Preparation process of mineralization-induced variable stiffness microcapsule solidification modifier and dispersed soil material
By using mineralization-induced variable stiffness microcapsule solidification modifiers, and utilizing dynamic bond construction and nanotextured protective layer technology, the problem of mechanical property degradation in dispersible soils was solved. This achieved mechanical interlocking and chemical grafting between microcapsules and soil particles, thereby improving the stability and durability of the roadbed.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CCCC FIRST HARBOR ENGINEERING CO LTD
- Filing Date
- 2026-02-05
- Publication Date
- 2026-06-09
AI Technical Summary
Existing technologies for improving dispersible soils suffer from problems such as high carbon emissions from high-temperature calcination processes, residual toxicity of synthetic polymers, easy degradation of natural polymers, and mechanical property deterioration due to microcapsule slippage. These issues prevent the effective resolution of long-term stability of soil dispersibility and mechanical properties.
A mineralization-induced variable stiffness microcapsule curing modifier was used. By adding a dynamic bond-building agent to a mixed aqueous solution of lignin sulfonate and polyvinyl alcohol, a shear-thinning hydrogel was formed. This hydrogel then reacted with modified nano-red mud powder and transparent active hot oil to form a nano-textured protective layer. This achieved mechanical interlocking between the microcapsules and soil particles, releasing calcium stearate plugs and bisphenol A epoxy resin for bonding, thus constructing a dense structure.
It significantly improves interfacial bonding force, achieves homogeneous integration between the modifier and the soil, enhances mechanical properties, prevents debonding and slippage, forms a hydrophobic system, and improves the stability and durability of the roadbed.
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Figure CN122168292A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of building materials technology, specifically to a preparation process for a mineralization-induced variable stiffness microcapsule solidification modifier and a dispersion soil material. Background Technology
[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.
[0003] The core hidden danger of dispersed subgrade soil stems from the combined effects of double-layer expansion caused by high exchangeable sodium ions and moisture sensitivity: Due to the significantly thickened double-layer (water film) on the surface of cohesive particles in the soil caused by high sodium ion content, the repulsive force between particles is enhanced. When exposed to rainwater or seepage, this water easily disperses and condenses into a suspended state, which is then eroded away by the water flow, leading to problems such as voids, settlement, and slope instability in the subgrade, seriously threatening the safety of road engineering. Currently, methods for improving dispersed soil mainly include traditional calcium-based inorganic modifiers, natural and synthetic organic polymer modifiers, and alkali-activated solid waste modifiers. Among them: Traditional calcium-based inorganic modifiers (such as cement and lime) rely on high-temperature calcination processes, which have problems such as high carbon emissions and the soil being prone to embrittlement and cracking during its service life. Moreover, the cracks expand when exposed to water and cannot resist water erosion.
[0004] While synthetic polymeric amendments (such as polyacrylamide) can improve soil cohesion in the short term, the acrylamide monomers remaining after the synthesis process are neurotoxic, and long-term retention in the soil can pollute groundwater and harm the ecosystem. In addition, polymer chains are easily degraded by ultraviolet light or microorganisms, and the improvement effect can only be maintained for 6 to 12 months, exhibiting poor durability.
[0005] Natural polymeric amendments (chitosan, starch, etc.) cannot prevent water intrusion. Even with ion exchange to compress the double electric layer, water can still seep into the soil and re-disperse the particles. Moreover, natural polymers are easily degraded by microorganisms, providing insufficient mechanical support, and the shear strength of the soil decreases rapidly after amendment.
[0006] Alkali-activated solid waste improvement mainly enhances soil strength by generating gels through hydration reactions. However, the system has strong hydrophilicity in its internal pores, allowing water to easily penetrate. Furthermore, it lacks the ability to regulate the double electric layer problem in dispersed soils, thus failing to fundamentally inhibit the dispersion of soil particles. The improvement effect is merely a temporary fix.
[0007] While existing microencapsulation technology addresses environmental concerns, the smooth surface of the coating layer leads to a low coefficient of friction between the microcapsules and soil particles after incorporation. Under dynamic loads, this causes the microcapsules to slip within the soil matrix, significantly reducing the internal friction angle of the improved soil. This not only fails to enhance the soil's performance but also degrades the overall mechanical properties of the subgrade. Furthermore, the coating layer presents challenges, such as easy breakage during mixing and difficulty in releasing its contents during compaction. Additionally, the weak interfacial bond between the coating layer and the inorganic soil makes the interface prone to peeling and debonding during service, leading to improvement failure. Summary of the Invention
[0008] This invention provides a process for preparing a mineralization-induced variable stiffness microcapsule solidification modifier and a dispersion soil material. This process not only changes the contact mode between the microcapsules and soil particles from slippage to mechanical interlocking, significantly improving interfacial adhesion, but also constructs a coating shell with good shear adaptability. Specifically, the technical solution of this invention is as follows.
