Preparation process and filling method of double-expansion-source double-layer micro-expansion self-closing top sealing material
By designing a dual-expansion-source, dual-layer micro-expansion self-sealing top material, and utilizing a combination of phase change and chemical foaming expansion layers, the problems of long construction cycle and poor sealing performance of mine sealing wall materials are solved, achieving a high-efficiency and low-cost sealing effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA UNIV OF MINING & TECH
- Filing Date
- 2025-09-30
- Publication Date
- 2026-06-23
AI Technical Summary
Existing mine sealing wall materials suffer from problems such as long construction cycles, easy collapse, and insufficient self-forming capacity. Furthermore, traditional expansion agents are costly, prone to delamination and air bubble escape, resulting in poor sealing performance.
The material employs a dual-expansion-source, dual-layer micro-expansion self-sealing material, including a phase change expansion layer and a chemical foaming expansion layer. Through the combination of slag powder, gypsum, tailings, red mud, and phase change/chemical foaming expansion agent, it achieves rapid and continuous expansion, strong bonding force, and reduced costs.
It achieves improvements in compressive strength, micro-expansion, and self-coating capability, while reducing material costs and enhancing sealing performance and construction efficiency.
Smart Images
Figure CN121135339B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of mining filling materials, and more specifically relates to the preparation process and filling method of a dual-expansion-source, dual-layer micro-expansion self-sealing material. Background Technology
[0002] Mining sealing wall materials are primarily used to rapidly construct sealed barriers underground that effectively isolate airflow, gas, and water. Expansive concrete is a commonly used material for mining sealing walls. Expansive concrete refers to a mixture with an expansive agent, possessing expansion characteristics that increase the compressive strength of concrete, improve the stress conditions of concrete structures, and reduce the probability of cracking. The prestress of expansive concrete is directly proportional to its restricted expansion rate; therefore, the prestress can be controlled by adjusting the expansive agent, thereby improving the mechanical properties of the expansive concrete.
[0003] Currently, the expansion mechanisms of expansive concrete mainly include chemical expansion and physical expansion. Commonly used expansive agents include alumina powder, aluminum powder, and kaolin. Chemical expansion involves adding chemical expansive agents, such as alumina powder or kaolin, to cause a portion of the slag powder to expand and generate air bubbles, thereby enhancing the volume stability of the concrete. Physical expansion involves adding granular or fibrous materials with a certain degree of water absorption, such as slag, expanded clay, or lava, to cause the concrete to expand in volume. However, chemical expansion agents are more expensive, and problems such as segregation and air bubble escape are prone to occur during concrete mixing and pouring. Physical expansion, due to the looser texture of the granular or fibrous materials, can easily affect the compactness and strength of the concrete. This leads to problems with traditional sealed walls, such as long construction periods, susceptibility to water collapse, and insufficient self-supporting capacity resulting in poor sealing performance.
[0004] Therefore, how to provide a micro-expansion mine filling material with reasonable proportions, simple operation, simple process, and high economic benefits is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention
[0005] The purpose of this invention is to provide a preparation process and filling method for a dual-expansion-source, dual-layer, micro-expansion, self-topping sealing material, in order to solve the problems existing in the prior art and achieve the effect of greatly reducing costs while taking into account compressive strength, micro-expansion, self-topping, and low density.
[0006] To achieve the above objectives, the present invention provides the following solution:
[0007] One of the technical solutions of this invention is to provide a dual-expansion-source, dual-layer, micro-expansion self-sealing material, comprising a phase change expansion layer disposed in the lower layer and a chemical foaming expansion layer disposed in the upper layer.
[0008] The raw materials for the phase change expansion layer include: slag powder, gypsum, tailings, red mud, phase change expansion agent, and water; the mass ratio of slag powder, gypsum, tailings, and red mud is 40:25:10:25; the amount of phase change expansion agent added is 2-12% of the mass of slag powder.
[0009] The raw materials for the chemically foamed expansion layer include: slag powder, chemical foaming expansion agent, stabilizer and water; the mass ratio of slag powder to chemical foaming expansion agent is 50:1 to 4.
[0010] Furthermore, the slag powder is selected from S105 slag powder or S90 slag powder. Slag powder has the characteristic of rapid hardening, can quickly undergo hydration reaction, reduce solidification time, and shorten the project cycle.
