Grouting material based on carbon nanofiber toughening and its preparation method and application

Abstract

The present application proposes a grouting material based on carbon nanofiber toughening, and its preparation method and application, wherein the grouting material based on carbon nanofiber toughening includes the following components by mass: 80-120 parts of sulphoaluminate cement clinker, 8-12 parts of carbon nanofiber, 1.2-1.8 parts of early strength agent, 0.4-0.6 parts of coagulant, 1.6-2.4 parts of toughening agent, 0.24-0.36 parts of defoamer, and 0.4-0.6 parts of water retaining agent. The grouting material based on carbon nanofiber toughening of the present application uses carbon nanofiber, early strength agent, toughening agent, coagulant, defoamer, water retaining agent and sulphoaluminate cement clinker gelling material in combination, which can reduce the production cost of the grouting material while improving the mechanical properties and impact resistance of the grouting material.

Description

Technical Field

[0001] The present application relates to the technical field of grouting reinforcement, and in particular to a grouting material based on carbon nanofiber toughening, and a preparation method and application thereof. Background Art

[0002] The sudden and violent destructive rock burst phenomenon caused by the instantaneous release of elastic deformation energy of coal and rock masses around underground mine tunnels or working faces is often accompanied by instantaneous displacement, ejection, loud noise, and air waves of coal and rock masses, causing equipment damage and casualties. Grouting reinforcement technology has achieved good results in tunnel grouting reinforcement applications, but in rock burst tunnel applications, there are problems such as tunnel deformation leading to destruction of grouting stone bodies and insufficient long-term dynamic durability. At present, the poor impact resistance of grouting stone bodies in coal tunnels has become a difficult problem restricting the control of surrounding rock in rock burst tunnels.

[0003] Therefore, it is urgent to develop new impact-resistant grouting materials that are suitable for surrounding rock control and tunnel reinforcement in rock burst tunnels and promote their application. Summary of the invention

[0004] In view of this, one purpose of the present application is to provide a grouting material toughened based on carbon nanofibers, by using carbon nanofibers, early strength agents, toughening agents, accelerators, defoaming agents, water retaining agents and sulphoaluminate cement clinker gelling materials in combination, which can reduce the production cost of the grouting material while improving the mechanical properties and impact resistance of the grouting material.

[0005] Another object of the present application is to provide a method for preparing a grouting material toughened based on carbon nanofibers.

[0006] Another object of the present application is to provide an application of a grouting material toughened based on carbon nanofibers.

[0007] To achieve the above-mentioned objectives, the first aspect of the present application proposes a grouting material based on carbon nanofiber toughening, comprising the following components in parts by weight: 80-120 parts of sulfoaluminate cement clinker, 8-12 parts of carbon nanofibers, 1.2-1.8 parts of an early strength agent, 0.4-0.6 parts of a coagulant, 1.6-2.4 parts of a toughening agent, 0.24-0.36 parts of a defoaming agent, and 0.4-0.6 parts of a water retaining agent.

[0008] Preferably, the carbon nanofiber-based toughening grouting material comprises the following components in parts by weight: 90-110 parts of sulphoaluminate cement clinker, 9-11 parts of carbon nanofibers, 1.35-1.65 parts of an early strength agent, 0.45-0.55 parts of a coagulant, 1.8-2.2 parts of a toughening agent, 0.27-0.33 parts of a defoaming agent, and 0.45-0.55 parts of a water retaining agent.

[0009] Further preferably, the carbon nanofiber-based toughening grouting material comprises the following components in parts by weight: 100 parts of sulphoaluminate cement clinker, 10 parts of carbon nanofibers, 1.5 parts of early strength agent, 0.5 parts of accelerator, 2 parts of toughening agent, 0.3 parts of defoaming agent, and 0.5 parts of water retaining agent.

[0010] In some embodiments, the early strength agent includes at least one of sodium metaaluminate, sodium aluminate, and nano zeolite powder.

[0011] Preferably, the early strength agent is composed of sodium metaaluminate, sodium aluminate and nano zeolite powder, and the mass ratio of sodium metaaluminate, sodium aluminate and nano zeolite powder is 1:1:(3-5), more preferably 1:1:4.

[0012] In some embodiments, the coagulant includes at least one of m-phenylenediamine and 1,3-diaminobenzene.

[0013] Preferably, the coagulant is composed of m-phenylenediamine and 1,3-diaminobenzene, and the mass ratio of m-phenylenediamine to 1,3-diaminobenzene is 1:(4-6), more preferably 1:5.

