Light energy-saving fireproof soil-based foam light soil and preparation method thereof

Abstract

The invention discloses lightweight energy-saving fireproof soil-based foam lightweight soil, which is prepared from the following raw materials in parts by weight: 20 to 30 parts of magnesium slag powder, 20 to 30 parts of granulated blast furnace slag powder, 15 to 25 parts of iron tailing powder, 40 parts of soil, 6 parts of water glass, 10 parts of desulfurized gypsum, 0.28 to 0.43 part of polycarboxylate superplasticizer, 57 to 75 parts of water, 0.76 to 1.00 parts of AOS foaming agent, 0.16 to 0.26 part of HPMC foam stabilizer and 0.16 to 0.26 part of calcium stearate foam stabilizer. The preparation method comprises the following steps: 1, mixing and stirring dry powder; 2, preparing slurry; 3, preparing soil-based foam light soil; and 4, molding and curing in a mold. According to the invention, a three-dimensional skeleton dense structure is constructed by optimizing the composition and proportion of the raw materials, the soil-based foam light soil with low heat conductivity, low density and high strength is obtained, and the soil-based foam light soil is suitable for the fields of roof heat preservation, wall body, roadbed filling, abutment back, foundation pit, pipeline backfilling and landscape engineering.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and particularly relates to a lightweight, energy-saving and fire-resistant soil-based foamed lightweight soil and a preparation method thereof. Background Art

[0002] Foamed lightweight soil is a new lightweight insulation material with a large number of closed pores. The foam is mechanically expanded using a foaming machine, uniformly mixed with a slurry, and then cast in place or molded, followed by natural curing. It can be used to make lightweight foam walls and backfill for roadbeds, bridge abutment backs, foundation pits, and municipal pipelines. It is a cellular insulation material characterized by the closed foam pores formed within the concrete, which reduces its weight and improves its thermal insulation properties. Traditional foamed lightweight soil often uses cement as its primary raw material, accounting for over 60% of the total material, resulting in high material costs, reliance on non-renewable resources, and high energy consumption. Furthermore, reducing the density of foamed lightweight soil often results in a significant decrease in compressive strength, making it difficult to meet both lightweight and high-strength requirements. Furthermore, shrinkage cracking of foamed lightweight soil, and the significant loss of compressive strength caused by prolonged fire exposure, are issues that need to be addressed urgently.

[0003] Patent publication number CN119263744A, "A Foamed Lightweight Soil and Its Preparation Method," uses 0.01% to 30.00% aeolian sand, 0.01% to 30.00% oil sludge pyrolysis residue, 25.00% to 76.00% cement, 3.00% to 5.00% foam group, and 20.00% to 25.00% water as raw materials to produce foamed lightweight soil. Although solid waste oil sludge pyrolysis residue is partially used as raw material, the primary binder is still cement. Cement is not only energy-intensive to produce, environmentally unfriendly, but also expensive.

[0004] The patent with publication number CN119019143A, "A multi-source solid waste-based foamed lightweight soil, 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 additionally adds calcium sulfoaluminate concrete expansion agent, which not only increases the material cost, but also may cause the expansion agent to fail to be completely dispersed, resulting in local expansion and cracking of the foamed lightweight soil.