[0009] First, this invention provides a preparation process for a mineralization-induced variable stiffness microcapsule solidification modifier, comprising the following steps: (1) Adjust the mixed aqueous solution of lignin sulfonate and polyvinyl alcohol to alkaline, and then add a dynamic bond building agent under stirring conditions. After the reaction, a hydrogel with shear thinning properties is obtained. Then, a mineralization induction modifier is added, and after stirring evenly, modified nano red mud powder is added. After ultrasonic dispersion treatment, an aqueous suspension is obtained for later use.
[0010] (2) The phase change solvent carrier is heated and melted into a liquid state, and then bisphenol A type epoxy resin and polymethylene polyphenyl polyisocyanate (PMDI) are added while stirring to obtain a transparent active hot oil phase for later use.
[0011] (3) Under shear stirring conditions, the transparent active hot oil phase is gradually added to the preheated aqueous suspension, and then shear stirring is performed. After completion, the resulting mixture is heated and stirred to react, and then cooled naturally to room temperature. The solid product is separated, washed, and dried to obtain the variable stiffness microcapsule curing modifier.
[0012] Further, in step (1), the ratio of lignin sulfonate: polyvinyl alcohol: dynamic bond building agent: mineralization inducing modifier: modified nano red mud powder is 10~20 parts by weight: 2~5 parts by weight: 0.5~2 parts by weight: 0.5~2 parts by weight: 1~5 parts by weight.
[0013] Further, in step (1), the pH of the mixed aqueous solution is adjusted to 8-9. Optionally, at least one of the alkaline solutions such as sodium hydroxide solution, potassium hydroxide solution, and ammonia water is used to adjust the pH.
[0014] Further, in step (1), the ratio of lignin sulfonate: polyvinyl alcohol: water in the mixed aqueous solution is 10~20 parts by weight: 2~5 parts by weight: 100~200 parts by weight.
[0015] Further, in step (1), the lignin sulfonate includes at least one of sodium lignin sulfonate, calcium lignin sulfonate, etc.
[0016] Further, in step (1), the dynamic bond building agent includes at least one of phenylboronic acid, borax, formylphenylboronic acid, etc. Optionally, the reaction time is 30-60 min.
[0017] Further, in step (1), the mineralization-inducing modifier includes at least one of phytic acid, sodium phytate, etc.
[0018] Further, in step (1), the ultrasonic dispersion treatment time is 10~20min and the power is 300~500W.
[0019] Further, in step (2), the phase change solvent carrier: bisphenol A type epoxy resin: polymethylene polyphenyl polyisocyanate (PMDI) = 40~60 parts by weight: 10~20 parts by weight: 3~8 parts by weight.
[0020] Further, in step (2), the phase change solvent carrier includes at least one of stearic acid, palmitic acid, paraffin, etc.
[0021] Further, in step (3), the ratio of the transparent active hot oil phase to the aqueous suspension is 53~88 parts by weight: 114~234 parts by weight.
[0022] Furthermore, in step (3), the temperature of the preheated aqueous suspension is 70~75℃.
[0023] Further, in step (3), the shearing and stirring rate is 8000~12000 rpm. Optionally, the shearing and stirring time is 5~10 min.
[0024] Further, in step (3), the temperature of the heating and stirring reaction is 70~80℃, and the time is 2~3 hours. Optionally, the stirring rate is 300~500 rpm.
[0025] Further, in step (1), the modified nano-red mud powder is prepared by the following method: (i) a silane coupling agent is added to a suspension of red mud and stirred under heating conditions to obtain a hydroxylated red mud suspension. (ii) The hydroxylated red mud suspension is then cooled and kept at a constant temperature, and at least one of the modifiers sodium dodecylbenzenesulfonate and polyethylene glycol fatty acid ester is added. After stirring and reacting, the solid product is separated, washed, dried, and pulverized to obtain the modified nano-red mud powder.
[0026] Further, in step (i), the ratio of red mud to silane coupling agent is 1.1-2 parts by weight: 0.5-1 parts by weight. Optionally, the silane coupling agent includes at least one of KH550, KH570, etc.
[0027] Furthermore, in step (i), the heating temperature is 60~80℃, and the stirring reaction time is 2~4 hours.
[0028] Further, in step (ii), the ratio of the modifier to the red mud is 0.3~0.8 parts by weight: 1.1~2 parts by weight.
[0029] Further, in step (ii), the hydroxylated red mud suspension is cooled to 40~50°C, and the stirring reaction time is 1~2 hours.