[0014] In some embodiments, the toughening agent includes at least one of polystyrene-acrylonitrile-butadiene block copolymer nanoparticles, polystyrene-isoprene-styrene block copolymer nanoparticles, and polystyrene and methyl methacrylate block copolymer nanoparticles.

[0015] Preferably, the toughening agent is composed of polystyrene-acrylonitrile-butadiene block copolymer nanoparticles, polystyrene-isoprene-styrene block copolymer nanoparticles, and polystyrene and methyl methacrylate block copolymer nanoparticles, and the mass ratio of polystyrene-acrylonitrile-butadiene block copolymer nanoparticles, polystyrene-isoprene-styrene block copolymer nanoparticles, and polystyrene and methyl methacrylate block copolymer nanoparticles is (2.4-3.6):(1.6-2.4):(1.6-2.4), more preferably 3:2:2.

[0016] In some embodiments, the defoaming agent includes at least one of dimethyl silicone oil, stearic acid, and alkylphenol polyoxyethylene ether.

[0017] Preferably, the defoaming agent is composed of dimethyl silicone oil, stearic acid and alkylphenol polyoxyethylene ether, and the mass ratio of dimethyl silicone oil, stearic acid and alkylphenol polyoxyethylene ether is (1.6-2.4):1:(5.6-8.4), more preferably 2:1:7.

[0018] In some embodiments, the water retaining agent includes at least one of potassium polyacrylate, sodium pyrophosphate, and sodium hexametaphosphate.

[0019] Preferably, the water retaining agent is composed of potassium polyacrylate, sodium pyrophosphate and sodium hexametaphosphate, and the mass ratio of potassium polyacrylate, sodium pyrophosphate and sodium hexametaphosphate is 1:(2.4-3.6):1, more preferably 1:3:1.

[0020] In some embodiments, the carbon nanofibers have a length of 200-250 nm, a diameter of 10-20 nm, and a tensile strength of 5000-5910 MPa.

[0021] The second aspect of the present application proposes a method for preparing a grouting material based on carbon nanofiber toughening, comprising:

[0022] The carbon nanofibers, the early strength agent, the coagulant, the toughening agent, the defoamer and the water retaining agent in the formula amount are added to the sulphoaluminate cement clinker gelling material and mixed evenly to obtain the grouting material toughened by the carbon nanofibers.

[0023] In some embodiments, the preparation method further comprises the step of preparing the carbon nanofibers; the preparation method of the carbon nanofibers comprises:

[0024] dissolving the carbon source in a solvent to obtain a uniform solution;

[0025] At least a portion of the uniform solution is subjected to electrostatic spinning, and then subjected to a carbonization reaction under the action of a catalyst to obtain the carbon nanofibers.

[0026] In some embodiments, the carbon source includes at least one of polyacrylonitrile, lignin, hydroxypropyl methylcellulose, hydroxyethyl cellulose, and cellulose ether.

[0027] In some embodiments, the solvent includes at least one of tetrahydrofuran, N-methylpyrrolidone, dimethylacetamide, and carbon tetrachloride.

[0028] In some embodiments, the method of dissolving the carbon source in the solvent includes at least one of ultrasonic dispersion, heating, stirring, and ball milling.

[0029] In some embodiments, the catalyst includes at least one of cobalt, nickel, manganese, gallium, platinum, and palladium.

[0030] In some embodiments, the amount of the catalyst used is 1-5 wt % of the amount of the carbon source used.

[0031] In some embodiments, the carbonization reaction is performed in a protective gas atmosphere.

[0032] In some embodiments, the temperature of the carbonization reaction is 650-700° C., and the time of the carbonization reaction is 100-120 min.

[0033] The third aspect of the present application also relates to the application of the carbon nanofiber-toughened grouting material described in the present application or the carbon nanofiber-toughened grouting material prepared by the preparation method of the carbon nanofiber-toughened grouting material described in the present application in the field of grouting reinforcement of coal mine rock burst tunnels.

[0034] The grouting material based on carbon nanofiber toughening described in this application can at least bring the following beneficial effects:

[0035] The combination of carbon nanofibers, early strength agents, toughening agents, accelerators, defoamers, water retaining agents and sulphoaluminate cement clinker gelling materials can reduce the production cost of grouting materials while improving the mechanical properties and impact resistance of the grouting materials.

[0036] Specifically:

[0037] 1. Carbon nanofibers as a reinforcing phase interact with the matrix phase (sulfoaluminate cement clinker cementitious material) to form a mutually supporting composite structure. This combination significantly improves the strength and stiffness of the grouting material.

