present invention rather than to limit it.

[0049] In the following examples and comparative examples, all reagents were commercially available products, and the length of the recycled fibers was 3-4 mm.

[0050] Table 1 Material Proportion (Mass Ratio)

[0051]

[0052] Example 1

[0053] The formulation of the high-strength and high-toughness gold tailings-based foamed lightweight soil of this embodiment is shown in Table 1, wherein the gypsum is fluorgypsum; the recycled fiber is waste fishing nets; the foam stabilizer is dodecyl dimethyl amine oxide; and the foaming agent is a protein foaming agent.

[0054] The method for preparing the high-strength and high-toughness gold tailings-based foamed lightweight soil used as roadbed filler in this embodiment includes the following steps:

[0055] (1) Ball mill blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, and incineration fly ash according to the proportions in Table 1. The ball milling time is 2 min and the speed is 400 r / min to obtain a uniform powder mixture, which is retained for later use.

[0056] (2) The recycled fiber was immersed in deionized water for ultrasonic cleaning for 2 minutes and dried at 60°C for 24 hours; anhydrous ethanol and deionized water were mixed in proportion to prepare an ethanol-water solution with a volume concentration of 95%, and a silane coupling agent KH550 (mass concentration of 5%) was added to obtain solution A; nano-silica and deionized water were mixed evenly (the mass concentration of nano-silica was 2%), and ultrasonically dispersed to obtain nano-silica dispersion B; the recycled fiber was immersed in solution A at a ratio of 1:10, and the water bath temperature was set to 60°C. After 120 minutes of water bath, the recycled fiber was taken out and repeatedly rinsed with deionized water; the recycled fiber treated with solution A was immersed in nano-silica dispersion B, stirred for 10 minutes, and then the recycled fiber was taken out and rinsed with deionized water, and then dried at 60°C for 24 hours to obtain modified recycled fiber for standby use.

[0057] (3) Sodium silicate and sodium hydroxide are weighed in a mass ratio of 15:1, and the sodium silicate is prepared into a sodium silicate solution with a mass concentration of 5%. Sodium hydroxide is dissolved in the sodium silicate solution, mixed evenly, allowed to stand, and naturally cooled to room temperature to prepare an alkaline activator, which is retained for later use;

[0058] (4) Weigh the foaming agent, foam stabilizer and water in a ratio of 1:30 (volume ratio), mix the foaming agent and foam stabilizer evenly and dissolve them in water to prepare a foaming liquid, which is retained for later use;

[0059] (5) Evenly mix the powder mixture, gold tailings sand, waste tire rubber powder, modified recycled fiber, alkaline activator and water in proportion, and stir to obtain a slurry;

[0060] (6) A foaming liquid with a dilution ratio of 30 times was used to prepare foam, and the foam was added to the resulting slurry, stirred at a speed of 300 r / min for 2 minutes, formed, and cured to obtain high-strength and high-toughness gold tailings-based foamed lightweight soil.

[0061] Example 2

[0062] The formulation of the high-strength and high-toughness gold tailings-based foamed lightweight soil of this embodiment is shown in Table 1: wherein the gypsum is fluorgypsum; the recycled fiber is from scrap ships (glass fiber reinforced plastic from the deck area of ​​the hull); the foam stabilizer is dodecyl dimethyl amine oxide; and the foaming agent is a protein foaming agent.

[0063] The method for preparing high-strength and high-toughness gold tailings-based foamed lightweight soil used as roadbed filler in this embodiment includes the following steps:

[0064] (1) Ball mill blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, and incineration fly ash in proportion, with a ball milling time of 2 minutes and a speed of 500 r / min to obtain a uniform powder mixture, which is retained for later use;

[0065] (2) Soak the recycled fiber in deionized water for ultrasonic cleaning for 3 minutes, and place it in an oven at 60°C for 24 hours; mix anhydrous ethanol and deionized water in proportion to prepare a 95% ethanol aqueous solution, and add silane coupling agent KH570 (mass concentration is 7%) to obtain solution A; mix nano-silica and deionized water (the mass concentration of nano-silica is 5%), and ultrasonically disperse to obtain nano-silica dispersion B; soak 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 the water bath for 160 minutes, and rinse it repeatedly with deionized water; soak 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, and then place it in an oven and dry it at 60°C for 24 hours for use.