[0011] This invention selects slag powder, gypsum, tailings, and red mud as the dry materials for the phase change expansion layer. Specifically, the CaO and Al2O3 in the slag powder react with water to generate Ca... 12 Al 14 O 33 Then it reacts with the main component of gypsum, CaSO4·2H2O, to produce Ca6Al2(SO4)3(OH). 12 The product, ·26H2O, also exhibits micro-expansion properties. The addition of red mud and tailings can significantly reduce costs. Furthermore, tailings contain numerous fine particles that can fill the gaps between material particles, making the material structure more compact and thus improving its density and impermeability. The inherent strong alkalinity of red mud (rich in NaOH and Na2CO3) can act as a natural alkaline activator to activate materials such as slag powder.
[0012] Preferably, the phase change expanding agent includes AEA expanding agent. AEA expanding agent has good expanding effect, is environmentally friendly, and has high economic benefits. The expansion rate of AEA expanding agent is moderate, which can avoid cracking problems caused by expansion.
[0013] Preferably, the chemical foaming expander is prepared from sodium bicarbonate and fly ash. The specific steps include: mixing sodium bicarbonate and fly ash at a mass ratio of 5:15 to obtain the chemical foaming expander. In the chemical foaming expander of this invention, sodium bicarbonate can be uniformly coated by fly ash. This invention employs a step-by-step mechanical mixing method. The core idea is to allow fly ash as the "coating phase" to first occupy the mixing space, then add sodium bicarbonate as the "coated phase," and utilize the combined effects of shearing and diffusion mixing to achieve the goal of "sodium bicarbonate being uniformly coated by fly ash." The chemical foaming expander mainly generates gas through sodium bicarbonate; the hydration reaction releases heat, promoting gas generation. The generated gas is coated by the slurry and cannot escape, forming bubbles, thereby achieving volume expansion. Testing showed that under the conditions of a mass ratio of slag powder to chemical foaming expander of 50:1, a temperature of 20℃, and a water-to-solid ratio of 0.6, the foaming duration of the chemical foaming expander layer can reach more than 40 minutes, increasing the slurry volume by more than 20%.
[0014] Preferably, the stabilizer includes one or more of FM500G, sodium stearate, and triethanolamine. Adding a stabilizer ensures that the expansion time is substantially consistent with the slurry setting time, reducing waste caused by slurry runoff.
[0015] Preferably, the amount of stabilizer added is 1% of the mass of the chemical foaming agent.
[0016] Preferably, the water-to-solid ratio of the phase change expansion layer is 0.25 to 0.65.
[0017] Preferably, the water-to-solid ratio of the chemically foamed expansion layer is 0.6 to 0.8.
[0018] The second technical solution of the present invention provides a method for filling the above-mentioned dual-expansion-source, dual-layer micro-expansion self-sealing material, comprising the following steps:
[0019] Slag powder, gypsum, tailings, red mud, phase change expansion agent and water are mixed evenly to obtain phase change expansion layer slurry;
[0020] Slag powder, chemical foaming expander, stabilizer and water are mixed evenly to obtain chemical foaming expander slurry.
[0021] First, fill the area to be filled with the phase change expansion layer slurry, and then fill it with the chemical foam expansion layer slurry.
[0022] Preferably, the chemically foamed expansion layer slurry is filled while the lower phase change expansion layer slurry is in a slurry state. When the lower material is in a slurry state, the upper material is rich in sodium and carbonate ions, which diffuse downwards within the slurry, while the lower slurry is rich in sulfate ions, which diffuse upwards. This forms the thickest transition layer in the contact area, exhibiting the strongest interlayer bonding and the best impact resistance.
[0023] Preferably, the volume ratio of the phase change expansion layer slurry to the chemical foaming expansion layer slurry is 1:5 to 2:4.
[0024] The dual-expansion source, dual-layer micro-expansion self-sealing material of this invention features a dual-layer expansion system: the lower layer expands through phase change, while the upper layer promotes expansion through chemical foaming. After casting, the upper layer rapidly undergoes chemical foaming, exhibiting a high expansion rate and extent, enabling rapid initial sealing. Subsequently, driven by the continuous hydration phase change expansion of the lower layer, the overall structure further expands upwards, thereby enhancing the sealing effect and ultimately achieving optimal sealing performance.