[0030] Further, in step (ii), the drying temperature is 80~100℃, and the time is 4~6 hours. Optionally, the washing method is to wash with anhydrous ethanol 3~5 times to remove unreacted free modifier.
[0031] Secondly, the present invention provides a dispersible soil material comprising the following components in the following proportions: 1000 parts by weight of dispersible soil, 30-80 parts by weight of mineralization inducing source, 50-150 parts by weight of fly ash, 20-60 parts by weight of phosphogypsum, and 10-30 parts by weight of the variable stiffness microcapsule solidification modifier.
[0032] Furthermore, the mineralization inducing source includes at least one of the following: calcium carbide slag powder, calcium hydroxide powder, steel slag powder, etc.
[0033] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects: This invention first adds a dynamic bond-building agent to a mixed aqueous solution of lignin sulfonate and polyvinyl alcohol. The borate groups provided by the agent form reversible dynamic borate ester bonds with the hydroxyl groups on the lignin sulfonate and polyvinyl alcohol, resulting in a hydrogel with shear-thinning properties. Then, a mineralization-inducing modifier and modified nano-red mud powder are added and uniformly distributed within the hydrogel to form an aqueous suspension. When this suspension reacts with a transparent, active hot oil phase, the modified nano-red mud spontaneously migrates to the oil-water interface and adsorbs, forming a nano-textured protective layer. Simultaneously, PMDI diffuses to the interface and prepolymerizes with the hydrogel to form a rigid framework, locking the dynamic borate ester bond network provided by the dynamic bond-building agent within it. It also undergoes a condensation reaction with the active hydroxyl groups on the mineralization-inducing modifier molecules, resulting in a microcapsule wall modified by the nano-textured protective layer. This transforms the contact mode between the microcapsule and soil particles from "slippage" to "mechanical interlocking," significantly improving the interfacial interlocking force and allowing the microcapsules to act as micro-aggregate reinforcement rather than reducing the internal friction angle. Meanwhile, the microcapsule walls exhibit flexibility during the mixing stage (low shear), effectively resisting accidental breakage; however, during the compaction stage (high pressure / high shear), brittle fracture occurs, enabling precise release of the internal core material. The released stearic acid reacts with calcium ions released by the mineralization induction source to form calcium stearate plugs that uniformly fill the pores, constructing a hydrophobic system. Simultaneously, the released bisphenol A epoxy resin provides in-situ bonding to microcracks in the soil, forming a dense "strong inside, loose outside" structure. Furthermore, the hydroxide ions released by the mineralization induction source upon contact with water, along with the Fe2O3 and Al2O3 metal oxides provided by the modified nano-red mud powder, act as electron transfer media, promoting the gain and loss of electrons in lignin molecules. This induces homolytic cleavage of chemical bonds, generating free radicals that chemically graft onto the soil, fundamentally solving the interfacial debonding problem. In addition, the crushed microcapsule walls can actively capture calcium ions released by the mineralization induction source using the phosphate ester / carboxyl groups on the mineralization induction modifier, inducing the formation of calcium carbonate / hydroxyapatite crystals, thereby gradually transforming the organic shell into a hard inorganic mineral shell, achieving "homogeneous fusion" with the surrounding soil, and further eliminating the risk of aging and debonding between the solidification modifier and the soil. Attached Figure Description
[0034] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.
[0035] Figure 1 The following image shows (b) a sample of the variable stiffness microcapsule curing modifier (a) and modified nano red mud powder prepared for Example 1.
[0036] Figure 2The following image shows (b) a sample of the variable stiffness microcapsule curing modifier (a) and modified nano red mud powder prepared for Example 2.
[0037] Figure 3 The following image shows (b) a sample of the variable stiffness microcapsule curing modifier (a) and modified nano red mud powder prepared for Example 3. Detailed Implementation
[0038] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer.
[0039] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as those skilled in the art. All reagents and raw materials used in this invention are readily available through conventional means, and unless otherwise specified, they shall be used in accordance with conventional methods in the art or as per the product instructions.
[0040] Furthermore, any methods and materials similar to or equivalent to those described herein can be applied to the method of this invention. The technical solution of this invention will now be further described in conjunction with the accompanying drawings and specific embodiments.
[0041] Example 1: 1. A method for preparing modified nano-red mud powder, comprising the following steps: (i) The nano-red mud powder and water were mixed at a mass ratio of 1:10 and ultrasonically dispersed for 30 min (power 600W) to obtain a red mud suspension. Then, silane coupling agent KH550 (the ratio of nano-red mud powder to silane coupling agent was 1.5 parts by weight: 0.8 parts by weight) was added to the red mud suspension, and the mixture was heated to 70°C and stirred for 3.5 hours to obtain a hydroxylated red mud suspension for later use.
