Lightweight energy-saving fireproof soil base foam lightweight soil and preparation method thereof

Abstract

This invention discloses a lightweight, energy-saving, and fire-resistant soil-based foam lightweight soil, made from the following raw materials in parts by weight: 20-30 parts magnesium slag powder, 20-30 parts granulated blast furnace slag powder, 15-25 parts iron tailings powder, 40 parts soil, 6 parts water glass, 10 parts desulfurized gypsum, 0.28-0.43 parts polycarboxylate superplasticizer, 57-75 parts water, 0.76-1.00 parts AOS foaming agent, 0.16-0.26 parts HPMC foam stabilizer, and 0.16-0.26 parts calcium stearate foam stabilizer. The preparation method is as follows: 1. Mixing and stirring dry powder materials; 2. Preparing slurry; 3. Preparing soil-based foam lightweight soil; 4. Molding and curing. This invention optimizes the composition and proportion of raw materials to construct a three-dimensional skeleton dense structure, resulting in soil-based foamed lightweight soil with low thermal conductivity, low density, and high strength. It is suitable for roof insulation, wall and roadbed filling, bridge abutment backfill, foundation pit, pipeline backfill, and landscape engineering.

Description

Technical Field

[0001] This invention belongs to the field of building materials technology, specifically relating to a lightweight, energy-saving, and fire-resistant soil-based foam lightweight soil and its preparation method. Background Technology

[0002] Foamed lightweight soil is a new type of lightweight thermal insulation material containing numerous closed pores. It is produced by mechanically foaming a foaming agent using a foaming machine, uniformly mixing the foam with slurry, and then applying it through on-site casting or molding, followed by natural curing. It can be used to construct foamed lightweight walls and as backfill material for roadbeds, bridge abutments, foundation pits, and municipal pipelines. It belongs to the category of aerated insulation materials, with its key feature being the formation of closed foam pores within the concrete, making the concrete lightweight and improving its thermal insulation performance. Traditional foamed lightweight soil primarily uses cement as its main raw material, with cement accounting for over 60%, resulting in high material costs and reliance on non-renewable resources, leading to high energy consumption. Furthermore, reducing the density of foamed lightweight soil often leads to a significant decrease in compressive strength, making it difficult to meet the requirements of lightweight yet high strength. In addition, the shrinkage and cracking problems of foamed lightweight soil, and the issue of the material becoming brittle and significantly reducing compressive strength after prolonged exposure to fire, also urgently need to be addressed.

[0003] The patent CN119263744A, entitled "A Foamed Lightweight Soil and Its Preparation Method," uses 0.01%~30.00% aeolian sand, 0.01%~30.00% oil sludge pyrolysis residue, 25.00%~76.00% cement, 3.00%~5.00% foam aggregate, and 20.00%~25.00% water as raw materials to prepare foamed lightweight soil. Although some of the raw materials use solid waste oil sludge pyrolysis residue, the main cementing material is still cement. Cement not only has high energy consumption and is not environmentally friendly, but also has high cost.

[0004] The patent with publication number CN119019143A, "A Multi-Source Solid Waste-Based Foamed Lightweight Soil and Its Preparation Method and Application", also uses multi-source solid waste to prepare foamed lightweight soil. However, in order to reduce the shrinkage of the foamed lightweight soil, it adds calcium sulfoaluminate concrete expansion agent, which not only increases the material cost, but may also cause the expansion agent to not be completely dispersed, resulting in local expansion and cracking of the foamed lightweight soil.

