CN113754371A

CN113754371A - Foamed light soil with high stone powder content and preparation method thereof

Info

Publication number: CN113754371A
Application number: CN202111004546.0A
Authority: CN
Inventors: 汪建斌; 稂合清; 韩健; 李佳
Original assignee: Guangdong Shengrui Technology Co ltd
Current assignee: Guangdong Shengrui Technology Co ltd
Priority date: 2021-08-30
Filing date: 2021-08-30
Publication date: 2021-12-07
Anticipated expiration: 2041-08-30
Also published as: CN113754371B

Abstract

The invention discloses foamed light soil with high stone powder content and a preparation method thereof.

Description

Foamed light soil with high stone powder content and preparation method thereof

Technical Field

The invention relates to a technology for recycling stone powder solid waste, in particular to foamed lightweight soil with high stone powder content and a preparation method thereof, belonging to the field of building materials.

Background

The foamed light soil is a porous light engineering filling material obtained by adding prefabricated foam groups into stirred cementing material slurry. The concrete has the characteristics of light weight, high compressive strength, adjustable strength, good integrity, high fluidity, good durability, condensation self-standing property, heat preservation and insulation, good constructability and the like. The method can be used for projects such as abutment back backfilling, road widening, bridge span reduction, steep slope embankment, landslide roadbed, soft soil roadbed unloading, underground structure thing unloading, tunnel cavity grouting, old bridge reinforcement, frozen soil roadbed heat preservation and insulation and the like.

The sand used for construction includes natural sand and machine-made sand. Natural sands include river sands, sea sands, and mountain sands. Among them, river sand has no problem in building quality, but mining has been prohibited in many areas; sea sand can not be directly used for building, needs to handle chloride ions, otherwise can seriously corrode steel bar structures, causes serious consequences, and the mud content of mountain sand is higher, can seriously influence the performance of concrete, causes the workability deterioration of concrete, and slump loss increases with time, and volume stability and durability deteriorate. In summary, the use of fine machine-made sand is not the second choice for building sand. The waste stone powder is a byproduct in the production process of a sand production line, and has the particle size of less than 75 mu m and larger fineness. According to relevant research studies, 50-200kg of stone powder is found to be produced for each ton of machine-made sand. The waste stone powder is easy to stack, causes barren soil, underground water pollution and dust pollution, and seriously damages the environment.

The asphalt mixing station processes asphalt, stone, binder and the like into asphalt mixture according to a certain mixing proportion, wherein the air-washing of the crushed stones by the asphalt mixing station can generate a large amount of dust. Due to the special properties of asphalt, a great amount of dust particles which seriously pollute the environment are generated, and the particle sizes of the dust particles are usually less than 0.075mm, so the dust is called recycled dust, and is called recycled powder for short. The piling of the recycled powder occupies a large area of land, causes the reduction of the land utilization rate, and brings more adverse effects to energy production, resource utilization and environmental protection. With the rapid development of highway construction, if the recovered dust is not recycled, the problem will be a major problem affecting sustainable development. In recent years, the mixing station adopts a dust removal mode of wind dust removal, wet dust removal and cloth bag dust removal, the air quality near the asphalt mixing station is obviously improved due to the wide application of a cloth bag dust removal system, the recovery condition of dust is greatly improved, the conditions of mechanical equipment damage, environmental pollution, harm to human health and the like are obviously improved, and how to treat the recovered dust becomes a new problem. There are data showing that about 45kg of dust is recovered per ton of bituminous mix produced, and these recovered dusts have not been currently treated well for a while, nor have there been any solutions to reduce the cost of the treatment. According to the regulations of environmental protection departments, the recovered dust can not be directly stacked but is buried, but secondary cost is increased due to the fact that a landfill site is found and the dust is treated, so that the treatment cost is beyond the budget range, and a proper landfill site is not easy to find, so that a method for effectively treating and utilizing the dust is imperative.

The light soil composition in the prior art still has a plurality of problems during construction and application; on the one hand, the curing time of the lightweight soil composition does not meet the needs of the construction site, and on the other hand, the resulting cured lightweight soil structure is still unsatisfactory in terms of density, strength and dimensional stability.

Disclosure of Invention

The foamed light soil with high stone powder content and the preparation method thereof are provided by the invention, waste stone powder generated in the sand making process of the existing sandstone plant and dust formed by air-washing crushed stones of an asphalt mixing station are utilized in the foamed light soil, so that the cement consumption can be reduced, the material production cost can be reduced, the stone powder and the waste stone powder can be subjected to resource treatment, the waste is changed into valuable, the raw material cost and natural resources can be effectively saved, the pollution to the environment is relieved, and the sustainable development is realized.

In the present application, blowing agents have the same meaning as blowing agents. "optional" means with or without (0).

In the present application, the expression "X mainly comprises or mainly consists of a plurality of components" means that the plurality of components accounts for 80 to 100wt%, preferably 90 to 100wt%, for example 95wt% or 98wt% of X.

Through a large number of experiments, the inventor of the application finds that the solid material consisting of cement, stone powder and mineral powder is combined with the surfactant type foaming agent, so that a lightweight soil structure with light weight (low density), high strength and stable size (durable structure) can be obtained in a reasonable curing time in the construction process.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

according to a first embodiment of the present invention, a foamed lightweight soil (composition) with a high stone dust content is provided.

A high stone dust content foamed lightweight soil composition having the following composition ratio, i.e. the lightweight soil (composition) comprises or consists essentially of (80-100 wt%, preferably 90-100wt%, for example 95wt% or 98 wt%) the following components:

A) cement: 30 to 70 parts by weight, preferably 32 to 68, preferably 34 to 66, preferably 36 to 64, preferably 38 to 62, preferably 40 to 60, preferably 42 to 58, preferably 44 to 56, more preferably 46 to 54 parts by weight;

B) stone powder: 30 to 50 parts by weight, preferably 31 to 49 parts by weight, preferably 32 to 48 parts by weight, preferably 34 to 46 parts by weight, preferably 36 to 44 parts by weight, more preferably 38 to 42 parts by weight;

C) mineral powder: 0 to 40 parts by weight, preferably 5 to 40 parts by weight, preferably 10 to 35 parts by weight, preferably 12 to 33 parts by weight, preferably 14 to 30 parts by weight, preferably 16 to 28 parts by weight, more preferably 18 to 26 parts by weight, more preferably 20 to 24 parts by weight;

E) water; and

F) and (3) foaming.

