CN112225512A

CN112225512A - Soil curing agent and using method thereof

Info

Publication number: CN112225512A
Application number: CN202010920486.6A
Authority: CN
Inventors: 屈升武; 李春迎
Original assignee: Xi'an Maohong Environmental Protection Technology Co ltd
Current assignee: Xi'an Tongxin Weiye Environmental Protection Technology Co ltd
Priority date: 2020-09-04
Filing date: 2020-09-04
Publication date: 2021-01-15
Anticipated expiration: 2040-09-04
Also published as: CN112225512B

Abstract

The invention relates to a soil stabilizer and a using method thereof. The soil curing agent comprises, by weight, 55-90% of calcined solid waste materials, 0.3-8% of sodium metasilicate, 5-20% of lignin, 0.5-8% of sodium naphthalene sulfonate formaldehyde condensate, 0.5-5% of polyacrylamide and 0.1-5% of hydroxymethyl cellulose. The soil curing agent provided by the invention has the advantages that on one hand, the solid waste material is secondarily utilized, and the environment is protected and the energy is saved. On the other hand, the soil stabilizer has a good curing effect on slag, aeolian sand, high liquid limit soil and collapsible loess, the strength of the cured material is higher than 2MP, and organic binders such as cement are not required to be added in the curing process by using the soil stabilizer, so that the construction mode is simpler, and more construction time is saved.

Description

Soil curing agent and using method thereof

Technical Field

The invention relates to the technical field of curing agents, in particular to a soil curing agent and a using method thereof.

Background

With the development of society, people have higher and higher requirements on innovative, environment-friendly and energy-saving materials. Due to the shortage of resources, the national requirements for environmental protection are continuously improved, and the prices of materials such as sand, stone, lime and the like are continuously increased, so that the engineering construction cost is continuously increased.

The soil stabilizer is a novel energy-saving and environment-friendly engineering material for curing various soils. After being mixed with soil, the soil modifier changes the engineering property of the soil through a series of physical and chemical reactions so as to achieve the purposes of improving the soil quality strength and improving the soil compactibility. The soil stabilizer prolongs the service life of the road, saves the engineering maintenance cost, has good economic and environmental benefits, and is an ideal road building material selection at present.

The types of soil firming agents in the current domestic market are polymer type, ionic type and biological enzyme type. However, the existing soil curing agent cannot meet the curing of all soil or some solid wastes in terms of performance, such as collapsible loess, high liquid limit soil, aeolian sand, various slag and the like. In addition, the existing soil curing agent needs to be added with cement and quicklime in a certain proportion, so that the new requirements of environmental protection and energy conservation are not met, the curing strength is not high enough, the unconfined compressive strength in 7 days is 1.8-2.0 MP, the later strength can be gradually weakened, and the requirements of national road standards cannot be met. Accordingly, there is a need to ameliorate one or more of the problems with the related art solutions described above.

It is noted that this section is intended to provide a background or context to the embodiments of the invention that are recited in the claims. The description herein is not admitted to be prior art by inclusion in this section.

Disclosure of Invention

It is an object of embodiments of the present invention to provide a soil stabilizer and a method of using the same, which overcome, at least to some extent, one or more of the problems due to the limitations and disadvantages of the related art.

According to a first aspect of embodiments of the present invention, there is provided a soil solidifying agent comprising, by weight, 55 to 90% of calcined solid waste material, 0.3 to 8% of sodium metasilicate, 5 to 20% of lignin, 0.5 to 8% of a sodium naphthalene sulfonate formaldehyde condensate, 0.5 to 5% of polyacrylamide, and 0.1 to 5% of hydroxymethyl cellulose.

In an embodiment of the present invention, the solid waste material includes fly ash, steel mill fly ash, hydrated lime and red mud.

In one embodiment of the invention, the soil curing agent comprises, by weight, 20-27% of fly ash, 30-45% of steel mill fly ash, 1-3% of slaked lime, 10-15% of red mud, 0.5-2% of sodium metasilicate, 5-10% of lignin, 0.5-5% of sodium naphthalenesulfonate formaldehyde condensate, 0.5-5% of polyacrylamide and 0.1-5% of hydroxymethyl cellulose.

