Two-component powder flexible die filling material and its preparation method

Abstract

This application discloses a two-component powder flexible mold filling material and its preparation method, belonging to the technical field of two-liquid grouting materials. The two-component powder flexible mold filling material consists of a mixture A and a mixture B in equal proportions. Mixture A contains modified cementitious materials, composite mineral admixtures, and thermally modulating fillers; mixture B contains composite coagulants, modified alkaline activators, and composite thermally modulating and responsive fillers. During preparation, mixture A and mixture B are separately slurried, ultrasonically treated, and then mixed in a 1:1 ratio. Both mixture A and mixture B in this application are powder materials, chemically stable in a dry state. After mixing, the components synergistically achieve rapid solidification and low heat damage, and possess adaptive capabilities to acidic / high-salt environments. The filling material exhibits high early strength and good durability. The process is simple and controllable, suitable for scenarios such as tunnel support and slope reinforcement.

Description

Technical Field

[0001] This application belongs to the technical field of two-component grouting materials, specifically, it relates to a two-component powder flexible mold filling material and its preparation method. Background Technology

[0002] In engineering scenarios such as mine roadway support, slope reinforcement and goaf filling, flexible formwork filling technology has been widely promoted due to its advantages of flexible construction and strong adaptability. The core of this technology lies in the filling material, the performance of which directly determines the support effect, construction efficiency and cost control of the project.

[0003] Currently, commonly used flexible formwork filling materials in the industry mainly adopt single-component or liquid-powder two-component systems. However, practical applications have revealed several inherent defects, including: 1. Inconvenient storage and transportation: Liquid components are prone to freezing at low temperatures and deterioration at high temperatures, requiring stringent storage and transportation conditions; 2. Poor performance stability: The on-site liquid-solid ratio is difficult to control precisely, easily leading to fluctuations in material performance and affecting project quality; 3. Poor curing performance: Traditional materials have slow curing speeds and low early strength, failing to meet the needs of rapid support and delaying construction progress; 4. High exothermic risk: The hydration reaction of highly active, rapidly solidifying material systems releases concentrated heat, easily causing the internal temperature of the filling body to exceed 70℃, leading to problems such as thermal aging of the flexible formwork bag, temperature cracks in the filling body, and deterioration of the construction environment; 5. Weak environmental adaptability: In special geological environments such as acidic groundwater, material performance is prone to uncontrollable deterioration, affecting the long-term reliability of the support.

[0004] In summary, the component system and performance characteristics of existing flexible mold filling materials are difficult to adapt to the actual needs of complex mining engineering. There is an urgent need to develop a new type of filling material that takes into account storage stability, rapid curing, low heat damage and environmental adaptability. Summary of the Invention

[0005] The purpose of this application is to provide a two-component powder flexible mold filling material and its preparation method, which can achieve rapid solidification and high early strength of the flexible mold filling material, and at the same time, through the synergistic effect of the components, achieve precise control of reaction temperature rise and adaptability to complex environments.

[0006] To achieve the above objectives, this application provides a two-component powder flexible mold filling material, comprising equal masses of mixed material A and mixed material B. Mixed material A comprises the following components by mass percentage: 30%–60% modified cementitious material, 25%–40% composite mineral admixtures and thermally modifying fillers, 0.8%–2.5% retarder, 1.5%–6% composite fiber reinforced material, 0.8%–3% high-efficiency water-reducing agent, and 0.5%–1.5% functional additives. Mixed material B comprises the following components by mass percentage: 3%–9% composite accelerator, 28%–55% modified alkaline activator, 12%–28% sulfate, 10%–22% polymer powder, and 1.2%–4.5% special water-reducing agent, with the balance being composite thermally modulating and responsive fillers.

[0007] Furthermore, the modified cementitious material was prepared by the following method: a suspension was prepared by mixing biochar and nano-calcium titanate with water; the suspension was ultrasonically dispersed for 25-35 minutes, then dried at 100-110℃ for 1.5-2.5 hours to obtain a dry powder; the dry powder was then mixed with a cementitious material base and ball-milled until a specific surface area of ​​450 m² was obtained. 2 / kg~500m 2 / kg, to obtain the modified cementitious material.

[0008] Furthermore, the composite mineral admixture and thermal conditioning filler includes mineral admixture, a first thermal conditioning filler, and waste ceramic powder; wherein, the first thermal conditioning filler is obtained by mixing expanded perlite powder and phase change microcapsules at a mass ratio of 2~4:1, the core material of the phase change microcapsules is n-octadecane, and the phase change temperature is 35℃~40℃; the mineral admixture includes fly ash and slag powder at a mass ratio of 2:1~1.5, and the mineral admixture is mixed evenly with solid sodium silicate and biochar before use and sealed and aged for more than 45 hours.

[0009] Furthermore, the composite fiber reinforced material is composed of polyacrylonitrile fibers with a length of 6mm to 12mm, basalt fibers accounting for 20% of the total fiber mass, and steel fibers accounting for 5%.

[0010] Furthermore, the high-efficiency water-reducing agent is obtained by combining polycarboxylate water-reducing agent with sodium lignosulfonate, with sodium lignosulfonate accounting for 8% to 12% of the mass of polycarboxylate water-reducing agent; the functional additive is graphene oxide with a particle size of 1μm to 5μm.

[0011] Furthermore, the composite coagulant was prepared by the following method: tourmaline powder was microwave-activated to obtain an electron transfer catalyst; the electron transfer catalyst was mixed with a lithium salt coagulant to obtain the composite coagulant; wherein the microwave activation power was 750W~850W, the power was 2450MHz, the time was 2min~4min, and the particle size of the tourmaline powder was 5μm~20μm.

[0012] Furthermore, the modified alkaline activator includes calcium hydroxide, sodium silicate, and nano-magnesium oxide. The mass ratio of calcium hydroxide to sodium silicate is 3:1~3, and the nano-magnesium oxide accounts for 2%~4% of the total mass of calcium hydroxide and sodium silicate. The particle size of the nano-magnesium oxide is 20nm~50nm. The calcium hydroxide requires microwave pretreatment before use. The microwave pretreatment power is 750W~850W, the frequency is 2450MHz, and the time is 2min~4min.