In general, the weight ratio (i.e.water-to-solid ratio) of E) water to the solid material (cement + stone dust + ore dust) is 0.5-0.7: 1, preferably 0.51-0.68: 1, preferably 0.52-0.66: 1, preferably 0.54-0.64: 1, preferably 0.56-0.62: 1, preferably 0.58-0.60: 1.

In general, the foam is formed by diluting a high molecular surfactant type foaming agent with additional water 60 to 120 times (preferably 62 to 110 times, more preferably 65 to 100 times, more preferably 67 to 95 times, more preferably 70 to 90 times, such as 75, 80 or 85 times) to form a foam concentrate, and then introducing air (e.g., compressed air) into the foam concentrate.

Here, the amount of water contained in the F) foam is not included or calculated in the amount of E) water.

In general, the polymeric surfactant type foaming agent is used in an amount of 0.055 to 0.8 wt. -%, preferably 0.06 to 0.75 wt. -%, preferably 0.07 to 0.7 wt. -%, preferably 0.08 to 0.65 wt. -%, preferably 0.09 to 0.6 wt. -%, preferably 0.1 to 0.55 wt. -%, preferably 0.11 to 0.5 wt. -%, e.g. 0.12 wt. -%, 0.13 wt. -%, 0.14 wt. -%, 0.15 wt. -%, 0.16 wt. -%, 0.17 wt. -%, 0.18 wt. -%, 0.19 wt. -%, 0.20 wt. -%, 0.25 wt. -%, 0.30 wt. -%, 0.35 wt. -%, 0.40 wt. -% or 0.45 wt. -%, based on the total weight of the solid material (cement + stone dust + ore fines).

The amount of foam used is sufficient such that the ratio of the volume of bubbles (or foam) to the total volume of the wet foamed polymeric soil composition obtained after all the materials have been mixed (or, the bubble fraction) is: 25% to 75%, preferably 28% to 70%, preferably 30% to 66%, preferably 32% to 64%, preferably 34% to 62%, preferably 36% to 60%, preferably 38% to 58%, preferably 40% to 56%, e.g. 45%, 50%. Alternatively, the foam is used in an amount sufficient to provide a wet foamed polymeric soil composition having a bubble ratio of: 25% to 75%, preferably 28% to 70%, preferably 30% to 66%, preferably 32% to 64%, preferably 34% to 62%, preferably 36% to 60%, preferably 38% to 58%, preferably 40% to 56%, e.g. 45%, 50%.

In the present application, the expression "X mainly comprises or mainly consists of a plurality of components" means that the plurality of components accounts for 80 to 100wt%, preferably 90 to 100wt%, for example 95wt% or 98wt% of X. Generally, the total weight or sum of the weight of the solid material, water and foam is 85 to 100wt%, preferably 87 to 100wt%, preferably 90 to 100wt%, preferably 92 to 100wt%, preferably 95 to 100wt%, preferably 97 to 100wt%, preferably 98 to 99wt%, based on the weight of the foamed polymeric soil composition.

Preferably, the cement is portland cement or ordinary portland cement, preferably ordinary portland cement. Such as ordinary portland cement meeting the 42.5, 42.5R, 52.5R strength ratings of "universal portland cement" GB 175. Ordinary portland cement of 42.5 strength grade or ordinary portland cement of 42.5R strength grade is preferred in view of cost performance.

Generally, the mass ratio of the stone powder to the ore powder is 30-50 (preferably 31-49, preferably 32-48, preferably 34-46, preferably 36-44, more preferably 38-42) to 0-40 (preferably 5-40, preferably 10-35, preferably 12-33, preferably 14-30, preferably 16-28, more preferably 18-26, more preferably 20-24).

The mass ratio of (stone dust + ore dust) to cement is (0.4-3): 1, preferably (0.45-2.8): 1, preferably (0.5-2.6): 1, preferably (0.55-2.4): 1, preferably (0.6-2.2): 1, preferably (0.65-2): 1, preferably (0.7-1.8): 1, preferably (0.75-1.6): 1, preferably (0.8-1.4): 1, preferably (0.85-1.3): 1, preferably (0.9-1.2): 1, preferably (0.95-1.1): 1, e.g. 1: 1.

Preferably, the stone powder is one or more of stone powder produced by a stone powder factory, stone powder produced by a stone processing factory, stone powder produced in a sand making process and stone powder formed by air washing of crushed stones by an asphalt mixing station. The stone powder produced in the sand making process comprises sand making stone powder and dust collecting stone powder.

Preferably, the particle size of the stone powder is less than or equal to 150 μm, preferably less than or equal to 110 μm, and more preferably less than or equal to 75 μm.

Preferably, the mineral powder is blast furnace slag powder. Preferably, the ore powder is selected from one or more of S75 ore powder, S95 ore powder and S105 ore powder. Preferably, the ore powder is selected from one or more of S75 ore powder, S95 ore powder and S105 ore powder defined in "granulated blast furnace slag powder for cement, mortar and concrete" GB/T18046.

Preferably, the high molecular surfactant type foaming agent is a composite surfactant consisting of a polyether surfactant and a small molecular organic surfactant.

More preferably, by using the above-mentioned curing agent in combination with a specific surfactant type foaming agent, a lightweight soil composition having more excellent properties can be obtained, so that the strength of the cured lightweight soil structure is further improved by about 17 to 45% as compared with the strength of the cured lightweight soil structure obtained by using a general foaming agent. The foaming agent is selected from one or more of SRS1 foaming agent, SRN2 foaming agent and SRL0 foaming agent.

Preferably, the SRS1 blowing agent comprises: 63-76wt% of sodium fatty alcohol-polyoxyethylene ether sulfate, 10-15wt% of triethanolamine, 9-15wt% of sodium dodecyl sulfate, 4-7wt% of diethanol monoisopropanolamine and 4-7wt% of lauramidopropyl betaine. The wt% is based on the mass of the SRS1 blowing agent. The sum of the amounts of all components amounts to 100 wt.%.

Preferably, the SRN2 blowing agent comprises: 33-55wt% of sodium fatty alcohol-polyoxyethylene ether sulfate, 5-10wt% of triethanolamine, 3-6wt% of sodium dodecyl sulfate, 2-5wt% of diethanol monoisopropanolamine, 20-35wt% of sodium alpha-alkenyl sulfonate, 15-25wt% of ethylene glycol monobutyl ether and 2-5wt% of 12-14 mixed alcohol. The wt% is based on the mass of SRN2 blowing agent. The sum of the amounts of all components amounts to 100 wt.%.