[0038] 2. Carbon nanofibers play a mechanical locking role. During the interaction between carbon nanofibers and the matrix (sulfoaluminate cement clinker cementitious material), the locking effect on the surface of carbon nanofibers can weaken the distribution of load in the composite material, so that the load can be more fully transmitted throughout the material.

[0039] 3. Carbon nanofibers play a role of chemical bonding. The matrix (sulfoaluminate cement clinker gelling material) forms hydrogen bonds with the active groups on the surface of carbon nanofibers, linking the carbon nanofibers and the matrix together on a microscopic scale, thereby enhancing the comprehensive performance of the entire composite grouting material.

[0040] 4. The high strength and high modulus of carbon nanofibers hinder the dislocation plastic deformation and fragmentation mechanism of the grouting material under the impact ground pressure, thereby making the grouting material have higher impact resistance and toughness.

[0041] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings.

[0043] in:

[0044] Figure 1 This is a diagram showing the structural changes of the common grouting material of Comparative Example 4 after being impacted.

[0045] Figure 2 This is a diagram showing the structural changes of the carbon nanofiber-reinforced grouting material according to Example 1 of the present application after being impacted. DETAILED DESCRIPTION

[0046] The embodiments of the present application are described in detail below. The embodiments are exemplary and intended to be used to explain the present application, but should not be construed as limiting the present application.

[0047] In this application, the disclosure of numerical ranges includes all values ​​within the entire range and the disclosure of further subdivided ranges, including the endpoints and sub-ranges given in these ranges.

[0048] In this application, the raw materials, equipment, etc. involved, unless otherwise specified, are all raw materials and equipment that can be made through commercial channels or known methods; the methods involved, unless otherwise specified, are all conventional methods.

[0049] <Grouting material based on carbon nanofiber toughening>

[0050] The grouting material based on carbon nanofiber toughening in the embodiment of the present application includes the following components in parts by weight: 80-120 parts of sulphoaluminate cement clinker, 8-12 parts of carbon nanofibers, 1.2-1.8 parts of early strength agent, 0.4-0.6 parts of accelerator, 1.6-2.4 parts of toughening agent, 0.24-0.36 parts of defoaming agent, and 0.4-0.6 parts of water retaining agent.

[0051] In the embodiments of the present application, the role of sulphoaluminate cement clinker is to serve as the matrix of the grouting material and provide compressive strength; the role of carbon nanofibers is to serve as stress concentration points, produce a large number of micro-nano silver shear bands, absorb impact energy, and significantly improve the toughness of the grouting material; the role of the early strength agent is to promote the rapid increase in the early strength of the grouting material; the role of the coagulant is to promote the solidification and hydration hardening of the grouting material; the role of the toughening agent is to improve the toughness of the grouting material; the role of the defoaming agent is to avoid the generation of bubbles in the grouting material during stirring and grouting, affecting its compressive strength; the role of the water-retaining agent is to avoid the loss of water in the grouting slurry during flow and penetration in the coal rock fissures, and reduce its fluidity loss.

[0052] In the embodiments of the present application, when the ratio of each component of the grouting material toughened by carbon nanofibers is within the above range, the obtained grouting slurry has a moderate setting time (not too fast, not too slow), and has good mechanical properties such as impact resistance, flexural strength and compressive strength. It should be noted that within the dosage range specified in the embodiments of the present application, the more sulphur-aluminium clinker, the faster the grouting material solidifies, the higher the compressive strength, but the impact resistance and flexural strength will be reduced; within the dosage range specified in the embodiments of the present application, the more carbon nanofibers are used, the slower the grouting material solidifies, the lower the compressive strength, but the impact resistance and flexural strength will be increased.

[0053] In the embodiments of the present application, if the ratio of each component of the grouting material based on carbon nanofiber toughening exceeds the above range, it will have a negative impact on the properties of the grouting material such as setting time, compressive strength, toughness, and fluidity. For example, if the carbon nanofiber content is too high, the carbon nanofiber dispersion will be weakened, agglomeration will be formed, and the compressive strength of the grouting body will be reduced; if the carbon nanofiber content is too low, it will be difficult to form enough stress concentration points, insufficient silver shear bands will be generated, the impact energy absorption will be reduced, and the toughening effect will be poor; if the sulphoaluminate cement clinker content is too high, the setting time of the grouting slurry will be too fast, and it will be easy to solidify or block the pipe during the on-site mixing process; if the sulphoaluminate cement clinker content is too low, the grouting slurry will solidify slowly, the compressive strength of the grouting stone body will be reduced, and the grouting reinforcement effect will be affected.