[0013] Furthermore, the sulfates include anhydrous gypsum and alunite powder, with the alunite powder accounting for 12% to 18% of the mass of anhydrous gypsum; the polymer powders include redispersible latex powder and waterborne polyurethane powder in a mass ratio of 100:12 to 18; and the special water-reducing agent includes naphthalene-based water-reducing agent and polyether polyol in a mass ratio of 100:12 to 18.

[0014] Furthermore, the composite thermally modulating and responsive filler includes a second thermally modulating filler and dual-response microcapsules with a mass ratio of 4~12:2~5; wherein, the second thermally modulating filler includes fly ash cenospheres and hollow glass microspheres with a mass ratio of 2:1~1.5, the shell of the dual-response microcapsules is a polymethyl methacrylate-sodium alginate composite membrane, and the core material includes fluoroaluminate coagulant and nano-calcium hydroxide with a mass ratio of 1:1.

[0015] This application also provides a method for preparing a two-component powder flexible mold filling material, including the following steps: Mixed materials A and B are respectively mixed with water to form slurries; The slurry is prepared by ultrasonic treatment followed by mixing at a 1:1 mass ratio; wherein, The ultrasonic treatment power is 500W~800W, the frequency is 20kHz~40kHz, and the time is 1min~30min.

[0016] In summary, this application has the following advantages: (1) This application constructs a two-stage thermal regulation system of a first thermal regulation filler and a second thermal regulation filler. The composite ratio of expanded perlite powder and phase change microcapsules (phase change temperature 35℃~40℃) in the mixed material A can passively adsorb and actively absorb the heat of hydration through latent heat. The composite of fly ash cenospheres and hollow glass microspheres in the mixed material B can form a thermal barrier layer. The synergistic effect of the two can reduce the peak hydration temperature of the filling body and completely solve the problems of thermal aging of flexible mold bags and temperature cracks in the filling body caused by the concentrated heat release of traditional materials. At the same time, the construction environment temperature is stabilized below 35℃, which significantly improves the safety and comfort of operation.

[0017] (2) The composite thermoregulatory and responsive filler in the composite material B of this application contains dual-response microcapsules, whose polymethyl methacrylate-sodium alginate composite shell can be precisely dissolved in an acidic environment of pH < 6 or a high-salt environment of salinity > 5%, and then release the internal fluoroaluminate coagulant and nano-calcium hydroxide core material to achieve the synergistic effect of coagulation and alkalinity compensation, so that the material retains ≥ 90% of its strength in an acidic environment after 28 days, which is far superior to traditional materials; at the same time, the dense structure of the modified cementitious material and the filling effect of waste ceramic powder further improve the impermeability of the filling body, which is suitable for the long-term support needs of complex geological environments.

[0018] (3) The modified cementitious material of this application, after being modified with biochar-supported nano-calcium titanate, can promote the formation of a dense ettringite crystal skeleton; the synergistic effect of composite fiber reinforcement material and graphene oxide can significantly improve the toughness and crack resistance of the filling body through fiber bridging and micropore filling.

[0019] (4) The fly ash, slag powder, fly ash cenospheres and waste ceramic powder in this application are all industrial solid wastes, which realizes resource utilization, reduces the amount of high-quality cementitious materials used, and reduces the environmental pressure of solid waste dumping, which is in line with the concept of green mine construction. At the same time, each component is a commercially available conventional raw material, and the compound ratio does not require special customized equipment. The preparation process is simple and controllable, and the difficulty of mass production is low. It takes into account both high performance and engineering economy, and has a wide range of application prospects. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is an illustration of the two-component powder flexible mold filling material system proposed in this application. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] In a first aspect, this application provides a two-component powder flexible mold filling material, comprising equal masses of a mixture A and a mixture B. Mixture A comprises the following components by mass percentage: 30%–60% modified cementitious material, 25%–40% composite mineral admixtures and heat-regulating fillers, 0.8%–2.5% retarder, 1.5%–6% composite fiber reinforced material, 0.8%–3% high-efficiency water-reducing agent, and 0.5%–1.5% functional additives. Mixture B comprises the following components by mass percentage: 3%–9% composite accelerator, 28%–55% modified alkaline activator, 12%–28% sulfate, 10%–22% polymer powder, and 1.2%–4.5% special water-reducing agent, with the balance being a composite heat-regulating and responsive filler.

[0024] This application employs separately formulated composite material A and composite material B. When stored separately in a dry, sealed state, both are chemically stable and can be stored for extended periods. However, once mixed in a 1:1 mass ratio and exposed to water, they undergo a rapid synergistic reaction, quickly solidifying and generating high early strength. Simultaneously, by introducing specific functional components, effective control of the reaction temperature rise and environmental adaptability are achieved. Specifically, composite material A incorporates porous adsorption and phase change thermal storage materials through composite mineral admixtures and thermally modulating fillers, while composite material B incorporates composite thermally modulating and responsive fillers, forming a two-stage thermal regulation system. This system effectively buffers the exothermic peak of the gelation hydration reaction, preventing excessively high internal temperatures in the filling material (traditional materials often exceed 70°C), thereby reducing problems such as thermal aging of the flexible molding bag and temperature cracks in the filling material. It also improves the ambient temperature during construction, enhancing operational safety. Meanwhile, the composite thermal regulation and responsive filler has dual functions of pH response and salinity response. Combined with the corrosion resistance of the modified alkaline activator, the material's performance will not deteriorate uncontrollably in special geological environments such as acidic groundwater and high-salinity formation water. At the same time, the optimized proportion of composite mineral admixtures in the mixed material A can improve the density of the filling body, reduce the infiltration of environmental media, and further enhance the reliability of long-term support.

[0025] As some optional embodiments of this application, the modified cementitious material is prepared by the following method: a suspension is prepared by mixing biochar and nano-calcium titanate with water; the suspension is ultrasonically dispersed for 25-35 minutes, then dried at 100-110°C for 1.5-2.5 hours to obtain a dry powder; the dry powder is mixed with a cementitious material base and ball-milled until a specific surface area of ​​450 m² is obtained. 2 / kg~500m 2 / kg, to obtain the modified cementitious material.