Preferably, the SRL0 blowing agent comprises: 40-55wt% of sodium fatty alcohol-polyoxyethylene ether sulfate, 3-6wt% of sodium dodecyl sulfate, 20-35wt% of sodium alpha-alkenyl sulfonate, 2-5wt% of lauramidopropyl betaine and 15-20wt% of water (preferably distilled water or softened water). The wt% is based on the mass of SRL0 blowing agent. The sum of the amounts of all components amounts to 100 wt.%.

Preferably, the weight ratio of the carbon dodecanol and the carbon tetradecanol in the 12-14 mixed alcohol is 3-9:1-5, preferably 4-8:2-4, preferably 5-7: 2-4, for example, the mass ratio is 7:3 or 6: 4.

Sodium alpha-alkenyl sulfonate, as defined in the prior art, is generally referred to herein as R¹-CH=CH-(CH₂)n-SO₃Na, R¹=C₉-C₁₃N =1, 2 or 3.

Sodium fatty alcohol Ether sulfate RO (CH)₂CH₂O)_n-SO₃Na (n =2 or 3, R is a 12-15 alkyl group (e.g., 13 or 14 alkyl group)) is a surfactant commonly used in detergents.

In general, the foams have a standard density (or apparent density) of from 45 to 55 kg/m³Preferably 48 to 52 kg/m³。

Preferably, the foamed polymeric soil composition has a wet density of 750-1050 kg/m³Preferably 800-³Preferably 810-950 kg/m³Preferably 820-900 kg/m³Preferably 830-880 kg/m³。

In general, the amount of foam used is: to form a wet composition per kg, the amount of foam used = standard density of foam (kg/m)³) X bubble rate (%) in the foamed light soil composition. Wherein the bubble rate (%) means a volume ratio of bubbles in a composition (i.e., wet material) formed by mixing all the materials.

According to a second embodiment of the present invention, there is provided a method of preparing a foamed lightweight soil with a high stone dust content or a method of preparing the foamed lightweight soil with a high stone dust content according to the first embodiment.

Namely, a method for preparing a foamed lightweight soil composition having a high stone dust content as described above, characterized in that: the method comprises the following steps:

1) weighing cement, stone powder, mineral powder, foaming agent and water in proportion for later use.

2) The foaming agent is diluted with water to obtain a foam concentrate, and then a foam is obtained by introducing air (e.g., compressed air) into the foam concentrate.

3) Firstly, stirring and mixing cement, stone powder, mineral powder and water uniformly; then adding foam, continuously stirring and uniformly mixing to obtain the wet foamed light soil composition.

Preferably, the method further comprises:

the wet foamed lightweight soil composition was spread on the surface of a substrate and cured to obtain a cured foamed lightweight soil.

Generally, in step 2), the polymeric surfactant based foaming agent is diluted 60 to 120 times (preferably 62 to 110 times, more preferably 65 to 100 times, more preferably 67 to 95 times, more preferably 70 to 90 times, such as 75, 80 or 85 times) with additional water.

Preferably, the foaming agent is diluted by adding water into the foaming agent solution, the dilution ratio of the foaming agent solution is 60-120 times, the prepared foaming agent solution is injected into a foaming device, the pressure of compressed air input into the foaming device is controlled (for example, 1.5-2 standard atmospheric pressures), and the compressed air is introduced into the foaming agent solution to prepare the foam. The prepared foam can be stored for no more than 10min alone and should be used as soon as possible. Wherein the compressed air is output from a compressed air source (e.g., an air compressor or a compressed air storage tank).

In particular, in step 2), it is important to control the pressure of the compressed air (1.5-2 atm) fed into the foaming device in order to achieve sufficient foaming and to allow the volume of the obtained foam to remain stable for 6-15 minutes. If the pressure of the compressed air fed into the foaming apparatus is low (below 1.5 atm), the foam concentrate cannot be sufficiently foamed, and if the pressure is high (above 2 atm), the volume of the obtained foam is unstable (a large amount of foam is broken when stored alone before use, resulting in a reduction in the volume of the foam).

Preferably, in step 3, the first stirring rate is 30-100r/min, and the stirring time is 1-30min (preferably 5-20min, such as 15 min). The second stirring speed is 40-120r/min, and the stirring time is 1-10min (preferably 4-7 min).

Preferably, the wet density of the foamed lightweight soil composition prepared in the step 3) is 500 to 1200kg/m³Preferably 600-³Preferably 700-1000kg/m³Preferably 750-950kg/m³Preferably 800-³. In addition, the 28-day unconfined compressive strength of the foamed lightweight soil obtained after the composition is cured is 0.82-5 MPa.

In general, the foam prepared should be used immediately, preferably, it has a single shelf life of no more than 10min, more preferably no more than 8 min.

Preferably, in step 2), the pressure of the compressed air fed into the foaming device is controlled to be 1.5 to 2 atm in order to achieve sufficient foaming and to allow the volume of the obtained foam to remain stable for 6 to 15 minutes.

Generally, the dry density of the cured lightweight soil is about equal to or slightly less than the wet density. Preferably, the dry density of the cured light soil is 640-1050 kg/m³Preferably 650-1000 kg/m³Preferably 670-990 kg/m³Preferably 700-950 kg/m³Preferably 720-920 kg/m³. In addition, its 28-day unconfined compressive strength (MPa) is in the range of 0.85 to 4.8MPa, preferably 0.9 to 4.5MPa, preferably 1.0 to 4.0 MPa,preferably 1.1 to 3.8 MPa, preferably 1.15 to 3.7 MPa, preferably 1.2 to 3.5 MPa, more preferably 1.25 to 3.3 MPa, more preferably 1.3 to 3.0 MPa, for example 1.8, 2 or 2.5 MPa.

The curing time of the foamed lightweight earth composition of the present invention can be controlled within a reasonable range suitable for construction, for example, 1 to 3 hours, such as 1.30, 2 or 2.5 hours. Further, the complete curing time (final setting time) is generally 6 to 20 hours, preferably 8 to 18 hours, more preferably 10 to 16 hours. The temperature in summer is higher, and the complete curing time is 6-12 hours.

