Lightweight thermal-insulation fluid soil consolidation material and preparation method thereof

Abstract

The invention relates to the technical field of civil engineering materials, and discloses a lightweight thermal-insulation fluidized soil consolidation material and a preparation method thereof, the lightweight thermal-insulation fluidized soil consolidation material comprises the following raw materials by weight: 10-20 parts of titanium gypsum, 55-75 parts of slag, 10-25 parts of wet water glass filter residue, and 1-8 parts of modified regenerated EPS particles; the modified regenerated EPS particles are obtained by atomizing and mixing EPS particles and a coupling agent solution and then carrying out surface coating with nano calcium carbonate. According to the invention, the excellent flowability and self-compaction property of the fluid soil are maintained, the thermal conductivity is low, the strength is adjustable, the requirements of different backfill scenes can be met, and the integration of thermal insulation and backfill functions is realized.

Description

Technical Field

[0001] This invention relates to the field of civil engineering materials technology, and in particular to a lightweight thermal insulation fluidized soil consolidation material and its preparation method. Background Technology

[0002] Fluidized soil is a novel geotechnical engineering material. It is produced by fully utilizing waste soil and slag generated from excavation of trenches and foundation pits, adding a certain proportion of cementitious materials (curing agents) and water, and mixing thoroughly to form a slurry that is self-leveling and self-compacting. After pumping, pouring, and curing, it solidifies into an engineering material with certain strength, impermeability, and long-term stability. Due to its significant advantages in construction convenience, high efficiency, good compaction, and reduced reliance on manual labor, fluidized soil has promising applications in building foundation pit backfilling, underground pipe gallery enclosure, and roadbed repair.

[0003] However, with the increasing demands for building energy conservation, especially the emphasis on the thermal performance of underground spaces, traditional backfill materials have high thermal conductivity and are prone to forming "thermal bridges," leading to heat loss from the basement exterior walls and affecting the overall energy efficiency of the building. Currently, to solve this problem, the common practice is to attach insulation boards to the basement exterior walls before backfilling. This process has the following drawbacks: (1) The construction procedure is complex and the construction period is long; (2) The insulation boards have low strength and are easily damaged by compression during backfilling, affecting the insulation effect; (3) There are gaps between the insulation boards and the backfill soil, which can easily form water seepage channels. On the other hand, lightweight materials that simply pursue insulation performance (such as foamed cement) often have low strength (often less than 0.2 MPa), which cannot meet the basic requirements of backfill materials for stability and lateral support, thus limiting their application range.

[0004] Therefore, developing a new type of composite material that can meet the strength requirements of backfilling projects and has good thermal insulation properties has become an urgent need in this field. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a lightweight thermal insulation fluid soil consolidation material and a preparation method, which maintains the excellent fluidity and self-compacting properties of fluid soil, and has a low thermal conductivity and high strength.

[0006] To address the aforementioned technical problems, this invention provides a lightweight, thermally insulating, fluidized soil consolidation material, comprising the following raw materials by weight: 10-20 parts titanium gypsum, 55-75 parts slag, 10-25 parts wet process water glass filter residue, and 1-8 parts modified recycled EPS particles. The modified recycled EPS particles are obtained by atomizing and mixing EPS particles with a coupling agent solution, and then coating the surface with nano-calcium carbonate.

[0007] In some embodiments, the titanium gypsum comprises the following chemical components by mass percentage: CaO 35%~40%, SiO2 1%~3%, Al2O3 1%~2%, Fe2O3 5%~10%, Na2O 0.5%~1%, TiO2 1%~5%, SO3 40%~50%, and LOI 1%~5%.

[0008] In some embodiments, the slag comprises the following chemical components by mass percentage: CaO 45%~50%, SiO2 30%~35%, Al2O3 10%~16%, Fe2O3 1%~2%, MgO 1%~3%, and LOI 0.5%~1%.

[0009] In some embodiments, the wet process water glass filter residue comprises the following chemical components by mass percentage: CaO 0.1%~0.5%, SiO2 65%~70%, Al2O3 5%~10%, Na2O 20%~25%, Fe2O3 0.2%~0.4%, MgO 0.1%~0.4%, and LOI 1%~3%.

[0010] In some embodiments, the chemical composition of the wet process water glass filter residue has a SiO2 to Na2O mass ratio of 2.8 to 3.2.

[0011] In some embodiments, the modified recycled EPS particles have a particle size of 1~10 mm and a bulk density of 1×10⁻⁶. -2 ~1.1×10 -2 g / cm 3 The apparent density is 1.8 × 10⁻⁶. -2 ~2×10 -2 g / cm 3 Water absorption rate ≤3.5%, thermal conductivity ≤0.2W / (mK).

