Backfill foaming agent, preparation method therefor, and use thereof

Abstract

Provided in the present invention are a backfill foaming agent, a preparation method therefor, and the use thereof. The preparation method comprises the following steps: (1) according to mass parts, adding 69.2-79.6 parts of water to a dispersion machine, then adding 0.2-0.4 part of cellulose ether, adding 0.2-0.4 part of a thickening agent, adding 20-30 parts of a surfactant, stirring same for 10-20 min, and stopping the stirring when the water temperature is lowered to 35℃ or below, so as to prepare a foaming agent component A; and (2) according to mass parts, adding 13.6-33.8 parts of water to the dispersion machine, then adding 3-6 parts of a foam stabilizer, stirring same for 5-10 min, adding 0.2-0.4 part of a biocide, adding 70-80 parts of the foaming agent component A, adding 7-9 parts of modified composite particles, and continuously stirring same for 10-20 min, so as to obtain the backfill foaming agent. The backfill foaming agent of the present invention improves the volume stability of foam concrete and therefore solves the problems of shrinkage and collapse of the foam concrete.

Description

Backfill foaming agent and preparation method and application thereof TECHNICAL FIELD

[0001] The present application relates to a foamed concrete backfill foaming agent, in particular to a backfill foaming agent and a preparation method and application thereof. BACKGROUND

[0002] Lightweight building materials are a new type of material widely used in the modern construction industry. Compared with traditional building materials (such as solid bricks and ordinary concrete), they have lighter weight, good heat and sound insulation performance, higher strength, and environmental protection characteristics. Foamed concrete is a new type of lightweight building material with a porous structure, widely used in construction, bridges, tunnels, roads, thermal insulation, sound insulation and other fields, and has the characteristics of fast construction speed, good flowability, good thermal insulation performance, adjustable density and low cost.

[0003] Foaming agents are key materials for producing foamed concrete. Foaming agents used in foamed concrete are mainly used to generate stable and uniform foam, which will then form pores in the concrete mixture, resulting in lightweight, thermal and sound insulation foamed concrete materials. Foaming agents can be divided into several categories, including chemical foaming agents, physical foaming agents and surfactant foaming agents. Chemical foaming agents: this type of foaming agent will decompose to produce gas (such as carbon dioxide, nitrogen, etc.) when heated or under certain conditions. These gases form bubbles in the concrete. Physical foaming agents: physical foaming agents produce bubbles through physical state changes, such as expansion of compressed gas, evaporation of liquid, or dissolution of solids. Surfactant foaming agents: this is the most commonly used type in foamed concrete, which mainly includes anionic, cationic, non-ionic surfactants and some natural surfactants, such as animal proteins, plant proteins, etc. This type of foaming agent significantly reduces the surface tension of the water solution, making air easy to disperse in the liquid to form foam, and helping the foam to exist stably and not easily break. TECHNICAL PROBLEM

[0004] Surfactant foaming agents have the advantages of relatively low cost, high availability of raw materials, and simple operation. However, as the market demands for foamed concrete become higher, the surfactant foaming agents produced by domestic and foreign companies such as BASF and other companies have already fallen behind other types of foaming agents in terms of foam stability, final strength and durability of concrete, etc. Therefore, how to further optimize the stability of surfactant foaming agents while utilizing their advantages, and at the same time obtain a balance between ideal lightweight and mechanical properties of foamed concrete, is a problem that needs to be solved. TECHNICAL SOLUTION

[0005] To solve the above problems, the purpose of the present application is to provide a backfilling foaming agent and its preparation method and application.

[0006] To achieve the above purpose, the present application provides the following technical solutions:

[0007] A preparation method of a backfilling foaming agent, comprising the following steps:

[0008] (1) Preparation of foaming agent component A: 69.2-79.6 parts by mass of water is added to a dispersing machine, then 0.2-0.4 parts of cellulose ether is added, and stirring is carried out for 5-15 min at a speed of 100-200 r / min, 0.2-0.4 parts of thickening agent is added, and stirring is continued for 5-15 min; 20-30 parts of surfactant is added, and stirring is carried out for 10-20 min, and when the water temperature is reduced to below 35℃, the stirring is stopped, and the foaming agent component A is prepared; wherein the surfactant is a mixture of sodium ethoxylated alkyl sulfate, sodium dodecyl benzene sulfonate, cocamide propyl betaine and tea saponin with a mass ratio of 1:0.2-0.6:1.2-1.4:1.6-1.9.