In the prior art, foamed lightweight soil is generally obtained by mixing cement, doping material and water to prepare cement slurry, then adding foam, stirring and mixing, and curing. At present, the admixture applied to the foamed lightweight soil mainly comprises fly ash, slag, silica fume and the like. The stone powder is a byproduct generated in the production process of stone processing enterprises (the stone powder is stone powder produced in stone powder plants, stone powder generated in the sand making process, stone powder formed by air washing of crushed stones in an asphalt mixing station and the like), and the main character of the stone powder is ultrafine solid powdery waste, and the main mineral components are limestone, hydrotalcite and the like. For a long time, because the economic added value of the stone powder is low, the stone powder is often discarded by production enterprises, so that the waste of resources and the environmental pollution are caused. In recent years, stone powder is used as a raw material for producing foamed lightweight soil to replace part of cementing materials such as cement and fly ash, so that the foamed lightweight soil has potential economic value. However, experiments show that the following factors mainly exist in whether the stone powder can be applied to the foamed lightweight soil: on one hand, the stone powder as superfine powder presents certain hydrophobicity, and the performance of the foaming agent is easily reduced or failed after being mixed with the existing composite foaming solution; on the other hand, calcium and magnesium ions are partially dissolved out of the stone powder after the stone powder contacts water, so that the hardness of an aqueous solution is increased, the foam duration is reduced, the foam is broken, a series of problems that the stone powder-doped foam part is poor in uniformity, easy to collapse, difficult to form, crack and the like are caused, the application of the stone powder in the field of foam concrete is limited, furthermore, in the prior art, the mobility of cement slurry is improved due to the increase of the adding amount of the stone powder, free water of a slurry is increased, foaming is easy to combine and communicate to form large bubbles when the slurry is initially set, communication holes are increased, and the compressive strength of foamed lightweight soil is reduced, so that the adding amount of the stone powder is not high in the prior art.

In the invention, the mineral powder is blast furnace slag powder, and the main chemical components of the mineral powder are CaO and SiO₂、Al₂O₃Etc. and also contain small amounts of SO₃、Fe₂O、MgO、K₂O、TiO₂、Na₂O, MnO, etc. The addition of the mineral powder can improve the recycling efficiency of the mineral waste residues, and on the other hand, the mineral powder can greatly improve the durability and the reinforcing effect of the foamed light soil, and can reduce the slump loss to a certain extent, improve the product performance of the foamed light soil, further reduce the use amount of cement and save the cost.

In the invention, the foaming agent is selected from an SRS1 foaming agent, an SRN2 foaming agent and an SRL0 foaming agent which are self-developed foaming agents, and the foaming agent is an enhanced foaming agent, can provide foam for cement slurry and can also play a role in enhancing the cement slurry. The enhanced foaming agent is less influenced by stone powder, has long foam duration and relatively strong foam strength, is not easy to combine to form large foam, so that the stone powder plays a 'crystal nucleus effect' as much as possible, namely the stone powder replaces a part of cement, mineral powder and other high-activity rubber materials to serve as crystal nuclei, and the cement, mineral powder and other high-activity rubber materials which originally serve as the crystal nuclei and do not participate in hydration are replaced to obtain sufficient hydration. Thereby improving strength. The strength of the product can be improved and the consumption of the stone powder can be improved as much as possible by using the special self-made enhanced foaming agent and the stone powder in a compatible manner. Thereby realizing high resource recycling of waste stone powder, relieving environmental pressure and changing waste into valuable.

In the invention, the SRS1 foaming agent is prepared by mixing the following components in percentage by mass: 63-76wt% of sodium fatty alcohol-polyoxyethylene ether sulfate, 10-15wt% of triethanolamine (content 99%), 9-15wt% of sodium dodecyl sulfate, 4-7wt% of diethanol monoisopropanolamine (content 85%) and 4-7wt% of lauramidopropyl betaine.

In the invention, the SRN2 foaming agent is prepared by mixing the following components in percentage by mass: 33-55wt% of sodium fatty alcohol-polyoxyethylene ether sulfate, 5-10wt% of triethanolamine (content 99%), 3-6wt% of sodium dodecyl sulfate, 2-5wt% of diethanol monoisopropanolamine (content 85%), 20-35wt% of sodium alpha-alkenyl sulfonate, 15-25wt% of ethylene glycol monobutyl ether and 2-5wt% of 12-14 mixed alcohol (weight ratio of carbon lauryl alcohol and carbon tetradecanol is 3-9:1-5, preferably 4-8:2-4, for example 7: 3).

In the invention, the SRL0 foaming agent is prepared by mixing the following components in percentage by mass: 40-55wt% of sodium fatty alcohol-polyoxyethylene ether sulfate, 3-6wt% of sodium dodecyl sulfate, 20-35wt% of sodium alpha-alkenyl sulfonate, 2-5wt% of lauramidopropyl betaine and 15-20wt% of water (distilled water or softened water).

Compared with the prior art, the invention has the following beneficial technical effects:

1: the invention adopts waste stone powder to replace part of cement, and simultaneously dopes mineral powder to prepare high-quality foam light soil, the utilization rate of solid waste is high, the economic benefit is obvious, and the problem of building material resource shortage is greatly relieved. And the used stone powder is waste stone powder generated by stone powder plants, sand making plants and asphalt mixing stations, so that the discharge of the waste stone powder can be reduced, the land and environment protection is facilitated, the use amount of cement is reduced, and the production cost is reduced.

2: the invention adopts the self-made enhanced foaming agent, can ensure that the prepared foamed lightweight soil with high stone powder content can absorb a large amount of stone powder, can ensure that the prepared foamed lightweight soil also has the characteristics of light weight, high strength, environmental protection, good working performance and the like, and can meet the engineering requirements and the standard requirements.

Drawings

FIG. 1 is a schematic flow diagram of the process of the present invention.

FIG. 2 is a photograph of the foam obtained in example 1.

FIG. 3 is a microstructure photograph of a cross section of the foamed polymer soil after curing in example 1.

FIG. 4 is a photograph of a test block of foamed polymer soil of example 1.

Fig. 5 is a microstructure photograph of a cross section of the solidified soil polymer of comparative example 1.

Detailed Description

The technical solution of the present invention is illustrated below, and the claimed scope of the present invention includes, but is not limited to, the following examples.

The preparation process of the foamed lightweight soil is shown in fig. 1.

The various components of the blowing agent used in the examples are commercially available products. For example, sodium fatty alcohol polyoxyethylene ether sulfate is sodium lauryl alcohol polyoxyethylene ether sulfate (n =3) available from Hubei Xin Rundchemical Co. Sodium alpha-olefin sulfonate is a sodium alpha-olefin sulfonate product purchased from medium light chemical industries, ltd.

In the examples, various indexes of the foamed lightweight soil were tested according to the technical specification of cast-in-place foamed lightweight soil (CECS 249: 2008) and the technical specification of foam mixed lightweight soil filling engineering (CJJ/T177-2012).

The ore fines used in the examples were those of grade S95 in GB/T18046 "granulated blast furnace slag powder for use in cement, mortar and concrete". The cement is ordinary Portland cement P.O 42.5 which accords with the general Portland cement GB 175.