In one embodiment of the invention, the soil solidifying agent comprises, by weight, 10-25% of fly ash, 25-60% of steel mill fly ash, 1.25-3.5% of slaked lime, 20-25% of red mud, 0.3-4% of sodium metasilicate, 5-12% of lignin, 0.5-3% of sodium naphthalene sulfonate formaldehyde condensate, 0.5-2.5% of polyacrylamide and 0.1-2% of hydroxymethyl cellulose.

In an embodiment of the present invention, the particle size of the solid waste material is 300-400 mesh.

In an embodiment of the present invention, the sodium metasilicate is sodium metasilicate nonahydrate.

In an embodiment of the present invention, the polyacrylamide is anionic polyacrylamide.

According to a second aspect of the embodiments of the present invention, there is provided a method for using the soil solidifying agent according to any one of the above, the soil solidifying agent is mixed into a material to be solidified, water is added into the material to be solidified, the mixture is uniformly stirred, and the mixture is compacted to obtain solidified soil;

wherein the doping amount of the soil curing agent is 3-15% of the mass of the material to be cured.

In one embodiment of the invention, the moisture content of the solidified soil is 15-18%.

In one embodiment of the present invention, the material to be solidified includes slag, aeolian sand, high liquid limit soil, and collapsible loess.

The technical scheme provided by the invention can have the following beneficial effects:

the soil curing agent provided by the invention contains a large amount of calcined solid waste materials, so that on one hand, the solid waste materials are secondarily utilized, and the soil curing agent is environment-friendly and energy-saving. On the other hand, the waste solid material, the sodium metasilicate, the lignin, the sodium naphthalene sulfonate formaldehyde condensation compound, the polyacrylamide and the hydroxymethyl cellulose have good curing effect on the slag, the aeolian sand, the high liquid limit soil and the collapsible loess, the strength of the cured material is higher than 2MP, and organic binders such as cement do not need to be added in the curing process by using the soil curing agent, so that the construction mode is simpler, and more construction time is saved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and together with the description, serve to explain the principles of the disclosure. It is to be understood that the drawings in the following description are merely exemplary of the disclosure, and that other drawings may be derived from those drawings by one of ordinary skill in the art without the exercise of inventive faculty.

FIG. 1 shows a schematic representation of the principle of soil solidification by a soil stabilizer in an exemplary embodiment of the invention;

FIG. 2 shows a schematic of the structure of soil before it is solidified in an exemplary embodiment of the invention;

fig. 3 shows a schematic view of the structure of the soil after it has been solidified in an exemplary embodiment of the invention.

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

In the present exemplary embodiment, a soil stabilizer is first provided, which comprises 55 to 90% by weight of calcined solid waste material, 0.3 to 8% by weight of sodium metasilicate, 5 to 20% by weight of lignin, 0.5 to 8% by weight of sodium naphthalenesulfonate formaldehyde condensate, 0.5 to 5% by weight of polyacrylamide, and 0.1 to 5% by weight of hydroxymethyl cellulose.

The soil stabilizer in the present exemplary embodiment will be described in more detail below.

The solid waste material is also called solid waste building material, contains a large amount of silicon, aluminum, calcium, magnesium and other components, and has hydraulic gelling property. After the soil stabilizer is mixed with soil, the solid waste material can provide calcium and magnesium ions for the soil, and the calcium and magnesium ions are exchanged with other low-valence ions in the soil stabilizer, so that the calcium and magnesium ions are more uniformly distributed, and chemical reaction is generated by taking the calcium and magnesium ions as centers to generate chemical bonds, so that a firm mesh structure is formed in the soil. In the soil curing agent provided by the invention, the solid waste material is used as a part of the raw material, so that the effect of recycling waste resources is achieved, and the strength of the cured material is improved by utilizing the chemical property of the waste material.