[0009] (2) Preparation of backfilling foaming agent: 13.6-33.8 parts by mass of water is added to a dispersing machine, then 3-6 parts of foam stabilizer is added, and stirring is carried out for 5-10 min at a speed of 100-200 r / min, 0.2-0.4 parts of bactericide is added, and stirring is continued for 5-10 min; 70-80 parts of foaming agent component A is added, and stirring is carried out for 15-20 min, 7-9 parts of modified composite particles is added, and stirring is continued for 10-20 min; and the backfilling foaming agent is obtained.

[0010] Further, the cellulose ether is one or more of hydroxyethyl cellulose, methyl hydroxyethyl cellulose and hydroxypropyl methyl cellulose.

[0011] Further, the cellulose ether is a mixture of hydroxyethyl cellulose, methyl hydroxyethyl cellulose and hydroxypropyl methyl cellulose with a mass ratio of 1.3-1.7:1:0.4-0.8.

[0012] Further, the thickening agent is one or two of guar gum and xanthan gum.

[0013] Further, the temperature of the water in step (1) is 60-80℃.

[0014] Further, the foam stabilizer is one or more of alcohol ether modified polyhydroxy polymer, silicone amide, calcium stearate emulsion and EVA emulsion.

[0015] Further, the foam stabilizer is a compound of alcohol ether modified polyol polymer, silicone amide, calcium stearate emulsion and EVA emulsion with a mass ratio of 2-2.5:1:0.4-0.7:1.4-1.6.

[0016] Further, the bactericide is one or more of isothiazolinone, sodium dichloroisocyanurate and bromochlorohydrin.

[0017] Further, the preparation method of the modified composite particle is as follows:

[0018] (1) mixing nano-alumina, nano-silica and hollow ceramic microbeads with a mass ratio of 1:1.3-1.6:0.4-0.8 to obtain mixed particles;

[0019] (2) mixing 0.1-0.15 parts by mass of glutaric anhydride, 0.2-0.4 parts by mass of silane coupling agent and 3-5 parts by mass of dimethyl sulfoxide, heating to 63-65℃ and reacting for 2-3h to obtain a mixed solution; mixing 10 parts by mass of the mixed particles and 60-80 parts by mass of water, adding the mixed solution, and reacting at 36-38℃ for 3-4h to obtain a first modified mixed solution;

[0020] (3) mixing 0.4-0.6 parts of fluorine surfactant and 10 parts of acetone, then adding to the first modified mixed solution, stirring for 2-3h; filtering to obtain a solid, washing and drying to obtain the modified composite particle.

[0021] Further, the silane coupling agent is KH560 or KH570.

[0022] Further, the fluorine surfactant is Capstone FS-30 fluorine surfactant. Manufacturer: Chemours.

[0023] Further, the nano-alumina has a particle size of 30-60nm and a specific surface area of 10-20m 2 / g. Zhejiang Zhiti Nano Micro New Material Co., Ltd.

[0024] Further, the nano-silica has an average particle size of 15nm and an average specific surface area of 250 m 2 / g. Beijing Dekedaojin Technology Co., Ltd.

[0025] Further, the hollow ceramic microbead has a particle size of 1-10μm. Shanghai Gurnan Nanometer Material Co., Ltd.

[0026] The second aspect of the present application provides the backfill foaming agent prepared by the preparation method.

[0027] The third aspect of the present application provides the application of the backfill foaming agent in the preparation of foam concrete. Advantages

[0028] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:

[0029] 1. This invention improves the volume stability of foamed concrete and solves the problems of shrinkage and collapse by utilizing the synergistic effect of multiple surfactants and foam stabilizers. It exhibits high pore closure, fewer interconnected pores, uniform pore size, and high sphericity. When used to prepare foamed concrete, it results in high compressive strength and thermal conductivity. The backfill foaming agent prepared by this invention has high stability, is easy to store, and facilitates widespread use, possessing extremely high application value and broad market prospects.

[0030] 2. In the backfill foaming agent system of the present invention, by using specific surfactants, foam stabilizers and cellulose ethers in combination, the foaming ratio, water bleeding rate and settling distance of the backfill foaming agent are improved through synergistic effects.

[0031] 3. The backfill foaming agent prepared by adding modified composite particles can improve the compressive strength, thermal conductivity and cracking age of foamed concrete. Embodiments of the present invention

[0032] The following are specific embodiments of the present invention. These embodiments are only for detailed description of the present invention and are not intended to limit the scope of protection of the present invention.