[0026] In the aforementioned scheme, this application introduces nano-calcium titanate as an active seed crystal, which possesses extremely high specific surface area and surface energy. In the early stages of hydration, it can serve as a nucleation site, inducing rapid hydration of cement minerals and accelerating the crystallization and precipitation of hydration products, thereby significantly improving the early strength of the material. Biochar, with its abundant porous structure, is uniformly dispersed in the cementitious material matrix. It can adsorb some of the mixing water and physically adsorb the heat generated by the hydration reaction, thus effectively delaying the appearance of the hydration heat peak, reducing internal thermal stress, and preventing the formation of temperature cracks.

[0027] Preferably, the biochar has a particle size of 50 μm to 100 μm, the biochar mass is 2 wt% to 5 wt% of the cementitious material matrix, the nano-calcium titanate mass is 1 wt% to 3 wt% of the cementitious material matrix, and the suspension mass fraction is 15 wt% to 25 wt%, preferably 20 wt%. Preferably, the cementitious material matrix includes one or more of sulfoaluminate cement, high-alumina cement, sulfoaluminate clinker, and alumina clinker.

[0028] As some optional embodiments of this application, the composite mineral admixture and thermal conditioning filler include mineral admixture, a first thermal conditioning filler, and waste ceramic powder; wherein, the first thermal conditioning filler is obtained by mixing expanded perlite powder and phase change microcapsules at a mass ratio of 2 to 4:1, the core material of the phase change microcapsules is n-octadecane, and the phase change temperature is 35°C to 40°C; the mineral admixture includes fly ash and slag powder at a mass ratio of 2:1 to 1.5, and the mineral admixture is mixed evenly with solid sodium silicate and biochar before use and sealed and aged for more than 45 hours.

[0029] In the above scheme, the mineral admixtures are pretreated and activated before use. The solid sodium silicate, as an alkali activator, can break the stable structure of the aluminosilicate glass in fly ash and slag powder, and activate its potential cementing activity. Biochar can adsorb some of the heat generated during the alkali activation process, avoiding activity decay caused by excessive local temperature. On the other hand, its porous structure can act as a carrier for active sites, promoting secondary reactions between the aluminosilicate components and the hydration products of the cementing materials (such as calcium hydroxide) after activation, generating more hydrated calcium silicate, ettringite and other strong crystals. Sealed aging for more than 45 hours can provide sufficient time for the alkali activation reaction to ensure full activation of activity. Furthermore, the primary thermal conditioning filler and the waste ceramic powder in the composite system complement each other. The primary thermal conditioning filler is a mixture of expanded perlite powder and phase change microcapsules (core material n-octadecane, phase change temperature 35℃~40℃). The porous structure of the expanded perlite powder can physically adsorb the heat released by the gelation hydration reaction, playing a passive heat control role. When the peak temperature of the hydration exothermic reaction reaches 35℃~40℃ (which precisely matches the peak range of the gelation reaction exothermic reaction), the phase change microcapsules will undergo a phase change (solid to liquid) and absorb a large amount of latent heat, achieving active heat control. The synergy of the two can accurately buffer the peak exothermic reaction. The waste ceramic powder (high hardness and good chemical stability) serves as an inert reinforcing filler, filling the internal pores of the system, increasing the density of the filler, and simultaneously enhancing wear resistance and later strength stability.

[0030] Preferably, the mass ratio of the first heat-conditioning filler, waste ceramic powder, and mineral admixture is 5~12:3~5:17~33. Preferably, solid sodium silicate and biochar account for 2%~5% and 1%~2% of the mass of the mineral admixture, respectively. Preferably, the particle size of the waste ceramic powder is 20μm~50μm, and it is used after being soaked in 5wt% hydrochloric acid solution for 2 hours to remove impurities. Preferably, the shell material of the first heat-conditioning filler is polymethyl methacrylate (PMMA), urea-formaldehyde resin (UF), or melamine-formaldehyde resin (MF).

[0031] As some optional embodiments of this application, the retarder includes at least one of sodium citrate, tartaric acid, and boric acid, used to ensure that the single-component slurry of mixed material A can be effectively pumped during the construction time.

[0032] In a preferred embodiment of this application, the retarder can be a mixture of materials, including sodium citrate and modified chitosan in a mass ratio of 3:1. The modified chitosan is prepared by pulverizing chitosan to a particle size of less than 100 μm, adding 5% (by mass) of anhydrous ethanol, ultrasonically dispersing for 20 min, adding 2% (by mass) of KH550 silane coupling agent, stirring and reacting at 80°C for 1 h, and then drying. Modified chitosan enhances the high-temperature stability of the retarder, preventing retarding failure under high-temperature conditions, and also improves its compatibility with cementitious materials.

[0033] As some optional embodiments of this application, the composite fiber reinforced material is composed of polyacrylonitrile fibers with a length of 6 mm to 12 mm, basalt fibers (0.1 mm to 5 mm in diameter) accounting for 20% of the total fiber mass, and steel fibers (0.1 mm to 0.2 mm in diameter) accounting for 5%.

[0034] As some optional embodiments of this application, the high-efficiency water-reducing agent is obtained by compounding a polycarboxylate-based water-reducing agent with sodium lignosulfonate, wherein the sodium lignosulfonate accounts for 8% to 12% of the mass of the polycarboxylate-based water-reducing agent; the functional additive is graphene oxide with a particle size of 1μm to 5μm. Preferably, the polycarboxylate-based water-reducing agent is an ether-based polycarboxylate-based water-reducing agent (such as polyethylene glycol monomethyl ether methacrylate or isopentenyl alcohol polyoxyethylene ether), and more preferably, the industrially commonly used PCA-I and PCA-II type powder polycarboxylate-based water-reducing agents.