[0066] (3) Sodium silicate and sodium hydroxide are weighed in a mass ratio of 28:1, and the sodium silicate is prepared into a sodium silicate solution with a mass concentration of 5%. Sodium hydroxide is dissolved in the sodium silicate solution, and the mixture is mixed and stirred evenly. The mixture is allowed to stand and cool to room temperature to obtain an alkaline activator, which is retained for later use;

[0067] (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 liquid, which is retained for later use;

[0068] (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;

[0069] (6) A foaming liquid with a dilution ratio of 50 times was used to prepare foam, and the foam was added to the resulting slurry. The slurry was stirred at a stirring speed of 350 r / min for 3 minutes, formed, and cured to obtain a high-strength and high-toughness gold tailings-based foamed lightweight soil.

[0070] Example 3

[0071] The composition ratio of the high-strength and high-toughness gold tailings-based foamed lightweight soil of this embodiment is shown in Table 1:

[0072] The above-mentioned gypsum is fluorgypsum; the recycled fiber is waste fishing nets; the foam stabilizer is dodecyl dimethyl amine oxide; and the foaming agent is protein foaming agent.

[0073] The method for preparing high-strength and high-toughness gold tailings-based foamed lightweight soil used as roadbed filler in this embodiment includes the following steps:

[0074] (1) Ball mill blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, and incineration fly ash in proportion, with a ball milling time of 3 minutes and a speed of 500 r / min to obtain a uniform powder mixture, which is retained for later use;

[0075] (2) The recycled fiber was soaked in deionized water for ultrasonic cleaning for 3 minutes, and then placed in an oven at 60°C for drying for 24 hours; anhydrous ethanol and deionized water were mixed in proportion to prepare a 95% ethanol aqueous solution, and a silane coupling agent KH792 (mass concentration was 10%) was added to obtain solution A; nano-silica and deionized water were mixed (the mass concentration of nano-silica was 5%), and ultrasonically dispersed to obtain nano-silica dispersion B; the recycled fiber was soaked in solution A at a ratio of 1:10, and the water bath temperature of the constant temperature water bath was set to 60°C. After the water bath was kept for 120 minutes, the recycled fiber was taken out and repeatedly rinsed with deionized water; the recycled fiber treated with solution A was soaked in nano-silica dispersion B, stirred with a magnetic stirrer for 10 minutes, and then the recycled fiber was taken out and rinsed with deionized water. Then, the recycled fiber was placed in an oven and dried at 60°C for 24 hours for use.

[0076] (3) Sodium silicate and sodium hydroxide are weighed in a mass ratio of 28:3, and the sodium silicate is prepared into a sodium silicate solution with a mass concentration of 5%. Sodium hydroxide is dissolved in the sodium silicate solution, and the mixture is mixed and stirred evenly. The mixture is allowed to stand and cool to room temperature to obtain an alkaline activator, which is retained for later use;

[0077] (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 liquid, which is retained for later use;

[0078] (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;

[0079] (6) A foaming liquid with a dilution ratio of 40 times was used to prepare foam, and the foam was added to the resulting slurry. The slurry was stirred at a stirring speed of 400 r / min for 2 min, shaped, and cured to obtain a high-strength and high-toughness gold tailings-based foamed lightweight soil.

[0080] Example 4

[0081] The composition ratio of the high-strength and high-toughness gold tailings-based foamed lightweight soil of this embodiment is shown in Table 1:

[0082] The above-mentioned gypsum is fluorgypsum; the recycled fiber is waste wind blades; the foam stabilizer is dodecyl dimethyl amine oxide; and the foaming agent is protein foaming agent.