[0054] As a preferred example, the above-mentioned carbon nanofiber-toughened grouting material includes the following components in parts by weight: 90-110 parts of sulphoaluminate cement clinker, 9-11 parts of carbon nanofibers, 1.35-1.65 parts of early strength agent, 0.45-0.55 parts of accelerator, 1.8-2.2 parts of toughening agent, 0.27-0.33 parts of defoaming agent, and 0.45-0.55 parts of water retaining agent.

[0055] As a more preferred example, the above-mentioned carbon nanofiber-toughened grouting material includes the following components in parts by weight: 100 parts of sulphoaluminate cement clinker, 10 parts of carbon nanofibers, 1.5 parts of early strength agent, 0.5 parts of accelerator, 2 parts of toughening agent, 0.3 parts of defoaming agent, and 0.5 parts of water retaining agent.

[0056] In the embodiments of the present application, sulphoaluminate cement clinker is a hydraulic cementitious material obtained by calcining raw materials with appropriate ingredients to obtain a clinker with anhydrous calcium sulphoaluminate and dicalcium silicate as the main mineral components, adding different amounts of limestone and appropriate amounts of gypsum to the mixture.

[0057] As an optional example, the composition of sulphoaluminate cement clinker is shown in Table 1.

[0058] Table 1 Composition of sulphoaluminate cement clinker

[0059]

[0060] Note: In Table 1, C4A3 is calcium aluminate (3CaO·Al2O3), C2S is calcium orthosilicate (2CaO·SiO2), and C4AF is tetracalcium aluminoferrite (4CaO·Al2O3·Fe2O3).

[0061] In some embodiments, the early strength agent includes but is not limited to at least one of sodium aluminate, sodium aluminate, nano zeolite powder, and the like.

[0062] As a preferred example, the early strength agent is composed of sodium metaaluminate, sodium aluminate and nano zeolite powder.

[0063] Exemplarily, when the early strength agent is composed of sodium aluminate, sodium aluminate and nano zeolite powder, the mass ratio of sodium aluminate, sodium aluminate and nano zeolite powder is 1:1:(3-5), including but not limited to 1:1:3, 1:1:4 or 1:1:5, etc., preferably 1:1:4.

[0064] In some embodiments, the coagulant includes, but is not limited to, at least one of m-phenylenediamine, 1,3-diaminobenzene, and the like.

[0065] As a preferred example, the coagulant is composed of m-phenylenediamine and 1,3-diaminobenzene.

[0066] Exemplarily, when the coagulant consists of m-phenylenediamine and 1,3-diaminobenzene, the mass ratio of m-phenylenediamine to 1,3-diaminobenzene is 1:(4-6), including but not limited to 1:4, 1:5 or 1:6, etc., preferably 1:5.

[0067] In some embodiments, the toughening agent includes, but is not limited to, at least one of polystyrene-acrylonitrile-butadiene block copolymer nanoparticles, polystyrene-isoprene-styrene block copolymer nanoparticles, polystyrene and methyl methacrylate block copolymer nanoparticles, and the like.

[0068] As a preferred example, the toughening agent is composed of polystyrene-acrylonitrile-butadiene block copolymer nanoparticles, polystyrene-isoprene-styrene block copolymer nanoparticles, and polystyrene and methyl methacrylate block copolymer nanoparticles.

[0069] Exemplarily, when the toughening agent is composed of polystyrene-acrylonitrile-butadiene block copolymer nanoparticles, polystyrene-isoprene-styrene block copolymer nanoparticles, and polystyrene and methyl methacrylate block copolymer nanoparticles, the mass ratio of polystyrene-acrylonitrile-butadiene block copolymer nanoparticles, polystyrene-isoprene-styrene block copolymer nanoparticles, and polystyrene and methyl methacrylate block copolymer nanoparticles is (2.4-3.6):(1.6-2.4):(1.6-2.4), including but not limited to 2.4:2:1.6, 3:1.6:1.6, 3.6:2:2.4 or 3:2:2, etc., preferably 3:2:2.

[0070] In some embodiments, the defoaming agent includes but is not limited to at least one of dimethyl silicone oil, stearic acid, alkylphenol polyoxyethylene ether, and the like.

[0071] As a preferred example, the defoaming agent is composed of dimethyl silicone oil, stearic acid, and alkylphenol polyoxyethylene ether.