[0035] In the above scheme, the polycarboxylate superplasticizer, a high-efficiency water-reducing agent, efficiently disperses cementitious material particles through steric hindrance, significantly reducing the water demand of the slurry and improving its fluidity. Sodium lignosulfonate assists in dispersion through electrostatic repulsion, and its molecular chains can be adsorbed onto the particle surface, slowing down particle agglomeration. The synergy of the two ensures a high water reduction rate (suitable for long-distance pumping) and improves the dispersion stability of the slurry, avoiding stratification and sedimentation problems after mixing and slurrying of powder A. Graphene oxide with a particle size of 1μm~5μm is selected, as it has a sheet-like microstructure and high specific surface area. On the one hand, the sheet-like structure of graphene oxide can fill the micropores of hydration products in cementitious materials, forming a physical barrier layer and reducing the infiltration channels for water and harmful media (such as acidic groundwater). On the other hand, its abundant oxygen-containing functional groups can form chemical bonds with hydration products (such as ettringite and hydrated calcium silicate), enhancing interfacial bonding and improving the compactness and mechanical properties of the filling. Simultaneously, the high thermal conductivity of graphene oxide can help disperse localized hydration heat, further alleviating the problem of heat accumulation. The particle size of 1μm to 5μm is well-suited to the micropore size of the cementitious system, ensuring uniform dispersion and maximizing its filling and reinforcing effects.

[0036] As some optional embodiments of this application, the composite coagulant is prepared by the following method: tourmaline powder is microwave-activated to obtain an electron transfer catalyst; the electron transfer catalyst (accounting for 28%~32% of the lithium salt coagulant by mass) is mixed with the lithium salt coagulant to obtain the composite coagulant; wherein the microwave activation power is 750W~850W, the power is 2450MHz, the time is 2min~4min, and the particle size of the tourmaline powder is 5μm~20μm. Preferably, the lithium salt coagulant is one or more of lithium carbonate, lithium chloride, and lithium nitrate.

[0037] In the above scheme, lithium salt coagulant, as the core of chemical coagulation, can directly react with the hydration products of cementitious materials to accelerate the formation of ettringite crystals; while the activated tourmaline powder can promote the binding efficiency of lithium salt ions with the active components (aluminum phase and calcium phase) of cementitious materials through electron transfer, and at the same time accelerate the charge transfer in the hydration reaction process, further enhancing the coagulation effect.

[0038] As some optional embodiments of this application, the modified alkaline activator includes calcium hydroxide, sodium silicate, and nano-magnesium oxide, wherein the mass ratio of calcium hydroxide to sodium silicate is 3:1 to 3, and the nano-magnesium oxide accounts for 2% to 4% of the total mass of silicon hydroxide and sodium silicate, with a particle size of 20 nm to 50 nm. The calcium hydroxide needs to undergo microwave pretreatment before use, with a power of 750 W to 850 W, a frequency of 2450 MHz, and a duration of 2 min to 4 min.

[0039] In the above scheme, microwave irradiation pretreatment can quickly remove the free water and crystal water adsorbed on the surface of calcium hydroxide particles, avoiding the impact of residual moisture on the subsequent alkaline release efficiency. Simultaneously, high-frequency microwaves can cause micro-distortions in the calcium hydroxide lattice, increasing the specific surface area, exposing more active sites, and improving its dissolution rate and alkalinity, providing a stronger alkaline environment for the subsequent activation reaction. Compared to single calcium hydroxide or sodium silicate activators, the compound system of this application can not only efficiently activate the activity of cementitious materials and mineral admixtures through strong alkalinity, ensuring rapid solidification and early strength, but also regulate the alkalinity release rate through nano-magnesium oxide, avoiding violent exothermic reactions, while simultaneously improving the density and corrosion resistance of the filling.

[0040] As some optional embodiments of this application, the sulfate includes anhydrous gypsum and alunite powder, with the alunite powder accounting for 12% to 18% of the mass of the anhydrous gypsum; the polymer powder includes redispersible latex powder and waterborne polyurethane powder in a mass ratio of 100:12 to 18; the special water-reducing agent includes a naphthalene-based water-reducing agent and a polyether polyol in a mass ratio of 100:12 to 18. The alunite powder can slowly release sulfate ions, prolonging the formation cycle of ettringite crystals and avoiding increased internal porosity due to excessive early crystal growth. Using a naphthalene-based water-reducing agent combined with 12% to 18% of its mass of polyether polyol can improve the fluidity and stability of the B component slurry, avoiding stratification caused by differences in component density. Preferably, the naphthalene-based water-reducing agent can be industrially common types such as NF, FDN, UNF, and HN. The polyether polyol should preferably be a propylene oxide-ethylene oxide copolymer polyether polyol (PPG-PEG copolymer), especially suitable for low-viscosity, high-activity grades (such as copolymer polyethers with a molecular weight of 2000-4000) for mine backfilling applications. Optionally, the anhydrous gypsum in this application can be replaced with hemihydrate gypsum or dihydrate gypsum, etc., according to operational requirements.

[0041] As some optional embodiments of this application, the composite thermally modulating and responsive filler includes a second thermally modulating filler and dual-response microcapsules in a mass ratio of 4~12:2~5; wherein, the second thermally modulating filler includes fly ash cenospheres and hollow glass microspheres in a mass ratio of 2:1~1.5, the shell of the dual-response microcapsules is a polymethyl methacrylate-sodium alginate composite membrane, and the core material includes fluoroaluminate coagulant and nano-calcium hydroxide in a mass ratio of 1:1. The mass ratio of polymethyl methacrylate to sodium alginate in the composite membrane is 1:1~3:1 (preferably 2:1), which can ensure the strength of the shell structure through polymethyl methacrylate and ensure the response sensitivity through sufficient sodium alginate, avoiding response lag due to excessive polymethyl methacrylate content.