[0083] The method for preparing high-strength and high-toughness gold tailings-based foamed lightweight soil used as roadbed filler in this embodiment includes the following steps:

[0084] (1) Ball mill blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, and incineration fly ash in proportion, with a ball milling time of 3 minutes and a rotation speed of 450 r / min to obtain a uniform powder mixture, which is retained for later use;

[0085] (2) Soak the recycled fiber in deionized water for ultrasonic cleaning for 2 minutes, and place it in an oven at 60°C for 24 hours; mix anhydrous ethanol and deionized water in proportion to prepare a 95% ethanol aqueous solution, and add silane coupling agent KH550 (mass concentration is 8%) to obtain solution A; mix nano-silica and deionized water (the mass concentration of nano-silica is 3%), and ultrasonically disperse to obtain nano-silica dispersion B; soak 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 the water bath for 150 minutes, and rinse it repeatedly with deionized water; soak 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, and then place it in an oven and dry it at 60°C for 24 hours for use.

[0086] (3) Sodium silicate and sodium hydroxide are weighed in a mass ratio of 15:3, and the sodium silicate is prepared into a sodium silicate solution with a mass concentration of 5%. Sodium hydroxide is dissolved in the sodium silicate solution, and the mixture is mixed and stirred evenly. The mixture is allowed to stand and cool to room temperature to obtain an alkaline activator, which is retained for later use;

[0087] (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 liquid, which is retained for later use;

[0088] (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;

[0089] (6) A foaming liquid with a dilution ratio of 40 times was used to prepare foam, and the foam was added to the resulting slurry. The slurry was stirred at a stirring speed of 380 r / min for 3 minutes, shaped, and cured to obtain a high-strength and high-toughness gold tailings-based foamed lightweight soil.

[0090] Example 5

[0091] The composition ratio of the high-strength and high-toughness gold tailings-based foamed lightweight soil of this embodiment is shown in Table 1:

[0092] The above-mentioned gypsum is fluorgypsum; the recycled fiber is waste fishing nets; the foam stabilizer is dodecyl dimethyl amine oxide; and the foaming agent is protein foaming agent.

[0093] The method for preparing high-strength and high-toughness gold tailings-based foamed lightweight soil used as roadbed filler in this embodiment includes the following steps:

[0094] (1) Ball mill blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, and incineration fly ash in proportion, with a ball milling time of 2 minutes and a speed of 500 r / min to obtain a uniform powder mixture, which is retained for later use;

[0095] (2) Soak the recycled fiber in deionized water for ultrasonic cleaning for 2 minutes, and place it in an oven at 60°C for 24 hours; mix anhydrous ethanol and deionized water in proportion to prepare a 95% ethanol aqueous solution, and add silane coupling agent KH550 (mass concentration is 6%) to obtain solution A; mix nano-silica and deionized water (the mass concentration of nano-silica is 4%), and ultrasonically disperse to obtain nano-silica dispersion B; soak 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 the water bath for 120 minutes, and rinse it repeatedly with deionized water; soak the recycled fiber treated with solution A in nano-silica dispersion B, stir it with a magnetic stirrer for 12 minutes, take out the recycled fiber, rinse it with deionized water, and then place it in an oven and dry it at 60°C for 24 hours for use.

[0096] (3) Sodium silicate and sodium hydroxide are weighed in a mass ratio of 20:3, and the sodium silicate is prepared into a sodium silicate solution with a mass concentration of 5%. Sodium hydroxide is dissolved in the sodium silicate solution, and the mixture is mixed and stirred evenly. The mixture is allowed to stand and cool to room temperature to obtain an alkaline activator, which is retained for later use;

[0097] (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 liquid, which is retained for later use;

[0098] (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;

[0099] (6) A foaming liquid with a dilution ratio of 35 times was used to prepare foam, and the foam was added to the resulting slurry. The slurry was stirred at a stirring speed of 360 r / min for 2 min, formed, and cured to obtain a high-strength and high-toughness gold tailings-based foamed lightweight soil.