[0005] The patent with publication number CN118993673A, entitled "A Foamed Lightweight Soil Based on High-Dosage Phosphogypsum and its Preparation Method," uses phosphogypsum, mineral powder, and quicklime as the main raw materials to prepare foamed lightweight soil. However, from its examples, it can be seen that the 28-day strength of the prepared foamed lightweight soil is generally around 1 MPa, which is relatively low. Only one group has the highest strength, reaching 2.2 MPa, and its wet density is 650 kg / m³. 3 ~890kg / m 3The density is too high. Summary of the Invention

[0006] The technical problem this invention aims to solve is to address the shortcomings of the existing technology by providing a lightweight, energy-saving, and fire-resistant soil-based foamed lightweight soil. This method uses industrial solid waste such as magnesium slag powder, granulated blast furnace slag powder, and iron tailings powder as cementing materials. By optimizing the composition and proportion of raw materials, a dense three-dimensional spatial skeleton structure is constructed, resulting in foamed lightweight soil that combines low density and high strength. This improves its structural density and safety, effectively reduces raw material costs, and utilizes industrial solid waste. It also solves the contradiction between density and strength in foamed lightweight soil, as well as the problem of a significant decrease in strength during fire.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a lightweight, energy-saving, and fireproof soil-based foam lightweight soil, characterized in that it is made from raw materials comprising the following parts by weight: 20-30 parts of magnesium slag powder, 20-30 parts of granulated blast furnace slag powder, 15-25 parts of iron tailings powder, 40 parts of soil, 6 parts of water glass, 10 parts of desulfurized gypsum, 0.28-0.43 parts of polycarboxylate superplasticizer, 57-75 parts of water, 0.76-1.00 parts of AOS foaming agent, 0.16-0.26 parts of HPMC foam stabilizer, and 0.16-0.26 parts of calcium stearate foam stabilizer.

[0008] In the raw materials of the soil-based foamed lightweight soil of this invention, magnesium slag, granulated blast furnace slag powder, and iron tailings powder are used as cementing materials, and water glass and desulfurized gypsum are used as activators. Water glass increases the alkalinity of the system, promoting the dissolution of active components in magnesium slag, slag powder, and iron tailings powder. Desulfurized gypsum, after dissolving in an alkaline environment, releases a large amount of Ca. 2+ and SO4 2- Ions promote the forward hydration reaction. Among the three cementing materials of this invention, magnesium slag powder has the highest hydration activity, and the glassy structure in granulated blast furnace slag powder is more prone to deagglomeration than that in iron tailings powder. Therefore, in the initial stage of hydration, after the magnesium slag dissolves, the Ca in the system... 2+ Mg 2+ and OH - As the concentration continues to increase, coupled with the effect of water glass on increasing the alkalinity of the system, the disordered silicon-oxygen tetrahedra and aluminum-oxygen tetrahedra in the slag depolymerize, generating a large number of active ions [SiO4]. 4- [AlO4] 5- These active ions react with Ca in the solution 2+ and SO4 2-The interaction of these elements generates ettringite (AFt, 3CaO・Al2O3・3CaSO4・32H2O) and hydrated calcium silicate (CSH) gel, etc. AFt crystals are interspersed and encapsulated within the CSH gel, filling and bridging to form a dense three-dimensional spatial framework structure, providing high strength to the material and thus giving the soil-based foamed lightweight soil high strength. Furthermore, the magnesium slag powder used in this invention contains 50%~70% dicalcium silicate by mass. Dicalcium silicate has a relatively long hydration period, typically starting to exert its strength effect after 28 days, effectively improving the later-stage strength of the soil-based foamed lightweight soil.

[0009] Meanwhile, iron tailings powder is usually prepared by ball milling and sieving. During the ball milling mechanical activation process, a large number of silicon-oxygen and aluminum-oxygen bonds are broken and lattice distortions occur on the surface of the iron tailings powder, which increases the hydration activity of the iron tailings powder. With the increase of Ca in the solution... 2+ SO4 2- and OH - With increasing concentration, the glassy phase of iron tailings powder begins to deagglomerate, forming [SiO4]. 4- and [AlO4] 5- Ca in tetrahedral and fused systems 2+ SO4 2- and OH - Plasma recombines to form a large amount of AFt and CSH gels, with needle-like AFt crystals interleaving with the CSH gels, gradually making the structure denser. Some unhydrated iron tailings powder particles act as fillers and micro-aggregates, further increasing the material's density and providing growth sites for hydration products. Furthermore, the incorporation of iron tailings powder can adjust the system's silica-alumina ratio. A high silica-alumina ratio leads to reduced strength and poor thermal stability. In this invention, the silica-alumina ratio of 3.5-4.0 when magnesium slag and granulated blast furnace slag powder are co-blended is relatively high, while the silica-alumina ratio of iron tailings powder is typically around 3. Therefore, this invention, by controlling the incorporation of an appropriate amount of iron tailings powder to reduce the system's silica-alumina ratio and adjust the system's alkalinity, is beneficial for promoting the polymerization reaction between low-polymerization-degree aluminosilicates and their complexes.