[0042] In the above scheme, the second thermal conditioning filler is a composite of fly ash cenospheres and hollow glass microspheres. Both are lightweight porous materials, and the core achieves hydration heat regulation through physical adsorption and pore buffering. The closed porous structure of the fly ash cenospheres can adsorb and store some of the hydration heat, reducing the rapid release of heat; the hollow glass microspheres, with their extremely low thermal conductivity, form a thermal barrier layer, delaying heat transfer. Simultaneously, the second thermal conditioning filler is paired with dual-response microcapsules, ensuring thermal control while reserving reasonable proportions for environmental response functions, avoiding interference between functional components. The specific environmental adaptation principle of the dual-response microcapsules is as follows: the dual-response microcapsules use polymethyl methacrylate-sodium alginate as a composite shell, and the core material is a 1:1 mixture of fluoroaluminate coagulant and nano-calcium hydroxide, achieving a pH-salinity dual-trigger response and performance compensation. The polymethyl methacrylate-sodium alginate composite shell exhibits specific environmental sensitivity. When exposed to acidic environments with a pH < 6 or high-salinity environments with a salinity > 5%, the shell structure dissolves rapidly. Subsequently, the fluoroaluminate coagulant in the core material accelerates the solidification of the cementitious material, while nano-calcium hydroxide neutralizes the acidic medium and increases local alkalinity. Both work synergistically to compensate for the performance degradation of the material under special conditions, ensuring the reliability of the support. The 1:1 core material ratio precisely balances the needs for coagulation acceleration and alkalinity regulation, ensuring stable performance after response.

[0043] The two-component powder flexible formwork filling material of this application possesses extremely high early strength and toughness, resisting the deformation pressure of the surrounding rock; it effectively controls heat damage, completely solving the problems of thermal aging and temperature cracking of flexible formwork bags; it exhibits high acid resistance in acidic environments with pH < 6, making it suitable for complex geological environments; and through a two-liquid grouting process, continuous operation can be achieved, ensuring a stable and safe construction environment temperature. Specifically: (1) In the mixed material A: the mineral admixture activates the potential cementitious activity through alkali activation pretreatment, and synergistically generates strength crystals such as ettringite and hydrated calcium silicate with the modified cementitious material; the first heat-regulating filler adsorbs the heat of hydration through its porous structure, and fills the pores of the cementitious system, thereby improving the density. The retarder can delay the early hydration rate of the modified cementitious material, ensuring the slurry pumping time, and the high-efficiency water-reducing agent reduces the water demand of the slurry, improves fluidity, and avoids the strength reduction caused by excessive water. The two work together to achieve a long flow and low water-cement ratio construction window. The composite fiber reinforcement material is uniformly dispersed in the cementitious system, and inhibits crack propagation through fiber bridging, improving the toughness and impact resistance of the filling body; the functional additive fills the micropores, further improving the density and impermeability.

[0044] (2) In the mixed material B: the modified alkaline activator provides a strongly alkaline environment, which disrupts the action mechanism of the retarder in the mixed material A, while enhancing the activity of the cementitious material; the composite accelerator accelerates the hydration reaction through electron transfer, and the two work together to achieve the effect of instant activation and rapid solidification after the mixture of A and B. Sulfate provides sufficient sulfate ions, which react rapidly with the aluminum and calcium phases in the cementitious material of component A to form an ettringite crystal skeleton, which strengthens the early strength; polymer powder (such as redispersible latex powder + waterborne polyurethane) enhances the flexibility and interfacial adhesion of the filler, avoiding cracks caused by curing shrinkage. Special water-reducing agent (1.2%~4.5%) ensures the uniformity and fluidity of the slurry of component B, and avoids the agglomeration of components such as accelerator and alkaline activator; the composite thermal regulation and responsive filler (balance) serves as a functional supplement, on the one hand buffering the heat release through porous materials, and on the other hand achieving performance compensation under special conditions through responsive microcapsules, while filling the pores of the system and improving the overall stability.

[0045] Secondly, based on a general inventive concept, this application also provides a method for preparing a two-component powder flexible mold filling material, comprising the following steps: S1. Mix material A and material B separately with water to form a slurry; S2. The slurry is treated with ultrasound and then mixed at a mass ratio of 1:1 to obtain the final product; wherein the power of the ultrasound treatment is 500W~800W, the frequency is 20kHz~40kHz, and the time is 1min~30min.

[0046] As some optional embodiments of this application, the mixed material A can be prepared by the following method: weigh the components according to the ratio, put them into a double helical conical dry powder mixer, stir at a speed of 15 rpm to 25 rpm for 5 min to 10 min, and then stir at a speed of 30 rpm to 50 rpm for 15 min to 20 min to obtain the mixed material A powder.

[0047] As some optional embodiments of this application, the mixed material B can be prepared by the following method: weigh the components according to the ratio, put them into a high-efficiency plow-type dry powder mixer, introduce inert gas for protection, stir at a speed of 15 rpm to 25 rpm for 1 min to 5 min, and then stir at a speed of 30 rpm to 50 rpm for 10 min to 15 min to obtain the mixed material B powder.

[0048] As some optional embodiments of this application, a two-component powder flexible mold filling material is prepared and used immediately, comprising the following steps: at the construction site, one bag of mixed material A powder and a predetermined amount of water (water-cement ratio 0.3~0.5) are added to a first mixer and mixed for 3 to 5 minutes to form a uniform A slurry; simultaneously, one bag of component B powder and a predetermined amount of water (water-cement ratio 0.3~0.5) are added to a second mixer and mixed for 3 to 5 minutes to form a uniform B slurry; the two slurries are kept in a constant state during the mixing process. Low-speed stirring (40r / min~50r / min) is used to prevent sedimentation. Slurry A and slurry B are respectively passed through an ultrasonic processor (power 500W~800W, frequency 20kHz~40kHz) to break up the tiny particles in the slurry by ultrasonic cavitation, thereby improving the dispersion uniformity of each component and enhancing the synergistic effect of the reaction after mixing. Slurry A and slurry B are respectively sent to two independent pumping systems of the two-component grouting pump, and the pump delivery ratio is precisely set to 1:1. The grouting pump is started to achieve synchronous and equal delivery.

[0049] The mixed material A in this application has gelling properties. When mixed with water alone, it can maintain its fluidity for more than 30 minutes under the action of a retarder, after which it will solidify slowly and normally. The mixed material B in this application, due to its component characteristics, is sensitive to moisture and requires moisture-proof packaging to isolate it from air in order to maintain its powder state and chemical activity.