[0033] Some of the raw materials used in this invention were purchased from the following manufacturers, while the rest were commercially available.

[0034] Hydroxyethyl cellulose, methyl hydroxyethyl cellulose, and hydroxypropyl methyl cellulose were purchased from Guangdong Longhu Technology Co., Ltd. Sodium ethoxylated alkyl sulfate was purchased from Greenlink (Jining) Chemical Technology Co., Ltd. Sodium dodecylbenzene sulfonate was purchased from Shanghai Shengzhong Fine Chemical Co., Ltd. Cocamidopropyl betaine was purchased from Suzhou Minghua Sugar Alcohol Co., Ltd. Tea saponin was purchased from Xi'an Rongbai Biotechnology Co., Ltd. Alcohol ether modified polyhydroxy polymer was purchased from Linyi Lusen Chemical Co., Ltd. Silicone amide was purchased from Shandong Qilu Chemical Technology Co., Ltd. Calcium stearate emulsion was purchased from Guangzhou Zhenghao New Material Technology Co., Ltd. EVA emulsion was purchased from Wuhan Jiyesheng Chemical Co., Ltd. Example 1

[0035] This embodiment provides a backfill foaming agent, the preparation method of which includes the following steps:

[0036] (1) Preparation of foaming agent component A: 72 parts by mass of water is added into a dispersing machine, then 0.3 parts of cellulose ether is added, stirring for 10 min at 150 rpm, 0.3 parts of thickening agent is added, and stirring is continued for 10 min; 24 parts of surfactant is added, and stirring is carried out for 15 min, and when the water temperature drops to 30℃, the stirring is stopped, and the foaming agent component A is prepared; wherein the surfactant is a mixture of sodium ethoxylated alkyl sulfate, sodium dodecyl benzene sulfonate, cocamidopropyl betaine and tea saponin with a mass ratio of 1:0.4:1.3:1.7;

[0037] (2) Preparation of backfill foaming agent: 25 parts by mass of water is added into a dispersing machine, then 5 parts of foam stabilizer is added, stirring for 10 min at 150 rpm, 0.3 parts of bactericide is added, and stirring is continued for 5 min; 76 parts of foaming agent component A is added, and stirring is carried out for 18 min, and 8 parts of modified composite particles is added, and stirring is continued for 15 min; to obtain the backfill foaming agent.

[0038] The cellulose ether is a mixture of hydroxyethyl cellulose, methyl hydroxyethyl cellulose and hydroxypropyl methyl cellulose with a mass ratio of 1.5:1:0.7.

[0039] The thickening agent is guar gum.

[0040] The temperature of the water in step (1) is 70℃.

[0041] The foam stabilizer is a mixture of alcohol ether modified polyhydroxy polymer, silicone amide, calcium stearate emulsion and EVA emulsion with a mass ratio of 2.2:1:0.6:1.5.

[0042] The bactericide is isothiazolinone.

[0043] The preparation method of the modified composite particles is:

[0044] (1) Mixing nano-alumina, nano-silicon dioxide and hollow ceramic microbeads with a mass ratio of 1:1.5:0.6 to obtain mixed particles;

[0045] (2) Mixing 0.12 parts by mass of glutaric anhydride, 0.3 parts by mass of silane coupling agent and 4 parts by mass of dimethyl sulfoxide, heating to 64℃ and reacting for 2.5h to obtain a mixed liquid; mixing 10 parts by mass of mixed particles and 70 parts by mass of water, adding the mixed liquid, and reacting at 37℃ for 3.5h to obtain a first modified mixed liquid;

[0046] (3) Mixing 0.5 parts of fluorine surfactant and 10 parts of acetone, and adding them into the first modified mixed liquid, stirring for 2.3h; filtering to obtain a solid, washing and drying to obtain the modified composite particles.

[0047] The silane coupling agent is KH560. The fluorosurfactant is Capstone® FS-30 fluorosurfactant. Manufacturer: Chemours.