[0010] The raw materials of the soil-based foamed lightweight soil of this invention use calcium stearate, a surface-active foam stabilizer, and hydroxypropyl methylcellulose ether (HPMC), a polymeric foam stabilizer. Calcium stearate can reduce the surface tension of the liquid film and slow down the thinning rate of the film layer, while hydroxypropyl methylcellulose ether can form an elastic film and enhance the mechanical strength of the liquid film. The two work synergistically to enhance the elasticity, strength, and water resistance of the bubble film, thereby effectively improving the cell stability of the foamed lightweight soil and reducing the thermal conductivity of the soil-based foamed lightweight soil.

[0011] This invention improves the refractory performance of soil-based foamed lightweight soil by incorporating a certain amount of soil into its raw materials. The minerals in the soil melt and recrystallize during high-temperature combustion, increasing the material's strength and preventing it from becoming brittle and experiencing a significant decrease in strength due to prolonged burning in special scenarios such as fires. Simultaneously, the cementing materials magnesium slag, granulated blast furnace slag powder, and iron tailings powder in the raw material system, when mixed with water (usually tap water), hydrolyze to generate a large amount of Ca. 2+ Mg 2+ Al 3+ and Fe 3+ High-valence cations are used to replace low-valence cations (Na+) in the soil through ion exchange. + K + The process (e.g., by using soil as a raw material) reduces the spacing between soil particles and increases the interparticle bonding force. Combined with the encapsulation effect of CSH gel, a hydration product of the system, on the soil particles, this improves the microstructure density of the soil-based foamed lightweight soil, thereby enhancing its pore stability. This results in higher compressive strength and lower thermal conductivity. Furthermore, the use of soil as a partial raw material in this invention effectively optimizes the particle size distribution of the raw materials, reducing raw material costs.

[0012] The aforementioned lightweight, energy-saving, and fire-resistant soil-based foam lightweight soil is characterized by being made from the following raw materials in parts by weight: 25-30 parts magnesium slag powder, 25-30 parts granulated blast furnace slag powder, 15-20 parts iron tailings powder, 40 parts soil, 6 parts water glass, 10 parts desulfurized gypsum, 0.33-0.40 parts polycarboxylate superplasticizer, 63-72 parts water, 0.84-0.96 parts AOS foaming agent, 0.20-0.24 parts HPMC foam stabilizer, and 0.20-0.24 parts calcium stearate foam stabilizer.

[0013] The aforementioned lightweight, energy-saving, and fire-resistant soil-based foam lightweight soil is characterized in that the magnesium slag powder is the undersize material after ball milling magnesium slag and passing through a 75µm sieve, and the iron tailings powder is the undersize material after ball milling iron tailings and passing through a 75µm sieve.

[0014] The aforementioned lightweight, energy-saving, and fire-resistant soil-based foam lightweight soil is characterized in that the soil is derived from natural soil, subway tunnel slag, and engineering waste soil, and is sieved through a 10mm sieve during use.

