Method for recycling high-water-content slag soil into composite stabilizing material and application of the method

Abstract

The application relates to a method for recycling high-water-content slag soil into a composite stabilizing material and application of the method, and the method comprises the following steps: (1) pretreatment: high-water-content slag soil is extruded and deblocked by using a mudstone separation device, large-diameter stone blocks are separated, and separated high-water-content slag soil is obtained; (2) dehydration and solidification: a solidifying agent and a soil body composite stabilizing agent are added into the separated high-water-content slag soil obtained in the step (1), the mixture is uniformly stirred, the water content of the separated high-water-content slag soil is reduced, the soil particle agglomeration state is destroyed, and soil particle dispersion is realized; (3) secondary separation: the material obtained in the step (2) is screened, powder with a particle diameter of less than 40 mm is obtained, and the powder is stacked for standby; and (4) road application: the powder in the step (3) is mixed with the solidifying agent, the soil body composite stabilizing agent and water to form a composite stabilizing material according to road application conditions, and the composite stabilizing material is used for construction of a road base layer, a bottom base layer and / or a cushion layer.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of soil solidification and stabilization technology, C09K17 / 40, and particularly relates to a method for resource utilization of high-water-content slag soil into composite stabilized material and application of the method. BACKGROUND

[0002] With the acceleration of urbanization process and large-scale development of urban underground space in China, more and more engineering slag soil is transported to the surrounding storage field for centralized stacking, and slag soil management has become a big problem for urban management. At present, various solid waste treatment methods have been developed for the treatment of slag soil, but there is still no high-value and efficient resource utilization method for high-water-content slag soil. Especially in the southeast coastal areas of China, the generated slag soil is mostly high-water-content, low-permeability clay or silt soil, which has a high water content, viscosity, and contains a large amount of stones, concrete, construction waste and other sundries, which is difficult to be directly utilized and causes problems such as over-capacity stacking of slag soil storage field. Therefore, selecting a suitable method to treat high-water-content slag soil so that its properties meet the specific requirements such as building foundation, road engineering foundation, mine reinforcement engineering, etc. can achieve the purpose of large-scale disposal of high-water-content slag soil.

[0003] Chinese patent CN114316996A discloses a composite solidifying agent for high-liquid-limit soil in the south, which comprises a main agent, a reinforcing agent, a plasticizing agent, an activating agent and a water reducing agent. The main agent is castor seed oil or palm oil, and the reinforcing agent is one or more of bagasse, bamboo stem or rapeseed cake. Although the raw materials are mostly plant fibers and are environmentally friendly, they are prone to breakage and inactivation in long-term water immersion environment, which greatly reduces the solidification effect and effective solidification time of the solidifying agent on the soil. Chinese patent CN11434937A provides a medicament for reducing the water content of silt, which needs to be used in combination with 9 kinds of raw materials such as slag, calcium sulfate, sodium hydroxide, magnesium oxide, magnesium acetate and ordinary Portland cement to achieve dehydration effect. The process is complex and the dehydration time is long. The existing technology mixes high-water-content slag soil with cement, lime and fly ash, and then stirs and mixes them. After 3 days of stuffing, the mixture is turned over and dried. The process is complex and the cycle is too long. In addition, the pollutants in the silt soil cannot be fixed, and mechanical automation cannot be achieved, resulting in low processing efficiency and small processing capacity. It is of great practical significance to explore the disposal method of high-water-content slag soil, overcome the difficulties and make waste useful, and build an environmentally friendly city. SUMMARY

[0004] To solve the above problems, the present application provides a method for resource utilization of high-water-content slag soil into composite stabilized material, wherein a soil composite solidifying agent is used in combination to regenerate the slag soil into a powder-particle filler after solidification treatment, reduce the water content, meet the water content requirement of the preparation of composite stabilized material, and improve the resource utilization and solidification efficiency of high-water-content slag soil.

[0005] Further, a method for recycling high-water-content slag soil into composite stabilized material is provided.