[0025] The present invention discloses the following technical effects:
[0026] The dual-expansion-source, dual-layer micro-expansion self-sealing material of this invention achieves a self-sealing effect through dual expansion sources, and its durability, sealing, strength and other properties are all improved. Attached Figure Description
[0027] Figure 1 The thickness and morphology of the interlayer transition region of the material in Example 1 are shown in (a), (b), and (c), and the thickness and morphology of the interlayer transition region of the material in Example 2 are shown in (d), (e), and (f).
[0028] Figure 2 The impact resistance simulation results of the materials in Examples 1 and 2 are shown, where (a), (c), and (e) are the X, Y, and Z directions of Example 1, respectively, and (b), (d), and (f) are the X, Y, and Z directions of Example 2, respectively.
[0029] Figure 3 The dry density of the upper layer material in Examples 1-6;
[0030] Figure 4 The compressive strength of the upper layer material in Examples 1-6;
[0031] Figure 5 The pore distribution of the material in Example 1 is shown in the CT three-dimensional reconstruction.
[0032] Figure 6 The results are the fitting results of the pore size distribution of the material in Example 1. Detailed Implementation
[0033] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.
[0034] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.
[0035] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.
[0036] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.
[0037] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.
[0038] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.
[0039] The main components of the slag powder, gypsum, tailings, and red mud used in the following embodiments and comparative examples of the present invention are as follows:
[0040] Slag powder:
[0041] Particle size: Specific surface area ≥ 420 m² 2 / kg (approximately corresponding to d50≤20μm).
[0042] Chemical composition (wt%): CaO: 35-45%, SiO2: 30-35%, Al2O3: 10-15%, MgO: 5-10%, others: ≤5%.
[0043] plaster:
[0044] Particle size: d50≤50μm, maximum particle size≤200μm.
[0045] Chemical composition (wt%): CaSO4·2H2O: ≥85%, SiO2: ≤5%, Al2O3: ≤2%, Fe2O3: ≤1%, water of crystallization: 17-19%.
[0046] Tailings:
[0047] Particle size: fineness modulus 1.8–2.2, d50 between 100 and 150 μm.
[0048] Chemical composition (wt%): SiO2: ≥70%, Al2O3: 5~10%, K2O+Na2O: 2~5%, Fe2O3: 3~8%, others: ≤10%.
[0049] Red mud:
[0050] Particle size: d50≤75μm, irregular particle shape.
[0051] Chemical composition (wt%): Fe2O3: 25-40%, Al2O3: 15-20%, SiO2: 10-20%, CaO: 5-15%, Na2O: 4-10%, TiO2: 3-8%, Loss on ignition (LOI): 8-12%.
[0052] The specific steps for using the chemical foaming expander (CEA) are as follows: Sodium bicarbonate and fly ash are mixed evenly at a mass ratio of 5:15 to obtain the chemical foaming expander.
[0053] Unless otherwise specified, all other raw materials used are commercially available products, and the source of these commercially available products does not affect the technical effect of this invention.
[0054] Unless otherwise specified, the room temperature involved in this invention is 25±5℃.
[0055] Example 1
[0056] This embodiment provides a dual-expansion-source, dual-layer, micro-expansion self-topping sealing material:
[0057] (1) At room temperature, mix the dry materials of the lower expansion material evenly. The dry materials are slag powder, gypsum, tailings, red mud, and phase change AEA expansion agent. The mass ratio of slag powder, gypsum, tailings, and red mud is 40:25:10:25. The amount of phase change AEA expansion agent added is 4% of the mass of slag powder.
[0058] (2) Mix the dry materials of the upper expansion layer evenly, and add FM500G as a stabilizer. The dry materials are slag powder and chemical foaming expansion agent. The mass ratio of slag powder to chemical foaming expansion agent is 50:1. The amount of stabilizer added is 1% of the mass of chemical foaming expansion agent.
[0059] (3) The upper and lower expansion materials are stirred into a uniform slurry according to the set water-solid ratio. The water-solid ratio of the lower slurry is 0.45 and the water-solid ratio of the upper slurry is 0.6.