[0072] Exemplarily, when the defoaming agent is composed of dimethyl silicone oil, stearic acid and alkylphenol polyoxyethylene ether, the mass ratio of dimethyl silicone oil, stearic acid and alkylphenol polyoxyethylene ether is (1.6-2.4):1:(5.6-8.4), including but not limited to 1.6:1:7, 2:1:5.6, 2.4:1:7 or 2:1:7, etc., more preferably 2:1:7.

[0073] In some embodiments, the water retaining agent includes but is not limited to at least one of potassium polyacrylate, sodium pyrophosphate, and sodium hexametaphosphate.

[0074] As a preferred example, the water retaining agent is composed of potassium polyacrylate, sodium pyrophosphate and sodium hexametaphosphate.

[0075] Exemplarily, when the water retaining agent is composed of potassium polyacrylate, sodium pyrophosphate and sodium hexametaphosphate, the mass ratio of potassium polyacrylate, sodium pyrophosphate and sodium hexametaphosphate is 1:(2.4-3.6):1, including but not limited to 1:2.6:1, 1:2.8:1, 1:3:1 or 1:3.3:1, etc., preferably 1:3:1.

[0076] In some embodiments, the length of the carbon nanofibers is 200-250 nm, including but not limited to 200 nm, 210 nm, 220 nm, 230 nm, 240 nm or 250 nm.

[0077] In some embodiments, the diameter of the carbon nanofibers is 10-20 nm, including but not limited to 10 nm, 12 nm, 15 nm, 18 nm or 20 nm.

[0078] In some embodiments, the tensile strength of the carbon nanofibers is 5000-5910 MPa, including but not limited to 5000 MPa, 5100 MPa, 5200 MPa, 5300 MPa, 5400 MPa, 5500 MPa, 5600 MPa, 5700 MPa, 5800 MPa or 5900 MPa, etc.

[0079] The grouting material based on carbon nanofiber toughening in the embodiment of the present application can at least bring the following beneficial effects:

[0080] The combination of carbon nanofibers, early strength agents, toughening agents, accelerators, defoamers, water retaining agents and sulphoaluminate cement clinker gelling materials can reduce the production cost of grouting materials while improving the mechanical properties and impact resistance of the grouting materials.

[0081] Specifically:

[0082] 1. Carbon nanofibers as a reinforcing phase interact with the matrix phase (sulfoaluminate cement clinker cementitious material) to form a mutually supporting composite structure. This combination significantly improves the strength and stiffness of the grouting material.

[0083] 2. Carbon nanofibers play a mechanical locking role. During the interaction between carbon nanofibers and the matrix (sulfoaluminate cement clinker cementitious material), the locking effect on the surface of carbon nanofibers can weaken the distribution of load in the composite material, so that the load can be more fully transmitted throughout the material.

[0084] 3. Carbon nanofibers play a role of chemical bonding. The matrix (sulfoaluminate cement clinker gelling material) forms hydrogen bonds with the active groups on the surface of carbon nanofibers, linking the carbon nanofibers and the matrix together on a microscopic scale, thereby enhancing the comprehensive performance of the entire composite grouting material.

[0085] 4. The high strength and high modulus of carbon nanofibers hinder the dislocation plastic deformation and fragmentation mechanism of the grouting material under the impact ground pressure, thereby making the grouting material have higher impact resistance and toughness.

[0086] <Preparation method of grouting material based on carbon nanofiber toughening>

[0087] The method for preparing the grouting material based on carbon nanofiber toughening according to the embodiment of the present application can be used to prepare the grouting material based on carbon nanofiber toughening according to the embodiment of the present application.

[0088] The method for preparing the grouting material based on carbon nanofiber toughening according to the embodiment of the present application comprises the following steps:

[0089] The carbon nanofibers, early strength agent, coagulant, toughening agent, defoamer and water retaining agent in the formulated amount are added into the sulphoaluminate cement clinker gelling material and mixed evenly to obtain the grouting material toughened by the carbon nanofibers.

[0090] In some embodiments, the carbon nanofibers, early strength agent, coagulant, toughening agent, defoamer, and water retaining agent in the formulated amount are added to the sulphoaluminate cement clinker gelling material and mixed in a manner including but not limited to stirring, ultrasonic dispersion, ball milling, etc.

[0091] It should be noted that in the embodiments of the present application, the carbon nanofibers can be commercially available products or homemade, as long as the technical effects of the present application can be achieved. However, since the surface of the commercially available carbon fibers has not been treated in the subsequent carbon nanofiber preparation method of the present application (for example, carbonization reaction under the action of a catalyst), the compatibility between the carbon nanofiber and the sulphoaluminate cement clinker phase interface is poor, which may lead to a reduction in the strength of the grouting slurry.