[0100] Example 6

[0101] The composition ratio of the high-strength and high-toughness gold tailings-based foamed lightweight soil of this embodiment is shown in Table 1:

[0102] The above-mentioned gypsum is fluorgypsum; the recycled fiber is waste fishing nets; the foam stabilizer is dodecyl dimethyl amine oxide; and the foaming agent is protein foaming agent.

[0103] The method for preparing high-strength and high-toughness gold tailings-based foamed lightweight soil used as roadbed filler in this embodiment includes the following steps:

[0104] (1) Ball mill blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, and incineration fly ash in proportion, with a ball milling time of 3 minutes and a rotation speed of 480 r / min to obtain a uniform powder mixture, which is retained for later use;

[0105] (2) Soak the recycled fiber in deionized water for ultrasonic cleaning for 2 minutes, and place it in an oven at 60°C for 24 hours; mix anhydrous ethanol and deionized water in proportion to prepare a 95% ethanol aqueous solution, and add silane coupling agent KH570 (mass concentration is 9%) to obtain solution A; mix nano-silica and deionized water (the mass concentration of nano-silica is 4%), and ultrasonically disperse to obtain nano-silica dispersion B; soak 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 170 minutes of water bath, and rinse it repeatedly with deionized water; soak the recycled fiber treated with solution A in nano-silica dispersion B, stir it with a magnetic stirrer for 18 minutes, take out the recycled fiber, rinse it with deionized water, and then place it in an oven and dry it at 60°C for 24 hours for use.

[0106] (3) Sodium silicate and sodium hydroxide are weighed in a mass ratio of 25:3, and the sodium silicate is prepared into a sodium silicate solution with a mass concentration of 5%. Sodium hydroxide is dissolved in the sodium silicate solution, and the mixture is mixed and stirred evenly. The mixture is allowed to stand and cool to room temperature to obtain an alkaline activator, which is retained for later use;

[0107] (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 liquid, which is retained for later use;

[0108] (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;

[0109] (6) A foaming liquid with a dilution ratio of 30 times was used to prepare foam, and the foam was added to the resulting slurry. The slurry was stirred at a stirring speed of 340 r / min for 2 min, formed, and cured to obtain a high-strength and high-toughness gold tailings-based foamed lightweight soil.

[0110] Comparative Example 1

[0111] The difference between this comparative example and Example 1 is that equal parts of ordinary silicate PO42.5 cement are used to replace "blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, incineration fly ash and alkaline activator".

[0112] The raw material ratio of this comparative example is: 81 parts of ordinary silicate PO42.5 cement, 30 parts of gold tailings sand, 1.2 parts of recycled fiber, 0.3 parts of foam stabilizer, 6 parts of foaming agent, and 76 parts of water. The other methods and steps are the same as those in Example 1 and are not repeated here.

[0113] Comparative Example 2

[0114] The difference between this comparative example and Example 1 is that the gold tailings sand in the raw material is replaced with equal parts of traditional silt soil. The other methods and steps are the same as those in Example 1 and are not repeated here.

[0115] Comparative Example 3

[0116] The difference between this comparative example and Example 1 is that ordinary recycled fiber is used instead of modified recycled fiber.

[0117] Comparative Example 4

[0118] The difference between this comparative example and Example 1 is that the raw materials do not contain recycled fiber.

[0119] Comparative Example 5

[0120] The difference between this comparative example and Example 1 is that no gold tailings powder is added, and the amount of coal gasification slag powder is adjusted to 27 parts.

[0121] Comparative Example 6

[0122] The difference between this comparative example and Example 1 is that no coal gasification slag powder is added, and the amount of gold tailings powder is adjusted to 27 parts.