[0012] In some embodiments, the particle size of the titanium gypsum is ≤ 75 μm; the particle size of the blast furnace slag is ≤ 75 μm; and the particle size of the wet process water glass filter residue is ≤ 100 μm.

[0013] Accordingly, the present invention provides a method for preparing lightweight thermal insulation fluidized soil consolidation material, comprising: The recycled EPS particles are pre-treated by washing and drying. Modified EPS particles are obtained by modifying EPS particles to obtain modified recycled EPS particles; By weight, 10-20 parts of titanium gypsum, 55-75 parts of blast furnace slag, 10-25 parts of wet process water glass filter residue, and 1-8 parts of modified recycled EPS particles are mixed to obtain the finished fluidized soil consolidation material.

[0014] In some embodiments, the modification method of the modified recycled EPS particles includes: Rinse the EPS particles with water and dry them to a constant weight; The coupling agent is mixed with ethanol solvent and stirred to allow it to fully hydrolyze, thus obtaining a coupling agent solution. After drying, the EPS particles are poured into a mixer or drum. The prepared coupling agent solution is then sprayed evenly onto the surface of the turning EPS particles in a mist form using a spraying device to obtain a mixture. Nano-calcium carbonate is added to the mixture for surface coating to obtain the modified recycled EPS particles.

[0015] In some embodiments, the amount of nano-calcium carbonate added is 0.45~0.55%wt of the total weight of the mixture; The coupling agent and ethanol solvent are mixed at a mass ratio of 1:7 to 1:10; The coupling agent is KH-560; The ethanol solvent includes anhydrous ethanol and deionized water, with a weight ratio of anhydrous ethanol to deionized water of 2:1 to 4:1. The drying temperature of the EPS particles is 40~50℃.

[0016] Implementing this invention has the following beneficial effects: This invention uses titanium gypsum, slag, wet-process water glass filter residue, and EPS particles to prepare a composite fluid soil consolidation material. It makes full use of solid waste, maintains the excellent fluidity and self-compacting properties of fluid soil, has a low thermal conductivity, and has high and adjustable strength, which can meet the needs of different backfilling scenarios and realize the integration of thermal insulation and backfilling functions.

[0017] (1) The wet-process water glass filter residue can react with Ca in the soil. 2+ (From the reaction of free calcium in the soil or hydration of blast furnace slag) to generate hydrated calcium silicate gel, which initially fills the gaps between soil particles, forming a preliminary cemented skeleton. At the same time, OH- produced by hydrolysis - Increasing the pH value of the reaction system disrupts the glassy structure of blast furnace slag, releasing active SiO2 and Al2O3, which hydrate to form gels such as hydrated sodium silicate and hydrated calcium aluminate, encapsulating soil particles and filling pores to form a continuous spatial network structure.

[0018] (2) The titanium gypsum, as a sulfate activator, can promote the hydration reaction of slag and react with the calcium aluminate hydrate produced by slag hydration to generate ettringite, which is interspersed between soil particles and gel, filling the micropores and improving the density.

[0019] (3) The modified recycled EPS particles have a low density, which can significantly reduce the density of fluid soil and reduce structural load. At the same time, the modified recycled EPS particles are filled with closed air pores, which can significantly reduce the thermal conductivity of fluid soil. The modified recycled EPS particles transform the hydrophobic surface of ordinary EPS particles into a hydrophilic surface, which allows the consolidation slurry to fully wet the particles, significantly enhancing the bonding force between the two. The strong interface prevents water from seeping along the edge of the EPS particles, thus improving the impermeability of the fluid soil backfill. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages clearer, the present invention will be further described in detail below with reference to specific embodiments.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0022] Unless otherwise stated or there is any contradiction, the terms or phrases used herein have the following meanings: In this document, “one or more” means any one, two or more of the listed items.

[0023] In this document, the optional range of "and / or", "or / and", and "and / or" includes any one of two or more of the related listed items, as well as any and all combinations of the related listed items, including any two related listed items, any more related listed items, or a combination of all the related listed items.

[0024] In this document, terms such as “further,” “even further,” and “especially” are used to describe the purpose and indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0025] In this document, terms such as "first aspect," "second aspect," "third aspect," and "fourth aspect" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly specifying the importance or quantity of the indicated technical features. Furthermore, "first," "second," "third," and "fourth" serve only as a non-exhaustive enumeration and should be understood as not constituting a closed limitation on quantity. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of those features. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0026] In the description of this application, "a number" means at least one, such as one, two, etc., unless otherwise expressly and specifically defined.