[0005] Patent publication number CN118993673A, "A Large-Amount Phosphogypsum Slag Powder-Based Foamed Lightweight Soil and Its Preparation Method," uses phosphogypsum, mineral powder, and slaked lime as the main raw materials to prepare foamed lightweight soil. However, as can be seen from its examples, the 28-day strength of the foamed lightweight soil prepared 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 / m 3 ~890kg / m 3, the density is too high. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to address the deficiencies of the above-mentioned existing technologies and provide a lightweight, energy-saving and fire-resistant soil-based foamed lightweight soil. This method uses industrial solid wastes such as magnesium slag powder, granulated blast furnace slag powder and iron tailings powder as cementitious materials. Combined with the optimization of the raw material composition and proportions, it constructs a three-dimensional spatial skeleton dense composite structure to obtain a foamed lightweight soil with both low density and high strength, and improves its structural density and safety. This effectively reduces raw material costs and absorbs industrial solid waste, resolving the contradiction between the density and strength of foamed lightweight soil and the significant drop in strength of foamed lightweight soil during fire.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: a lightweight, energy-saving and fire-proof soil-based foamed lightweight soil, characterized in that it is made of the following raw materials in 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 desulfurization gypsum, 0.28-0.43 parts of polycarboxylic acid water reducer, 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] The raw materials of the soil-based foamed lightweight soil of the present invention include magnesium slag, granulated blast furnace slag powder and iron tailings powder as gelling materials, water glass and desulfurized gypsum as activators, the alkalinity of the system is increased by water glass, and the active ingredients in magnesium slag, slag powder and iron tailings powder are dissolved, while the desulfurized gypsum releases a large amount of Ca after dissolving in an alkaline environment. 2+ and SO4 2- ions, promoting the positive progress of the hydration reaction. Among the three types of cementitious materials of the present invention, magnesium slag powder has the highest hydration activity, and the glass structure in granulated blast furnace slag powder is more likely to depolymerize than iron tailings powder. Therefore, in the early stage of hydration, after the magnesium slag dissolves, the Ca 2+ Mg 2+ and OH - The concentration continues to increase, and the water glass increases the alkalinity of the system, which causes the disordered silicon-oxygen tetrahedron and aluminum-oxygen tetrahedron in the slag to depolymerize and generate a large amount of active ions [SiO4]. 4- 、[AlO4] 5- These active ions react with Ca in the solution 2+ and SO4 2-The interaction between these two materials creates ettringite (AFt, 3CaO・Al2O3・3CaSO4・32H2O) and calcium silicate hydrate (CSH) gel. AFt crystals intersperse and encapsulate the CSH gel, filling and bridging the gaps to form a dense, three-dimensional, skeletal composite structure, providing high strength for the material and ultimately contributing to the high strength of the soil-based foamed lightweight soil. Furthermore, the magnesium slag powder used in this invention contains 50% to 70% dicalcium silicate by weight. This dicalcium silicate has a relatively long hydration cycle, typically beginning to exert its strength effects after 28 days, effectively improving the later-stage strength of the soil-based foamed lightweight soil.

[0009] At the same time, iron tailings powder is usually prepared by ball milling and screening. During the mechanical activation process of ball milling, a large number of silicon-oxygen bond breaks, aluminum-oxygen bond breaks and lattice distortions will be generated on the surface of the iron tailings powder, which will increase the hydration activity of the iron tailings powder. 2+ 、SO4 2- and OH - As the concentration increases, the iron tailings powder glass begins to deagglomerate and form [SiO4] 4- and [AlO4] 5- Ca in tetrahedral and halogenated systems 2+ 、SO4 2- and OH - The plasma recombine to form a large amount of AFt and CSH gel, and the needle-shaped AFt crystals are staggered and overlapped with the CSH gel, making the structure gradually dense. The partially unhydrated iron tailings powder particles play a filling effect and a micro-aggregate effect, which further improves the density of the material and provides a growth site for the generation of hydration products. In addition, the addition of iron tailings powder can adjust the silicon-aluminum ratio of the system. When the silicon-aluminum ratio in the system is relatively high, it will lead to a decrease in its strength and poor thermal stability. The silicon-aluminum ratio of the magnesium slag and granulated blast furnace slag powder of the present invention is 3.5~4.0 when it is mixed. The silicon-aluminum ratio is high, and the silicon-aluminum ratio of the iron tailings powder is usually about 3. Therefore, the present invention controls the addition of an appropriate amount of iron tailings powder to reduce the silicon-aluminum ratio of the system and adjust the alkalinity of the system, which is conducive to promoting the polymerization reaction between low-polymerization degree aluminosilicates and their complexes.