[0050] The technical solutions described above in this application will be explained in detail below with reference to specific embodiments.

[0051] The modified cementitious material in the following examples was prepared by the following method: Biochar (5 wt% of the cementitious material matrix) and nano-calcium titanate (3 wt% of the cementitious material matrix) were mixed and then mixed with water to prepare a suspension (20 wt%); the suspension was ultrasonically dispersed for 30 min and then dried at 105 °C for 2 h to obtain a dry powder; the dry powder was mixed with sulfoaluminate cement and ball-milled to a specific surface area of ​​450 m². 2 / kg~500m 2 / kg, to obtain the modified cementitious material.

[0052] The composite coagulant in the following examples was prepared by the following method: tourmaline powder was microwave activated to obtain an electron transfer catalyst; the electron transfer catalyst (accounting for 30% of the lithium salt coagulant by mass) was mixed with the lithium salt coagulant to obtain the composite coagulant; wherein, the microwave activation power was 800W, the power was 2450MHz, the time was 3min, and the particle size of the tourmaline powder was 5μm~20μm.

[0053] Example 1 This embodiment provides a two-component powder flexible mold filling material, which includes a mixture of material A and material B with a mass ratio of 1:1, wherein... The mixed material group A (calculated per 100kg) includes: 50kg modified cementitious material, 40kg composite mineral admixture and heat-regulating filler, 2.5kg retarder, 6kg composite fiber reinforced material, 0.8kg high-efficiency water-reducing agent, and 0.7kg graphene oxide.

[0054] The composite mineral admixture and heat-regulating filler includes 8 kg of primary heat-regulating filler, 3 kg of waste ceramic powder, and 29 kg of mineral admixture. The primary heat-regulating filler includes 6 kg of expanded perlite powder and 2 kg of phase change microcapsules. The core material of the phase change microcapsules is n-octadecane, and the shell is PMMA. The mineral admixture includes fly ash and slag powder in a mass ratio of 2:1. Before use, the mineral admixture is mixed evenly with solid sodium silicate (5% of the mineral admixture mass) and biochar (2% of the mineral admixture mass) and then sealed and aged for 60 hours.

[0055] Among them, the composite fiber reinforced material is composed of polyacrylonitrile fiber, basalt fiber accounting for 20% of the total fiber mass, and steel fiber accounting for 5% of the total fiber mass; the high-efficiency water-reducing agent is obtained by combining PCA-II type powder polycarboxylate water-reducing agent with sodium lignosulfonate, and sodium lignosulfonate accounts for 10% of the mass of polycarboxylate water-reducing agent.

[0056] The mixed material group B includes: 9 kg of composite coagulant, 55 kg of modified alkaline activator, 12 kg of sulfate, 10 kg of polymer powder, 4 kg of special water-reducing agent, and 10 kg of composite thermal regulation and responsive filler.

[0057] The modified alkaline activator includes calcium hydroxide, sodium silicate, and nano-magnesium oxide. The mass ratio of calcium hydroxide to sodium silicate is 3:1, and nano-magnesium oxide accounts for 3% of the total mass of calcium hydroxide and sodium silicate. The particle size of nano-magnesium oxide is 20nm~50nm. Calcium hydroxide needs to undergo microwave pretreatment before use (the same applies below). The microwave pretreatment power is 800W, the frequency is 2450MHz, and the time is 3min.

[0058] The sulfates include anhydrous gypsum (10.2 kg) and alum stone powder (1.8 kg); the polymer powders include redispersible latex powder (8.5 kg) and waterborne polyurethane powder (1.5 kg); the special water-reducing agent includes naphthalene-based water-reducing agent NF and PPG-PEG copolymer polyether polyol in a mass ratio of 100:15.

[0059] The composite thermal regulation and responsive filler includes a second thermal regulation filler (8 kg) and dual-response microcapsules (2 kg). The second thermal regulation filler includes fly ash cenospheres and hollow glass microspheres in a mass ratio of 2:1. The shell of the dual-response microcapsules is a polymethyl methacrylate-sodium alginate composite membrane (the mass ratio of polymethyl methacrylate to sodium alginate is 2:1), and the core material includes fluoroaluminate coagulant and nano-calcium hydroxide in a mass ratio of 1:1.

[0060] The preparation and usage method of the two-component powder flexible mold filling material in this embodiment is as follows: (1) Weigh the components according to the proportion of mixed material A, put them into a double helix cone dry powder mixer, stir at 15 rpm for 5 min, and then stir at 30 rpm for 15 min to obtain mixed material A powder.

[0061] (2) Weigh the components according to the proportion of mixed material B, put them into a high-efficiency plow-type dry powder mixer, introduce inert gas for protection, stir at 20 rpm for 3 minutes, and then stir at 40 rpm for 10 minutes to obtain mixed material B powder.

[0062] (3) At the construction site, put one bag of mixed material A powder and a preset amount of clean water (water-cement ratio 0.38) into the first mixer and stir for 5 minutes to form a uniform A slurry; at the same time, put one bag of component B powder and an equal amount of clean water into the second mixer and stir for 5 minutes to form a uniform B slurry; process the A slurry and B slurry respectively through an ultrasonic processor (power 500W, frequency 20kHz), and keep the stirring at a low speed (50rpm) throughout the stirring process to prevent sedimentation.

[0063] (4) Slurry A and slurry B are respectively sent to the two independent pumping systems of the two-component grouting pump. The pump delivery ratio is precisely set to 1:1, and the grouting pump is started to achieve synchronous and equal delivery. Among them, slurry A and slurry B have good stability before mixing, and there is no change after standing for 30 minutes. The initial fluidity of the slurry after mixing is 260 mm.

[0064] The slurry performance test results of the two-component powder flexible mold filling material in this embodiment are as follows: initial setting within 4 minutes and final setting within 10 minutes; the peak temperature at the center of the filling body is 48℃; the compressive strength reaches 7MPa in 1 hour, 18MPa in 6 hours, and 32MPa in 28 hours. In simulated acidic water with pH=4, the initial setting time is shortened to 2 minutes, and the compressive strength retention rate is 90% after 28 days of soaking.