[0006] (1) Pretreatment: The high-water-content slag soil is extruded and debulked by a mudstone separation device to separate large-diameter stone blocks, thereby obtaining separated high-water-content slag soil;

[0007] (2) Dehydration and solidification: A solidifying agent and a soil composite stabilizer are added to the separated high-water-content slag soil obtained in step (1) and uniformly stirred to reduce the water content of the separated high-water-content slag soil and destroy the soil particle aggregation state, thereby realizing soil particle dispersion;

[0008] (3) Secondary separation: The material obtained in step (2) is sieved to obtain powder with a particle diameter of less than 40 mm, which is stacked for standby use;

[0009] (4) Road application: The powder in step (3) is mixed with a solidifying agent, a soil composite stabilizer and water to form a composite stabilized material for the construction of a road base layer, a bottom base layer and / or a cushion layer according to the road application conditions.

[0010] The mudstone separation device used in step (1) can be the mudstone separation device disclosed in Chinese patent application documents CN114644437A or CN114671580A.

[0011] Further, the large-diameter stone blocks obtained in step (1) and the large-diameter stone blocks sieved out in step (3) are directly used for roadbed laying.

[0012] Further, the solidifying agent is one or more of cement, lime, fly ash, etc.

[0013] Further, the soil composite stabilizer is composed of the following substances: 15-25% of a polymer, 5-12% of polyvinyl acetate, 1-5% of a coupling agent, 2-6% of a borate, 35-50% of a metal salt, 3-9% of a surfactant, 1-3% of glycerol, and the balance of water to make up the total amount to 100% by weight.

[0014] In the present application, the tightness of the high-water-content slag soil is increased by the crosslinking of the polymer and polyvinyl acetate, the relative content of which is adjusted to enhance the mechanical strength and low-temperature resistance of the composite stabilized material; the metal salt has ion exchange and water absorption and solidification effects to reduce the water content of the slag soil; the borate changes the molecular arrangement in the sludge to form a water-impermeable membrane in the system, thereby preventing water penetration; the surfactant forms an adsorption layer on the surface of the treated powder, and the hydrophobic molecular chain segment produces a repulsive force, thereby further improving the water permeability resistance of the powder; through the synergistic effect of the components, the water content of the high-water-content slag soil is reduced, and the compressive strength, low-temperature resistance and service life of the prepared composite stabilized material are improved.

[0015] Further, the preparation method of the polymer is: mixing acrylic acid, styrene, initiator, solvent, adjusting pH, and incubating at 60-80℃ for 2-3h.

[0016] Further, the mass ratio of the acrylic acid and styrene is (2-5):1.

[0017] When the mass ratio of the acrylic acid and styrene is 2-5:1, the composite stabilizing material prepared from the treated high-water-content slag soil has excellent mechanical strength and low-temperature resistance, which is presumably because: in the polymer chain, the -COOH in the acrylic acid has hydrophilicity, when the content of the acrylic acid is too high, the hydrophobic ability of the composite stabilizing material prepared from the treated high-water-content slag soil is reduced, and when the content of the styrene is too high, the activity of the molecular chains of the polymer and polyvinyl acetate in the system is reduced, the molecular chains cannot well expand or move at low temperature, resulting in that the prepared composite stabilizing material cannot well cope with the cracking phenomenon, and the low-temperature resistance is significantly reduced.

[0018] Further, the initiator is ammonium persulfate or potassium persulfate, and the addition amount is 0.3-0.5% of the total mass of the acrylic acid and styrene.

[0019] Further, the pH is 7.5-8.0.

[0020] Further, the average molecular weight of the polyvinyl acetate is 50000-150000 Dalton; the application produces enhancement, toughening and curing effects on the powder through the crosslinking of the polyvinyl acetate and the copolymer in the system, but the application finds that when the average molecular weight of the polyvinyl acetate is limited to 50000-150000 Dalton, the composite stabilizing material prepared by this method has excellent anti-cracking performance and maintains good mechanical strength at low temperature, which is presumably because when the average molecular weight of the polyvinyl acetate is too high, the entanglement degree of the molecular chain increases and the activity decreases, and the intermolecular force generated between the polymer and the polyvinyl acetate can further aggravate this internal action, the material brittleness increases, and it is difficult to adapt to the impact at low temperature, however, when the molecular weight is too small, the enhancement effect on the solid waste powder is not enough.

[0021] Further, the average molecular weight of the polyvinyl acetate is 50000-120000 Dalton.