[0048] The nano-aluminum oxide has a particle size of 30-60 nm and a specific surface area of 10-20 m 2 / g. Zhejiang Zhiti Nano Micro New Material Co., Ltd. The nano-silica has an average particle size of 15 nm and an average specific surface area of 250 m 2 / g. Beijing Deke Daojin Technology Co., Ltd. The hollow ceramic microbeads have a particle size of 1-10 μm. Shanghai Guren Asia Nano Material Co., Ltd. Example 2

[0049] The present embodiment provides a backfill foaming agent, and a preparation method of the backfill foaming agent comprises the following steps:

[0050] (1) Preparation of foaming agent component A: 69.2 parts by mass of water is added into a dispersing machine, then 0.4 parts of cellulose ether is added, stirring is performed by using the dispersing machine for 5 min at a speed of 200 r / min, 0.2 parts of thickening agent is added, and stirring is continuously performed for 15 min; 20 parts of surfactant is added, and stirring is performed for 20 min, and when the water temperature is reduced to below 35°C, the stirring is stopped, and the foaming agent component A is prepared; wherein the surfactant is a mixture of sodium ethoxylated alkyl sulfate, sodium dodecyl benzene sulfonate, cocamidopropyl betaine and tea saponin with a mass ratio of 1:0.2:1.4:1.6.

[0051] (2) Preparation of backfill foaming agent: 33.8 parts by mass of water is added into a dispersing machine, then 3 parts of foam stabilizer is added, stirring is performed by using the dispersing machine for 10 min at a speed of 100 r / min, 0.2 parts of bactericide is added, and stirring is continuously performed for 10 min; 80 parts of foaming agent component A is added, and stirring is performed for 15 min, and 9 parts of modified composite particles is added, and stirring is continuously performed for 10 min; and the backfill foaming agent is obtained.

[0052] The cellulose ether is a mixture of hydroxyethyl cellulose, methyl hydroxyethyl cellulose and hydroxypropyl methyl cellulose with a mass ratio of 1.7:1:0.4.

[0053] The thickening agent is guar gum.

[0054] The temperature of the water in step (1) is 80°C.

[0055] The foam stabilizer is a mixture of alcohol ether modified polyhydroxy polymer, silicone amide, calcium stearate emulsion and EVA emulsion with a mass ratio of 2:1:0.7:1.4.

[0056] The bactericide is isothiazolinone.

[0057] The preparation method of the modified composite particles is:

[0058] (1) Mix nano-alumina, nano-silica and hollow ceramic microbeads in a mass ratio of 1:1.3:0.8 to obtain mixed particles;

[0059] (2) Mix 0.1 parts by mass of glutaric anhydride, 0.4 parts by mass of a silane coupling agent and 3 parts by mass of dimethyl sulfoxide, heat to 65°C and react for 2 hours to obtain a mixed solution; mix 10 parts by mass of the mixed particles and 60 parts by mass of water, add the mixed solution, and react at 36°C for 4 hours to obtain a first modified mixed solution;

[0060] (3) Mix 0.4 parts of a fluorosurfactant and 10 parts of acetone, add to the first modified mixed solution, and stir for 2 hours; filter to obtain a solid, wash and dry to obtain modified composite particles.

[0061] The silane coupling agent is KH560. The fluorosurfactant is Capstone® FS-30 fluorosurfactant. Manufacturer: Chemours.

[0062] The nano-alumina has a particle size of 30-60 nm and a specific surface area of 10-20 m 2 / g. Zhejiang Zhiti Nano Micro New Material Co., Ltd. The nano-silica has an average particle size of 15 nm and an average specific surface area of 250 m 2 / g. Beijing Dekedaojin Technology Co., Ltd. The hollow ceramic microbeads have a particle size of 1-10 μm. Shanghai Gurnano Nanometer Material Co., Ltd.

[0063] Comparative Example 1

[0064] The difference between this comparative example and Example 1 is that the surfactant is a mixture of sodium ethoxylated alkyl sulfate, sodium dodecylbenzenesulfonate, cocamidopropyl betaine and tea saponin in a mass ratio of 1:1:1:1.

[0065] Comparative Example 2

[0066] The difference between this comparative example and Example 1 is that the surfactant is a mixture of sodium ethoxylated alkyl sulfate, fatty alcohol polyoxyethylene ether, dodecyl dimethyl betaine and sodium dodecylaminopropionate in a mass ratio of 1:0.4:1.3:1.7.

[0067] Comparative Example 3

[0068] The difference between this comparative example and Example 1 is that the cellulose ether is a mixture of hydroxyethyl cellulose, methylhydroxyethyl cellulose and hydroxypropyl methyl cellulose in a mass ratio of 1:1:1.