[0010] The raw materials of the soil-based foamed lightweight soil of the present invention include a surfactant-type foam stabilizer calcium stearate and a polymer-type foam stabilizer hydroxypropyl methylcellulose ether (HPMC). The calcium stearate can reduce the surface tension of the liquid film and reduce the thinning speed of the film layer, and the hydroxypropyl methylcellulose ether can form an elastic film and enhance the mechanical strength of the liquid film. The two ingredients synergistically 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. The soil-based foamed lightweight soil of the present invention is mixed with a certain amount of soil to improve the fire resistance of the material. The minerals in the soil will melt and recrystallize under the high temperature of combustion, thereby improving the strength of the material and avoiding the undesirable phenomenon of soil-based foamed lightweight soil becoming brittle and significantly reducing its strength due to long-term burning in special scenarios such as fire. At the same time, the cementitious materials magnesium slag, granulated blast furnace slag powder and iron tailings powder in the raw material system will hydrolyze to generate a large amount of Ca after mixing with water (usually tap water). 2+ Mg 2+ 、Al 3+ and Fe 3+ High-valent cations such as Na + , K + The CSH gel, a hydration product of the system, encapsulates the soil particles, thereby improving the microstructural density of the soil-based foamed lightweight soil. This in turn enhances the cell stability of the soil-based foamed lightweight soil, resulting in higher compressive strength and lower thermal conductivity. Furthermore, the present invention utilizes soil as part of the raw material, effectively optimizing the raw material particle size distribution and reducing raw material costs.

[0011] The above-mentioned lightweight, energy-saving and fire-proof soil-based foamed lightweight soil is characterized in that it is made of the following raw materials in parts by weight: 25-30 parts of magnesium slag powder, 25-30 parts of granulated blast furnace slag powder, 15-20 parts of iron tailings powder, 40 parts of soil, 6 parts of water glass, 10 parts of desulfurized gypsum, 0.33-0.40 parts of polycarboxylic acid water reducer, 63-72 parts of water, 0.84-0.96 parts of AOS foaming agent, 0.20-0.24 parts of HPMC foam stabilizer, and 0.20-0.24 parts of calcium stearate foam stabilizer.

[0012] The above-mentioned lightweight, energy-saving and fire-proof soil-based foamed lightweight soil is characterized in that the magnesium slag powder is the undersize of the magnesium slag after ball milling and passing through a 75µm sieve, and the iron tailings powder is the undersize of the iron tailings after ball milling and passing through a 75µm sieve.

[0013] The above-mentioned lightweight, energy-saving and fire-proof soil-based foamed lightweight soil is characterized in that the soil comes from natural soil, subway shield slag and engineering waste soil, and passes through a 10mm sieve when used.

[0014] The above-mentioned lightweight, energy-saving and fireproof soil-based foamed lightweight soil is characterized in that the dosage of polycarboxylic acid water-reducing agent 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 the soil, the dosage of AOS foaming agent is 0.8% of the total mass of the cementitious material and the soil, the dosage 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. The present invention ensures the highest strength of the soil-based foamed lightweight soil by controlling the dosage of polycarboxylic acid water-reducing agent; by controlling the dosage of water, the slurry workability of the soil-based foamed lightweight soil before adding the foam is ensured, which facilitates the addition of foam; by controlling the dosage of AOS foaming agent, the wet density of the soil-based foamed lightweight soil is ensured to be 650kg / m 3 ~700kg / m 3 ; By controlling the dosage of HPMC foam stabilizer and calcium stearate foam stabilizer, the foam stability of soil-based foam lightweight soil is guaranteed to be the best.

[0015] At the same time, the present invention also discloses a method for preparing the soil-based foamed lightweight soil as described above, characterized in that the method comprises the following steps: Step 1: Mixing and stirring dry powder: according to the designed ratio of the target product, magnesium slag powder, granulated blast furnace slag powder, iron tailings powder, soil, desulfurized gypsum, polycarboxylate water reducer, HPMC foam stabilizer, and calcium stearate foam stabilizer are put into a blender and stirred at low speed to obtain a uniformly mixed dry powder; Step 2: Prepare slurry: Mix water glass and water evenly, add to the dry powder obtained in step 1 and stir at low speed to obtain slurry; Step 3: Prepare foam: dilute the AOS foaming agent and foam it to obtain uniform foam, then add it to the slurry obtained in step 2 and stir at a 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 the triple mold, and ensure that the triple mold is densely filled. Scrape the surface with a scraper, cover with plastic wrap, and place in a curing box with a temperature of 70℃±2℃ and a humidity of more than 80% for curing for 8 hours. After the curing is completed, demold and perform standard curing to obtain a soil-based foam lightweight soil molded part.