[0015] The aforementioned lightweight, energy-saving, and fire-resistant soil-based foamed lightweight soil is characterized by the following: the dosage of polycarboxylate superplasticizer is 0.5% of the mass of the cementitious material; the dosage of water is 60% of the total mass of the cementitious material and soil; the dosage of AOS foaming agent is 0.8% of the total mass of the cementitious material and soil; and the dosages of HPMC foam stabilizer and calcium stearate foam stabilizer are both 0.3% of the mass of the cementitious material. The cementitious material includes magnesium slag, granulated blast furnace slag powder, and iron tailings powder. This invention ensures the highest strength of the soil-based foamed lightweight soil by controlling the dosage of polycarboxylate superplasticizer; it ensures the workability of the slurry before adding foam by controlling the dosage of water, facilitating foam addition; and it ensures a wet density of 650 kg / m³ by controlling the dosage of AOS foaming agent. 3 ~700kg / m 3 By controlling the dosage of HPMC foam stabilizer and calcium stearate foam stabilizer, the foam stability of the soil-based foamed lightweight soil is best ensured.

[0016] Meanwhile, the present invention also discloses a method for preparing the above-mentioned soil-based foamed lightweight soil, characterized in that the method includes the following steps:

[0017] Step 1: Mixing and stirring dry powder materials: According to the design ratio of the target product, take magnesium slag powder, granulated blast furnace slag powder, iron tailings powder, soil, desulfurized gypsum, polycarboxylate superplasticizer, HPMC foam stabilizer, and calcium stearate foam stabilizer and put them into a mixer and stir at low speed to obtain a uniformly mixed dry powder material.

[0018] Step 2: Prepare the slurry: Mix water glass and water evenly, then add the dry powder obtained in Step 1 and stir at low speed to obtain the slurry;

[0019] Step 3: Foam preparation: After diluting the AOS foaming agent, uniform foam is prepared by foaming. Then, it is added to the slurry obtained in Step 2 and stirred at low speed to obtain soil-based foamed lightweight soil.

[0020] Step 4: Molding and Curing: Pour the soil-based foam lightweight soil prepared in Step 3 into a triple mold, ensuring that the triple mold is filled tightly. Smooth the surface with a scraper, cover with plastic wrap, and place in a curing chamber with a temperature of 70℃±2℃ and a humidity of over 80% for 8 hours. After curing, demold and perform standard curing to obtain the soil-based foam lightweight soil molded part.

[0021] The standard curing conditions in step four of this invention refer to GB / T50081-2019 "Standard for Test Methods of Physical and Mechanical Properties of Concrete": relative humidity reaches 95% or above, and temperature is 20℃±2℃.

[0022] The method described above is characterized in that, in step one, the low-speed stirring speed is 60 r / min and the time is 60 s; in step two, the low-speed stirring speed is 60 r / min and the time is 2 min; and in step three, the low-speed stirring speed is 60 r / min and the time is 3 min to 4 min.

[0023] The method described above is characterized in that the dimensions of the triple mold in step four are 100mm × 100mm × 100mm.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] 1. This invention uses magnesium slag powder, granulated blast furnace slag powder, and iron tailings powder as cementing materials, and water glass and desulfurized gypsum as activators. Through hydration reaction, a three-dimensional spatial skeleton dense composite structure is formed, improving the material density. Thus, while ensuring the low-density characteristics of the soil-based foamed lightweight soil, high strength is also obtained. The prepared material has a 3-day compressive strength greater than 2.0 MPa, a 28-day compressive strength greater than 3.0 MPa, and a dry density of 500 kg / m³. 3 ~550kg / m 3 The soil-based foamed lightweight soil solves the problem of low density (below 600 kg / m³) in traditional foamed lightweight soil. 3 It addresses the contradiction between high strength (28-day compressive strength is typically below 1.5MPa) and is suitable for applications such as roof insulation, wall filling, roadbed filling, bridge abutment backfilling, foundation pit backfilling, municipal pipeline backfilling, and landscape engineering.

[0026] 2. The soil-based foamed lightweight soil of this invention uses solid waste magnesium slag powder, granulated blast furnace slag powder and iron tailings powder as cementing materials (approximately 2 / 3 to 3 / 4 by mass) and adds soil (approximately 1 / 4 to 1 / 3 by mass). This improves the fire resistance of the soil-based foamed lightweight soil (achieving A1 fire resistance). At the same time, the minerals in the soil melt and recrystallize at high combustion temperatures, improving the material's structural compactness, further enhancing the strength of the soil-based foamed lightweight soil, and improving structural safety. Furthermore, by improving the pore stability of the soil-based foamed lightweight soil, its thermal conductivity is reduced, achieving energy-saving effects. This solves the problem of traditional foamed lightweight soil becoming brittle and experiencing a significant decrease in strength during prolonged burning.