[0065] Example 2 This embodiment provides a two-component powder flexible mold filling material, which includes a mixture of material A and material B with a mass ratio of 1:1; wherein, The composition of mixed material group A (calculated per 100 kg) includes: 51 kg of modified cementitious material, 40 kg of composite mineral admixtures and heat-regulating fillers, 1.8 kg of retarder, 4 kg of composite fiber reinforcing material, 2 kg of high-efficiency water-reducing agent, and 1.2 kg of graphene oxide. Except for the aforementioned proportions, the components are the same as in Example 1.

[0066] The composition of component B (based on 100 kg) includes: 6 kg of composite coagulant, 43.5 kg of modified alkaline activator, 20 kg of sulfate, 16 kg of polymer powder, 2.5 kg of special water-reducing agent, and 12 kg of composite thermoregulatory and responsive filler. The sulfate comprises anhydrous gypsum (17 kg) and alum stone powder (3 kg). The polymer powder comprises redispersible latex powder (13.6 kg) and waterborne polyurethane powder (2.4 kg). The composite thermoregulatory and responsive filler comprises a second thermoregulatory filler (9 kg) and dual-response microcapsules (3 kg). Except for the aforementioned proportions, the components are identical to those in Example 1. The preparation method is also the same as in Example 1.

[0067] The water-cement ratio of the two-component powder flexible mold filling material in this embodiment is 0.42. The slurry performance test results of the two-component powder flexible mold filling material are as follows: initial setting within 6 minutes, final setting within 15 minutes, peak temperature at the center of the filling body of 52℃, compressive strength reaching 7 MPa in 1 hour, 18 MPa in 6 hours, and 40 MPa in 28 hours. After immersion in a pH 4 sulfuric acid solution for 28 days, the compressive strength retention rate is 93%.

[0068] Example 3 This embodiment provides a two-component powder flexible mold filling material, which includes a mixture of material A and material B with a mass ratio of 1:1; wherein, The composition of mixed material group A (calculated per 100 kg) includes: 54 kg of modified cementitious material, 40 kg of composite mineral admixture and heat-regulating filler, 0.8 kg of retarder, 1.5 kg of composite fiber reinforcement material, 3 kg of high-efficiency water-reducing agent, and 0.7 kg of graphene oxide. Except for the aforementioned proportions, the components are the same as in Example 1.

[0069] The composition of component B (based on 100 kg) includes: 3.5 kg of composite coagulant, 28 kg of modified alkaline activator, 28 kg of sulfate, 22 kg of polymer powder, 4.5 kg of special water-reducing agent, and 14 kg of composite thermally modulating and responsive filler. The sulfate comprises anhydrous gypsum (23.8 kg) and alum stone powder (4.2 kg); the polymer powder comprises redispersible latex powder (18.7 kg) and waterborne polyurethane powder (3.3 kg); and the composite thermally modulating and responsive filler comprises a second thermally modulating filler (12 kg) and dual-response microcapsules (2 kg). Except for the aforementioned proportions, the components are identical to those in Example 1. The preparation method is also the same as in Example 1.

[0070] The two-component powder flexible mold filling material of this embodiment has a water-cement ratio of 0.4. The performance test results are as follows: initial setting time 5 min, final setting time 20 min; compressive strength 11.8 MPa at 1 h, 27.6 MPa at 6 h, and 45 MPa at 28 h; hydration peak temperature 45℃; and 91% compressive strength retention rate after immersion in sulfuric acid solution at pH=4 for 28 days.

[0071] Comparative Example 1 The difference between this comparative example and Example 1 is that the first thermal conditioning filler in mixture A is replaced with an equal amount of fly ash, and the second thermal conditioning filler in mixture B is replaced with an equal amount of calcium oxide. Performance test results: initial setting time 3 min, final setting time 26 min; 1-hour compressive strength 7.2 MPa, 6-hour compressive strength 18.5 MPa, 28-hour compressive strength 32 MPa; hydration peak temperature 68℃; 92% compressive strength retention rate after 28 days of immersion in pH=4 sulfuric acid solution.

[0072] Comparative Example 2 The difference between this comparative example and Example 1 is that the dual-response microcapsules in mixture B are replaced with an equal amount of redispersible latex powder. Performance test results: initial setting time 3 min, final setting time 27 min; 1-hour compressive strength 6.3 MPa, 6-hour compressive strength 21.8 MPa, 28-hour compressive strength 39 MPa; hydration peak temperature 46℃; compressive strength retention rate after 28 days of immersion in pH=4 sulfuric acid solution 62%.

[0073] Comparative Example 3 The difference between this comparative example and Example 1 is that the modified cementitious material in mixture A is replaced with unmodified high-alumina cement. Performance test results: initial setting time 10 min, final setting time 65 min; 1-hour compressive strength 4.1 MPa, 6-hour compressive strength 10.3 MPa, 28-hour compressive strength 28 MPa; hydration peak temperature 48℃; 80% compressive strength retention rate after 28 days of immersion in pH=4 sulfuric acid solution.

[0074] Based on the above embodiments and comparative examples, it can be seen that Comparative Example 1, lacking the composite thermal regulation system (i.e., the first and second thermal regulation fillers), experienced a surge in its hydration peak temperature, demonstrating that the composite thermal regulation system of this application can effectively buffer exothermic reactions and mitigate the risk of high exothermic activity. Simultaneously, its strength decreased slightly, indicating that it plays an auxiliary role in strength formation. Comparative Example 2, lacking pH-salinity dual-response microcapsules, experienced a decrease in its acid resistance strength retention rate, demonstrating that this component can improve the material's adaptability to acidic environments, thereby achieving environmental self-adaptation. Comparative Example 3, without modified cementitious materials, exhibited a prolonged initial setting time and a corresponding decrease in compressive strength, indicating that modifying the cementitious materials can significantly improve curing speed and early strength, ensuring the requirements for rapid support.