[0069] Comparative Example 4

[0070] The difference between the present comparative example and Example 1 is that the foam stabilizer is a mixture of alcohol ether modified polyol polymer, silicone amide, calcium stearate emulsion and EVA emulsion at a mass ratio of 1:1:1:1.

[0071] Comparative Example 5

[0072] The difference between the present comparative example and Example 1 is that the foam stabilizer is a mixture of polyvinyl alcohol, polyacrylamide, calcium stearate emulsion and lauryl alcohol at a mass ratio of 2.2:1:0.6:1.5.

[0073] Comparative Example 6

[0074] The preparation method of the modified composite particles is as follows:

[0075] (1) mixing nano-alumina, nano-silica and hollow ceramic microspheres at a mass ratio of 1:1.5:0.6 to obtain mixed particles;

[0076] (2) mixing 0.3 parts by mass of silane coupling agent, 10 parts by mass of mixed particles and 70 parts by mass of water, adding the mixture, heating to 37°C and reacting for 3.5 hours, filtering to obtain a solid, washing and drying to obtain modified composite particles.

[0077] Comparative Example 7

[0078] The difference between the present comparative example and Example 1 is that the nano-alumina has a particle size of 1-10 μm and a specific surface area of 5-10 m2 / g (Zhejiang Zhiti Nano New Material Co., Ltd.). The hollow ceramic microspheres have a particle size of 20-500 μm (Dalian Yibang Technology Co., Ltd., model: E-SPHERES hollow ceramic microspheres). The nano-silica has an average particle size of 30 nm and a specific surface area of 200 m2 / g (Beijing Dekedaojin Technology Co., Ltd.). 2

[0079] Comparative Example 8

[0080] The difference between the present comparative example and Example 1 is that the modified composite particles are replaced by ordinary composite particles. Mixing nano-alumina, nano-silica and hollow ceramic microspheres at a mass ratio of 1:1.5:0.6 to obtain ordinary composite particles. The nano-alumina has a particle size of 30-60 nm and a specific surface area of 10-20 m2 / g (Zhejiang Zhiti Nano New Material Co., Ltd.). The nano-silica has an average particle size of 15 nm and a specific surface area of 250 m2 / g (Beijing Dekedaojin Technology Co., Ltd.). The hollow ceramic microspheres have a particle size of 1-10 μm (Shanghai Gelun Yana Nano Materials Co., Ltd.). 2 2

[0081] Performance test

[0082] ​​​1. According to JG / T 266-2011, the foaming ratio, 1h bleeding rate and settlement distance (1h settlement distance) of the backfill foaming agent of Example 1-2 and Comparative Examples 1-8 were tested.

[0083] 2. The backfill foaming agent of Example 1-2 and Comparative Examples 1-8 was added into the cement slurry (P.O. 42.5 ordinary portland cement was used, the cement dosage was 580 kg / m 3 , the water dosage was 290 kg / m 3 , and the foam dosage was 0.62 m 3 / m 3 ), and stirred uniformly to obtain a foam concrete slurry. The test block size was 100 mm x 100 mm x 100 mm, the curing room temperature was 20±1℃, the relative humidity was 90%, and the test block was cured for 48h after molding with a film, and then demolded and cured until the test age. The foam concrete sample was obtained, and the following tests were performed.

[0084] The compressive test was performed by using a pressure testing machine.

[0085] The cracking age of the foam concrete within 360d was tested according to JC / T 951-2005 under the condition of 20±1℃ and relative humidity (43±2)%.

[0086] The foam concrete sample was placed into a double-plate heat conductivity coefficient tester to test, and the cold-hot plate temperature difference was set to 20℃, the preheating time was 30 min, and the test time was 180 min. The heat conductivity coefficient was determined.

[0087] The pore size range was determined by using an X-ray tomography instrument.

[0088] The results are shown in Table 1.

[0089]

[0090] 3. Storage stability

[0091] The backfill foaming agent of Example 1-2 and Comparative Examples 1-8 was stored for 180 days under low temperature (4℃), normal temperature (25℃), high temperature (45℃) and variable temperature conditions (placed for 10 days at 4℃, 25℃ and 40℃ in turn), and whether delamination or precipitation phenomenon occurred was observed. The results are shown in Table 2.

[0092]

[0093] The above is a preferred embodiment of the present application. It should be noted that, for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which should also be considered within the scope of protection of the present application.