[0016] The standard curing conditions in step 4 of the present invention refer to GB / T50081-2019 "Standard for Test Methods for Physical and Mechanical Properties of Concrete": relative humidity reaches above 95% and temperature is 20°C ± 2°C.

[0017] The above method is characterized in that the speed of the low-speed stirring in step 1 is 60 r / min and the time is 60 s; the speed of the low-speed stirring in step 2 is 60 r / min and the time is 2 min; the speed of the low-speed stirring in step 3 is 60 r / min and the time is 3 min~4 min.

[0018] The above method is characterized in that the dimensions of the triple mold in step 4 are 100 mm in length × 100 mm in width × 100 mm in height.

[0019] Compared with the prior art, the present invention has the following advantages: 1. The present invention uses magnesium slag powder, granulated blast furnace slag powder and iron tailings powder as gelling materials, water glass and desulfurized gypsum as activators, and forms a three-dimensional spatial skeleton dense composite structure through hydration reaction to improve the density of the material, thereby ensuring the low density characteristics of the soil-based foam lightweight soil while also obtaining high strength. The 3d compressive strength is greater than 2.0MPa, the 28d compressive strength is greater than 3.0MPa, and the dry density is 500kg / m 3 ~550kg / m 3 The soil-based foam lightweight soil solves the low density (less than 600kg / m 3 ) and high strength (28d compressive strength is usually less than 1.5MPa), and is suitable for roof insulation, wall filling, roadbed filling, abutment backfill, foundation pit backfill, municipal pipeline backfill and landscape engineering.

[0020] 2. The soil-based foamed lightweight soil of the present invention uses solid waste magnesium slag powder, granulated blast furnace slag powder and iron tailings powder as cementitious materials (accounting for about 2 / 3 to 3 / 4 by mass) and adds soil (accounting for about 1 / 4 to 1 / 3 by mass), thereby improving the fire resistance of the soil-based foamed lightweight soil (reaching A1 level fire resistance). At the same time, the minerals in the soil are melted and recrystallized at high combustion temperatures to improve the structural tightness of the material, further enhance the strength of the soil-based foamed lightweight soil, improve structural safety, and reduce its thermal conductivity by improving the pore stability of the soil-based foamed lightweight soil, thereby achieving energy-saving effects and solving the problem that traditional foamed lightweight soil becomes brittle and its strength decreases significantly when burned for a long time.

[0021] 3. The soil-based foam lightweight soil of the present invention has good thermal insulation performance, its thermal conductivity coefficient does not exceed 0.10W / (m·K), and the 3d compressive strength is greater than 2.0MPa, the 28d compressive strength is greater than 3.0MPa, and the compressive strength from 28d to 56d can be further increased by 0.5MPa~1.0MPa, which solves the problems of low early strength and insufficient late strength development commonly found in existing soil-based foam lightweight soil.

[0022] 4. The cementitious material magnesium slag powder used in the present invention contains about 7% magnesium oxide. The magnesium hydroxide generated by hydration has a certain expansion effect, and no additional expansion agent is needed. This solves the problem that the existing soil-based foam lightweight soil is added with additional expansion agents or fibers to prevent shrinkage, which not only increases material costs but also may cause uneven dispersion of fibers or expansion agents, resulting in excessive local stress in the material.