[0042] (ii) The hydroxylated red mud suspension was cooled to 40°C and kept at that temperature. Sodium dodecylbenzenesulfonate was added to the suspension in a ratio of 0.45 parts by weight to 0.5 parts by weight of the sodium dodecylbenzenesulfonate and the nano-red mud powder. After stirring for 2 hours, the solid product was separated by centrifugation, washed three times with anhydrous ethanol, heated to 100°C and vacuum dried for 4 hours. The resulting product was then pulverized to obtain modified nano-red mud powder (e.g., ...). Figure 1 (As shown in b), for later use.
[0043] 2. A preparation process for a mineralization-induced variable stiffness microcapsule solidification modifier, comprising the following steps: (1) According to the ratio of calcium lignosulfonate: polyvinyl alcohol: water: dynamic bond building agent (formylphenylboronic acid): mineralization inducing modifier (sodium phytate): modified nano red mud powder prepared in this embodiment = 20 parts by weight: 5 parts by weight: 200 parts by weight: 2 parts by weight: 2 parts by weight: 5 parts by weight, the calcium lignosulfonate and polyvinyl alcohol are first added to water and stirred until fully dissolved to obtain a mixed aqueous solution. Then, ammonia water is added to adjust the pH of the mixed aqueous solution to 8.5. Then, the dynamic bond building agent is added under stirring conditions. After reacting for 60 min, a hydrogel with shear thinning characteristics is obtained. Then, the mineralization inducing modifier is added, and after stirring evenly, the modified nano red mud powder is added. Then, ultrasonic dispersion is performed for 20 min (power 300W) to obtain an aqueous suspension for later use.
[0044] (2) According to the ratio of phase change solvent carrier (stearic acid): bisphenol A type epoxy resin: polymethylene polyphenyl polyisocyanate = 60 parts by weight: 20 parts by weight: 8 parts by weight, the phase change solvent carrier is first heated to melt into a liquid state, and then the bisphenol A type epoxy resin and polymethylene polyphenyl polyisocyanate are added while stirring to obtain a transparent active hot oil phase for later use.
[0045] (3) Under shear-stirring conditions, the transparent active hot oil phase was gradually added to the aqueous suspension preheated to 70°C, with a ratio of 53 parts by weight to 114 parts by weight. The mixture was then shear-stirred at 10,000 rpm for 5 minutes. After this, the resulting mixture was heated and stirred at 70°C for 3 hours at a stirring rate of 350 rpm. After this, the mixture was allowed to cool naturally to room temperature. The solid product was separated by filtration, washed with water, and then vacuum-dried at 50°C to remove moisture, thus obtaining the variable stiffness microcapsule curing modifier (e.g., ...). Figure 1 (as shown in a).
[0046] 3. A dispersed soil material, comprising the following components in the following proportions: 1000 parts by weight of dispersed soil, 60 parts by weight of calcium carbide slag powder, 110 parts by weight of fly ash, 40 parts by weight of phosphogypsum, and 20 parts by weight of the variable stiffness microcapsule curing modifier prepared in this embodiment. After mixing the above components, 220 parts by weight of mixing water are added, stirred evenly, and allowed to stand for 30 minutes. The resulting dispersed soil material is then poured into a mold, compacted, and naturally cured for 7 days to obtain the test specimen. The various properties of the specimen are then tested according to JTG 3430-2020 "Specifications for Geotechnical Testing of Highways" and JTG 3441-2024 "Specifications for Testing Inorganic Binder Stabilized Materials for Highway Engineering". The results are shown in Table 1 below.
[0047] Table 1
[0048] Example 2: 1. A method for preparing modified nano-red mud powder, comprising the following steps: (i) Mix nano-red mud powder with water at a mass ratio of 1:10 and then ultrasonically disperse for 30 min (power 600W) to obtain a red mud suspension. Then add silane coupling agent KH550 (the ratio of nano-red mud powder to silane coupling agent is 2 parts by weight: 1 part by weight) to the red mud suspension, and heat to 80°C and stir for 2 hours to obtain a hydroxylated red mud suspension for later use.
[0049] (ii) The hydroxylated red mud suspension was cooled to 45°C and kept at that temperature. Sodium dodecylbenzenesulfonate was added to the suspension in a ratio of 0.8 parts by weight to 1 part by weight of the nano-red mud powder. After stirring for 1.5 hours, the solid product was separated by centrifugation, washed three times with anhydrous ethanol, heated to 100°C and vacuum dried for 4 hours. The resulting product was then pulverized to obtain modified nano-red mud powder (e.g., ...). Figure 2 (As shown in b), for later use.