[0060] (4) A continuous casting device is used to inject the upper and lower slurries into the flexible membrane bag for casting. The lower slurry is cast first, and the upper slurry is injected and bonded to it while the lower slurry is in a slurry state. The filling volume ratio of the phase change expansion layer slurry and the chemical foam expansion layer slurry is 1:5.
[0061] Example 2
[0062] This embodiment provides a dual-expansion-source, dual-layer, micro-expansion self-topping sealing material:
[0063] (1) At room temperature, mix the dry materials of the lower expansion material evenly. The dry materials are slag powder, gypsum, tailings, red mud, and phase change AEA expansion agent. The mass ratio of slag powder, gypsum, tailings, and red mud is 40:25:10:25. The amount of phase change AEA expansion agent added is 2% of the mass of slag powder.
[0064] (2) Mix the dry materials of the upper expansion layer evenly, and add FM500G as a stabilizer. The dry materials are slag powder and chemical foaming expansion agent. The mass ratio of slag powder to chemical foaming expansion agent is 50:1. The amount of stabilizer added is 1% of the mass of chemical foaming expansion agent.
[0065] (3) The upper and lower expansion materials are stirred into a uniform slurry according to the set water-solid ratio. The water-solid ratio of the lower slurry is 0.45 and the water-solid ratio of the upper slurry is 0.6.
[0066] (4) A continuous casting device is used to inject the upper and lower slurries into the flexible membrane bag for casting. The lower slurry is cast first, and the upper slurry is injected and bonded to it while the lower slurry is in a slurry state. The filling volume ratio of the phase change expansion layer slurry and the chemical foaming expansion layer slurry is 1:5.
[0067] Example 3
[0068] This embodiment provides a dual-expansion-source, dual-layer, micro-expansion self-topping sealing material:
[0069] (1) At room temperature, mix the dry materials of the lower expansion material evenly. The dry materials are slag powder, gypsum, tailings, red mud, and phase change AEA expansion agent. The mass ratio of slag powder, gypsum, tailings, and red mud is 40:25:10:25. The amount of phase change AEA expansion agent added is 8% of the mass of slag powder.
[0070] (2) Mix the dry materials of the upper expansion layer evenly, and add FM500G as a stabilizer. The dry materials are slag powder and chemical foaming expansion agent. The mass ratio of slag powder to chemical foaming expansion agent is 50:1. The amount of stabilizer added is 1% of the mass of chemical foaming expansion agent.
[0071] (3) The upper and lower expansion materials are stirred into a uniform slurry according to the set water-solid ratio. The water-solid ratio of the lower slurry is 0.45 and the water-solid ratio of the upper slurry is 0.6.
[0072] (4) A continuous casting device is used to inject the upper and lower slurries into the flexible membrane bag for casting. The lower slurry is cast first, and the upper slurry is injected and bonded to it while the lower slurry is in a slurry state. The filling volume ratio of the phase change expansion layer slurry and the chemical foaming expansion layer slurry is 1:5.
[0073] Example 4
[0074] This embodiment provides a dual-expansion-source, dual-layer, micro-expansion self-topping sealing material:
[0075] (1) At room temperature, mix the dry materials of the lower expansion material evenly. The dry materials are slag powder, gypsum, tailings, red mud, and phase change AEA expansion agent. The mass ratio of slag powder, gypsum, tailings, and red mud is 40:25:10:25. The amount of phase change AEA expansion agent added is 4% of the mass of slag powder.
[0076] (2) Mix the dry materials of the upper expansion layer evenly, and add FM500G as a stabilizer. The dry materials are slag powder and chemical foaming expansion agent. The mass ratio of slag powder to chemical foaming expansion agent is 50:1. The amount of stabilizer added is 1% of the mass of chemical foaming expansion agent.
[0077] (3) The upper and lower expansion materials are stirred into a uniform slurry according to the set water-solid ratio. The water-solid ratio of the lower slurry is 0.45 and the water-solid ratio of the upper slurry is 0.8.
[0078] (4) A continuous casting device is used to inject the upper and lower slurries into the flexible membrane bag for casting. The lower slurry is cast first, and the upper slurry is injected and bonded to it while the lower slurry is in a slurry state. The filling volume ratio of the phase change expansion layer slurry and the chemical foaming expansion layer slurry is 1:5.