[0027] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0028] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0029] Unless otherwise specified, the percentage content mentioned in this application refers to mass percentage for solid-liquid mixtures and solid-phase-solid mixtures, and volume percentage for liquid-phase-liquid mixtures.

[0030] Unless otherwise specified, all percentage concentrations mentioned in this application refer to the final concentration. The final concentration refers to the proportion of the added component in the system after the addition of that component.

[0031] This invention provides a lightweight, thermally insulating, fluidized bed binder, comprising the following raw materials by weight: 10-20 parts titanium gypsum, 55-75 parts slag, 10-25 parts wet process water glass filter residue, and 1-8 parts modified recycled EPS particles.

[0032] Preferably, the lightweight thermal insulation fluidized bed binder comprises the following raw materials in parts by weight: 10-15 parts titanium gypsum, 60-70 parts slag, 15-20 parts wet process water glass filter residue, and 1-5 parts modified recycled EPS particles.

[0033] More preferably, the lightweight thermal insulation fluidized bed binder comprises the following raw materials in parts by weight: 12-15 parts titanium gypsum, 65-70 parts slag, 15-20 parts wet process water glass filter residue, and 2-5 parts modified recycled EPS particles.

[0034] This invention uses titanium gypsum, slag, wet-process water glass filter residue, and EPS particles to prepare a composite fluid soil consolidation material, making full use of solid waste, alleviating the problems of solid waste accumulation and disposal to a certain extent, and improving the utilization rate of solid waste.

[0035] The slag can be selected from blast furnace slag, a byproduct of blast furnace ironmaking. It is formed by the rapid cooling of molten slag, resulting from insufficient crystallization. It is mainly composed of silicates and aluminosilicates, exhibiting a glassy state. The alkaline environment provided by the wet-process water glass filter residue dissolves the glassy structure of the blast furnace slag, [SiO4]. 4- and [AlO4] 5- With Ca in titanium gypsum 2+ ions and Ca produced by the hydration of blast furnace slag 2+ Ionic reactions generate gels such as hydrated sodium silicate and hydrated calcium aluminate, which encapsulate soil particles and fill pores, forming a continuous spatial network structure. The amount of blast furnace slag added can be illustratively 55-75 parts, specifically 55, 58, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 72, and 75 parts, but is not limited thereto. Preferably, the amount of blast furnace slag added is 60-70 parts. In one embodiment, the slag comprises the following chemical components by mass percentage: CaO 45%~50%, SiO2 30%~35%, Al2O3 10%~16%, Fe2O3 1%~2%, MgO 1%~3%, and LOI 0.5%~1%.

[0036] In one embodiment, the slag has a particle size ≤ 75μm; a 7d activity index = 96%; a 28d activity index = 108%; and the activity index test method refers to (GB / T 18046-2017 "Granulated Blast Furnace Slag Powder for Cement, Mortar and Concrete"). Under these conditions, the blast furnace slag has high early and late reaction activity, can efficiently participate in pozzolanic reaction and hydration reaction, significantly optimize the microstructure of the cementitious system, thereby improving the early strength development and long-term mechanical properties of the composite material.

[0037] This invention uses the wet-process water glass filter residue as an activator, which can react with Ca in the soil. 2+ (From the reaction of free calcium in the soil or hydration of blast furnace slag) to generate hydrated calcium silicate gel, which initially fills the gaps between soil particles, forming a preliminary cemented skeleton. At the same time, OH- produced by hydrolysis - Increasing the pH value of the reaction system disrupts the glassy structure of blast furnace slag, releasing active SiO2 and Al2O3, which hydrate to form gels such as hydrated sodium silicate and hydrated calcium aluminate, encapsulating soil particles and filling pores to form a continuous spatial network structure.

[0038] The wet process water glass filter residue is one of the manufacturing methods for producing water glass using a wet (liquid phase) process. It involves reacting caustic soda and quartz sand under specific temperature and pressure to produce liquid sodium silicate. The resulting filter residue can be reused. Indicatively, the amount of wet process water glass filter residue added can be selected from 10 to 25 parts, specifically 10, 12, 15, 16, 17, 18, 19, 20, 21, 23, and 25 parts, but is not limited to these. Preferably, the amount of wet process water glass filter residue added is 15 to 20 parts.

[0039] In one embodiment, the wet-process water glass filter residue, by mass percentage, comprises the following chemical components: CaO 0.1%~0.5%, SiO2 65%~70%, Al2O3 5%~10%, Na2O 20%~25%, Fe2O3 0.2%~0.4%, MgO 0.1%~0.4%, and LOI 1%~3%. Under these conditions, the wet-process water glass filter residue exhibits a reasonable setting rate and can fully dissolve the glassy structure of blast furnace slag, generating products such as hydrated calcium silicate and hydrated calcium aluminate, which cement soil particles and improve soil strength.