The sodium metasilicate has strong basicity, and silicate anions contained in the sodium metasilicate can generate insoluble matters with calcium ions and magnesium ions in the slurry to promote the exchange effect of sodium ions, so that the viscosity of the slurry is reduced, the fluidity is increased, and the material to be solidified can be more completely reacted with a soil solidifying agent in the solidification process.

The lignin has low cost, and can react with a material to be solidified to generate a derivative lignosulfonate, and the lignosulfonate has the capability of dispersing biological slime, iron oxide scale and calcium phosphate scale and can generate a stable complex with zinc ions and calcium ions. For example, sodium lignosulfonate and calcium lignosulfonate are often used as water reducing agents, most of which are surfactants, the hydrophobic groups of the water reducing agents are directionally adsorbed on the surfaces of the particles, and the hydrophilic groups are directed to an aqueous solution to form a monomolecular or polymolecular adsorption membrane, so that the particles are dispersed due to mutual repulsion of the same charges on the surfaces, and redundant water is released from the particles to achieve the purpose of reducing water. Meanwhile, the surface tension of water and the interfacial tension between particles are reduced, so that the water consumption is correspondingly reduced under the condition of keeping the same fluidity, and the water reducing effect is also realized. It can greatly reduce hydration of curing agent, reduce porosity and increase compactness of curing agent so as to greatly raise strength and impermeability of curing agent.

The sodium naphthalenesulfonate formaldehyde condensate belongs to anionic surfactant, is dispersant of water hardening gelatinizing material, and can strengthen the dispersivity, flowability and diffusivity of solid waste material in soil curing agent in soil and make the solid waste material react with soil fully.

Polyacrylamide is a linear organic high molecular polymer and is a high molecular water treatment flocculant product, and can specially adsorb suspended particles in water, so that the particles have a bridging effect, fine particles form larger flocs, the settling speed is accelerated, the solidification speed is accelerated, and the compressive strength is increased.

In particular, polyacrylamides can be classified as anionic, cationic, and nonionic. In one embodiment, the polyacrylamide is selected to be anionic, i.e. after hydrolysis, part of amide groups are changed into carboxyl groups, so that the water phase permeability in soil can be reduced, the permeability is reduced, and the compressive strength is further enhanced.

The hydroxymethyl cellulose is easy to dissolve in water, mainly plays roles in thickening and water retention, and can effectively improve the binding power and the anti-sagging property of the slurry. Specifically, the hydroxymethyl cellulose can wrap all solid particles and form a layer of wetting film, and the moisture in the wetting film is gradually released for a long time to perform hydration reaction with the gel material, so that the bonding strength and the compressive strength of the material are ensured.

As described above, when the raw materials of the soil stabilizer are mixed with the material to be solidified and water, and then interact and promote each other at a specific ratio, large aggregates inside the material to be solidified are broken up into a fine granular structure, and ions having positive charges and ions having negative charges interact with each other, so that the chargeability of the aggregates is reduced and the repulsive force between the aggregates is greatly reduced, as shown in fig. 1. Referring to fig. 2 and 3, a dense, water-stable, high-strength, ultra-durable ettringite-like structure is finally formed, while having good freeze-thaw resistance and crack resistance.

In one embodiment, sodium metasilicate nonahydrate sodium metasilicate may be selected. The sodium metasilicate nonahydrate has an effect of promoting the formation of a porcelain body as compared with sodium metasilicate pentahydrate, and the curing strength of the sodium metasilicate nonahydrate can be further increased by having a porcelain component in a solid waste material such as slag.

In one embodiment, the solid waste materials include fly ash, steel mill fly ash, hydrated lime and red mud, and the combination of the solid waste materials in a specific ratio can maximize hydraulic gelation.

Specifically, in one embodiment, the soil stabilizer comprises 20-27% of fly ash, 30-45% of steel mill fly ash, 1-3% of slaked lime, 10-15% of red mud, 0.5-2% of sodium metasilicate, 5-10% of lignin, 0.5-5% of sodium naphthalene sulfonate formaldehyde condensate, 0.5-5% of polyacrylamide and 0.1-5% of hydroxymethyl cellulose by weight.