[0050] 2. A preparation process for a mineralization-induced variable stiffness microcapsule solidification modifier, comprising the following steps: (1) According to the ratio of sodium lignosulfonate: polyvinyl alcohol: water: dynamic bond building agent (phenylboronic acid): mineralization inducing modifier (phytic acid): modified nano red mud powder prepared in this embodiment = 10 parts by weight: 2 parts by weight: 100 parts by weight: 0.5 parts by weight: 0.5 parts by weight: 1 part by weight, the sodium lignosulfonate and polyvinyl alcohol are first added to water and stirred until fully dissolved to obtain a mixed aqueous solution. Then, sodium hydroxide solution is added to adjust the pH of the mixed aqueous solution to 8. Then, the dynamic bond building agent is added under stirring conditions. After reacting for 30 minutes, a hydrogel with shear thinning characteristics is obtained. Then, the mineralization inducing modifier is added and stirred evenly. Then, the modified nano red mud powder is added. Then, ultrasonic dispersion is performed for 15 minutes (power 400W) to obtain an aqueous suspension for later use.
[0051] (2) According to the ratio of phase change solvent carrier (paraffin): bisphenol A type epoxy resin: polymethylene polyphenyl polyisocyanate = 40 parts by weight: 10 parts by weight: 3 parts by weight, the phase change solvent carrier is first heated to melt into a liquid state, and then the bisphenol A type epoxy resin and polymethylene polyphenyl polyisocyanate are added while stirring to obtain a transparent active hot oil phase for later use.
[0052] (3) Under shear-stirring conditions, the transparent active hot oil phase is gradually added to the aqueous suspension preheated to 75°C, with a ratio of 88 parts by weight to 234 parts by weight. Then, the mixture is shear-stirred at 8000 rpm for 10 minutes. After this, the resulting mixture is heated to 80°C and stirred for 2 hours at a stirring rate of 500 rpm. After this, the mixture is allowed to cool naturally to room temperature. The solid product is separated by filtration, washed with water, and then vacuum-dried at 50°C to remove moisture, thus obtaining the variable stiffness microcapsule curing modifier (e.g., ...). Figure 2 (as shown in a).
[0053] 3. A dispersed soil material comprising the following components in the following proportions: 1000 parts by weight of dispersed soil, 80 parts by weight of calcium carbide slag powder, 150 parts by weight of fly ash, 60 parts by weight of phosphogypsum, and 30 parts by weight of the variable stiffness microcapsule curing modifier prepared in this embodiment. After mixing the above components, 240 parts by weight of mixing water are added, stirred evenly, and allowed to stand for 30 minutes. The resulting dispersed soil material is then poured into a mold, compacted, and naturally cured for 7 days to obtain the test specimen. The performance of the specimen is then tested using the same method as in Example 1 above, and the results are shown in Table 2 below.
[0054] Table 2
[0055] Example 3: 1. A method for preparing modified nano-red mud powder, comprising the following steps: (i) Mix nano-red mud powder with water at a mass ratio of 1:10 and then ultrasonically disperse for 30 min (power 600W) to obtain a red mud suspension. Then add silane coupling agent KH570 (the ratio of nano-red mud powder to silane coupling agent is 1.1 parts by weight: 0.5 parts by weight) to the red mud suspension, and heat to 60°C and stir for 4 hours to obtain a hydroxylated red mud suspension for later use.
[0056] (ii) The hydroxylated red mud suspension was cooled to 50°C and kept at that temperature. Sodium dodecylbenzenesulfonate was added to the suspension in a ratio of 0.3 parts by weight to 1.1 parts by weight of the sodium dodecylbenzenesulfonate. After stirring for 1 hour, the solid product was separated by centrifugation, washed five times with anhydrous ethanol, heated to 80°C and vacuum dried for 6 hours. The resulting product was then pulverized to obtain modified nano-red mud powder (e.g., ...). Figure 3 (As shown in b), for later use.
[0057] 2. A preparation process for a mineralization-induced variable stiffness microcapsule solidification modifier, comprising the following steps: (1) According to the ratio of sodium lignosulfonate: polyvinyl alcohol: water: dynamic bond building agent (borax): mineralization inducing modifier (phytic acid): modified nano red mud powder prepared in this embodiment = 15 parts by weight: 3 parts by weight: 160 parts by weight: 1.4 parts by weight: 1.0 parts by weight: 3.5 parts by weight, the sodium lignosulfonate and polyvinyl alcohol are first added to water and stirred until fully dissolved to obtain a mixed aqueous solution. Then, sodium hydroxide solution is added to adjust the pH of the mixed aqueous solution to 9. Then, the dynamic bond building agent is added under stirring conditions. After reacting for 40 min, a hydrogel with shear thinning characteristics is obtained. Then, the mineralization inducing modifier is added, and after stirring evenly, the modified nano red mud powder is added. Then, ultrasonic dispersion is performed for 10 min (power 500W) to obtain an aqueous suspension for later use.