[0022] Further, the coupling agent is a silane coupling agent or a phthalate coupling agent.

[0023] Preferably, the coupling agent is a silane coupling agent.

[0024] Further, the metal salt is at least two of sulfate, silicate, phosphate or chloride of metal ions.

[0025] Further, the metal salt is selected from one or more of aluminum sulfate, aluminum silicate, aluminum phosphate, potassium silicate, potassium phosphate, ferric chloride, aluminum chloride, calcium chloride.

[0026] Further, the metal salt is a combination of aluminum phosphate and ferric chloride.

[0027] Further, the metal salt is aluminum phosphate and ferric chloride in a mass ratio of 1: (3-6).

[0028] In a preferred embodiment, the mass ratio of aluminum phosphate and ferric chloride is 1:4.5; the ferric chloride in the system will combine with the polymer, the combined substance will ion exchange with cations such as sodium ions and potassium ions in the high-water-content clay, thin the double-layer thickness in the high-water-content clay, and can chemically react in it to consume water to generate insoluble iron-based oxides or iron-based hydroxides, enhancing the mechanical strength of the treated powder, but its water absorption and curing capacity is limited; the aluminum phosphate can hydrolyze in an alkaline environment, the released hydrogen ions combine with the hydroxyl ions in the high-water-content clay to reduce the internal moisture, and the aluminum phosphate releasing hydrogen ions will encapsulate and fix the alkali metal ions in the treatment system, forming a solid that is hard and insoluble in water, improving the mechanical strength and water resistance of the prepared composite stabilizer, but when its content is too high, the treated high-water-content clay has a large shrinkage ratio and poor frost resistance.

[0029] Further, the surface active agent is at least one of stearate, glyceryl stearate, and sodium dodecyl benzene sulfonate.

[0030] Preferably, the surface active agent is stearate.

[0031] Further, the spraying amount of the soil composite stabilizer in step (2) is 0.01-0.8wt% of the weight of the separated high-water-content clay.

[0032] Further, the spraying amount of the soil composite stabilizer in step (2) is 0.01-0.5wt% of the weight of the separated high-water-content clay.

[0033] Further, the spraying amount of the soil composite stabilizer in step (2) is 0.01-0.1wt% of the weight of the separated high-water-content clay, and the spraying amount of the soil composite stabilizer is controlled to reduce the amount of curing agents such as cement and lime.

[0034] Further, the addition amount of the curing agent in step (2) is 2-15wt% of the weight of the separated high-water-content clay.

[0035] Further, the addition amount of the curing agent in step (2) is 2-5wt% of the weight of the separated high-water-content clay.

[0036] Further, the large particle size stone separated in step (3) is also used for roadbed laying, and the particle diameter of the powder is less than 30 mm.

[0037] Further, the addition amount of the soil composite stabilizer in step (4) is 0.01-0.05wt% of the total weight of the powder and the curing agent.

[0038] Further, the addition amount of the soil composite stabilizer in step (4) is 0.01-0.03wt% of the total weight of the powder and the curing agent.

[0039] Further, the preparation method of the composite stabilizer in step (4) is road mixing or plant mixing.

[0040] Beneficial effects:

[0041] (1) The method for recycling high-moisture slag soil into a composite stabilizer provided in the present application not only solves the current situation of difficult treatment of high-moisture slag soil, but also effectively separates large particle size stones, and realizes modification of high-moisture slag soil by adding a soil composite stabilizer, reduces the moisture content, and is suitable for treating high-moisture slag soil, providing more options for subsequent recycling.

[0042] (2) The soil composite stabilizer used in the present application can be "one dose for two purposes". When added for pretreatment, it can control the moisture content of high-moisture solid waste and change its agglomeration, reduce its viscosity, control the size of soil particles, and make it meet the particle size requirements of the composite stabilizer. When added for road application, it can change the hydrophilic property of soil to hydrophobic property, and undergo hydration reaction to form a fibrous crystalline reinforcing network structure, thereby improving the performance strength of the road base and subbase.

[0043] (3) In the method of the present application, by limiting the average molecular weight of polyvinyl acetate, the mass ratio of acrylic acid and styrene in the polymer, and the relative content of the polymer and polyvinyl acetate, the composite stabilizer prepared from the high-moisture solid waste treated by the soil composite stabilizer has good compression resistance and freeze-thaw resistance.