[0092] In some embodiments, in the method for preparing a grouting material toughened based on carbon nanofibers in the embodiments of the present application, the carbon nanofibers are obtained by a homemade method.

[0093] As an optional example, the method for preparing carbon nanofibers includes the following steps:

[0094] S101, dissolving a carbon source in a solvent to obtain a uniform solution.

[0095] In some embodiments, the carbon source includes, but is not limited to, at least one of polyacrylonitrile, lignin, hydroxypropyl methylcellulose, hydroxyethyl cellulose, cellulose ether, and the like.

[0096] As a preferred example, the carbon source consists of polyacrylonitrile, lignin, hydroxypropyl methylcellulose, hydroxyethyl cellulose, and cellulose ether.

[0097] Exemplarily, when the carbon source consists of polyacrylonitrile, lignin, hydroxypropyl methylcellulose, hydroxyethyl cellulose and cellulose ether, the mass ratio of polyacrylonitrile, lignin, hydroxypropyl methylcellulose, hydroxyethyl cellulose and cellulose ether is 5:1:2:1:1.

[0098] In some embodiments, the solvent includes but is not limited to at least one of tetrahydrofuran, N-methylpyrrolidone, dimethylacetamide, carbon tetrachloride, and the like.

[0099] As a preferred example, the solvent consists of tetrahydrofuran, N-methylpyrrolidone, dimethylacetamide and carbon tetrachloride.

[0100] Exemplarily, when the solvent consists of tetrahydrofuran, N-methylpyrrolidone, dimethylacetamide and carbon tetrachloride, the mass ratio of tetrahydrofuran, N-methylpyrrolidone, dimethylacetamide and carbon tetrachloride is 6:1:3:1.

[0101] In some embodiments, the method of dissolving the carbon source in the solvent includes but is not limited to at least one of ultrasonic dispersion, heating, stirring, and ball milling.

[0102] Exemplarily, the frequency of ultrasonic dispersion is 150-160 kHz, including but not limited to 150 kHz, 155 kHz or 160 kHz.

[0103] Exemplarily, the ultrasonic dispersion time is 10-12 min, including but not limited to 10 min, 11 min or 12 min, etc.

[0104] Exemplarily, the power density of ultrasonic dispersion is 8-10 W / cm 2 , including but not limited to 8W / cm 2 , 9W / cm 2 or 10W / cm 2 wait.

[0105] In some embodiments, the heating method is oil bath heating.

[0106] In some embodiments, the heating temperature is 135-140°C, including but not limited to 135°C, 138°C or 140°C, etc.

[0107] In some embodiments, the heating time is 20-25 min, including but not limited to 20 min, 23 min or 25 min, etc.

[0108] As an optional example, the method of dissolving the carbon source in a solvent is: adding polyacrylonitrile, lignin, hydroxypropyl methylcellulose, hydroxyethyl cellulose, and cellulose ether to a mixed solvent of tetrahydrofuran, N-methylpyrrolidone, dimethylacetamide, and carbon tetrachloride, and assisting with ultrasonic dispersion and heating to promote dissolution.

[0109] S102, electrospinning at least a portion of the uniform solution obtained in step S101, and then subjecting it to a carbonization reaction under the action of a catalyst to obtain carbon nanofibers.

[0110] It can be understood that, in the embodiments of the present application, according to the amount of carbon nanofibers used in the grouting slurry, part or all of the uniform solution obtained in step S101 can be subjected to electrospinning.

[0111] In the embodiments of the present application, electrospinning can be performed in an electrospinning machine. The specific operation method and process parameter setting of electrospinning are well known in the art and will not be described in detail here.

[0112] In some embodiments, the catalyst includes, but is not limited to, at least one of cobalt, nickel, manganese, gallium, platinum, palladium, and the like.

[0113] As a preferred example, the catalyst is composed of cobalt, nickel, manganese, gallium, platinum and palladium.

[0114] Exemplarily, when the catalyst is composed of cobalt, nickel, manganese, gallium, platinum and palladium, the mass ratio of cobalt, nickel, manganese, gallium, platinum and palladium is 5:1:1:1:3:1.

[0115] In some embodiments, the amount of the catalyst is 1-5wt% of the amount of the carbon source, including but not limited to 1wt%, 2wt%, 3wt%, 4wt% or 5wt%, etc. In the examples of the present application, the amount of the catalyst is within the above-defined range, and the more the amount of the catalyst is, the smaller the size and particle size of the generated carbon nanofibers are, and the higher the strength is.