[0123] Performance Verification

[0124] According to the "Technical Code for Bubble Mixed Lightweight Soil Fill Engineering" (CJJ / T 177-2012) and the "Test Method for Performance of Autoclaved Aerated Concrete" (GB / T 11969-2020) and combined with the on-site use environment, the foam lightweight soil specimens of Examples 1-6 and Comparative Examples 1-6 were subjected to 3d, 7d and 28d compressive strength tests, flexural strength tests, dry-wet cycle tests, and freeze-thaw cycle tests. The test results are shown in Table 2.

[0125] Table 2 Performance test results

[0126]

[0127] Figure 1 The foamed lightweight soil specimens prepared using the high-strength, high-toughness gold tailings-based foamed lightweight soil of Example 1 were produced in an indoor test. As can be seen in Table 2, the compressive strength of Examples 1-6 at 3d, 7d, 28d, and 90d was higher than that of Comparative Examples 1-6, and the flexural toughness and dry-wet strength coefficient were higher than those of Comparative Examples 1-6. This indicates that the high-strength, high-toughness gold tailings-based foamed lightweight soil prepared in Examples 1-6 has superior compressive strength and water stability to Comparative Examples 1-6. The freeze-thaw strength loss of Examples 1-6 was lower than that of Comparative Examples 1-6, indicating that the high-strength, high-toughness gold tailings-based foamed lightweight soil prepared in Examples 1-6 has superior frost resistance to Comparative Examples 1-6.

[0128] It can be seen that the present invention uses multi-source solid waste to replace traditional cement, adds waste tire rubber powder and modified recycled fiber, and through the mutual stimulation of multiple solid wastes and the addition of alkaline stimulators, promotes the depolymerization reaction of the silicon-aluminum active components in the solid waste to release [SiO4] 4- 、[AlO4] 5- Plasma chemically bonds with the elastic sulfide network of rubber powder and the polar groups grafted on the fiber surface, and eventually reconstructs into a multi-scale composite structure with C-(A)-SH 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.

[0129] From the comparison between Example 1 and Comparative Examples 5 and 6, it can be seen that, compared with the use of gold tailings powder or coal gasification slag powder alone, the simultaneous addition of both can better improve the strength, bending toughness, water stability and frost resistance of the material.

[0130] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A high-strength and high-toughness gold tailings-based foamed lightweight soil, characterized in that: The invention 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, characterized in that: The blast furnace slag is of grade S95 or above, and the mass percentage of SiO2+CaO is greater than 80%; Or, the particle size of the gold tailings powder is less than 45 μm, and the particle size of the gold tailings sand is less than 300 μm; Or, the mass percentage of SiO2+CaO+Al2O3 in the coal gasification slag powder is greater than 80%; Or, the gypsum is selected from at least one of phosphogypsum, desulfurized gypsum or fluorinated gypsum; Alternatively, the mass percentage of SiO2+CaO+Al2O3 in the incineration fly ash 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 consists 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 blades and waste fishing nets, and the fiber length is 3-4 mm.

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

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 dodecyl dimethyl amine oxide, polyvinyl alcohol, and diethanolamide.

7. The high-strength and high-toughness gold tailings-based foamed lightweight soil according to claim 1, characterized in that: The foaming agent is selected from at least one of a protein foaming agent, sodium lauryl sulfate, and lignin sulfonate.

8. A method for preparing the high-strength and high-toughness gold tailings-based foamed lightweight soil according to any one of claims 1 to 7, characterized in that: include: Blast furnace slag, gold tailings powder, coal gasification slag powder, carbide slag, gypsum, and incineration fly ash are mixed and ball-milled to obtain a powder mixture; The foaming agent and the foam stabilizer are mixed evenly and then dissolved in water to prepare a foaming liquid; The powder mixture, gold tailings sand, waste tire rubber powder, modified recycled fiber, alkaline activator and water are uniformly mixed to obtain a slurry; The foaming liquid is used to prepare foam, and the foam is added into the obtained slurry, mixed evenly, formed, and cured to obtain the product.

9. The method for preparing high-strength and high-toughness gold tailings-based foamed lightweight soil according to claim 8, characterized in that: The dilution ratio of the foaming liquid is 30-50 times.

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

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