[0044] (4) The present application utilizes the synergistic effect of aluminum phosphate and ferric chloride to strengthen the dewatering and curing efficiency of the method for high-moisture solid waste, and improve its tightness; the dual action of borate and surfactant changes the hydrophobic property of the treated high-moisture solid waste, reduces the water permeability of the prepared composite stabilizer, and further improves its service life. DETAILED DESCRIPTION

[0045] EMBODIMENT

[0046] EMBODIMENT 1

[0047] The method for recycling high-moisture slag soil into a composite stabilizer is:

[0048] (1) Pretreatment: The high-water-content slag soil is extruded and deblocked by a mud and stone separation device to separate large-diameter stone blocks, and the separated high-water-content slag soil is obtained.

[0049] (2) Dehydration and solidification: 0.025 parts of the soil composite stabilizer and 5 parts of lime are sprayed on 125 parts of the separated high-water-content slag soil obtained in step (1) according to weight parts, and the separated high-water-content slag soil is uniformly turned and mixed to reduce the water content of the separated high-water-content slag soil and destroy the soil particle aggregation state to realize soil particle dispersion.

[0050] (3) Secondary separation: The material obtained in step (2) is sieved to obtain a powder with a particle size of less than 20 mm, which is stacked for standby use.

[0051] (4) Road application: 50 parts of the powder obtained in step (3) are uniformly mixed with 8 parts of cement, 0.012 parts of the soil composite stabilizer, and 10 parts of water according to weight parts, and are used for road water-stable layer construction.

[0052] The soil composite stabilizer is composed of the following substances: 20% of a polymer, 9% of polyvinyl acetate, 3% of a silane coupling agent (KH550), 4% of triphenyl carbonium tetra(pentafluorophenyl) borate (CAS: 136040-19-2), 42% of a metal salt, 6% of calcium stearate (CAS: 1592-23-0), 2% of glycerol, and water to make up the rest to 100% of the total amount; the polyvinyl acetate has an average molecular weight of 80000 Dalton and is purchased from Jiangsu Shengda New Material Technology Co., Ltd.; the metal salt is a combination of aluminum phosphate (CAS: 7784-30-7) and iron chloride (CAS: 7705-08-0) with a mass ratio of 1:4.5;

[0053] The preparation method of the polymer is as follows: 13 parts of acrylic acid, 5 parts of styrene, 0.072 parts of ammonium persulfate, and 25 parts of ethyl acetate are mixed, the pH of the system is adjusted to 7.8, and the system is incubated at 70°C for 3h.

[0054] Example 2

[0055] The method for recycling the high-water-content slag soil into a composite stabilizer is as follows:

[0056] (1) Pretreatment: The high-water-content slag soil is extruded and deblocked by a mud and stone separation device to separate large-diameter stone blocks, and the separated high-water-content slag soil is obtained.

[0057] (2) Dehydration and solidification: 0.0125 parts of the soil composite stabilizer and 7 parts of lime are sprayed on 125 parts of the separated high-water-content slag soil obtained in step (1) according to weight parts, and the separated high-water-content slag soil is uniformly turned and mixed to reduce the water content of the separated high-water-content slag soil and destroy the soil particle aggregation state to realize soil particle dispersion.

[0058] (3) Secondary separation: the material obtained in step (2) is sieved to obtain a powder with a particle size of less than 40 mm, which is stacked for standby;

[0059] (4) Road application: 95 parts of the powder obtained in step (3), 5 parts of cement, 0.03 parts of the soil composite stabilizer, and 20 parts of water are uniformly mixed according to weight parts, and used for road water stable layer construction.

[0060] The soil composite stabilizer is composed of: 15% of polymer, 12% of polyvinyl acetate, 1% of silane coupling agent (KH550), 6% of triphenyl carbon tetra (pentafluorophenyl) borate (CAS: 136040-19-2), 35% of metal salt, 9% of calcium stearate (CAS: 1592-23-0), 3% of glycerol, and the balance is water to make up the total amount to 100% by weight; the average molecular weight of the polyvinyl acetate is 120000 Dalton, which is purchased from Jiangsu Shengda New Material Technology Co., Ltd.; the metal salt is a combination of aluminum phosphate (CAS: 7784-30-7) and iron chloride (CAS: 7705-08-0) with a mass ratio of 1:3;

[0061] The preparation method of the polymer is: mixing 14.4 parts of acrylic acid, 3.6 parts of styrene, 0.09 parts of ammonium persulfate, and 28 parts of ethyl acetate, adjusting the pH of the system to 8.0, and incubating at 80°C for 2h.