[0040] Preferably, the mass ratio of SiO2 to Na2O is 2.8~3.2, which provides more soluble silicon, facilitating the formation of a dense structure, delaying the setting time, which is beneficial for construction operations, and resulting in high later-stage strength. The mass percentage of SiO2 / Na2O in the wet-process water glass filter residue determines its ability to provide an alkaline environment. If the mass percentage of SiO2 / Na2O is too low, it will cause flash setting of the solidified slurry, which is not conducive to construction and leads to problems such as low later-stage strength and large shrinkage of the fluidized soil. If the mass percentage of SiO2 / Na2O is too high, it will result in insufficient alkaline environment, failing to stimulate the slag to produce enough gel products, resulting in insufficient strength of the fluidized soil backfill.

[0041] In one embodiment, the particle size of the wet-process water glass filter residue is ≤100μm. Preferably, the particle size of the wet-process water glass filter residue is 50μm~75μm. The quartz sand in the wet-process water glass filter residue has a physical filling effect, which can fill the pores and improve the compaction of the fluid soil backfill.

[0042] Compared to conventional activators such as sodium hydroxide, the wet-process water glass filter residue can effectively activate blast furnace slag, but the generated product is mainly a low-calcium-silicon ratio CSH gel with a poor structure, and the reaction is too fast, easily leading to large shrinkage and cracking. This invention requires the use of titanium gypsum and modified recycled EPS particles.

[0043] The titanium gypsum, acting as a sulfate activator, promotes the hydration reaction of slag and reacts with the calcium aluminate hydrate produced during slag hydration to form ettringite, which intersperses between soil particles and gel, filling micropores and increasing density. The amount of titanium gypsum added is illustratively 10-20 parts, specifically 10, 11, 12, 13, 15, 17, 18, or 20 parts, but is not limited thereto. Preferably, the amount of titanium gypsum added is 10-15 parts.

[0044] In one embodiment, the titanium gypsum comprises the following chemical components by mass percentage: CaO 35%~40%, SiO2 1%~3%, Al2O3 1%~2%, Fe2O3 5%~10%, Na2O 0.5%~1%, TiO2 1%~5%, SO3 40%~50%, and LOI 1%~5%.

[0045] In one embodiment, the particle size of the titanium plaster is ≤ 75 μm.

[0046] The modified recycled EPS particles of this invention are obtained by atomizing and mixing EPS particles with a coupling agent solution, followed by surface coating with nano-calcium carbonate. It should be noted that the EPS particles are expanded polystyrene (EPS) particles. In some embodiments, the modified recycled EPS particles have a particle size of 1~10 mm and a bulk density of 1×10⁻⁶. -2 ~1.1×10 -2 g / cm 3 The apparent density is 1.8 × 10⁻⁶. -2 ~2×10 -2 g / cm 3 The modified recycled EPS particles have a water absorption rate ≤3.5% and a thermal conductivity ≤0.2 W / (mK). Preferably, the particle size of the modified recycled EPS particles is 3~5 mm, and the bulk density is 1×10⁻⁶. -2 ~1.1×10 -2 g / cm 3 The apparent density is 1.8 × 10⁻⁶. -2 ~2×10 -2 g / cm 3 Water absorption rate ≤3.5%, thermal conductivity ≤0.2W / (mK).

[0047] The modified recycled EPS particles have a low density, which can significantly reduce the density of fluidized soil and alleviate structural load. Simultaneously, the modified recycled EPS particles are filled with closed air pores, which can significantly reduce the thermal conductivity of the fluidized soil. Furthermore, compared to lightweight materials such as perlite and vitrified microspheres, the fragile interface after mixing with the binder slurry leads to reduced material strength, and the interface gaps become rapid channels for water and corrosive ions. The modified recycled EPS particles transform the hydrophobic surface of ordinary EPS particles into a hydrophilic surface, allowing the binder slurry to fully wet the particles, significantly enhancing the adhesion between the two. The strong interface prevents water from seeping along the edges of the EPS particles, improving the impermeability of the fluidized soil backfill.

[0048] If the EPS particles used in this invention are ordinary shockproof packaging EPS particles, although these EPS particles themselves have the characteristics of low density, lightweight structure, and good thermal insulation performance, directly mixing them with fluidized soil binder and slurry to form composite fluidized soil will lead to uneven stratification and severe segregation in the composite fluidized soil. At the same time, the binder made from the titanium gypsum, slag, and wet-process water glass filter residue is a hydrophilic material, which will result in poor bonding between the EPS particles and the inorganic matrix such as the binder and slurry. This will cause many weak interface transition zones to form inside the fluidized soil backfill. These interface transition zones are prone to interface separation and microcracks when the fluidized soil backfill is under stress, ultimately affecting the backfill's construction and mechanical properties.