Example 1

The SRS1 foaming agent consists of: 69wt% of sodium fatty alcohol-polyoxyethylene ether sulfate, 11wt% of triethanolamine, 9wt% of sodium dodecyl sulfate, 6wt% of diethanol monoisopropanolamine and 5wt% of lauramidopropyl betaine.

241kg of cement, 103kg of stone powder and 223kg of water are weighed, stirred and mixed for 20min (45 r/min) to obtain a mixed material (the water-solid ratio is 0.5: 1). Then 0.55kg of SRS1 foaming agent is weighed, 50kg of water is added for dilution to obtain foam liquid, the prepared foam liquid is injected into a foaming device, and compressed air with the output pressure of 2 atm is introduced into the foaming deviceThe foam was allowed to foam sufficiently in the foam concentrate to give a foam (approximately 50ml was sampled and placed in a measuring cylinder and the change in height of the foam in the cylinder was observed. the height of the foam gradually decreased after 16min, indicating that the volume of the foam when stored alone could remain stable for 16 min). The appearance of the white foam is shown in fig. 2. Then, immediately after obtaining the foam (within 10 min), the foam was added to the above-mentioned mixed material and further stirred and mixed for 10min (50 r/min) to obtain a wet foamed lightweight soil composition (i.e., a homogeneously stirred material), the flow value (i.e., fluidity) of which was measured to be 168mm, and the wet density of which was measured to be 620 kg/m³. The resulting wet composition was spread on the ground and cured for 90 minutes to obtain a cured foamed lightweight soil I.

Sampling from the solidified foamed lightweight soil I, cutting and observing the structure of cells, wherein the cells are very fine and smooth as shown in figure 3. The foam holes are circular and have good hole wall structures, and the foam holes are not communicated with each other.

In addition, test pieces were prepared from the resulting wet composition, as shown in fig. 4.

After 28 days, the 28d unconfined strength (MPa) of the cured foamed lightweight soil I was measured to be 1.03 MPa.

Example 2

The procedure was similar to that in example 1.

206kg of cement, 137kg of stone powder and 223kg of water are weighed and stirred for 20min (45 r/min) to obtain a mixture. Then 0.55kg of SRS1 foaming agent is weighed, 50kg of water is added for dilution to obtain foam liquid, the prepared foam liquid is injected into a foaming device, and foam is prepared (the volume of the obtained foam can be kept stable for 17 min when the obtained foam is stored independently). And finally, adding the foam into the mixture, and continuously stirring and mixing for 10min (50 r/min) to obtain the foamed lightweight soil II with high stone powder content.

The SRS1 foaming agent consists of: 71 weight percent of sodium fatty alcohol-polyoxyethylene ether sulfate, 10 weight percent of triethanolamine, 8 weight percent of sodium dodecyl sulfate, 6 weight percent of diethanol monoisopropanolamine and 5 weight percent of lauramidopropyl betaine.

Example 3

The procedure was similar to that in example 1.

Firstly, 120kg of cement, 103kg of stone powder, 120kg of mineral powder and 223kg of water are weighed, stirred and mixed for 20min (45 r/min) to obtain a mixture. Then 0.55kg of SRS1 foaming agent is weighed, 50kg of water is added for dilution to obtain foam liquid, the prepared foam liquid is injected into a foaming device, and foam is prepared (the volume of the obtained foam can be kept stable for 16min when the obtained foam is stored independently). The standard density of the foam was 50.5 kg/m³. And finally, adding the foam into the mixture, and continuously stirring and mixing for 10min (50 r/min) to obtain the foamed lightweight soil III with high stone powder content.

The SRS1 foaming agent consists of: 68 weight percent of sodium fatty alcohol-polyoxyethylene ether sulfate, 11 weight percent of triethanolamine, 10 weight percent of sodium dodecyl sulfate, 6 weight percent of diethanol monoisopropanolamine and 5 weight percent of lauramidopropyl betaine.

Example 4

The procedure was similar to that in example 1.

Firstly, 103kg of cement, 138kg of stone powder, 103kg of mineral powder and 223kg of water are weighed, stirred and mixed for 20min (45 r/min) to obtain a mixed material. Then 0.55kg of SRS1 foaming agent is weighed, 50kg of water is added for dilution to obtain foam liquid, the prepared foam liquid is injected into a foaming device, and foam is prepared (the volume of the obtained foam can be kept stable for 17 min when the obtained foam is stored independently). And finally, adding the foam into the mixed material, and continuously stirring and mixing for 10min (50 r/min) to obtain the foamed lightweight soil IV with high stone powder content.

The SRS1 foaming agent consists of: 66 weight percent of sodium fatty alcohol-polyoxyethylene ether sulfate, 12 weight percent of triethanolamine, 10 weight percent of sodium dodecyl sulfate, 7 weight percent of diethanol monoisopropanolamine and 5 weight percent of lauramidopropyl betaine.

Example 5

The procedure was similar to that in example 1.

338kg of cement, 145kg of stone powder and 290kg of water are weighed and stirred for 20min (45 r/min) to obtain a mixed material. Then 0.45kg of SRN2 foaming agent is weighed, 45kg of water is added for dilution to obtain foam liquid, the prepared foam liquid is injected into a foaming device, and foam is prepared (the volume of the obtained foam can be kept stable for 16min when the obtained foam is stored independently). And finally, adding the foam into the mixed material, and continuously stirring and mixing for 10min (50 r/min) to obtain the foamed lightweight soil V with high stone powder content.

The foaming agent of SRN2 is composed of: 39 weight percent of sodium fatty alcohol-polyoxyethylene ether sulfate, 9 weight percent of triethanolamine, 5.5 weight percent of sodium dodecyl sulfate, 3 weight percent of diethanol monoisopropanolamine, 24 weight percent of alpha-alkenyl sodium sulfonate, 17 weight percent of ethylene glycol butyl ether and 2.5 weight percent of 12-14 mixed alcohol (the weight ratio of the carbon lauryl alcohol to the carbon tetradecanol is 7: 3).

Example 6

The procedure was similar to that in example 1.

290kg of cement, 193kg of stone powder and 290kg of water are weighed and stirred for 20min (45 r/min) to obtain a mixed material. Then 0.45kg of SRN2 foaming agent is weighed, 45kg of water is added for dilution to obtain foam liquid, the prepared foam liquid is injected into a foaming device, and foam is prepared (the volume of the obtained foam can be kept stable for 16min when the obtained foam is stored independently). And finally, adding the foam into the first mixed material, and continuously stirring and mixing for 10min (50 r/min) to obtain the foamed lightweight soil VI with high stone powder content.