[0062] Example 3

[0063] The method for recycling high-water-content slag soil into composite stabilizing material is:

[0064] (1) Pretreatment: using a mud and stone separator to extrude and deblock the high-water-content slag soil, and separating out large-diameter stone blocks to obtain separated high-water-content slag soil;

[0065] (2) Dehydration and solidification: 0.0625 parts of soil composite stabilizer and 2.5 parts of lime are sprayed on 125 parts of the separated high-water-content slag soil obtained in step (1), and uniformly stirred to reduce the water content of the separated high-water-content slag soil and destroy the soil particle aggregation state to realize soil particle dispersion;

[0066] (3) Secondary separation: the material obtained in step (2) is sieved to obtain a powder with a particle size of less than 30 mm, which is stacked for standby;

[0067] (4) Road application: 30 parts of the powder obtained in step (3), 5 parts of cement, 0.0035 parts of the soil composite stabilizer, and 5 parts of water are uniformly mixed according to weight parts, and used for road water stable layer construction.

[0068] The soil body composite stabilizer is composed of the following substances: 25% of polymer, 5% of polyvinyl acetate, 5% of silane coupling agent (KH550), 2% of triphenyl carbonium tetra(pentafluorophenyl) borate (CAS: 136040-19-2), 50% of metal salt, 3% of calcium stearate (CAS: 1592-23-0), 1% of glycerol, and the balance of water to make up the total amount of 100% by weight; the average molecular weight of the polyvinyl acetate is 50000 Dalton, which is purchased from Jiangsu Shengda New Material Technology Co., Ltd.; the metal salt is a combination of aluminum phosphate (CAS: 7784-30-7) and ferric chloride (CAS: 7705-08-0) with a mass ratio of 1:6;

[0069] The preparation method of the polymer is as follows: 10 parts of acrylic acid, 5 parts of styrene, 0.045 parts of ammonium persulfate, and 20 parts of ethyl acetate are mixed, the pH of the system is adjusted to 8.0, and the system is incubated at 80℃ for 2h.

[0070] Example 4

[0071] The example 1 is basically the same, except that in step (2) of dehydration and solidification, 0.0375 parts of soil body composite stabilizer and 7.5 parts of lime are sprayed on 125 parts of separated high-moisture slag soil obtained in step (1) by weight, and the mixture is uniformly stirred.

[0072] Example 5

[0073] The example 1 is basically the same, except that in step (2) of dehydration and solidification, 0.0875 parts of soil body composite stabilizer and 7.5 parts of lime are sprayed on 125 parts of separated high-moisture slag soil obtained in step (1) by weight, and the mixture is uniformly stirred.

[0074] Example 6

[0075] The example 1 is basically the same, except that the metal salt is a combination of aluminum phosphate and ferric chloride with a mass ratio of 1:1.

[0076] Example 7

[0077] The example 1 is basically the same, except that the metal salt is a combination of aluminum phosphate and ferric chloride with a mass ratio of 1:8.

[0078] Example 8

[0079] The example 1 is basically the same, except that the average molecular weight of the polyvinyl acetate is 150000.

[0080] Example 9

[0081] The preparation method of the polymer is as follows: 9 parts of acrylic acid, 9 parts of styrene, 0.072 parts of ammonium persulfate, and 25 parts of ethyl acetate are mixed, the pH of the system is adjusted to 7.8, and the mixture is incubated at 70°C for 3h.

[0082] Example 10

[0083] The preparation method of the polymer is as follows: 9 parts of acrylic acid, 9 parts of styrene, 0.072 parts of ammonium persulfate, and 25 parts of ethyl acetate are mixed, the pH of the system is adjusted to 7.8, and the mixture is incubated at 70°C for 3h.