[0116] In some embodiments, the carbonization reaction is performed in a protective gas atmosphere.

[0117] Exemplarily, the protective gas includes but is not limited to at least one of argon, nitrogen, helium, etc., preferably argon.

[0118] In some embodiments, the temperature of the carbonization reaction is 650-700°C, including but not limited to 650°C, 660°C, 670°C, 680°C, 690°C or 700°C, etc.

[0119] In some embodiments, the carbonization reaction time is 100-120 min, including but not limited to 100 min, 105 min, 110 min, 115 min or 120 min, etc.

[0120] The preparation method of the grouting material based on carbon nanofiber toughening of the embodiment of the present application is by adding polyacrylonitrile, lignin, hydroxypropyl methylcellulose, hydroxyethyl cellulose, cellulose ether, etc. to tetrahydrofuran, N-methylpyrrolidone, dimethylacetamide, carbon tetrachloride and other solvents, assisting ultrasound, heating to promote dissolution, and then electrostatic spinning, carbonization under the action of a catalyst, and preparing a high-strength carbon nanofiber. The prepared carbon nanofiber, early strength agent, toughening agent, coagulant, defoamer, and water-retaining agent are added to sulphoaluminate cement clinker gelling material to prepare a new composite grouting material suitable for rock burst tunnels. In the composite grouting material, the prepared high-strength carbon nanofiber, the fiber interacts with the matrix phase (sulphoaluminate cement clinker gelling material) as a reinforcing phase to form a composite structure that supports each other. This combination significantly improves the strength and stiffness of the material. The prepared high-strength carbon nanofibers play a mechanical locking role. In the process of interaction between the carbon nanofibers and the matrix (sulfoaluminate cement clinker gelling material), the locking effect of the carbon nanofiber surface can weaken the distribution of the load in the composite material, so that the load can be more fully transmitted in the entire material. At the same time, the prepared high-strength carbon nanofibers play a chemical bond bonding role, and the matrix and the active groups on the surface of the carbon nanofibers form hydrogen bonds, which connect the carbon nanofibers with the matrix on a microscopic scale, thereby enhancing the comprehensive performance of the entire composite grouting material. In addition, the high strength and high modulus of the high-strength carbon nanofibers hinder the dislocation plastic deformation and fragmentation mechanism of the grouting material under the impact ground pressure, thereby making the grouting material have higher impact resistance and toughness. The preparation method is simple in process, low in cost, has an outstanding effect on improving the mechanical properties of the grouting slurry, and is impact-resistant. The prepared grouting slurry is suitable for grouting reinforcement of coal mine impact ground pressure tunnels.

[0121] <Application of grouting materials based on carbon nanofiber toughening>

[0122] The carbon nanofiber-toughened grouting material of the embodiment of the present application or the carbon nanofiber-toughened grouting material prepared by the preparation method of the carbon nanofiber-toughened grouting material of the embodiment of the present application can be widely used in the field of grouting reinforcement of coal mine rock burst tunnels, etc.

[0123] Certain features of the present technology are further illustrated in the following non-limiting examples.

[0124] The compositions of the sulphoaluminate cement clinkers involved in the following examples and comparative examples are shown in Table 2.

[0125] Table 2 Composition of sulphoaluminate cement clinker involved in each embodiment and comparative example

[0126]

[0127] Note: In Table 2, C4A3 is calcium aluminate (3CaO·Al2O3), C2S is calcium orthosilicate (2CaO·SiO2), and C4AF is tetracalcium aluminoferrite (4CaO·Al2O3·Fe2O3).

[0128] Example 1 (the amount of catalyst is 5wt% of the carbon source)

[0129] (Grouting material based on carbon nanofiber toughening)

[0130] The carbon nanofiber-toughened grouting material of this embodiment is composed of the following components in parts by weight: 100 parts of sulphoaluminate cement clinker, 10 parts of carbon nanofibers, 1.5 parts of early strength agent, 0.5 parts of accelerator, 2 parts of toughening agent, 0.3 parts of defoaming agent, and 0.5 parts of water retaining agent.