The foaming agent of SRN2 is composed of: 42 weight percent of sodium fatty alcohol-polyoxyethylene ether sulfate, 8 weight percent of triethanolamine, 5.5 weight percent of sodium dodecyl sulfate, 3 weight percent of diethanol monoisopropanolamine, 22 weight percent of alpha-sodium alkenyl sulfonate, 17 weight percent of ethylene glycol butyl ether and 2.5 weight percent of 12-14 mixed alcohol (the weight ratio of the carbon lauryl alcohol to the carbon tetradecanol is 7: 3).

Example 7

The procedure was similar to that in example 1.

169kg of cement, 145kg of stone powder, 169kg of mineral powder and 290kg of water are weighed, stirred and mixed for 20min (45 r/min) to obtain a mixed material. Then 0.45kg of SRN2 foaming agent is weighed, 45kg of water is added for dilution to obtain foam liquid, the prepared foam liquid is injected into a foaming device, and foam is prepared (the volume of the obtained foam can be kept stable for 16min when the obtained foam is stored independently). And finally, adding the foam into the mixed material, and continuously stirring and mixing for 10min (50 r/min) to obtain the foamed lightweight soil VII with high stone powder content.

The foaming agent of SRN2 is composed of: 45 weight percent of sodium fatty alcohol-polyoxyethylene ether sulfate, 10 weight percent of triethanolamine, 5 weight percent of sodium dodecyl sulfate, 3 weight percent of diethanol monoisopropanolamine, 20 weight percent of alpha-alkenyl sodium sulfonate, 15 weight percent of ethylene glycol butyl ether and 2 weight percent of 12-14 mixed alcohol (the weight ratio of the carbon lauryl alcohol to the carbon tetradecanol is 7: 3).

Example 8

The procedure was similar to that in example 1.

145kg of cement, 193kg of stone powder, 145kg of mineral powder and 290kg of water are weighed, stirred and mixed for 20min (45 r/min) to obtain a mixed material. Then 0.45kg of SRN2 foaming agent is weighed, 45kg of water is added for dilution to obtain foam liquid, the prepared foam liquid is injected into a foaming device, and foam is prepared (the volume of the obtained foam can be kept stable for 16min when the obtained foam is stored independently). And finally, adding the foam into the mixed material, and continuously stirring and mixing for 10min (50 r/min) to obtain the foam light soil VIII with high stone powder content.

The foaming agent of SRN2 is composed of: 35 weight percent of sodium fatty alcohol-polyoxyethylene ether sulfate, 10 weight percent of triethanolamine, 5 weight percent of sodium dodecyl sulfate, 3 weight percent of diethanol monoisopropanolamine, 24 weight percent of alpha-alkenyl sodium sulfonate, 21 weight percent of ethylene glycol butyl ether and 2 weight percent of 12-14 mixed alcohol (the weight ratio of the carbon lauryl alcohol to the carbon tetradecanol is 7: 3).

Example 9

The procedure was similar to that in example 1.

456kg of cement, 195kg of stone powder and 326kg of water are weighed and stirred and mixed for 20min (45 r/min) to obtain a mixed material. Then 0.37kg of SRL0 foaming agent is weighed, 40kg of water is added for dilution to obtain foam liquid, the prepared foam liquid is injected into a foaming device, and foam is prepared (the volume of the obtained foam can be kept stable for 15min when the obtained foam is stored independently). And finally, adding the foam into the mixed material, and continuously stirring and mixing for 10min (50 r/min) to obtain the foamed lightweight soil IX with high stone powder content.

The foaming agent of SRL0 is composed of: 48 weight percent of sodium fatty alcohol-polyoxyethylene ether sulfate, 6 weight percent of sodium dodecyl sulfate, 22 weight percent of alpha-sodium alkenyl sulfonate, 5 weight percent of lauramidopropyl betaine and 19 weight percent of distilled water.

Example 10

The procedure was similar to that in example 1.

391kg of cement, 261kg of stone powder and 326kg of water are weighed and stirred for 20min (45 r/min) to obtain a mixed material. Then 0.37kg of SRL0 foaming agent is weighed, 40kg of water is added for dilution to obtain foam liquid, the prepared foam liquid is injected into a foaming device, and foam is prepared (the volume of the obtained foam can be kept stable for 15min when the obtained foam is stored independently). And finally, adding the foam into the mixed material, and continuously stirring and mixing for 10min (50 r/min) to obtain the foamed lightweight soil X with high stone powder content.

The foaming agent of SRL0 is composed of: 50 weight percent of sodium fatty alcohol-polyoxyethylene ether sulfate, 6 weight percent of sodium dodecyl sulfate, 21 weight percent of alpha-sodium alkenyl sulfonate, 5 weight percent of lauramidopropyl betaine and 18 weight percent of distilled water.

Example 11

The procedure was similar to that in example 1.

228kg of cement, 196kg of stone powder, 228kg of mineral powder and 326kg of water are weighed, stirred and mixed for 20min (45 r/min) to obtain a mixed material. Then 0.37kg of SRL0 foaming agent is weighed, 40kg of water is added for dilution to obtain foam liquid, the prepared foam liquid is injected into a foaming device, and foam is prepared (the volume of the obtained foam can be kept stable for 16min when the obtained foam is stored independently). And finally, adding the foam into the mixed material, and continuously stirring and mixing for 10min (50 r/min) to obtain the foamed lightweight soil XI with high stone powder content.

The foaming agent of SRL0 is composed of: 52 weight percent of sodium fatty alcohol-polyoxyethylene ether sulfate, 6 weight percent of sodium dodecyl sulfate, 20 weight percent of alpha-sodium alkenyl sulfonate, 5 weight percent of lauramidopropyl betaine and 17 weight percent of distilled water.

Example 12

The procedure was similar to that in example 1.

196kg of cement, 261kg of stone powder, 196kg of mineral powder and 326kg of water are weighed and stirred and mixed for 20min (45 r/min) to obtain a mixed material. Then 0.37kg of SRL0 foaming agent is weighed, 40kg of water is added for dilution to obtain foam liquid, the prepared foam liquid is injected into a foaming device, and foam is prepared (the volume of the obtained foam can be kept stable for 16min when the obtained foam is stored independently). And finally, adding the foam into the mixed material, and continuously stirring and mixing for 10min (50 r/min) to obtain the foamed light soil XII with high stone powder content.

The foaming agent of SRL0 is composed of: 42 weight percent of sodium fatty alcohol-polyoxyethylene ether sulfate, 6 weight percent of sodium dodecyl sulfate, 29 weight percent of alpha-sodium alkenyl sulfonate, 5 weight percent of lauramidopropyl betaine and 18 weight percent of distilled water.