[0058] (2) According to the ratio of phase change solvent carrier (stearic acid): bisphenol A type epoxy resin: polymethylene polyphenyl polyisocyanate = 55 parts by weight: 17 parts by weight: 6.5 parts by weight, the phase change solvent carrier is first heated to melt into a liquid state, and then the bisphenol A type epoxy resin and polymethylene polyphenyl polyisocyanate are added while stirring to obtain a transparent active hot oil phase for later use.
[0059] (3) Under shear-stirring conditions, the transparent active hot oil phase is gradually added to the aqueous suspension preheated to 75°C, with a ratio of 80 parts by weight to 205 parts by weight. Then, the mixture is shear-stirred at 12000 rpm for 5 minutes. After this, the resulting mixture is heated and stirred at 75°C for 2.5 hours at a stirring rate of 400 rpm. After this, the mixture is allowed to cool naturally to room temperature. The solid product is separated by filtration, washed with water, and then vacuum-dried at 50°C to remove moisture, thus obtaining the variable stiffness microcapsule curing modifier (e.g., ...). Figure 3 (as shown in a).
[0060] 3. A dispersed soil material, comprising the following components in the following proportions: 1000 parts by weight of dispersed soil, 30 parts by weight of calcium hydroxide powder, 50 parts by weight of fly ash, 20 parts by weight of phosphogypsum, and 10 parts by weight of the variable stiffness microcapsule curing modifier prepared in this embodiment. After mixing the above components, 195 parts by weight of mixing water are added, stirred evenly, and allowed to stand for 30 minutes. The resulting dispersed soil material is then poured into a mold, compacted, and naturally cured for 7 days to obtain the test specimen. The performance of the specimen is then tested using the same method as in Example 1 above, and the results are shown in Table 3 below.
[0061] Table 3
[0062] Example 4: 1. A preparation process of a mineralization-induced variable stiffness microcapsule solidification modifier is the same as that of Example 1 above, except that the modified nano red mud powder prepared in step (1) of Example 1 is replaced by the nano red mud powder that has not undergone any modification treatment, and the variable stiffness microcapsule solidification modifier is prepared.
[0063] 2. A dispersed soil material comprising the following components in the indicated proportions: 1000 parts by weight of dispersed soil, 60 parts by weight of calcium carbide slag powder, 110 parts by weight of fly ash, 40 parts by weight of phosphogypsum, and 20 parts by weight of the variable stiffness microcapsule curing modifier prepared in this embodiment. After mixing the above components, 220 parts by weight of mixing water are added, stirred evenly, and allowed to stand for 30 minutes. The resulting dispersed soil material is then poured into a mold, compacted, and naturally cured for 7 days to obtain the test specimen. The performance of the specimen is then tested using the same method as in Example 1 above, and the results are shown in Table 4 below.
[0064] Table 4
[0065] Example 5: 1. A preparation process for a mineralization-induced variable stiffness microcapsule solidification modifier, the same as in Example 1 above, except that: in this example, the aqueous suspension is prepared by the following method: Following the ratio of calcium lignosulfonate: polyvinyl alcohol: water: dynamic bond building agent (formylphenylboronic acid): modified nano red mud powder = 20 parts by weight: 5 parts by weight: 200 parts by weight: 2 parts by weight: 5 parts by weight, the calcium lignosulfonate and polyvinyl alcohol were first added to water and stirred until fully dissolved to obtain a mixed aqueous solution. Then, ammonia water was added to adjust the pH of the mixed aqueous solution to 8.5. Then, the dynamic bond building agent was added under stirring. After reacting for 60 minutes, a hydrogel with shear thinning properties was obtained. After stirring evenly, the modified nano red mud powder was added, and then ultrasonically dispersed for 20 minutes (power 300W) to obtain an aqueous suspension.
[0066] 2. A dispersed soil material, comprising the following components in the following proportions: 1000 parts by weight of dispersed soil, 60 parts by weight of calcium carbide slag powder, 110 parts by weight of fly ash, 40 parts by weight of phosphogypsum, and 20 parts by weight of the variable stiffness microcapsule curing modifier prepared in this embodiment. After mixing the above components, 220 parts by weight of mixing water are added, stirred evenly, and allowed to stand for 30 minutes. The resulting dispersed soil material is then poured into a mold, compacted, and naturally cured for 7 days to obtain the test specimen. The performance of the specimen is then tested using the same method as in Example 1 above, and the results are shown in Table 5 below.
