Soil curing agent, preparation method and application thereof, and soil curing method

Abstract

The invention relates to a soil stabilizer and a preparation method and application thereof and a soil solidification method.The soil stabilizer is prepared from, by weight, 40-45 parts of converter slag, 20-25 parts of phosphate, 25-40 parts of silicate, 10-13 parts of clay mineral, 1-35 parts of water and 0-25 parts of polar organic solvent, and the total weight part of the polar organic solvent and the water is 25-35. The soil stabilizer has the beneficial effects that a soil matrix of the soil stabilizer is quickly reinforced, the reinforcing effect is remarkable, the compressive strength after 7 days of curing can reach 90% of the strength after 28 days of curing, follow-up construction can be directly carried out, and convenience and rapidness are achieved; and the bearing capacity of the solidified body is high. The converter slag as an industrial waste residue, phosphate, silicate and clay minerals are low in cost, the curing agent is wide in raw material source, traditional cement and lime are replaced, the production cost is low, and wide application prospects are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of road engineering, and particularly relates to a soil stabilizer, a preparation method and application thereof, and a soil solidification method. Background Art

[0002] As a new type of building material, soil stabilizers are widely used in infrastructure construction and have remarkable effects in improving the engineering properties of soil. Soil stabilizers can significantly improve the strength, bearing capacity and durability of soil through physical, chemical or biological actions, which are crucial for application scenarios such as road engineering, foundation treatment and slope reinforcement engineering.

[0003] Soil stabilizers are usually divided into inorganic, organic, ionic and bio-enzymatic soil stabilizers. Among them, inorganic stabilizers have become the most widely used type of stabilizers due to their low cost, wide source of raw materials, large application range and other advantages. At present, although inorganic stabilizers have a wide application range, their durability and adaptability to different soil types still need to be further improved. In addition, inorganic stabilizers may also release harmful substances, such as heavy metal ions, during the production and application processes, and these substances may pollute groundwater or have a negative impact on the surrounding ecological environment. Summary of the Invention

[0004] (1) Technical Problems to be Solved

[0005] In view of the above-mentioned disadvantages and deficiencies of the prior art, the present invention provides a soil stabilizer, a preparation method and application thereof, and a soil solidification method, which solve the technical problems that the durability, soil adaptability and environmental protection of existing soil stabilizers need to be improved.

[0006] (2) Technical Solutions

[0007] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0008] In a first aspect, an embodiment of the present invention provides a soil stabilizer, comprising, by weight: 40-45 parts of converter slag, 20-25 parts of phosphate, 25-40 parts of silicate, 10-13 parts of clay mineral, 1-35 parts of water, and 0-25 parts of polar organic solvent, wherein the total weight of the polar organic solvent and the water is 25-35 parts;

[0009] Among them, the mass ratio of silicon dioxide in the silicate is 60-75%; the mass ratio of exchangeable calcium ions in the clay mineral is 0.2-0.8%, which helps the formation of hydroxyapatite products.

[0010] As a preferred embodiment of the present invention, for the soil stabilizer, the soil stabilizer comprises the following components by weight: 40-41 parts of converter slag, 22-23 parts of phosphate, 35-37 parts of silicate, 12-13 parts of clay mineral, 20-22 parts of water, and 10-12 parts of polar organic solvent.

[0011] As a preferred embodiment of the present invention, for the soil stabilizer, the clay mineral is one or more of montmorillonite, zeolite, and kaolinite;

[0012] The silicate is one or more of sodium silicate, asbestos, and feldspar;

[0013] The phosphate is one or more of diammonium hydrogen phosphate, ammonium dihydrogen phosphate, sodium dihydrogen phosphate, or potassium dihydrogen phosphate.

[0014] As a preferred embodiment of the present invention, for the soil stabilizer, the particle size of the converter slag is less than 1 mm; the particle sizes of the phosphate, silicate, and clay mineral are all less than 2 mm.

[0015] As a preferred embodiment of the present invention, for the soil stabilizer, the polar organic solvent is one or more of ethylene glycol, isopropyl alcohol, or acrylic acid.

[0016] In a second aspect, an embodiment of the present invention provides a preparation method of the soil stabilizer described in the first aspect, comprising the following steps:

[0017] S1. Add phosphate and silicate to water or a mixture of water and polar organic solvent, and mix evenly until the phosphate is fully dissolved to obtain a first blend;

[0018] S2. Add clay mineral and converter slag to the first blend and mix evenly to obtain the soil stabilizer.