Comparative example 1

The procedure was similar to that in example 1.

The existing composite foaming agent a comprises the following components: 50wt% of tea saponin, 20wt% of sodium dodecyl sulfate, 10wt% of polyethylene glycol, 10wt% of gelatin and 10wt% of carboxymethyl cellulose.

206kg of cement, 137kg of stone powder and 223kg of water are weighed, stirred and mixed for 20min (45 r/min) to obtain a mixed material serving as a mixed material. Then 0.55kg of the existing composite foaming agent a is weighed, 50kg of water is added for dilution to obtain foam liquid, the prepared foam liquid is injected into a foaming device, compressed air with the output pressure of 2 atm is introduced into the foam liquid to fully foam the foam liquid, and foam is obtained (50 ml of sample is placed into a measuring cylinder, the height change of the foam in the measuring cylinder is observed, the height of the foam is gradually reduced after about 2 min, which shows that the volume of the foam can only be kept stable for about 2 min when the foam is stored independently). And finally, adding the foam into the mixture, and continuously stirring and mixing for 10min (50 r/min) to obtain the foam light soil XIII with high stone powder content.

A sample was taken from the cured foamed lightweight earth XIII (the foamed lightweight earth XIII was cured for 90 minutes), cut, and observed the structure of cells, the foamed lightweight earth exhibited a hollow phenomenon, and an enlarged view of the microstructure of the hollow portion thereof is shown in fig. 5.

Comparative example 2

The procedure was similar to that in example 1.

The existing composite foaming agent b comprises the following components: 15wt% of sodium dodecyl sulfate, 15.8wt% of sodium hexadecyl sulfonate, 9.2wt% of tea saponin, 4wt% of dodecanol, 1wt% of cellulose ether, 2wt% of triethanolamine, 8wt% of sodium sulfate and 45wt% of water.

169kg of cement, 145kg of stone powder, 169kg of mineral powder and 290kg of water are weighed, stirred and mixed for 20min (45 r/min) to obtain a mixture. Then 0.45kg of the existing composite foaming agent b is weighed, 45kg of water is added for dilution to obtain a foam liquid, the prepared foam liquid is injected into a foaming device, and foam is prepared (the volume of the obtained foam can only be kept stable for about 3 min when the obtained foam is stored independently). Finally, adding the foam into the mixture, and continuously stirring and mixing for 10min (50 r/min) to obtain the foamed lightweight soil XIV with high stone powder content.

Comparative example 3

The procedure was similar to that in example 1.

The existing composite foaming agent c comprises the following components: 72wt% of hydrogen peroxide (content: 30%) and 28wt% of calcium stearate.

145kg of cement, 193kg of stone powder, 145kg of mineral powder and 290kg of water are weighed and stirred for 20min (45 r/min) to obtain a mixture. Then 0.45kg of the existing composite foaming agent c is weighed, 45kg of water is added for dilution to obtain a foam liquid, the prepared foam liquid is injected into a foaming device, and foam is prepared (the volume of the obtained foam can only be kept stable for about 1 min when the obtained foam is stored independently). And finally, adding the foam into the mixture, and continuously stirring and mixing for 10min (50 r/min) to obtain the foam lightweight soil XV with high stone powder content.

Comparative example 4

The procedure was similar to that in example 1.

The existing composite foaming agent d comprises the following components: 12 weight percent of sodium dodecyl sulfate, 12 weight percent of sodium dodecyl benzene sulfonate, 1.5 weight percent of silicone polyether emulsion, 1.5 weight percent of alkyl alcohol ether polyhydroxy polymer, 9 weight percent of triethanolamine, 15 weight percent of organosilicon water repellent, 15 weight percent of dodecanol and 34 weight percent of water.

391kg of cement, 261kg of stone powder and 326kg of water are weighed and stirred for 20min (45 r/min) to obtain a mixture. Then 0.37kg of the existing composite foaming agent d is weighed, 40kg of water is added for dilution to obtain a foam liquid, the prepared foam liquid is injected into a foaming device, and foam is prepared (the volume of the obtained foam can only be kept stable for about 4.5 min when the obtained foam is stored independently). And finally, adding the foam into the mixture, and continuously stirring and mixing for 10min (50 r/min) to obtain the foamed lightweight soil XVI with high stone powder content.

Comparative example 5

The procedure was similar to that in example 1.

The existing composite foaming agent e comprises the following components: 12.9wt% of triethanolamine cocoyl alanine, 13.1wt% of sodium cocoyl glycinate, 13.3wt% of potassium cocoyl fatty acid glycinate, 14.7wt% of sodium lauroyl amphoacetate, 21.2wt% of disodium cocoyl amphodiacetate, 1.5wt% of triterpenoid saponin, 1.5wt% of tea saponin, 2wt% of isooctyl glucoside, 1wt% of lauroyl monoisopropanolamine, 1.3wt% of ferric thiocyanate, 1.3wt% of sodium thiocyanate, 2wt% of calcium formate, 1wt% of triethanolamine, 1wt% of triisopropanolamine, 2wt% of calcium nitrate, 4.8wt% of gelatin, 1.2wt% of glucomannan, 1wt% of carrageenan, and 3.2wt% of water.

290kg of cement, 193kg of stone powder and 290kg of water are weighed and stirred for 20min (45 r/min) to obtain a mixture. Then 0.45kg of the existing composite foaming agent e is weighed, 45kg of water is added for dilution to obtain a foam liquid, the prepared foam liquid is injected into a foaming device, and foam is prepared (the volume of the obtained foam can only be kept stable for about 6min when the obtained foam is stored independently). And finally, adding the foam into the mixture, and continuously stirring and mixing for 10min (50 r/min) to obtain the foamed lightweight soil XVII with high stone powder content.

TABLE 1 Performance test results for foamed lightweight soils

Comparative examples 1 to 5 the foamed lightweight soils XIII to XVII having high stone dust content were prepared to have various degrees of subsidence and slumping.