[0084] Example 11

[0085] The preparation method of the polymer is as follows: 9 parts of acrylic acid, 9 parts of styrene, 0.072 parts of ammonium persulfate, and 25 parts of ethyl acetate are mixed, the pH of the system is adjusted to 7.8, and the mixture is incubated at 70°C for 3h.

[0086] Example 12

[0087] The preparation method of the polymer is as follows: 9 parts of acrylic acid, 9 parts of styrene, 0.072 parts of ammonium persulfate, and 25 parts of ethyl acetate are mixed, the pH of the system is adjusted to 7.8, and the mixture is incubated at 70°C for 3h.

[0088] Comparative Example 1

[0089] The preparation method of the polymer is as follows: 9 parts of acrylic acid, 9 parts of styrene, 0.072 parts of ammonium persulfate, and 25 parts of ethyl acetate are mixed, the pH of the system is adjusted to 7.8, and the mixture is incubated at 70°C for 3h.

[0090] Comparative Example 2

[0091] The preparation method of the polymer is as follows: 9 parts of acrylic acid, 9 parts of styrene, 0.072 parts of ammonium persulfate, and 25 parts of ethyl acetate are mixed, the pH of the system is adjusted to 7.8, and the mixture is incubated at 70°C for 3h.

[0092] Comparative Example 3

[0093] The preparation method of the polymer is as follows: 9 parts of acrylic acid, 9 parts of styrene, 0.072 parts of ammonium persulfate, and 25 parts of ethyl acetate are mixed, the pH of the system is adjusted to 7.8, and the mixture is incubated at 70°C for 3h.

[0094] Comparative Example 4

[0095] The preparation method of the polymer is as follows: 9 parts of acrylic acid, 9 parts of styrene, 0.072 parts of ammonium persulfate, and 25 parts of ethyl acetate are mixed, the pH of the system is adjusted to 7.8, and the mixture is incubated at 70°C for 3h.

[0096] Performance Test Method

[0097] 1. Unconfined compressive strength: according to the provisions of the specification CJ / T 486-2015, the mixture in step (4) of each example and comparative example is made into a test piece according to the requirements of the specification, and after curing according to the requirements, the unconfined compressive strength and water stability coefficient of the test piece after 7 days of immersion and non-immersion are tested;

[0098] 2. Freeze-thaw cycle test: the test piece size is the same as that of the unconfined compressive strength, the test piece is soaked in normal temperature water for 24 h, and then the following cycle is performed: -18℃ freezing for 4 h, 20℃ warm water melting for 4 h, after 10 cycles, the compressive strength loss rate of the test piece is measured.

[0099] Performance test results

[0100] Table 1

[0101]

[0102] It can be seen from Comparative Examples 1-5 that when the addition amount of the soil body composite stabilizer in step (2) increases, the solidification efficiency of the high-water-content slag soil is improved, and the compressive strength and low-temperature resistance of the composite stabilized material prepared from the treated solid powder are also gradually improved. However, because the soil body composite stabilizer is a liquid stabilizer, and the metal ions in the soil body are limited, when the addition amount is too much, there is no obvious effect on the improvement of the solidification efficiency and solidification effect.

[0103] It can be seen from Comparative Example 1 and Examples 6-7 that the mass ratio of aluminum phosphate and ferric chloride in the metal salt has a great influence on the solidification effect. After water absorption, part of the ferric chloride forms a ferric hydroxide colloid, but the solidification enhancement effect on the powder is not good. After hydrolysis of the aluminum phosphate, the alkali metal ions in the treatment system are wrapped and fixed, forming a hard and water-insoluble solid, which has good enhancement effect and water stability effect on the powder. However, the dry shrinkage ratio is too large, which has an adverse effect on the frost resistance of the composite stabilized material obtained after treatment.

[0104] It can be seen from Comparative Example 1 and Example 8 that when the average molecular weight of polyvinyl acetate is too large, the activity of the molecular chain inside is poor, and it is difficult to adapt to the cyclic change of temperature and impact at low temperature.

[0105] It can be seen from Comparative Example 1 and Examples 9-11 that as the styrene content in the polymer increases, the unconfined compressive strength of the composite stabilized material is enhanced. However, when the styrene content is too high, the cross-linking and entanglement of the polymer and polyvinyl acetate is enhanced, the space rotation and activity of the molecular chain are hindered, and the structure cannot be adjusted well to adapt to the change of high and low temperature. When the acrylic acid content is too high, the water absorption of the filler will increase to a certain extent, and the penetration of water molecules in the composite stabilized material will reduce the unconfined compressive strength after immersion, and the water stability will decrease.