[0019] Among them, the phosphate is first fully dissolved, and then a weakly alkaline reaction environment is formed under the action of the silicate, and then the clay mineral and converter slag are added to provide sufficient calcium to fully react to form hydroxyapatite products.

[0020] As a preferred embodiment of the present invention, for the preparation method, in S2, the mixing step is to stir at 60-70 rpm for 10-15 min. Among them, too slow or too fast stirring speed will cause uneven stirring.

[0021] In a third aspect, an embodiment of the present invention provides a use of the aforementioned soil stabilizer in road engineering, slope reinforcement, and soil solidification of foundations.

[0022] In a fourth aspect, an embodiment of the present invention provides a soil solidification method, in which the aforementioned soil stabilizer is mixed with the soil to be solidified, and then the solidified soil is obtained through compaction and curing;

[0023] Among them, the weight ratio of the soil stabilizer to the dry weight of the soil to be solidified is 7-10%. The dry weight of the soil refers to the weight corresponding to the soil without water.

[0024] As a preferred embodiment of the present invention, in the soil solidification method, before the soil to be solidified is mixed with the soil stabilizer, the water content state of the soil to be solidified is the optimal water content ±1%; after the soil to be solidified is mixed with the soil stabilizer, the relative compaction degree ≥93%.

[0025] The optimal water content is an inherent property of soil particles, which is determined by a standard compaction test (such as the Proctor test). In this test, the maximum dry density of the soil at different water contents is measured. The optimal water content refers to the water content at which the soil can be compacted to its maximum dry density. The soil can be compacted to its maximum dry density at the optimal water content.

[0026] (III) Beneficial effects

[0027] The beneficial effects of the present invention are as follows: For a soil stabilizer, its preparation method and application, and a soil solidification method of the present invention, among them, the raw materials of the soil stabilizer adopt a combination of converter slag, phosphate, silicate and clay mineral. Among them, the converter slag can react with phosphate to generate hydroxyapatite. Hydroxyapatite has good adhesion, chemical stability, as well as relatively high strength, stiffness and specific surface area, so as to be able to solidify the soil base to improve the bearing capacity of the solidified soil base (solidified body). The clay mineral provides more calcium, which helps the formation of hydroxyapatite products; the silicate is used to provide a weak alkaline environment to further promote the forward progress of the hydroxyapatite formation reaction.

[0028] As a highly alkaline material, the main components of converter slag, SiO2, CaO, Al2O3 and Fe2O3, can have acid buffering ability when the stabilizer is eroded by carbon dioxide or acid rain; at the same time, the converter slag reacts with acidic substances to generate CaCO3 crystals, further filling the pores of the solidified body, effectively reducing the infiltration amount of acidic solution, and further increasing the stability of the solidified body in a harsh environment. The silicate and clay mineral can effectively wrap the hydroxide precipitation of heavy metals, efficiently absorb heavy metals, and have a good repair effect on heavy metal soil, being environmentally friendly. It has strong soil adaptability and low environmental impact.

[0029] Compared with the prior art, the soil base reinforcement of the soil stabilizer in the present invention is rapid and the reinforcement effect is remarkable. The compressive strength after curing for 7 days can reach 90% of the strength after curing for 28 days, and subsequent construction can be directly carried out, which is convenient and fast; the bearing capacity of the solidified body is high. As an industrial waste residue, converter slag, phosphate, silicate and clay mineral are low in cost, and the raw materials of the stabilizer are widely sourced, replacing traditional cement and lime, with low production cost.

[0030] Water and polar organic solvents act as media to help other components disperse evenly and promote chemical reactions. Organic solvents can also adjust the amount of water, keeping the soil moisture content at the optimal moisture content, being highly adaptable to different soil types (with different moisture contents), helping to accelerate the curing process of the soil stabilizer, and enhancing the compressive strength of the solidified body. The particle size of the converter slag is less than 1 mm, and the particle sizes of phosphate, silicate, and clay minerals are all less than 2 mm, which is conducive to the full reaction between active components and improves the curing strength.