Claims

1. A foamed lightweight soil composition having a high stone dust content, characterized in that: the foamed lightweight soil composition with high stone powder content comprises the following components or consists of the following components:

E) water; and

F) foaming;

wherein E) the weight ratio (i.e. water-to-solid ratio) of water to solid material (cement + stone powder + mineral powder) is 0.5-0.7: 1, preferably 0.51-0.68: 1, preferably 0.52-0.66: 1, preferably 0.54-0.64: 1, preferably 0.56-0.62: 1, preferably 0.58-0.60: 1;

wherein the foam is formed by diluting a high molecular surfactant type foaming agent with additional water by 60 to 120 times (preferably 62 to 110 times, more preferably 65 to 100 times, more preferably 67 to 95 times, more preferably 70 to 90 times, such as 75, 80 or 85 times) to form a foam concentrate, and then introducing air (such as compressed air) into the foam concentrate;

wherein the amount of water contained in the F) foam is not included or calculated in the amount of E) water; and

wherein the polymeric surfactant based foaming agent is used in an amount of 0.055 to 0.8 wt. -%, preferably 0.06 to 0.75 wt. -%, preferably 0.07 to 0.7 wt. -%, preferably 0.08 to 0.65 wt. -%, preferably 0.09 to 0.6 wt. -%, preferably 0.1 to 0.55 wt. -%, preferably 0.11 to 0.5 wt. -%, e.g. 0.12 wt. -%, 0.13 wt. -%, 0.14 wt. -%, 0.15 wt. -%, 0.16 wt. -%, 0.17 wt. -%, 0.18 wt. -%, 0.19 wt. -%, 0.20 wt. -%, 0.25 wt. -%, 0.30 wt. -%, 0.35 wt. -%, 0.40 wt. -% or 0.45 wt. -%, based on the total weight of the solid material (cement + stone dust + ore fines); or

The foam is used in an amount sufficient to provide a ratio of the volume of the bubbles to the total volume of the wet foamed polymeric soil composition obtained after all the materials are mixed: 25% to 75%, preferably 28% to 70%, preferably 30% to 66%, preferably 32% to 64%, preferably 34% to 62%, preferably 36% to 60%, preferably 38% to 58%, preferably 40% to 56%.

2. The foamed lightweight soil composition according to claim 1, wherein: the cement is Portland cement, preferably ordinary Portland cement; and/or

The mass ratio of the stone powder to the mineral powder is 30-50 (preferably 31-49, preferably 32-48, preferably 34-46, preferably 36-44, more preferably 38-42) to 0-40 (preferably 5-40, preferably 10-35, preferably 12-33, preferably 14-30, preferably 16-28, more preferably 18-26, more preferably 20-24); and/or

3. The foamed lightweight earth composition according to claim 1 or 2, characterized in that: the stone powder is one or more of stone powder produced by a stone powder plant, stone powder produced in the sand making process and stone powder formed by air washing of crushed stones by an asphalt mixing station; and/or

The particle size of the stone powder is less than or equal to 150 mu m, preferably less than or equal to 110 mu m, and more preferably less than or equal to 75 mu m; and/or

The cement is Portland cement, preferably ordinary Portland cement; preferably, the cement is ordinary portland cement P.O 42.5 or P. O42.5R in accordance with "general portland cement" GB 175.

4. The foamed lightweight soil composition according to any one of claims 1 to 3, characterized in that: the mineral powder is blast furnace slag powder; preferably, the mineral powder is selected from one or more of S75 mineral powder, S95 mineral powder and S105 mineral powder defined in 'granulated blast furnace slag powder for cement, mortar and concrete' GB/T18046; and/or

The high molecular surfactant foaming agent is a composite surfactant consisting of polyether surfactant and small molecular organic surfactant.

5. The foamed lightweight soil composition according to any one of claims 1 to 4, characterized in that: the foaming agent is selected from one or more of SRS1 foaming agent, SRN2 foaming agent and SRL0 foaming agent;

the SRS1 blowing agent includes: 63-76wt% of sodium fatty alcohol-polyoxyethylene ether sulfate, 10-15wt% of triethanolamine, 9-15wt% of sodium dodecyl sulfate, 4-7wt% of diethanol monoisopropanolamine and 4-7wt% of lauramidopropyl betaine;

the SRN2 foaming agent comprises: 33-55wt% of sodium fatty alcohol-polyoxyethylene ether sulfate, 5-10wt% of triethanolamine, 3-6wt% of sodium dodecyl sulfate, 2-5wt% of diethanol monoisopropanolamine, 20-35wt% of sodium alpha-alkenyl sulfonate, 15-25wt% of ethylene glycol butyl ether and 2-5wt% of 12-14 mixed alcohol;

the SRL0 foaming agent comprises: 40-55wt% of sodium fatty alcohol-polyoxyethylene ether sulfate, 3-6wt% of sodium dodecyl sulfate, 20-35wt% of alpha-sodium alkenyl sulfonate, 2-5wt% of lauramidopropyl betaine and 15-20wt% of water.

6. The foamed lightweight soil composition according to claim 5, wherein: the weight ratio of the carbon dodecanol to the carbon tetradecanol in the 12-14 mixed alcohol is 3-9:1-5, preferably 4-8: 2-4.

7. A process for preparing a high stone dust content foamed lightweight soil composition according to any one of claims 1 to 6, characterized in that: the method comprises the following steps:

1) weighing cement, stone powder, mineral powder, a foaming agent and water in proportion for later use;

2) diluting a foaming agent with water to obtain a foam liquid, and then introducing air (such as compressed air) into the foam liquid to obtain foam;

8. The method of claim 7, further comprising:

9. The method of claim 8, wherein: in step 2, the polymeric surfactant based foaming agent is diluted 60 to 120 times (preferably 62 to 110 times, more preferably 65 to 100 times, more preferably 67 to 95 times, more preferably 70 to 90 times, such as 75, 80 or 85 times) with additional water; and/or

In the step 3, the first stirring speed is 30-100r/min, and the stirring time is 1-30 min; the second stirring speed is 40-120r/min, and the stirring time is 1-10 min; and/or

The wet density of the foamed lightweight soil composition prepared in the step 3) is 500-1200 kg/m³Preferably 600-³Preferably 700-1000kg/m³(ii) a In addition, the 28-day unconfined compressive strength of the foamed lightweight soil obtained after the composition is cured is 0.82-5 MPa; and/or

In step 2), the pressure of the compressed air fed into the foaming device is controlled to be 1.5 to 2 atm in order to achieve sufficient foaming and to allow the volume of the obtained foam to remain stable for 6 to 15 minutes.

10. A foamed lightweight soil produced by the method of any one of claims 8 or 9; preferably, the dry density of the cured light soil is 640-1050 kg/m³Preferably 650-1000 kg/m³Preferably 700-950 kg/m³And its 28-day unconfined compressive strength (MPa) is in the range of 0.85 to 4.8MPa, preferably 0.9 to 4.5MPa, preferably 1.0 to 4.0 MPa, preferably 1.1 to 3.8 MPa, preferably 1.15 to 3.7 MPa, preferably 1.2 to 3.5 MPa, more preferably 1.25 to 3.3 MPa, more preferably 1.3 to 3.0 MPa.