[0023] 5. The present invention adopts industrial solid wastes such as magnesium slag powder, mineral powder and iron tailings powder as cementitious materials, which not only solves the problem of industrial waste slag storage occupying land and polluting the environment, but also realizes the recycling of solid waste resources, reduces the cost of raw materials, and solves the problem that the existing foam lightweight soil mostly uses silicate cement as the main raw material, and the cement production process not only has high energy consumption, but also causes pollution to the environment.

[0024] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a process flow chart for preparing soil-based foamed lightweight soil in the present invention.

[0026] Figure 2 This is a diagram of the mold-forming process of soil-based foam lightweight soil in the preparation process of soil-based foam lightweight soil of the present invention.

[0027] Figure 3 This is the XRD pattern of the soil-based foamed lightweight soil in Example 1 of the present invention.

[0028] Figure 4 This is a physical picture of the soil-based foam lightweight soil in Example 2 of the present invention.

[0029] Figure 5 These are enlarged views of different positions of the soil-based foam lightweight soil in Example 2 of the present invention.

[0030] Figure 6 This is a physical picture of the combustion performance test sample of the soil-based foamed lightweight soil in Example 6 of the present invention. DETAILED DESCRIPTION

[0031] Example 1 The soil-based foamed lightweight soil of this embodiment is made of the following raw materials in parts by weight: 20 parts of magnesium slag powder, 30 parts of granulated blast furnace slag powder, 20 parts of iron tailings powder, 40 parts of soil, 6 parts of water glass, 10 parts of desulfurized gypsum, 0.35 parts of polycarboxylic acid water reducer, 66 parts of water, 0.88 parts of AOS foaming agent, 0.21 parts of HPMC foam stabilizer, and 0.21 parts of calcium stearate foam stabilizer; the magnesium slag powder is the undersize of the magnesium slag after ball milling and passing through a 75µm sieve, and the iron tailings powder is the undersize of the iron tailings after ball milling and passing through a 75µm sieve; the soil comes from natural soil, subway shield slag and engineering spoil, and is sieved through a 10mm sieve when used.

[0032] like Figure 1 As shown, the soil-based foam lightweight soil preparation method of this embodiment includes the following steps: Step 1: Mix and stir dry powder: according to the designed ratio of the target product, take magnesium slag powder, granulated blast furnace slag powder, iron tailings powder, soil, desulfurized gypsum, polycarboxylate water reducer, HPMC foam stabilizer, and calcium stearate foam stabilizer, put them into a blender and stir at a speed of 60 r / min for 60 seconds to obtain a uniformly mixed dry powder; Step 2: Prepare slurry: Mix water glass and water evenly, add to the dry powder obtained in step 1, and stir at a speed of 60 r / min for 2 minutes to obtain slurry; Step 3: Prepare foam: dilute the AOS foaming agent and foam it in 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 60r / min for 3 minutes to obtain soil-based foam lightweight soil; Step 4: Molding and curing: Figure 2 As shown, the soil-based foam lightweight soil prepared in step 3 is poured into a triple mold with dimensions of 100 mm × 100 mm × 100 mm in length × width × height, and ensure that the triple mold is densely filled. The surface is flattened with a scraper, and after covering with plastic wrap, it is placed in a curing box with a temperature of 70°C ± 2°C and a humidity of more than 80% for curing for 8 hours. After the curing is completed, the mold is removed and standard curing is performed to obtain a soil-based foam lightweight soil molded part.

[0033] Figure 3 The XRD pattern of the soil-based foamed lightweight soil in this embodiment is as follows: Figure 3 It can be seen that the main hydration products of the soil-based foamed lightweight soil are CSH, CaCO3 and AFt, and a small amount of hydrotalcite and Mg(OH)2 are generated. Among them, a large amount of gel-like CSH and crystalline CaCO3 and AFt wrap and fill each other, making the microstructure of the foamed lightweight soil denser 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.