[0031] Generally speaking, compared with existing soil stabilizers, the soil stabilizer in the present invention has the advantages of rapid reinforcement, high bearing capacity of the solidified body, environmental friendliness, strong soil adaptability, as well as few types of raw materials used, wide sources, and low cost, and has broad application prospects. Specific embodiments

[0032] To better explain the present invention for easy understanding, the present invention will be described in detail below through specific embodiments.

[0033] A soil stabilizer of the present invention, its preparation method and application, and a soil curing method proposed in the embodiments of the present invention aim at the technical problems that the durability, soil adaptability, and environmental friendliness of existing soil stabilizers need to be improved; the raw materials of the soil stabilizer adopt a combination of converter slag, phosphate, silicate, and clay minerals. Among them, the converter slag can react with phosphate to generate hydroxyapatite. Hydroxyapatite has good adhesion, chemical stability, as well as relatively high strength, stiffness, and specific surface area, so as to be able to solidify the soil base to improve the bearing capacity of the solidified soil base (solidified body). Clay minerals provide more calcium, which helps the formation of hydroxyapatite products; silicate is used to provide a weakly alkaline environment to further promote the forward progress of the hydroxyapatite formation reaction. As a highly alkaline material, the converter slag, whose main components are SiO2, CaO, Al2O3, and Fe2O3, can have acid buffering ability when the stabilizer is eroded by carbon dioxide or acid rain; at the same time, the converter slag reacts with acidic substances to generate CaCO3 crystals, further filling the pores of the solidified body, effectively reducing the infiltration amount of acidic solutions, and further increasing the stability of the solidified body in a harsh environment. Silicate and clay minerals can effectively wrap the hydroxide precipitates of heavy metals, efficiently absorb heavy metals, have a good repair effect on heavy metal-contaminated soil, and are environmentally friendly. They have strong soil adaptability and are less affected by the environment. Compared with the prior art, the soil base reinforcement of the soil stabilizer is rapid and the reinforcement effect is remarkable. The compressive strength after 7 days of curing can reach 90% of the strength after 28 days of curing, and subsequent construction can be directly carried out, which is convenient and fast; the bearing capacity of the solidified body is high. As an industrial waste residue, the converter slag, phosphate, silicate, and clay minerals are low in cost, the raw materials of the stabilizer are widely sourced, replacing traditional cement and lime, with low production cost, and have broad application prospects.

[0034] To better understand the above technical solution, exemplary embodiments of the present invention will be described in more detail below. It should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0035] Example 1

[0036] This example provides a preparation method of a soil stabilizer, including the following steps:

[0037] (1) Use a grinder to grind 40 kg of converter slag to a particle size less than 1 mm;

[0038] (2) Take 20 kg of water and 10 kg of isopropyl alcohol and mix them evenly. Add 22 kg of diammonium hydrogen phosphate and 35 kg of sodium silicate thereto, and use a magnetic stirrer to stir evenly for 4 min to obtain a mixed solution;

[0039] (3) Add 13 kg of clay minerals and 40 kg of converter slag to the mixed solution successively, and stir at 60 rpm for 15 min to obtain a soil stabilizer.

[0040] Example 2

[0041] This example provides a preparation method of a soil stabilizer, including the following steps:

[0042] (1) Use a grinder to grind 45 kg of converter slag to a particle size less than 1 mm;

[0043] (2) Take 25 kg of water and 5 kg of ethylene glycol and mix them evenly. Add 20 kg of sodium dihydrogen phosphate and 25 kg of asbestos thereto, and use a magnetic stirrer to stir evenly for 4 min to obtain a mixed solution;

[0044] (3) Add 12 kg of clay minerals and 45 kg of converter slag to the mixed solution successively, and stir at 60 rpm for 15 min to obtain a soil stabilizer.

[0045] Example 3

[0046] This example provides a soil curing method for a road project using a soil stabilizer, specifically including the following steps:

[0047] (1) Mix the soil stabilizer prepared in Example 1 with the soil of the foundation to be cured (dry soil) in two layers at a ratio of 8%, and stir and mix it fully with the soil mass;

[0048] (2) Use a compactor to roll layer by layer. After the compaction degree of each layer reaches 93%, the construction is completed. After curing for 7 days, a solidified subgrade can be obtained. Take a local solidified subgrade as the test soil body, and cure it until 28 days. Take a local solidified subgrade as the test soil body.