[0049] In some embodiments, the modification method of the modified recycled EPS particles includes: Rinse the EPS particles with water and dry them to a constant weight; The coupling agent is mixed with ethanol solvent and stirred to allow it to fully hydrolyze, thus obtaining a coupling agent solution. After drying, EPS particles are poured into a mixer or drum. The prepared coupling agent solution is sprayed evenly onto the surface of the turning EPS particles in a mist form using a spraying device to obtain a mixture. The mixture includes EPS particles and a coupling agent layer, with the coupling agent layer coating the outer surface of the EPS particles. Nano-calcium carbonate is added to the mixture for surface coating to obtain the modified recycled EPS particles.

[0050] Preferably, the coupling agent is KH-560, but not limited thereto. The organic functional groups of the coupling agent can bind to the surface of EPS particles through van der Waals forces, while the silanol groups generated by hydrolysis are exposed to the outside, providing active sites for subsequent adhesion to nano-calcium carbonate and binder, thereby constructing an organic-inorganic transition interface on the surface of EPS particles.

[0051] Preferably, the ethanol solvent comprises anhydrous ethanol and deionized water, wherein the weight ratio of anhydrous ethanol to deionized water is 2:1 to 4:1, more preferably 3:1, but not limited thereto.

[0052] Preferably, the coupling agent and ethanol solvent are mixed at a mass ratio of 1:7 to 1:10. If the concentration of the coupling agent / ethanol-water mixed solvent is too high, it is easy to cause the coating layer to be too thick and the EPS particles to stick together and clump together; if the concentration is too low, a complete monomolecular coating layer cannot be formed on the particle surface, and the modification effect is insufficient.

[0053] Preferably, the amount of nano-calcium carbonate added is 0.45~0.55%wt of the total weight of the mixture. The addition of nano-calcium carbonate allows it to adhere to the coupling agent layer, filling the tiny voids and forming a denser surface structure. The hydroxyl groups on the surface of nano-calcium carbonate undergo a condensation reaction with the residual silanol groups in the coupling agent (forming -Si-O-Ca - bonds), further consolidating the coating layer and strengthening the interfacial bond strength between the EPS particles and the inorganic matrix. Furthermore, as an early-strength agent, nano-calcium carbonate can accelerate the hydration reaction rate of the consolidated material and improve the early strength of the fluidized soil backfill.

[0054] Preferably, the drying temperature of the EPS particles is 40~50℃, specifically 40℃, 42℃, 43℃, 45℃, 47℃, 48℃, or 50℃, but is not limited thereto.

[0055] Preferably, the nano-calcium carbonate particles have a diameter ≤80nm. More preferably, the nano-calcium carbonate particles have a diameter of 60nm~70nm.

[0056] Accordingly, the present invention provides a method for preparing lightweight thermal insulation fluidized soil consolidation material, comprising: The recycled EPS particles are pre-treated by washing and drying. Modified EPS particles are obtained by modifying EPS particles to obtain modified recycled EPS particles; By weight, 10-20 parts of titanium gypsum, 55-75 parts of blast furnace slag, 10-25 parts of wet process water glass filter residue, and 1-8 parts of modified recycled EPS particles are mixed to obtain the finished fluidized soil consolidation material.

[0057] This invention uses titanium gypsum, slag, wet-process water glass filter residue, and EPS particles to prepare a composite fluid soil consolidation material. It makes full use of solid waste, maintains the excellent fluidity and self-compacting properties of fluid soil, has a low thermal conductivity, and has high and adjustable strength, which can meet the needs of different backfilling scenarios and realize the integration of thermal insulation and backfilling functions.

[0058] In some embodiments, the modification method of the modified recycled EPS particles includes: Rinse the EPS particles with water and dry them to a constant weight; The coupling agent is mixed with ethanol solvent and stirred to allow it to fully hydrolyze, thus obtaining a coupling agent solution. After drying, EPS particles are poured into a mixer or drum. The prepared coupling agent solution is sprayed evenly onto the surface of the turning EPS particles in a mist form using a spraying device to obtain a mixture. The mixture includes EPS particles and a coupling agent layer, with the coupling agent layer coating the outer surface of the EPS particles. Nano-calcium carbonate is added to the mixture for surface coating to obtain the modified recycled EPS particles.