[0034] Example 2 The difference between this embodiment and embodiment 1 is that the soil-based foamed lightweight soil is made of the following raw materials in parts by weight: 30 parts of magnesium slag powder, 20 parts of granulated blast furnace slag powder, 20 parts of iron tailings powder, 40 parts of soil, 6 parts of water glass, 10 parts of desulfurized gypsum, 0.35 parts of polycarboxylate water reducer, 66 parts of water, 0.88 parts of AOS foaming agent, 0.21 parts of HPMC foam stabilizer, and 0.21 parts of calcium stearate foam stabilizer; the actual picture of the soil-based foamed lightweight soil and the enlarged pictures of different positions are shown in FIG. Figure 4 and Figure 5 shown.

[0035] Example 3 The difference between this embodiment and Example 1 is that the soil-based foamed lightweight soil is made of the following raw materials in parts by weight: 25 parts of magnesium slag powder, 25 parts of granulated blast furnace slag powder, 20 parts of iron tailings powder, 40 parts of soil, 6 parts of water glass, 10 parts of desulfurization gypsum, 0.35 parts of polycarboxylic acid water reducer, 66 parts of water, 0.88 parts of AOS foaming agent, 0.21 parts of HPMC foam stabilizer, and 0.21 parts of calcium stearate foam stabilizer.

[0036] Example 4 The difference between this embodiment and Example 1 is that the soil-based foamed lightweight soil is made of the following raw materials in parts by weight: 25 parts of magnesium slag powder, 25 parts of granulated blast furnace slag powder, 15 parts of iron tailings powder, 40 parts of soil, 6 parts of water glass, 10 parts of desulfurization gypsum, 0.325 parts of polycarboxylic acid water reducer, 63 parts of water, 0.84 parts of AOS foaming agent, 0.195 parts of HPMC foam stabilizer, and 0.195 parts of calcium stearate foam stabilizer.

[0037] Example 5 The difference between this embodiment and Example 1 is that the soil-based foamed lightweight soil is made of the following raw materials in parts by weight: 25 parts of magnesium slag powder, 25 parts of granulated blast furnace slag powder, 25 parts of iron tailings powder, 40 parts of soil, 6 parts of water glass, 10 parts of desulfurization gypsum, 0.375 parts of polycarboxylic acid water reducer, 69 parts of water, 0.92 parts of AOS foaming agent, 0.225 parts of HPMC foam stabilizer, and 0.225 parts of calcium stearate foam stabilizer.

[0038] Example 6 The difference between this embodiment and Example 1 is that the soil-based foamed lightweight soil is made of the following raw materials in parts by weight: 20 parts of magnesium slag powder, 20 parts of granulated blast furnace slag powder, 25 parts of iron tailings powder, 40 parts of soil, 6 parts of water glass, 10 parts of desulfurization gypsum, 0.325 parts of polycarboxylic acid water reducer, 63 parts of water, 0.84 parts of AOS foaming agent, 0.195 parts of HPMC foam stabilizer, and 0.195 parts of calcium stearate foam stabilizer.

[0039] Figure 6 This is a physical picture of the combustion performance test sample of the soil-based foam lightweight soil in this embodiment.

[0040] Example 7 The difference between this embodiment and Example 1 is that the soil-based foamed lightweight soil is made of the following raw materials in parts by weight: 30 parts of magnesium slag powder, 30 parts of granulated blast furnace slag powder, 15 parts of iron tailings powder, 40 parts of soil, 6 parts of water glass, 10 parts of desulfurization gypsum, 0.375 parts of polycarboxylic acid water reducer, 69 parts of water, 0.92 parts of AOS foaming agent, 0.225 parts of HPMC foam stabilizer, and 0.225 parts of calcium stearate foam stabilizer.

[0041] Example 8 The difference between this embodiment and Example 1 is that the soil-based foamed lightweight soil is made of the following raw materials in parts by weight: 20 parts of magnesium slag powder, 20 parts of granulated blast furnace slag powder, 15 parts of iron tailings powder, 40 parts of soil, 6 parts of water glass, 10 parts of desulfurization gypsum, 0.28 parts of polycarboxylic acid water reducer, 57 parts of water, 0.76 parts of AOS foaming agent, 0.16 parts of HPMC foam stabilizer, and 0.16 parts of calcium stearate foam stabilizer.