[0106] From Comparative Example 1 and Example 12, it can be seen that when the average particle size of the powder is too large, the soil body composite stabilizer cannot be well combined with the powder, and the powder contains a large number of untreated parts, and the prepared composite stabilized material has unsatisfactory compressive performance and frost resistance.

[0107] From Comparative Examples 1-12 and Comparative Example 1, it can be seen that the soil body stabilizer can effectively improve the compressive strength of the composite stabilized material. In the soil body stabilizer of Comparative Example 2, all polymers are added, and no polyvinyl acetate is added. In the soil body stabilizer of Comparative Example 3, no polymer is added, and all polyvinyl acetate is added. The 7-day unconfined compressive strength of the prepared test piece is decreased, and the low-temperature resistance is also decreased, indicating that the addition of both polymers and polyvinyl acetate is beneficial to improving the tightness of soil particles and is helpful to improving the strength and low-temperature resistance. In Comparative Example 4, all borate is replaced by metal salt, and the strength and low-temperature resistance of the prepared test piece are decreased, and the 7-day water stability coefficient is low, indicating that the addition of borate is helpful to improving the strength and low-temperature resistance, and is helpful to forming a water-impermeable net film in the system, preventing water penetration, and improving water resistance.

Claims

1. A method for recycling high-water-content slag soil into a composite stabilizing material, characterized by, The method is: (1) Pretreatment: using a mud and stone separation device to extrude and deblock the high-water-content slag soil, separating out large-diameter stone blocks, and obtaining separated high-water-content slag soil; (2) Dehydration and solidification: adding a solidifying agent and a soil composite stabilizer to the separated high-water-content slag soil of step (1), stirring evenly, reducing the water content of the separated high-water-content slag soil, and destroying the soil particle aggregation state to realize soil particle dispersion; (3) Secondary separation: screening the material obtained in step (2) to obtain a powder with a particle diameter of less than 40 mm, and stacking for standby; (4) Road application: mixing the powder in step (3) with a solidifying agent, a soil composite stabilizer, and water according to the road application situation to form a composite stabilized material, which is used for the construction of road base, subbase, and / or cushion; The soil composite stabilizer is composed of the following substances: 15-25% of a polymer, 5-12% of polyvinyl acetate, 1-5% of a coupling agent, 2-6% of a borate, 35-50% of a metal salt, 3-9% of a surfactant, 1-3% of glycerol, and water making up the rest to 100% by total weight; The preparation method of the polymer is: mixing acrylic acid, styrene, and an initiator, adjusting the pH to 7.5-8.0, and incubating at 60-80°C for 2-3h; The mass ratio of acrylic acid to styrene is (2-5):1; The initiator is ammonium persulfate or potassium persulfate.

2. The method for recycling high-water-content slag soil as composite stabilizing material according to claim 1, characterized in that, The average molecular weight of the polyvinyl acetate is 50,000-150,000 Daltons.

3. The method of claim 1, wherein the high-water-content slag soil is a resource for a composite stabilizing material. The metal salt is at least two of a sulfate, a silicate, a phosphate, or a chloride of a metal ion.

4. The method for recycling high-water-content slag soil as composite stabilizing material according to claim 1, characterized in that, The metal salt is a combination of aluminum phosphate and iron chloride.

5. The method for recycling high-water-content slag soil as composite stabilizing material according to claim 1, characterized in that, The spraying amount of the soil composite stabilizer in step (2) is 0.01-0.8wt% of the weight of the separated high-water-content slag soil.

6. The method for recycling high-water-content slag soil as composite stabilizing material according to claim 1, characterized in that, The addition amount of the solidifying agent in step (2) is 2-15wt% of the weight of the separated high-water-content slag soil.

7. The method of recycling high-water-content slag soil as composite stabilizing material according to claim 1, characterized in that, The addition amount of the soil composite stabilizer in step (4) is 0.01-0.05wt% of the total weight of the powder and the solidifying agent.

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