[0049] Then, conduct the following performance tests on the test soil body:

[0050] 1) Unconfined compressive strength test

[0051] The unconfined compressive strength test is carried out with reference to the specification JTG 3441-2024 "Test Procedures for Inorganic Binding Material Stabilized Materials in Highway Engineering". Use a cylindrical test soil body with a size of φ50mm×50mm. After soaking in water for 24 hours, dry the surface moisture, place it on a pavement material strength tester for compressive test, and record the maximum pressure P (N) when the specimen fails. The test results are shown in Table 1.

[0052] 2) California Bearing Ratio (CBR) test

[0053] The CBR test refers to the specification JTG 3430-2020 ( "Highway Geotechnical Test Procedures"). Determine the air-dried moisture content of the specimen, and pour the specimen into the test cylinder in 3 times. After the first layer is compacted, "roughen" the surface of the specimen layer, then install the sleeve, and repeat the above method for compaction of the remaining layers of the specimen. Take a representative specimen for moisture content test. When the specimen is formed by static pressure, calculate the required specimen amount according to the determined compaction degree and form it by static pressure at one time. The test results of the California Bearing Ratio (CBR) are shown in Table 2.

[0054] Example 4

[0055] This example provides a soil solidification method for road engineering using a soil stabilizer. The difference between this example and Example 3 is that the soil stabilizer is prepared by the preparation method of Example 2. The remaining steps are the same.

[0056] Example 5

[0057] This example provides a soil solidification method for road engineering using a soil stabilizer. The difference between this example and Example 3 is that in step (1), the soil stabilizer is mixed with the foundation soil to be solidified (dry soil) at a ratio of 10%.

[0058] Comparative Example 1

[0059] This comparative example provides a preparation method of a soil stabilizer. The difference from Example 1 is that the addition amount of converter slag is 50 kg, and the remaining steps are the same.

[0060] Comparative Example 2

[0061] This comparative example provides a soil solidification method for road engineering using a soil stabilizer. The difference between this comparative example and Example 3 is that the soil stabilizer is prepared from Comparative Example 1. The remaining steps are the same.

[0062] Comparative Example 3

[0063] This comparative example provides a preparation method of a soil stabilizer. The difference from Example 1 is that 15 kg of water and 5 kg of isopropanol are uniformly mixed, and the remaining steps are the same.

[0064] Comparative Example 4

[0065] This comparative example provides a soil solidification method for road engineering using a soil stabilizer. The difference between this comparative example and Example 3 is that the soil stabilizer is prepared from Comparative Example 3. The remaining steps are the same.

[0066] Comparative Example 5

[0067] This comparative example provides a preparation method of a soil stabilizer. The difference from Example 1 is that 20 kg of sodium silicate and 5 kg of clay minerals are added, and the remaining steps are the same.

[0068] Comparative Example 6

[0069] This comparative example provides a soil solidification method for road engineering using a soil stabilizer. The difference between this comparative example and Example 3 is that the soil stabilizer is prepared from Comparative Example 5. The remaining steps are the same.

[0070] Comparative Example 7

[0071] This comparative example provides a soil solidification method for road engineering using a soil stabilizer. The difference between this comparative example and Example 3 is that the soil stabilizer is reinforced with P.O 32.5 cement, the cement dosage is 6% of the soil mass, and the optimum moisture content is 13.8%. The remaining steps are the same.

[0072] Table 1 Unconfined Compressive Strength Test Results

[0073]

[0074] Table 2 California Bearing Ratio Test Results

[0075]

[0076] Based on the above examples and comparative examples, combined with Table 1 and Table 2, the analysis is as follows:

[0077] Combined with Example 3, it can be seen that Example 1 is the best example in the preparation method of the soil stabilizer. The soil stabilizer prepared in Example 1 is mixed with the soil body at a ratio of 8% respectively. After compaction and curing, the test soil body (corresponding to Example 3) can reach more than 90% of the strength after 28 days of curing in 7 days of curing, and the strength reaches the constructible level, so as to shorten the construction period. The highest compressive strength reaches 2730.4 kPa. Compared with the cement soil stabilizer in Comparative Example 7, the compressive strength of the test soil body in Example 3 increases significantly, and the corresponding bearing ratio also increases significantly.