[0059] Preferably, the coupling agent is KH-560, but not limited thereto. The organic functional groups of the coupling agent can bind to the surface of EPS particles through van der Waals forces, while the silanol groups generated by hydrolysis are exposed to the outside, providing active sites for subsequent adhesion to nano-calcium carbonate and binder, thereby constructing an organic-inorganic transition interface on the surface of EPS particles.

[0060] Preferably, the ethanol solvent comprises anhydrous ethanol and deionized water, wherein the weight ratio of anhydrous ethanol to deionized water is 2:1 to 4:1, more preferably 3:1, but not limited thereto.

[0061] Preferably, the coupling agent and ethanol solvent are mixed at a mass ratio of 1:7 to 1:10. If the concentration of the coupling agent / ethanol-water mixed solvent is too high, it is easy to cause the coating layer to be too thick and the EPS particles to stick together and clump together; if the concentration is too low, a complete monomolecular coating layer cannot be formed on the particle surface, and the modification effect is insufficient.

[0062] Preferably, the amount of nano-calcium carbonate added is 0.45~0.55%wt of the total weight of the mixture. The addition of nano-calcium carbonate allows it to adhere to the coupling agent layer, filling the tiny voids and forming a denser surface structure. The hydroxyl groups on the surface of nano-calcium carbonate undergo a condensation reaction with the residual silanol groups in the coupling agent (forming -Si-O-Ca - bonds), further consolidating the coating layer and strengthening the interfacial bond strength between the EPS particles and the inorganic matrix. Furthermore, as an early-strength agent, nano-calcium carbonate can accelerate the hydration reaction rate of the consolidated material and improve the early strength of the fluidized soil backfill.

[0063] Preferably, the drying temperature of the EPS particles is 40~50℃, specifically 40℃, 42℃, 43℃, 45℃, 47℃, 48℃, or 50℃, but is not limited thereto.

[0064] Preferably, the nano-calcium carbonate particles have a diameter ≤80nm. More preferably, the nano-calcium carbonate particles have a diameter of 60nm~70nm.

[0065] Example 1 This embodiment provides a lightweight thermal insulation fluidized bed consolidation material, which includes the following components by weight: 14 parts titanium gypsum, 66 parts blast furnace slag, 16 parts wet process water glass filter residue, and 4 parts modified recycled EPS particles.

[0066] The chemical composition of titanium gypsum is as follows: CaO 36.58%, SiO2 1.27%, Al2O3 1.34%, Fe2O3 7.54%, Na2O 0.51%, TiO2 2.11%, SO3 48.92%, LOI 1.73%.

[0067] The chemical composition of blast furnace slag is as follows: CaO 48.19%, SiO2 34.42%, Al2O3 14.38%, Fe2O3 1.02%, MgO 1.44%, LOI 0.55%. The 7-day activity index is 0.96, and the 28-day activity index is 107.

[0068] The chemical composition of wet process water glass filter residue is as follows: CaO 0.41%, SiO2 66.61%, Al2O3 8.23%, Na2O2 3.13%, Fe2O3 0.26%, MgO 0.29%, LOI 1.07%.

[0069] The chemical composition of the wet process water glass filter residue has a SiO2 to Na2O mass ratio of 2.88.

[0070] The modified recycled EPS particles have a particle size of 3.5~4.0mm and a bulk density of 1.04×10⁻⁶. -2 g / cm 3 The apparent density is 1.86 × 10⁻⁶. -2 g / cm 3 Water absorption rate = 0.5%, thermal conductivity = 0.113 W / (mK).

[0071] Modification methods for modified recycled EPS particles include: Rinse the EPS particles with clean water and dry them thoroughly at 45°C until constant weight. KH-560 coupling agent and ethanol solvent (anhydrous ethanol: deionized water = 3:1) were mixed at a mass ratio of 1:9 and stirred to allow for complete hydrolysis, thus obtaining a coupling agent solution. After drying, the EPS particles are poured into a mixer or drum. The prepared coupling agent solution is then sprayed evenly onto the surface of the turning EPS particles in a mist form using a spraying device to obtain a mixture. 0.45% wt of nano-calcium carbonate was added to the mixture for surface coating to obtain the modified recycled EPS granules.

[0072] Example 2 This embodiment provides a lightweight, thermally insulating, fluidized bed binder, which differs from Embodiment 1 in that it comprises the following components by weight: 12 parts titanium gypsum, 68 parts blast furnace slag, 18 parts wet-process water glass filter residue, and 2 parts modified recycled EPS particles. All other components are the same as in Embodiment 1.

[0073] Example 3 This embodiment provides a lightweight, thermally insulating, fluidized bed binder, which differs from Embodiment 1 in that it comprises the following components by weight: 10 parts titanium gypsum, 55 parts blast furnace slag, 10 parts wet-process water glass filter residue, and 1 part modified recycled EPS particles. All other components are the same as in Embodiment 1.