[0075] In summary, the strongly alkaline environment, heat of reaction, and sulfate ions provided by the composite material B in this application instantly disrupt the slow-setting equilibrium of composite material A, rapidly stimulating the activity of the modified cementitious material of composite material A. This promotes the rapid formation and interweaving of ettringite crystals into a skeleton, achieving rapid curing with initial setting in 3-10 minutes and final setting in 1 hour. Furthermore, it exhibits excellent early strength after 3-6 hours. Simultaneously, the first thermally regulating filler of composite material A and the second thermally regulating filler of composite material B work synergistically to form a two-stage temperature control, effectively reducing the peak hydration temperature. The composite fiber reinforcement of composite material A enhances interfacial toughness, while the ettringite skeleton ensures strength. The combination of these three elements enables the material to achieve a compressive strength of 5-12 MPa after 1 hour and 15-28 MPa after 6 hours, while also exhibiting excellent crack resistance. Moreover, the internal addition of thermally regulating filler reduces the core peak temperature of the filling body by 15-30°C, significantly reducing heat damage and preventing aging and temperature cracking of the flexible mold bag.

[0076] The responsive filler in composite material B of this application, combined with the dense system of composite material A, can improve the corrosion resistance of the material in complex geological environments and ensure long-term support effectiveness. Simultaneously, the equal-mass mixing of components A and B, along with the regulating effect of the water-reducing agent in each component, allows the mixed grout to solidify rapidly while maintaining temporary uniformity during grouting, preventing pipe blockage. Furthermore, the all-powder system simplifies the construction process and improves operational efficiency by requiring only the simultaneous preparation and proportional pumping of grouts A and B on-site.

[0077] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. Although preferred embodiments of the present application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are interpreted only to include the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0078] Finally, it should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes the element.

[0079] This application uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A two-component powder flexible die filling material, characterized by, The mixed material A and the mixed material B are included in equal mass, wherein the mixed material A includes the following mass percentages of components: modified cementitious material 30%~60%, composite mineral admixture and thermal regulation filler 25%~40%, retarder 0.8%~2.5%, composite fiber reinforced material 1.5%~6%, high efficiency water reducing agent 0.8%~3%, and functional additive 0.5%~1.5%; The mixed material B includes the following mass percentages of components: composite accelerator 3%~9%, modified alkaline activator 28%~55%, sulfate 12%~28%, polymer powder 10%~22%, and special water reducing agent 1.2%~4.5%, and the rest is composite thermal regulation and response filler.

2. The two-component powder plastic foam filling material according to claim 1, characterized by The modified cementitious material is prepared by the following method: The biochar and nano calcium titanate are mixed and then mixed with water to prepare a suspension; After ultrasonic dispersion of the suspension for 25min~35min, drying is performed at 100℃~110℃ for 1.5h~2.5h to obtain a dry powder; mixing the dry powder with a cementitious binder in a ball mill to a specific surface area of 450 m 2 / kg ~ 500 m 2 / kg, obtaining the modified cementitious material.

3. The two-component powder plastic foam filling material according to claim 1, wherein The composite mineral admixture and thermal regulation filler include mineral admixture, first thermal regulation filler, and waste ceramic powder; wherein, The first thermal regulation filler is obtained by mixing expanded perlite powder and phase change microcapsules in a mass ratio of 2~4:1, and the core material of the phase change microcapsules is n-octadecane with a phase change temperature of 35℃~40℃; The mineral admixture includes fly ash and slag powder in a mass ratio of 2:1~1.

5.

4. The two-component powder plastic foam filling material according to claim 1, wherein The composite fiber reinforced material is obtained by mixing polyacrylonitrile fibers with a length of 6mm~12mm, 20% basalt fibers, and 5% steel fibers.

5. The two-part powder plasticating charge material of claim 1, wherein, The high efficiency water reducing agent is obtained by compounding polycarboxylic acid water reducing agent and sodium lignosulfonate, and the sodium lignosulfonate accounts for 8%~12% of the mass of the polycarboxylic acid water reducing agent. The functional additive is graphene oxide with a particle size of 1μm~5μm.

6. The two-part powder plasticating charge material of claim 1, wherein, The composite accelerator is prepared by the following method: The tourmaline powder is subjected to microwave activation treatment to obtain an electron transfer catalyst; The electron transfer catalyst is mixed with a lithium salt accelerator to obtain the composite accelerator; The microwave activation treatment has a power of 750W~850W, a power of 2450MHz, and a time of 2min~4min, and the tourmaline powder has a particle size of 5μm~20μm.

7. The two-part powder plasticating charge material of claim 1, wherein, The modified alkaline activator includes calcium hydroxide, sodium silicate, and nano magnesium oxide, wherein the mass ratio of the calcium hydroxide to the sodium silicate is 3:1~3, the nano magnesium oxide accounts for 2%~4% of the total mass of the calcium hydroxide and the sodium silicate, and the nano magnesium oxide has a particle size of 20nm~50nm.

8. The two-component powder plastic foam filling material according to claim 1, wherein The sulfate includes anhydrous gypsum and alunite powder, and the mass of the alunite powder is 12%~18% of the mass of the anhydrous gypsum; The polymer powder includes redispersible latex powder and waterborne polyurethane powder in a mass ratio of 100:12~18; The special water reducing agent includes naphthalene series water reducing agent and polyether polyol in a mass ratio of 100:12~18.

9. The two-part powder plasticating charge material of claim 1, wherein, The composite thermally modulating and responsive filler includes a second thermally modulating filler and dual-response microcapsules in a mass ratio of 4~12:2~5; wherein, the second thermally modulating filler includes fly ash cenospheres and hollow glass microspheres in a mass ratio of 2:1~1.5, and the shell of the dual-response microcapsules is a polymethyl methacrylate-sodium alginate composite membrane, and the core material includes fluoroaluminate coagulant and nano-calcium hydroxide in a mass ratio of 1:

1.

10. A method of producing a two-component powder plasticized compacting material according to any one of claims 1 to 9, characterized in that, Includes the following steps: Mixed materials A and B are respectively mixed with water to form slurries; The slurry is prepared by ultrasonic treatment and then mixed at a 1:1 mass ratio; wherein, The ultrasonic treatment has a power of 500W~800W and a frequency of 20kHz~40kHz.

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