[0042] Example 9 The difference between this embodiment and Example 1 is that the soil-based foamed lightweight soil is made of the following raw materials in parts by weight: 30 parts of magnesium slag powder, 30 parts of granulated blast furnace slag powder, 20 parts of iron tailings powder, 40 parts of soil, 6 parts of water glass, 10 parts of desulfurization gypsum, 0.40 parts of polycarboxylic acid water reducer, 72 parts of water, 0.96 parts of AOS foaming agent, 0.24 parts of HPMC foam stabilizer, and 0.24 parts of calcium stearate foam stabilizer.

[0043] Example 10 The difference between this embodiment and Example 1 is that the soil-based foamed lightweight soil is made of the following raw materials in parts by weight: 30 parts of magnesium slag powder, 30 parts of granulated blast furnace slag powder, 25 parts of iron tailings powder, 40 parts of soil, 6 parts of water glass, 10 parts of desulfurization gypsum, 0.43 parts of polycarboxylic acid water reducer, 75 parts of water, 1.00 parts of AOS foaming agent, 0.26 parts of HPMC foam stabilizer, and 0.26 parts of calcium stearate foam stabilizer.

[0044] The properties of the soil-based foamed lightweight soil prepared in Examples 1 to 10 of the present invention were tested, and the results are shown in Table 1 below.

[0045] Table 1

[0046] As can be seen from Table 1, the soil-based foamed lightweight soil prepared by the present invention has the remarkable characteristics of light weight and high strength. 3 ~550kg / m 3 The compressive strength is 3.0 MPa to 3.5 MPa, significantly higher than the 0.3 MPa to 0.8 MPa of conventional soil-based foamed lightweight soil at the same dry density, and higher than the 0.8 MPa to 1.2 MPa of conventional foamed concrete at the same dry density. Furthermore, the soil-based foamed lightweight soil prepared in the present invention not only exhibits excellent thermal insulation and combustion resistance, but also meets the requirements of JGJ / T 341-2014, "Technical Specifications for the Application of Foamed Concrete," for its fluidity and drying shrinkage.

[0047] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent variation made to the above embodiment based on the essence of the invention technology shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A lightweight, energy-saving and fire-resistant soil-based foamed lightweight soil, characterized in that: The invention is prepared from the following raw materials in 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 water reducer, 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.

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

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

4. The lightweight, energy-saving and fire-resistant soil-based foamed lightweight soil according to claim 1, characterized in that: The soil is derived from natural soil, subway shield slag and engineering spoil, and is sieved through a 10mm sieve when used.

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

6. A method for preparing the soil-based foamed lightweight soil according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: Step 1: Mixing and stirring dry powder: according to the designed ratio of the target product, magnesium slag powder, granulated blast furnace slag powder, iron tailings powder, soil, desulfurized gypsum, polycarboxylate water reducer, HPMC foam stabilizer, and calcium stearate foam stabilizer are put into a blender and stirred at low speed to obtain a uniformly mixed dry powder; Step 2: Prepare slurry: Mix water glass and water evenly, add to the dry powder obtained in step 1 and stir at low speed to obtain slurry; Step 3: Prepare foam: dilute the AOS foaming agent and foam it to obtain uniform foam, then add it to the slurry obtained in step 2 and stir at a 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 the triple mold, and ensure that the triple mold is densely filled. Scrape the surface with a scraper, cover with plastic wrap, and place in a curing box with a temperature of 70℃±2℃ and a humidity of more than 80% for curing for 8 hours. After the curing is completed, demold and perform standard curing to obtain a soil-based foam lightweight soil molded part.

7. The method according to claim 6, characterized in that The speed of the low-speed stirring in step 1 is 60 r / min, and the time is 60 s; the speed of the low-speed stirring in step 2 is 60 r / min, and the time is 2 min; the speed of the low-speed stirring in step 3 is 60 r / min, and the time is 3 min~4 min.

8. The method according to claim 6, characterized in that The dimensions of the triple mold described in step 4 are 100 mm in length × 100 mm in width × 100 mm in height.

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