[0078] Comparing Example 3 and Example 4, the compressive strength and bearing ratio of the soil stabilizer prepared in Example 2 decrease, indicating that the soil stabilizer prepared with the material ratio in Example 1 has the best effect.

[0079] Comparing Example 3 and Example 5, increasing the dosage of the soil stabilizer will significantly increase the compressive strength of the test soil body after 28 days of curing, but the change in the compressive strength after 7 days of curing is not significant. Considering the economic benefits, compared with Example 5, the dosage of the soil stabilizer can be appropriately reduced.

[0080] Comparing Comparative Example 2 and Example 3, when the amount of converter slag in the soil stabilizer is relatively large, it will significantly affect the compressive strength and bearing ratio of the corresponding test soil body. Excessive converter slag will not react fully with phosphoric acid, affecting the formation of hydroxyapatite.

[0081] Comparing Comparative Example 4 and Example 3, reducing the water and isopropanol in the soil stabilizer will significantly affect the compressive strength and bearing ratio of the corresponding test soil body. When the amounts of water and isopropanol are small, the dispersion effect on other components is weakened, thus affecting the full reaction between components.

[0082] Comparing Comparative Example 6 and Example 3, reducing the sodium silicate and clay minerals in the soil stabilizer will significantly affect the compressive strength and bearing ratio of the corresponding test soil body. The reason is that the clay minerals cannot provide sufficient calcium for the converter slag, affecting the formation of hydroxyapatite. When the dosage of silicate is reduced, it cannot provide a sufficient weak alkaline environment, which also affects the formation of hydroxyapatite.

[0083] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing examples, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A soil stabilizer, characterized in that, Comprising, by weight parts: 40 - 45 parts of converter slag, 20 - 25 parts of phosphate, 25 - 40 parts of silicate, 10 - 13 parts of clay mineral, 1 - 35 parts of water, 0 - 25 parts of polar organic solvent, wherein the total weight parts of the polar organic solvent and the water is 25 - 35 parts.

2. The soil stabilizer according to claim 1, characterized in that, The soil stabilizer comprises, by weight parts: 40 - 41 parts of converter slag, 22 - 23 parts of phosphate, 35 - 37 parts of silicate, 12 - 13 parts of clay mineral, 20 - 22 parts of water, 10 - 12 parts of polar organic solvent.

3. The soil stabilizer according to claim 1, characterized in that, The clay mineral is one or more of montmorillonite, zeolite, kaolinite; The silicate is one or more of sodium silicate, asbestos, feldspar; The phosphate is one or more of diammonium hydrogen phosphate, ammonium dihydrogen phosphate, sodium dihydrogen phosphate or potassium dihydrogen phosphate.

4. The soil stabilizer according to claim 1, characterized in that, The particle size of the converter slag is less than 1 mm; the particle sizes of the phosphate, silicate and clay mineral are all less than 2 mm.

5. The soil stabilizer according to claim 1, characterized in that, The polar organic solvent is one or more of ethylene glycol, isopropyl alcohol or acrylic acid.

6. A preparation method of a soil stabilizer according to any one of claims 1-5, characterized in that, Comprising the following steps: S1. Add phosphate and silicate to water or a mixture of water and polar organic solvent, mix evenly until the phosphate is fully dissolved to obtain a first blend. S2. Add clay mineral and converter slag to the first blend and mix evenly to obtain the soil stabilizer.

7. The preparation method according to claim 6, characterized in that, In S2, the mixing step is to stir at 60 - 70 rpm for 10 - 15 min.

8. A soil stabilizer according to any one of claims 1 - 5 or a soil stabilizer prepared by the preparation method according to claim 6 or 7, which is used in road engineering, slope reinforcement and soil solidification of foundation.

9. A soil solidification method, characterized in that, Mix the soil stabilizer according to any one of claims 1 - 5 or the soil stabilizer prepared by the preparation method according to claim 6 or 7 with the soil to be solidified by dry weight, and then obtain the solidified soil through compaction and curing. Wherein, the weight ratio of the soil stabilizer to the dry weight of the soil to be solidified is 7 - 10%.

10. For the soil solidification method according to claim 9, before the soil to be solidified is mixed with the soil stabilizer, the water content state of the soil to be solidified is the optimal water content ±1%; After the soil to be solidified is mixed with the soil stabilizer, the relative compaction degree ≥93%.

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