[0079] Example 5
[0080] This embodiment provides a dual-expansion-source, dual-layer, micro-expansion self-topping sealing material:
[0081] (1) At room temperature, mix the dry materials of the lower expansion material evenly. The dry materials are slag powder, gypsum, tailings, red mud, and phase change AEA expansion agent. The mass ratio of slag powder, gypsum, tailings, and red mud is 40:25:10:25. The amount of phase change AEA expansion agent added is 2% of the mass of slag powder.
[0082] (2) Mix the dry materials of the upper expansion layer evenly, and add FM500G as a stabilizer. The dry materials are slag powder and chemical foaming expansion agent. The mass ratio of slag powder to chemical foaming expansion agent is 50:1. The amount of stabilizer added is 1% of the mass of chemical foaming expansion agent.
[0083] (3) The upper and lower expansion materials are stirred into a uniform slurry according to the set water-solid ratio. The water-solid ratio of the lower slurry is 0.45 and the water-solid ratio of the upper slurry is 0.8.
[0084] (4) A continuous casting device is used to inject the upper and lower slurries into the flexible membrane bag for casting. The lower slurry is cast first, and the upper slurry is injected and bonded to it while the lower slurry is in a slurry state. The filling volume ratio of the phase change expansion layer slurry and the chemical foaming expansion layer slurry is 1:5.
[0085] Example 6
[0086] This embodiment provides a dual-expansion-source, dual-layer, micro-expansion self-topping sealing material:
[0087] (1) At room temperature, mix the dry materials of the lower expansion material evenly. The dry materials are slag powder, gypsum, tailings, red mud, and phase change AEA expansion agent. The mass ratio of slag powder, gypsum, tailings, and red mud is 40:25:10:25. The amount of phase change AEA expansion agent added is 8% of the mass of slag powder.
[0088] (2) Mix the dry materials of the upper expansion layer evenly, and add FM500G as a stabilizer. The dry materials are slag powder and chemical foaming expansion agent. The mass ratio of slag powder to chemical foaming expansion agent is 50:1. The amount of stabilizer added is 1% of the mass of chemical foaming expansion agent.
[0089] (3) The upper and lower expansion materials are stirred into a uniform slurry according to the set water-solid ratio. The water-solid ratio of the lower slurry is 0.45 and the water-solid ratio of the upper slurry is 0.8.
[0090] (4) A continuous casting device is used to inject the upper and lower slurries into the flexible membrane bag for casting. The lower slurry is cast first, and the upper slurry is injected and bonded to it while the lower slurry is in a slurry state. The filling volume ratio of the phase change expansion layer slurry and the chemical foaming expansion layer slurry is 1:5.
[0091] Comparative Example 1
[0092] Similar to Example 1, except that the upper slurry is injected and combined with the lower slurry when the lower slurry initially sets.
[0093] Figure 1 The thickness and morphology of the interlayer transition region of the material in Example 1 are shown in (a), (b), and (c), and the thickness and morphology of the interlayer transition region of the material in Comparative Example 1 are shown in (d), (e), and (f). Figure 1 As shown, CT tests were performed on the materials of Example 1 and Comparative Example 1, and it was found that Example 1 formed a clear transition zone in the contact area of the upper and lower double-layer expansion materials.
[0094] Figure 2 The impact resistance simulation results for the materials in Example 1 and Comparative Example 1 are shown, where (a), (c), and (e) represent the X, Y, and Z directions of Example 1, respectively, and (b), (d), and (f) represent the X, Y, and Z directions of Comparative Example 1, respectively. The simulations were performed using FLAC. 3d Mechanical impact simulation of the sealed wall revealed that the sealed wall of Example 1 was far superior to that of Comparative Example 1 in terms of impact resistance, verifying that it is best to pour the lower layer material in a slurry state to achieve the best interlayer bonding effect.
[0095] Figure 3 The dry density of the upper layer material in Examples 1-6.
[0096] Figure 4 The compressive strength of the upper layer material in Examples 1-6.
[0097] Figure 5 The pore distribution of the material in Example 1 is shown in the CT three-dimensional reconstruction.