[0027] 3. The soil-based foamed lightweight soil of the present invention has good thermal insulation performance, with a thermal conductivity not exceeding 0.10 W / (m·K), and a 3-day compressive strength greater than 2.0 MPa, a 28-day compressive strength greater than 3.0 MPa, and a compressive strength that can increase again by 0.5 MPa to 1.0 MPa from 28 days to 56 days. This solves the problems of low early strength and insufficient later strength development that are common in existing soil-based foamed lightweight soils.

[0028] 4. The magnesium slag powder used in this invention contains about 7% magnesium oxide, and the magnesium hydroxide generated by hydration has a certain expansion effect. There is no need to add an additional expansion agent. This solves the problem that existing soil-based foamed lightweight soil requires the addition of an expansion agent or fiber to prevent shrinkage, which not only increases the material cost, but may also lead to uneven dispersion of fibers or expansion agents, resulting in excessive local stress in the material.

[0029] 5. This invention uses industrial solid waste such as magnesium slag powder, mineral powder and iron tailings powder as cementing materials, which not only solves the problem of industrial waste piles occupying land and polluting the environment, but also realizes the recycling of solid waste resources, reduces raw material costs, and solves the problem that existing foamed lightweight soils mostly use silicate cement as the main raw material, while the cement production process is not only energy-intensive, but also pollutes the environment.

[0030] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0031] Figure 1 This is a flowchart illustrating the preparation process of the soil-based foamed lightweight soil in this invention.

[0032] Figure 2 This is a diagram showing the molding process of the soil-based foamed lightweight soil in the preparation process of the soil-based foamed lightweight soil of the present invention.

[0033] Figure 3 The image shows the XRD pattern of the soil-based foamed lightweight soil in Example 1 of this invention.

[0034] Figure 4 This is a physical image of the soil-based foamed lightweight soil in Embodiment 2 of the present invention.

[0035] Figure 5 This is an enlarged view of different locations of the soil-based foamed lightweight soil in Embodiment 2 of the present invention.

[0036] Figure 6 This is a physical image of the combustion performance test sample of the soil-based foamed lightweight soil in Example 6 of the present invention. Detailed Implementation

[0037] Example 1

[0038] The soil-based foamed lightweight soil of this embodiment is made from the following raw materials in parts by weight: 20 parts magnesium slag powder, 30 parts granulated blast furnace slag powder, 20 parts iron tailings powder, 40 parts soil, 6 parts water glass, 10 parts desulfurized gypsum, 0.35 parts polycarboxylate superplasticizer, 66 parts water, 0.88 parts AOS foaming agent, 0.21 parts HPMC foam stabilizer, and 0.21 parts calcium stearate foam stabilizer. The magnesium slag powder is the undersize material after ball milling magnesium slag and passing through a 75µm sieve, and the iron tailings powder is the undersize material after ball milling iron tailings and passing through a 75µm sieve. The soil is derived from natural soil, subway tunnel slag, and engineering waste soil, and is used after passing through a 10mm sieve.

[0039] like Figure 1 As shown, the method for preparing soil-based foamed lightweight soil in this embodiment includes the following steps:

[0040] Step 1: Mixing and stirring dry powder materials: According to the design ratio of the target product, take magnesium slag powder, granulated blast furnace slag powder, iron tailings powder, soil, desulfurized gypsum, polycarboxylate superplasticizer, HPMC foam stabilizer, and calcium stearate foam stabilizer and put them into a mixer and stir at a speed of 60r / min for 60s to obtain a uniformly mixed dry powder material.