In another embodiment, the soil stabilizer comprises 10-25% of fly ash, 25-60% of steel mill fly ash, 1.25-3.5% of slaked lime, 20-25% of red mud, 0.3-4% of sodium metasilicate, 5-12% of lignin, 0.5-3% of sodium naphthalene sulfonate formaldehyde condensate, 0.5-2.5% of polyacrylamide and 0.1-2% of hydroxymethyl cellulose by weight ratio.

In one embodiment, the particle size of the solid waste material is 300-400 mesh, so as to achieve the best fusion effect, and the particle size is too large and the reaction is not sufficient, and the particle size is too small and the production cost is increased.

The embodiment also provides a using method of the soil stabilizer, which comprises the steps of mixing the soil stabilizer into a material to be solidified, adding water, uniformly stirring, and compacting to obtain solidified soil; wherein, the mixing amount of the soil curing agent is 3-15% of the mass of the material to be cured. The mixing amount of the soil curing agent is too small, the curing effect is poor, and indexes such as compressive strength and the like are unqualified. And the excessive doping amount of the soil curing agent increases the cost and easily causes uneven curing of the finally obtained cured soil.

In one embodiment, the moisture content of the resulting consolidated soil is 15-18%. When the water content of the solidified soil is within the range, the solidified soil has the best compaction effect and the highest compactness. The water content below this range causes the solidified soil to be not compacted and to have a low density, while the water content above this range causes the solidified soil to have more drying cracks.

In the embodiment, the materials to be solidified comprise slag, aeolian sand, high liquid limit soil and collapsible loess, and various tests prove that the soil solidifying agent provided by the invention has good solidifying effect on the poor soil or solid waste and improves various indexes. Specifically, the unconfined compressive strength of the steel is greater than 2MP in 7 days, 14 days and 28 days; the bending-resistant tensile (splitting) strength is more than 0.5 MP; the water stability coefficient is more than 80; the compression resistant resilience modulus is more than 1500 MP; the freezing tolerance index is more than 0.65.

Example 1 solidification of slag soil

The method comprises the following steps of adding 3%, 10% and 15% of soil curing agents of 27% of fly ash, 30% of steel mill fly ash, 3% of hydrated lime, 15% of red mud, 2% of sodium metasilicate, 10% of lignin, 3% of sodium naphthalene sulfonate formaldehyde condensate, 5% of polyacrylamide and 5% of hydroxymethyl cellulose in the slag according to the weight ratio, adding a proper amount of water, uniformly stirring, compacting by ramming to obtain cured slag soil, testing various properties of the cured slag soil, and comparing the cured slag soil with the properties of a common curing agent, wherein the results are as follows:

1. unconfined compressive strength test (7 days, 14 days, 28 days)

2. Modulus of restitution against compression test

3. Freeze thaw test

4. Water stability test

5. Bending strength (splitting strength)

Example 2 curing of aeolian Sand

The method comprises the following steps of adding 20% of fly ash, 45% of steel mill fly ash, 1% of hydrated lime, 10% of red mud, 1% of sodium metasilicate, 8% of lignin, 5% of sodium naphthalene sulfonate formaldehyde condensate, 5% of polyacrylamide and 5% of hydroxymethyl cellulose into the aeolian sand according to the doping amount of 3%, 10% and 15%, adding a proper amount of water, uniformly stirring, compacting by ramming to obtain cured aeolian sandy soil, testing various performances of the cured aeolian sandy soil, and comparing the performances with the performances of a common curing agent after curing, wherein the results are as follows:

1. unconfined compressive strength test (7 days, 14 days, 28 days)