[0067] Table 5
[0068] Example 6: 1. A preparation process for a mineralization-induced variable stiffness microcapsule solidification modifier, the same as in Example 2 above, except that: in this example, the aqueous suspension is prepared by the following method: (1) According to the ratio of sodium lignosulfonate: polyvinyl alcohol: water: mineralization inducing modifier (phytic acid): modified nano red mud powder = 10 parts by weight: 2 parts by weight: 100 parts by weight: 0.5 parts by weight: 1 part by weight, the sodium lignosulfonate and polyvinyl alcohol are first added to water and stirred until fully dissolved to obtain a mixed aqueous solution. Then, sodium hydroxide solution is added to adjust the pH of the mixed aqueous solution to 8. Then, the dynamic bond building agent is added under stirring conditions. After reacting for 30 minutes, a hydrogel with shear thinning characteristics is obtained. Then, the mineralization inducing modifier is added and stirred evenly. Then, the modified nano red mud powder is added and ultrasonically dispersed for 15 minutes (power 400W) to obtain an aqueous suspension for later use.
[0069] 2. A dispersed soil material comprising the following components in the following proportions: 1000 parts by weight of dispersed soil, 80 parts by weight of calcium carbide slag powder, 150 parts by weight of fly ash, 60 parts by weight of phosphogypsum, and 30 parts by weight of the variable stiffness microcapsule curing modifier prepared in this embodiment. After mixing the above components, 240 parts by weight of mixing water are added, stirred evenly, and allowed to stand for 30 minutes. The resulting dispersed soil material is then poured into a mold, compacted, and naturally cured for 7 days to obtain the test specimen. The performance of the specimen is then tested using the same method as in Example 1 above, and the results are shown in Table 6 below.
[0070] Table 6
[0071] Example 7: 1. A preparation process for a mineralization-induced variable stiffness microcapsule solidification modifier, the same as in Example 3 above, except that: in this example, the transparent active hot oil phase is prepared by the following method: According to the ratio of phase change solvent carrier (stearic acid): bisphenol A type epoxy resin = 55 parts by weight: 17 parts by weight, the phase change solvent carrier is first heated to melt into a liquid state, and then the bisphenol A type epoxy resin is added while stirring to obtain a transparent active hot oil phase for later use.
[0072] 2. A dispersed soil material, comprising the following components in the following proportions: 1000 parts by weight of dispersed soil, 30 parts by weight of calcium hydroxide powder, 50 parts by weight of fly ash, 20 parts by weight of phosphogypsum, and 10 parts by weight of the variable stiffness microcapsule curing modifier prepared in this embodiment. After mixing the above components, 195 parts by weight of mixing water are added, stirred evenly, and allowed to stand for 30 minutes. The resulting dispersed soil material is then poured into a mold, compacted, and naturally cured for 7 days to obtain the test specimen. The performance of the specimen is then tested using the same method as in Example 1 above, and the results are shown in Table 7 below.
[0073] Table 7
[0074] Example 8: A dispersed soil material comprising the following components in the following proportions: 1000 parts by weight of dispersed soil, 150 parts by weight of fly ash, 60 parts by weight of phosphogypsum, and 30 parts by weight of the variable stiffness microcapsule curing modifier prepared in Example 2 above. After mixing the above components, 225 parts by weight of mixing water were added, stirred evenly, and allowed to stand for 30 minutes. The resulting dispersed soil material was then poured into a mold, compacted, and naturally cured for 7 days to obtain the test specimen. The performance of the specimen was then tested using the same method as in Example 1 above, and the results are shown in Table 8 below.
[0075] Table 8
[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A preparation process for a mineralization-induced variable stiffness microcapsule solidification modifier, characterized in that, Includes the following steps: (1) Adjust the mixed aqueous solution of lignin sulfonate and polyvinyl alcohol to alkaline, and then add a dynamic bond building agent under stirring conditions. After the reaction, a hydrogel with shear thinning properties is obtained. Then, a mineralization induction modifier is added, and after stirring evenly, modified nano red mud powder is added. After ultrasonic dispersion treatment, an aqueous suspension is obtained for later use. (2) The phase change solvent carrier is heated and melted into a liquid state, and then bisphenol A type epoxy resin and polymethylene polyphenyl polyisocyanate are added while stirring to obtain a transparent active hot oil phase for later use; (3) Under shear stirring conditions, the transparent active hot oil phase is gradually added to the preheated aqueous suspension, and then shear stirring is performed; after completion, the resulting mixture is heated and stirred to react, and then cooled naturally to room temperature. After separating the solid product, it is washed and dried to obtain the variable stiffness microcapsule curing modifier.