[0041] Step 2: Prepare the slurry: Mix water glass and water evenly, then add the dry powder obtained in Step 1 and stir at 60 r / min for 2 min to obtain the slurry;

[0042] Step 3: Foam preparation: After diluting the AOS foaming agent, foam it using a foaming machine to obtain a uniform foam group. Then add it to the slurry obtained in Step 2 and stir at a speed of 60 r / min for 3 min to obtain soil-based foamed lightweight soil.

[0043] Step 4: Molding and Curing: (e.g.) Figure 2 As shown, the soil-based foam lightweight soil prepared in step three is poured into a triple mold with dimensions of 100mm×100mm×100mm (length×width×height), ensuring that the triple mold is filled tightly. The surface is smoothed with a scraper, covered with plastic wrap, and then placed in a curing chamber with a temperature of 70℃±2℃ and a humidity of over 80% for 8 hours. After curing, the mold is removed and standard curing is performed to obtain the soil-based foam lightweight soil molded part.

[0044] Figure 3 The XRD pattern of the lightweight foamed soil in this embodiment is shown below. Figure 3It can be seen that the main hydration products of this foamed lightweight soil are CSH, CaCO3, and AFt, with a small amount of hydrotalcite and Mg(OH)2 also generated. Among them, a large amount of gel-like CSH, crystalline CaCO3, and AFt are mutually wrapped and filled, making the microstructure of the foamed lightweight soil more compact and the pores more stable, which is also the main source of the strength of the foamed lightweight soil. The formation of hydrotalcite also indicates that the granulated blast furnace slag powder and magnesium slag powder have a high degree of hydration, and the expansion effect of Mg(OH)2 can effectively reduce the chemical shrinkage and drying shrinkage of the foamed lightweight soil.

[0045] Example 2

[0046] The difference between this embodiment and Embodiment 1 is that the soil-based foamed lightweight soil is made from the following raw materials in parts by weight: 30 parts magnesium slag powder, 20 parts granulated blast furnace slag powder, 20 parts iron tailings powder, 40 parts soil, 6 parts water glass, 10 parts desulfurized gypsum, 0.35 parts polycarboxylate superplasticizer, 66 parts water, 0.88 parts AOS foaming agent, 0.21 parts HPMC foam stabilizer, and 0.21 parts calcium stearate foam stabilizer. See the actual product image and enlarged images of different locations of this soil-based foamed lightweight soil. Figure 4 and Figure 5 As shown.

[0047] Example 3

[0048] The difference between this embodiment and Embodiment 1 is that the soil-based foamed lightweight soil is made from the following raw materials in parts by weight: 25 parts magnesium slag powder, 25 parts granulated blast furnace slag powder, 20 parts iron tailings powder, 40 parts soil, 6 parts water glass, 10 parts desulfurized gypsum, 0.35 parts polycarboxylate superplasticizer, 66 parts water, 0.88 parts AOS foaming agent, 0.21 parts HPMC foam stabilizer, and 0.21 parts calcium stearate foam stabilizer.

[0049] Example 4

[0050] The difference between this embodiment and Embodiment 1 is that the soil-based foamed lightweight soil is made from the following raw materials in parts by weight: 25 parts magnesium slag powder, 25 parts granulated blast furnace slag powder, 15 parts iron tailings powder, 40 parts soil, 6 parts water glass, 10 parts desulfurized gypsum, 0.325 parts polycarboxylate superplasticizer, 63 parts water, 0.84 parts AOS foaming agent, 0.195 parts HPMC foam stabilizer, and 0.195 parts calcium stearate foam stabilizer.

[0051] Example 5

[0052] The difference between this embodiment and Embodiment 1 is that the soil-based foamed lightweight soil is made from the following raw materials in parts by weight: 25 parts magnesium slag powder, 25 parts granulated blast furnace slag powder, 25 parts iron tailings powder, 40 parts soil, 6 parts water glass, 10 parts desulfurized gypsum, 0.375 parts polycarboxylate superplasticizer, 69 parts water, 0.92 parts AOS foaming agent, 0.225 parts HPMC foam stabilizer, and 0.225 parts calcium stearate foam stabilizer.