[0098] Figure 6 The results are the fitting results of the pore size distribution of the material in Example 1.
[0099] The slurry expansion rate, initial setting time, and continuous expansion time of the prepared dual-expansion-source, double-layer micro-expansion self-closing sealing material were tested.
[0100] Test method: The slurry expansion rate was calculated using the volume ratio method. The mixed slurry was poured into a graduated mold, and the slurry volume was recorded every 20 minutes. The expansion rate was then calculated using the ratio method: Expansion rate = (Expanded slurry volume - Initial slurry volume) / Initial slurry volume × 100%. The continuous expansion time of the slurry was determined by observing two consecutive instances where the slurry volume did not change during the expansion rate calculation; the previous time was recorded as the continuous expansion time of the slurry.
[0101] The initial setting time of the slurry was determined using a modified tilting method. The slurry was injected into a φ100mm×150mm cylindrical mold, and the mold was disturbed at a 45° tilting angle every 60 seconds. The changes in the surface morphology of the slurry were observed. When the mold was tilted to the set angle (45°), the slurry interface remained vertical and intact without any signs of flow, indicating that the initial setting state had been reached. The cumulative time was recorded as the initial setting time.
[0102] Test results:
[0103] Table 1 Slurry Expansion Rate
[0104]
[0105] The test results in Table 1 show that all embodiments exhibit good expansion effects, effectively meeting the self-sealing requirements. Furthermore, the expansion rates of both the upper and lower expansion materials in each embodiment reach high levels, indicating excellent sealing performance.
[0106] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.
[0107] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A dual-expansion-source, dual-layer, micro-expansion self-sealing material, characterized in that, It includes a phase change expansion layer in the lower layer and a chemical foaming expansion layer in the upper layer: The raw materials for the phase change expansion layer include: slag powder, gypsum, tailings, red mud, phase change expansion agent, and water; the mass ratio of slag powder, gypsum, tailings, and red mud is 40:25:10:25; the amount of phase change expansion agent added is 2-12% of the mass of slag powder. The raw materials for the chemically foamed expansion layer include: slag powder, chemical foaming expansion agent, stabilizer, and water; the mass ratio of slag powder to chemical foaming expansion agent is 50:1~4. The phase change expanding agent includes AEA expanding agent; the chemical foaming expanding agent is prepared from sodium bicarbonate and fly ash.
2. The dual-expansion-source, dual-layer micro-expansion self-sealing material according to claim 1, characterized in that, The chemical foaming expander is prepared from sodium bicarbonate and fly ash. The specific steps include: mixing sodium bicarbonate and fly ash evenly at a mass ratio of 5:15 to obtain the chemical foaming expander.
3. The dual-expansion-source, dual-layer micro-expansion self-sealing material according to claim 1, characterized in that, The stabilizer includes one or more of FM500G, sodium stearate, and triethanolamine.
4. The dual-expansion-source, dual-layer micro-expansion self-sealing material according to claim 1, characterized in that, The amount of stabilizer added is 1% of the mass of the chemical foaming agent.
5. The dual-expansion-source, dual-layer micro-expansion self-sealing material according to claim 1, characterized in that, The water-to-solid ratio of the phase change expansion layer is 0.25 to 0.
65.
6. The dual-expansion-source, dual-layer micro-expansion self-sealing material according to claim 1, characterized in that, The water-to-solid ratio of the chemically foamed expansion layer is 0.6 to 0.
8.
7. The filling method of the dual-expansion-source, double-layer micro-expansion self-closing sealing material according to any one of claims 1 to 6, characterized in that, Includes the following steps: The raw materials for the phase change expansion layer are mixed evenly to obtain the phase change expansion layer slurry; The raw materials for the chemically foamed expansion layer are mixed evenly to obtain the chemically foamed expansion layer slurry; First, fill the area to be filled with the phase change expansion layer slurry, and then fill it with the chemical foam expansion layer slurry.
8. The filling method according to claim 7, characterized in that, The chemically foamed expansion layer slurry is filled when the lower phase change expansion layer slurry is in a slurry state.
9. The filling method according to claim 7, characterized in that, The volume ratio of the phase change expansion layer slurry to the chemical foaming expansion layer slurry is 1:5 to 2:4.