2. The preparation process of the mineralization-induced variable stiffness microcapsule solidification modifier according to claim 1, characterized in that, In step (1), the ratio of lignin sulfonate: polyvinyl alcohol: dynamic bond building agent: mineralization inducing modifier: modified nano red mud powder is 10~20 parts by weight: 2~5 parts by weight: 0.5~2 parts by weight: 0.5~2 parts by weight: 1~5 parts by weight; Optionally, in step (1), the pH of the mixed aqueous solution is adjusted to 8-9; Optionally, at least one of sodium hydroxide solution, potassium hydroxide solution, and ammonia water may be used to adjust the pH.
3. The preparation process of the mineralization-induced variable stiffness microcapsule solidification modifier according to claim 1, characterized in that, In step (1), the ratio of lignin sulfonate: polyvinyl alcohol: water in the mixed aqueous solution is 10~20 parts by weight: 2~5 parts by weight: 100~200 parts by weight; Optionally, in step (1), the lignin sulfonate includes at least one of sodium lignin sulfonate and calcium lignin sulfonate; Optionally, in step (1), the dynamic bond building agent includes at least one of phenylboronic acid, borax, and formylphenylboronic acid; Optionally, in step (1), the reaction time is 30~60 min; Optionally, in step (1), the mineralization-inducing modifier includes at least one of phytic acid and sodium phytate; Optionally, in step (1), the ultrasonic dispersion treatment time is 10~20 min and the power is 300~500W.
4. The preparation process of the mineralization-induced variable stiffness microcapsule solidification modifier according to claim 1, characterized in that, In step (1), the modified nano-red mud powder is prepared by the following method: (i) A silane coupling agent is added to a suspension of red mud and the mixture is stirred under heating conditions to obtain a hydroxylated red mud suspension; (ii) The hydroxylated red mud suspension is then cooled and kept warm, and at least one of the modifiers sodium dodecylbenzenesulfonate and polyethylene glycol fatty acid ester is added. After stirring and reacting, the solid product is separated, washed, dried and pulverized to obtain the modified nano red mud powder.
5. The preparation process of the mineralization-induced variable stiffness microcapsule solidification modifier according to claim 1, characterized in that, In step (i), the ratio of red mud to silane coupling agent is 1.1~2 parts by weight: 0.5~1 parts by weight; Optionally, in step (i), the silane coupling agent includes at least one of KH550 and KH570; Optionally, in step (i), the heating temperature is 60~80℃, and the stirring reaction time is 2~4 hours; Optionally, in step (ii), the ratio of the modifier to the red mud is 0.3~0.8 parts by weight: 1.1~2 parts by weight; Optionally, in step (ii), the hydroxylated red mud suspension is cooled to 40-50°C, and the stirring reaction time is 1-2 hours; Optionally, in step (ii), the drying temperature is 80~100℃ and the time is 4~6 hours.
6. The preparation process of the mineralization-induced variable stiffness microcapsule solidification modifier according to claim 1, characterized in that, In step (2), the phase change solvent carrier is: bisphenol A type epoxy resin: polymethylene polyphenyl polyisocyanate = 40~60 parts by weight: 10~20 parts by weight: 3~8 parts by weight.
7. The preparation process of the mineralization-induced variable stiffness microcapsule solidification modifier according to claim 1, characterized in that, In step (2), the phase change solvent carrier includes at least one of stearic acid, palmitic acid, and paraffin.
8. The preparation process of the mineralization-induced variable stiffness microcapsule solidification modifier according to any one of claims 1-7, characterized in that, In step (3), the ratio of the transparent active hot oil phase to the aqueous phase suspension is 53~88 parts by weight: 114~234 parts by weight; Optionally, in step (3), the temperature of the preheated aqueous suspension is 70~75℃; Optionally, in step (3), the shearing and stirring rate is 8000~12000 rpm; Optionally, in step (3), the time for continuing shearing and stirring is 5 to 10 minutes; Optionally, in step (3), the temperature of the heating and stirring reaction is 70~80℃ and the time is 2~3 hours; optionally, the stirring rate is 300~500 rpm.
9. A type of dispersed soil material, characterized in that, The composition includes the following components in the following proportions: 1000 parts by weight of dispersible soil, 30-80 parts by weight of mineralization inducing source, 50-150 parts by weight of fly ash, 20-60 parts by weight of phosphogypsum, and 10-30 parts by weight of the variable stiffness microcapsule curing modifier.
10. The dispersed soil material according to claim 9, characterized in that, The mineralization inducing source includes at least one of the following: calcium carbide slag powder, calcium hydroxide powder, phosphogypsum, and steel slag powder.