[0074] The chemical composition of the wet-process water glass filter residue has a SiO2 to Na2O mass ratio of 3.05. All other components are the same as in Example 1.

[0075] Example 4 This embodiment provides a lightweight thermal insulation fluid soil consolidation material, which differs from Embodiment 1 in that it includes the following components by weight: 20 parts titanium gypsum, 75 parts blast furnace slag, 23 parts wet process water glass filter residue, and 8 parts modified recycled EPS particles.

[0076] The modified recycled EPS particles have a particle size of 3.0~5.0mm and a bulk density of 1.08×10⁻⁶. -2 g / cm 3 The apparent density is 1.92 × 10⁻⁶. -2 g / cm 3 Water absorption rate = 1.0%, thermal conductivity = 0.115 W / (mK).

[0077] Modification methods for modified recycled EPS particles include: Rinse the EPS particles with clean water and dry them thoroughly at 50°C until constant weight. KH-560 coupling agent and ethanol solvent (anhydrous ethanol: deionized water = 3:1) were mixed at a mass ratio of 1:8 and stirred to allow for complete hydrolysis, thus obtaining a coupling agent solution. After drying, the EPS particles are poured into a mixer or drum. The prepared coupling agent solution is then sprayed evenly onto the surface of the turning EPS particles in a mist form using a spraying device to obtain a mixture. 0.50% wt of nano-calcium carbonate was added to the mixture for surface coating to obtain the modified recycled EPS granules.

[0078] Everything else is the same as in Example 1.

[0079] Example 5 This embodiment provides a lightweight, thermally insulating, fluidized soil consolidation material, which differs from Embodiment 1 in that the chemical composition of the wet-process water glass filter residue is: CaO 0.46%, SiO268.05%, Al2O37.95%, Na2O 21.81%, Fe2O30.37%, MgO 0.35%, LOI1.01%.

[0080] The chemical composition of the wet-process water glass filter residue has a SiO2 to Na2O mass ratio of 3.12. All other components are the same as in Example 1.

[0081] Comparative Example 1 The difference between this comparative example and Example 1 is that the modified recycled EPS particles are replaced with EPS particles that have only undergone washing and drying pretreatment. Everything else is the same as in Example 1.

[0082] Comparative Example 2 The difference between this comparative example and Example 1 is that the mass ratio of SiO2 to Na2O in the chemical composition of the wet process water glass filter residue is 3.36. All other aspects are the same as in Example 1.

[0083] Comparative Example 3 In this comparative example, PO42.5 cement was used as the cementing material for the fluid soil. This cement is ordinary Portland cement.

[0084] Fluidized soils were prepared using Examples 1-3 and Comparative Examples 1-3 as cementing materials, respectively, and the specific steps are as follows: (1) Preparation of mud Soil samples were all taken from soil excavated by the tunnel boring machine. The basic performance indicators of the soil samples are shown in Table 1.

[0085] Table 1 Basic properties of soil samples

[0086] (2) Preparation of fluid soil The preparation methods for mud, fluidized soil, and fluidized soil test blocks were in accordance with T / CECS 1037-2022 "Technical Standard for Filling with Premixed Fluidized Solidified Soil" and DBJ51 / T 188-2022 "Technical Standard for Engineering Application of Premixed Fluidized Solidified Soil". The net mud density obtained from the soil excavated by the tunnel boring machine was 1400 kg / m³. 3 The amount of cementitious material added is 15% of the weight of the mud.

[0087] The wet density of the fluidized soil made with added cementitious materials was tested according to JGJ / T 70-2009 "Standard for Test Methods of Basic Performance of Building Mortar". The permeability coefficient, unconfined compressive strength and loss rate of unconfined compressive strength of the specimens after 7, 14 and 28 days of molding were tested (the test methods for permeability coefficient and unconfined compressive strength refer to JGJ / T 233-2011 "Specification for Mix Proportioning Design of Cement Soil", and the test method for wet-dry cycle refers to JTG 3430-2020 "Specification for Geotechnical Tests of Highway"). The test results are shown in Table 2.

[0088] Table 2 Test results of various test performance parameters of the test block

[0089] Further, thermal conductivity tests were conducted, and the test method referred to GB / T 10294-2008 "Determination of Steady-State Thermal Resistance and Related Properties of Thermal Insulation Materials - Protective Hot Plate Method". The thermal conductivity of the fluid soil after standard curing for 28 days and air drying for 48 hours was measured.