Claims

1. A method of preparing a backfill foaming agent, characterized by, The method comprises the following steps: (1) preparing the foaming agent component A: 69.2-79.6 parts by mass of water is added into a dispersing machine, then 0.2-0.4 parts by mass of cellulose ether is added, and stirring is performed for 5-15 min at a speed of 100-200 rpm; 0.2-0.4 parts by mass of thickening agent is added, and stirring is continued for 5-15 min; 20-30 parts by mass of surfactant is added, and stirring is performed for 10-20 min; when the water temperature is reduced to below 35℃, the stirring is stopped, and the foaming agent component A is prepared; wherein the surfactant is a mixture of sodium ethoxylated alkyl sulfate, sodium dodecyl benzene sulfonate, cocamide propyl betaine and tea saponin with a mass ratio of 1:0.2-0.6:1.2-1.4:1.6-1.9; (2) preparing the backfill foaming agent: 13.6-33.8 parts by mass of water is added into a dispersing machine, then 3-6 parts by mass of foam stabilizer is added, and stirring is performed for 5-10 min at a speed of 100-200 rpm; 0.2-0.4 parts by mass of bactericide is added, and stirring is continued for 5-10 min; 70-80 parts by mass of the foaming agent component A is added, and stirring is performed for 15-20 min; 7-9 parts by mass of modified composite particles is added, and stirring is continued for 10-20 min; and the backfill foaming agent is obtained.

2. The method of claim 1, wherein the backfill foaming agent is prepared by mixing the foaming agent and the water in a ratio of 1 : 1 to 1 :

3. The cellulose ether is one or more of hydroxyethyl cellulose, methylhydroxyethyl cellulose and hydroxypropyl methyl cellulose.

3. The method of claim 2, wherein the backfill foaming agent is prepared by mixing the foaming agent and the water in a ratio of 1 : 1 to 1 :

3. The cellulose ether is a mixture of hydroxyethyl cellulose, methylhydroxyethyl cellulose and hydroxypropyl methyl cellulose with a mass ratio of 1.3-1.7:1:0.4-0.

8.

4. The method of claim 1, wherein the backfill foaming agent is prepared by mixing the foaming agent and the water in a ratio of 1 : 1 to 1 :

3. The temperature of the water in step (1) is 60-80℃.

5. The method of claim 1, wherein the backfill foaming agent is prepared by mixing the foaming agent and the water in a ratio of 1: 1 to 1:

3. The foam stabilizer is one or more of alcohol ether modified polyhydroxy polymer, silicone amide, calcium stearate emulsion and EVA emulsion.

6. The method of claim 1, wherein the backfill foaming agent is prepared by mixing the foaming agent and the water in a ratio of 1: 1 to 1:

3. The preparation method of the modified composite particles is as follows: (1) mixing nano-alumina, nano-silicon dioxide and hollow ceramic microbeads with a mass ratio of 1:1.3-1.6:0.4-0.8 to obtain mixed particles; (2) mixing 0.1-0.15 parts by mass of glutaric anhydride, 0.2-0.4 parts by mass of silane coupling agent and 3-5 parts by mass of dimethyl sulfoxide, heating to 63-65℃ and reacting for 2-3 h to obtain a mixed solution; mixing 10 parts by mass of the mixed particles and 60-80 parts by mass of water, adding the mixed solution and reacting at 36-38℃ for 3-4 h to obtain a first modified mixed solution; (3) mixing 0.4-0.6 parts by mass of fluorine surfactant and 10 parts of acetone, adding the mixture into the first modified mixed solution and stirring for 2-3 h; filtering to obtain a solid, washing and drying to obtain the modified composite particles.

7. The method of claim 6, wherein the backfill foaming agent is prepared by mixing the foaming agent and the water in a ratio of 1 : 1 to 1 :

3. The silane coupling agent is KH560 or KH570; and the fluorine surfactant is Capstone® FS-30 fluorine surfactant.

8. The method of claim 6, wherein the backfill foaming agent is prepared by mixing the foaming agent and the water in a ratio of 1 : 1 to 1 :

3. The nano-alumina has a particle size of 30-60 nm and a specific surface area of 10-20 m 2 / g; the nano-silica has an average particle size of 15 nm and an average specific surface area of 250 m 2 / g; and the hollow ceramic microbeads have a particle size of 1-10 μm.

9. A backfill foaming agent prepared by the method of any one of claims 1-8.

10. Use of the backfill foaming agent of claim 9 in the preparation of foam concrete.

Images