2. Modulus of restitution against compression test

3. Freeze thaw test

4. Water stability test

5. Bending strength (splitting strength)

Example 3 curing of high liquid Limited soil

The method comprises the following steps of adding 10 wt% of fly ash, 60 wt% of steel mill fly ash, 3.5 wt% of hydrated lime, 20 wt% of red mud, 0.3 wt% of sodium metasilicate, 5 wt% of lignin, 0.5 wt% of sodium naphthalene sulfonate formaldehyde condensate, 0.6 wt% of polyacrylamide and 0.1 wt% of hydroxymethyl cellulose soil curing agent into high liquid limit soil according to the doping amounts of 3 wt%, 10 wt% and 15 wt% respectively, adding a proper amount of water, uniformly stirring, compacting by ramming to obtain the cured high liquid limit soil, testing various performances of the cured high liquid limit soil, and comparing the performances with those of a common curing agent, wherein the results are as follows:

1. unconfined compressive strength test (7 days, 14 days, 28 days)

2. Modulus of restitution against compression test

3. Freeze thaw test

4. Water stability test

5. Bending strength (splitting strength)

Example 4 curing of moisture-limited loess

The method comprises the following steps of adding 3%, 10% and 15% of soil curing agent of fly ash, 25% of steel mill fly ash, 1.25% of hydrated lime, 25% of red mud, 4% of sodium metasilicate, 12% of lignin, 2.25% of sodium naphthalene sulfonate formaldehyde condensate, 1.5% of polyacrylamide and 2% of hydroxymethyl cellulose into the moisture-limited loess respectively in the weight ratio, adding a proper amount of water, uniformly stirring, compacting by ramming to obtain the cured moisture-limited loess, testing various performances of the cured moisture-limited loess and comparing the performances with the performances of a common curing agent after curing, wherein the results are as follows:

1. unconfined compressive strength test (7 days, 14 days, 28 days)

2. Modulus of restitution against compression test

3. Freeze thaw test

4. Water stability test

5. Bending strength (splitting strength)

In conclusion, the tests show that the soil curing agent provided by the invention has a good curing effect on slag, aeolian sand, high liquid limit soil and collapsible loess compared with a common curing agent.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples described in this specification can be combined and combined by those skilled in the art.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

Claims

1. The soil curing agent is characterized by comprising, by weight, 55-90% of calcined solid waste material, 0.3-8% of sodium metasilicate, 5-20% of lignin, 0.5-8% of sodium naphthalene sulfonate formaldehyde condensate, 0.5-5% of polyacrylamide and 0.1-5% of hydroxymethyl cellulose.

2. The soil stabilizer according to claim 1, wherein the solid waste material comprises fly ash, steel mill fly ash, hydrated lime and red mud.

3. The soil stabilizer according to claim 2, wherein the soil stabilizer comprises 20-27% of fly ash, 30-45% of steel mill fly ash, 1-3% of slaked lime, 10-15% of red mud, 0.5-2% of sodium metasilicate, 5-10% of lignin, 0.5-5% of sodium naphthalene sulfonate formaldehyde condensate, 0.5-5% of polyacrylamide and 0.1-5% of hydroxymethyl cellulose by weight.

4. The soil stabilizer according to claim 2, wherein the soil stabilizer comprises 10-25% of fly ash, 25-60% of steel mill fly ash, 1.25-3.5% of slaked lime, 20-25% of red mud, 0.3-4% of sodium metasilicate, 5-12% of lignin, 0.5-3% of sodium naphthalene sulfonate formaldehyde condensate, 0.5-2.5% of polyacrylamide and 0.1-2% of hydroxymethyl cellulose by weight.

5. The soil stabilizer according to claim 1, wherein the particle size of the solid waste material is 300-400 mesh.

6. The soil stabilizer of claim 1, wherein the sodium metasilicate is sodium metasilicate nonahydrate.

7. The soil stabilizer of claim 1, wherein the polyacrylamide is an anionic polyacrylamide.

8. A method for using the soil stabilizer according to any one of claims 1 to 6, wherein the soil stabilizer is added into the material to be stabilized, water is added, the mixture is stirred uniformly, and the soil is compacted to obtain the stabilized soil;

9. The method for using a soil stabilizer according to claim 7, wherein the moisture content of the stabilized soil is 15-18%.

10. The method for using a soil stabilizer according to claim 7, wherein the material to be stabilized includes slag, aeolian sand, high liquid limit soil and collapsible loess.