[0090] Table 3 Test results of thermal conductivity of the test blocks

[0091] As can be seen from the above results, the composite fluid soil consolidation material prepared by the present invention using titanium gypsum, slag, wet-process water glass filter residue and modified recycled EPS particles has high unconfined compressive strength, low permeability coefficient, low unconfined compressive strength loss rate after wet-dry cycles, and low thermal conductivity. Therefore, the present invention can make full use of solid waste and meet the basic requirements of backfill material for stability and lateral support force, while also having good thermal insulation function.

[0092] The above description is a preferred embodiment of the invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the invention, and these improvements and modifications are also considered to be within the scope of protection.

Claims

1. A lightweight, thermally insulating, fluid soil consolidation material, characterized in that, The ingredients include the following by weight: 10-20 parts titanium gypsum, 55-75 parts slag, 10-25 parts wet process water glass filter residue, and 1-8 parts modified recycled EPS particles. The modified recycled EPS particles are obtained by atomizing and mixing EPS particles with a coupling agent solution, and then coating the surface with nano-calcium carbonate.

2. The lightweight thermal insulation fluidized soil consolidation material as described in claim 1, characterized in that, The titanium gypsum comprises the following chemical components by mass percentage: CaO 35%~40%, SiO2 1%~3%, Al2O3 1%~2%, Fe2O3 5%~10%, Na2O 0.5%~1%, TiO2 1%~5%, SO3 40%~50%, and LOI 1%~5%.

3. The lightweight thermal insulation fluidized soil consolidation material as described in claim 1, characterized in that, The slag comprises the following chemical components by mass percentage: CaO 45%~50%, SiO2 30%~35%, Al2O3 10%~16%, Fe2O3 1%~2%, MgO 1%~3%, and LOI 0.5%~1%.

4. The lightweight thermal insulation fluidized soil consolidation material as described in claim 1, characterized in that, The wet process water glass filter residue comprises the following chemical components by mass percentage: CaO 0.1%~0.5%, SiO2 65%~70%, Al2O3 5%~10%, Na2O2 0%~25%, Fe2O3 0.2%~0.4%, MgO 0.1%~0.4%, and LOI 1%~3%.

5. The lightweight thermal insulation fluidized soil consolidation material as described in claim 4, characterized in that, The chemical composition of the wet process water glass filter residue has a SiO2 to Na2O mass ratio of 2.8 to 3.

2.

6. The lightweight thermal insulation fluidized soil consolidation material as described in claim 1, characterized in that, The modified recycled EPS particles have a particle size of 1~10mm and a bulk density of 1×10⁻⁶. -2 ~1.1×10 -2 g / cm 3 The apparent density is 1.8 × 10⁻⁶. -2 ~2×10 -2 g / cm 3 Water absorption rate ≤3.5%, thermal conductivity ≤0.2W / (mK).

7. The lightweight thermal insulation fluidized soil consolidation material as described in claim 1, characterized in that, The particle size of the titanium gypsum is ≤ 75μm; the particle size of the blast furnace slag is ≤ 75μm; and the particle size of the wet process water glass filter residue is ≤ 100μm.

8. A method for preparing a lightweight thermal insulation fluidized soil consolidation material as described in any one of claims 1 to 7, characterized in that, include: The recycled EPS particles are pre-treated by washing and drying. EPS particles are modified to obtain modified recycled EPS particles; By weight, 10-20 parts of titanium gypsum, 55-75 parts of blast furnace slag, 10-25 parts of wet process water glass filter residue, and 1-8 parts of modified recycled EPS particles are mixed to obtain the finished fluidized soil consolidation material.

9. The method for preparing lightweight thermal insulation fluidized soil consolidation material as described in claim 8, characterized in that, The modification method for the modified recycled EPS particles includes: Rinse the EPS particles with water and dry them to a constant weight; The coupling agent is mixed with ethanol solvent and stirred to allow it to fully hydrolyze, thus obtaining a coupling agent solution. After drying, the EPS particles are poured into a mixer or drum. The prepared coupling agent solution is then sprayed evenly onto the surface of the turning EPS particles in a mist form using a spraying device to obtain a mixture. Nano-calcium carbonate is added to the mixture for surface coating to obtain the modified recycled EPS particles.

10. The method for preparing lightweight thermal insulation fluidized soil consolidation material as described in claim 9, characterized in that, The amount of nano-calcium carbonate added is 0.45~0.55%wt of the total weight of the mixture; The coupling agent and ethanol solvent are mixed at a mass ratio of 1:7 to 1:10; The coupling agent is KH-560; The ethanol solvent includes anhydrous ethanol and deionized water, with a weight ratio of anhydrous ethanol to deionized water of 2:1 to 4:

1. The drying temperature of the EPS particles is 40~50℃.

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