[0053] Example 6

[0054] The difference between this embodiment and Embodiment 1 is that the soil-based foamed lightweight soil is made from the following raw materials in parts by weight: 20 parts magnesium slag powder, 20 parts granulated blast furnace slag powder, 25 parts iron tailings powder, 40 parts soil, 6 parts water glass, 10 parts desulfurized gypsum, 0.325 parts polycarboxylate superplasticizer, 63 parts water, 0.84 parts AOS foaming agent, 0.195 parts HPMC foam stabilizer, and 0.195 parts calcium stearate foam stabilizer.

[0055] Figure 6 This is a photograph of the actual sample of the soil-based foamed lightweight soil used in the combustion performance test in this embodiment.

[0056] Example 7

[0057] The difference between this embodiment and Embodiment 1 is that the soil-based foamed lightweight soil is made from the following raw materials in parts by weight: 30 parts magnesium slag powder, 30 parts granulated blast furnace slag powder, 15 parts iron tailings powder, 40 parts soil, 6 parts water glass, 10 parts desulfurized gypsum, 0.375 parts polycarboxylate superplasticizer, 69 parts water, 0.92 parts AOS foaming agent, 0.225 parts HPMC foam stabilizer, and 0.225 parts calcium stearate foam stabilizer.

[0058] Example 8

[0059] The difference between this embodiment and Embodiment 1 is that the soil-based foamed lightweight soil is made from the following raw materials in parts by weight: 20 parts magnesium slag powder, 20 parts granulated blast furnace slag powder, 15 parts iron tailings powder, 40 parts soil, 6 parts water glass, 10 parts desulfurized gypsum, 0.28 parts polycarboxylate superplasticizer, 57 parts water, 0.76 parts AOS foaming agent, 0.16 parts HPMC foam stabilizer, and 0.16 parts calcium stearate foam stabilizer.

[0060] Example 9

[0061] The difference between this embodiment and Embodiment 1 is that the soil-based foamed lightweight soil is made from the following raw materials in parts by weight: 30 parts magnesium slag powder, 30 parts granulated blast furnace slag powder, 20 parts iron tailings powder, 40 parts soil, 6 parts water glass, 10 parts desulfurized gypsum, 0.40 parts polycarboxylate superplasticizer, 72 parts water, 0.96 parts AOS foaming agent, 0.24 parts HPMC foam stabilizer, and 0.24 parts calcium stearate foam stabilizer.

[0062] Example 10

[0063] The difference between this embodiment and Embodiment 1 is that the soil-based foamed lightweight soil is made from the following raw materials in parts by weight: 30 parts magnesium slag powder, 30 parts granulated blast furnace slag powder, 25 parts iron tailings powder, 40 parts soil, 6 parts water glass, 10 parts desulfurized gypsum, 0.43 parts polycarboxylate superplasticizer, 75 parts water, 1.00 part AOS foaming agent, 0.26 parts HPMC foam stabilizer, and 0.26 parts calcium stearate foam stabilizer.

[0064] The properties of the soil-based foamed lightweight soils prepared in Examples 1-10 of this invention were tested, and the results are shown in Table 1 below.

[0065] Table 1

[0066]

[0067] As can be seen from Table 1, the soil-based foamed lightweight soil prepared by this invention has the significant characteristics of being lightweight and high-strength, with a dry density of 500 kg / m³. 3 ~550kg / m 3 At that time, its compressive strength was 3.0MPa~3.5MPa, which is much higher than that of ordinary soil-based foamed lightweight soil at the same dry density (0.3MPa~0.8MPa), and also higher than that of ordinary foamed concrete at the same dry density (0.8MPa~1.2MPa). Furthermore, the soil-based foamed lightweight soil prepared in this invention not only has good thermal insulation and fire resistance, but its fluidity and drying shrinkage value also meet the requirements of JGJ / T 341-2014 "Technical Specification for Application of Foamed Concrete".

[0068] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A lightweight, energy-saving, fire-resistant, soil-based foamed lightweight soil, characterized in that, It is made from the following raw materials in parts by weight: 20-30 parts magnesium slag powder, 20-30 parts granulated blast furnace slag powder, 15-25 parts iron tailings powder, 40 parts soil, 6 parts water glass, 10 parts desulfurized gypsum, 0.28-0.43 parts polycarboxylate superplasticizer, 57-75 parts water, 0.76-1.00 parts AOS foaming agent, 0.16-0.26 parts HPMC foam stabilizer, and 0.16-0.26 parts calcium stearate foam stabilizer.

2. The lightweight, energy-saving, fire-resistant soil-based foam lightweight soil according to claim 1, characterized in that, It is made from the following raw materials in parts by weight: 25-30 parts magnesium slag powder, 25-30 parts granulated blast furnace slag powder, 15-20 parts iron tailings powder, 40 parts soil, 6 parts water glass, 10 parts desulfurized gypsum, 0.33-0.40 parts polycarboxylate superplasticizer, 63-72 parts water, 0.84-0.96 parts AOS foaming agent, 0.20-0.24 parts HPMC foam stabilizer, and 0.20-0.24 parts calcium stearate foam stabilizer.

3. The lightweight, energy-saving, fire-resistant soil-based foam lightweight soil according to claim 1, characterized in that, The magnesium slag powder is the undersize material after ball milling magnesium slag and passing through a 75µm sieve, and the iron tailings powder is the undersize material after ball milling iron tailings and passing through a 75µm sieve.

4. The lightweight, energy-saving, fire-resistant soil-based foam lightweight soil according to claim 1, characterized in that, The soil is derived from natural soil, tunnel boring machine excavation soil, and engineering waste soil, and is sieved through a 10mm sieve before use.

5. The lightweight, energy-saving, fire-resistant soil-based foam lightweight soil according to claim 1, characterized in that, The dosage of polycarboxylate superplasticizer is 0.5% of the mass of cementitious material, the dosage of water is 60% of the total mass of cementitious material and soil, the dosage of AOS foaming agent is 0.8% of the total mass of cementitious material and soil, and the dosage of HPMC foam stabilizer and calcium stearate foam stabilizer are both 0.3% of the mass of cementitious material; the cementitious material includes magnesium slag, granulated blast furnace slag powder and iron tailings powder.

6. A method for preparing soil-based foamed lightweight soil as described in any one of claims 1 to 5, characterized in that, The method includes the following steps: Step 1: Mixing and stirring dry powder materials: According to the design ratio of the target product, take magnesium slag powder, granulated blast furnace slag powder, iron tailings powder, soil, desulfurized gypsum, polycarboxylate superplasticizer, HPMC foam stabilizer, and calcium stearate foam stabilizer and put them into a mixer and stir at low speed to obtain a uniformly mixed dry powder material. Step 2: Prepare the slurry: Mix water glass and water evenly, then add the dry powder obtained in Step 1 and stir at low speed to obtain the slurry; Step 3: Foam preparation: After diluting the AOS foaming agent, uniform foam is prepared by foaming. Then, it is added to the slurry obtained in Step 2 and stirred at low speed to obtain soil-based foamed lightweight soil. Step 4: Molding and Curing: Pour the soil-based foam lightweight soil prepared in Step 3 into a triple mold, ensuring that the triple mold is filled tightly. Smooth the surface with a scraper, cover with plastic wrap, and place in a curing chamber with a temperature of 70℃±2℃ and a humidity of over 80% for 8 hours. After curing, demold and perform standard curing to obtain the soil-based foam lightweight soil molded part.

7. The method according to claim 6, characterized in that, In step one, the low-speed stirring speed is 60 r / min for 60 s; in step two, the low-speed stirring speed is 60 r / min for 2 min; and in step three, the low-speed stirring speed is 60 r / min for 3 to 4 min.

8. The method according to claim 6, characterized in that, The dimensions of the triple mold mentioned in step four are 100mm × 100mm × 100mm (length × width × height).

Images