[0131] in:

[0132] The early strength agent is composed of sodium aluminate, sodium aluminate and nano zeolite powder, and the mass ratio of sodium aluminate, sodium aluminate and nano zeolite powder is 1:1:4;

[0133] The coagulant is composed of m-phenylenediamine and 1,3-diaminobenzene, and the mass ratio of m-phenylenediamine to 1,3-diaminobenzene is 1:5;

[0134] The toughening agent is composed of polystyrene-acrylonitrile-butadiene block copolymer nanoparticles, polystyrene-isoprene-styrene block copolymer nanoparticles, and polystyrene and methyl methacrylate block copolymer nanoparticles, and the mass ratio of the polystyrene-acrylonitrile-butadiene block copolymer nanoparticles, the polystyrene-isoprene-styrene block copolymer nanoparticles, and the polystyrene and methyl methacrylate block copolymer nanoparticles is 3:2:2;

[0135] The defoaming agent is composed of dimethyl silicone oil, stearic acid and alkylphenol polyoxyethylene ether, and the mass ratio of dimethyl silicone oil, stearic acid and alkylphenol polyoxyethylene ether is 2:1:7;

[0136] The water retaining agent is composed of potassium polyacrylate, sodium pyrophosphate and sodium hexametaphosphate, and the mass ratio of potassium polyacrylate, sodium pyrophosphate and sodium hexametaphosphate is 1:3:1;

[0137] The carbon nanofibers have a length of 205 nm, a diameter of 13 nm, and a tensile strength of 5910 MPa.

[0138] (Preparation method of grouting material based on carbon nanofiber toughening)

[0139] The method for preparing the grouting material based on carbon nanofiber toughening of this embodiment comprises the following steps:

[0140] Step S1, adding 20 parts by mass of carbon source into 100 parts by mass of solvent, assisting ultrasonic dispersion, heating to promote dissolution, stirring for 30 minutes, and obtaining a uniform solution.

[0141] The carbon source is composed of polyacrylonitrile, lignin, hydroxypropyl methylcellulose, hydroxyethyl cellulose and cellulose ether, and the mass ratio of polyacrylonitrile, lignin, hydroxypropyl methylcellulose, hydroxyethyl cellulose and cellulose ether is 5:1:2:1:1; the solvent is a mixed solvent composed of tetrahydrofuran, N-methylpyrrolidone, dimethylacetamide and carbon tetrachloride in a mass ratio of 6:1:3:1; the frequency of ultrasonic dispersion is 155kHz, the time is 11min, and the power density is 9W / cm 2 ; The heating temperature is 138℃.

[0142] Step S2, weighing 20 parts of the uniform solution by mass, adding it to an electrospinning machine to obtain nanofibers; then, carbonizing the obtained nanofibers under the action of 1 part by mass of a catalyst, and then stirring, filtering, and drying in sequence to obtain carbon nanofibers.

[0143] The temperature of the carbonization reaction is 675° C., the protective gas of the carbonization reaction is argon, and the time of the carbonization reaction is 110 minutes; the catalyst is a mixture of cobalt, nickel, manganese, gallium, platinum, and palladium in a mass ratio of 5:1:1:1:3:1.

[0144] Step S3, weigh 10 parts of carbon nanofibers, 1.5 parts of early strength agent, 0.5 parts of accelerator, 2 parts of toughening agent, 0.3 parts of defoaming agent, and 0.5 parts of water retaining agent obtained in step S2 according to mass, add them to 100 parts of sulphoaluminate cement clinker gelling material, mix in a dry powder mixer for 15 minutes, and obtain the grouting material based on carbon nanofiber toughening of this embodiment.

[0145] After testing, the final setting time of the grouting material based on carbon nanofiber toughening in this embodiment is 82 minutes, and the impact resistance is 7.3 J / cm 2 The flexural strength is 17.1MPa and the compressive strength is 55MPa.

[0146] Example 2 (the amount of catalyst used is 4 wt% of the carbon source)

[0147] This embodiment is basically the same as Embodiment 1, except that:

[0148] Grouting materials based on carbon nanofiber toughening:

[0149] The carbon nanofibers have a length of 211 nm, a diameter of 15 nm, and a tensile strength of 5821 MPa.

[0150] In the preparation method of grouting material based on carbon nanofiber toughening:

[0151] In step S2, the amount of the catalyst used is 0.8 parts by mass.

[0152] After testing, the final setting time of the grouting material based on carbon nanofiber toughening in this embodiment is 82 minutes, and the impact resistance is 7.1 J / cm 2 The flexural strength is 16.3MPa and the compressive strength is 53MPa.

[0153] Example 3 (the amount of catalyst used is 3 wt% of the carbon source)

[0154] This embodiment is basically the same as Embodiment 1, except that:

[0155] Grouting materials based on carbon nanofiber toughening:

[0156] The carbon nanofibers have a length of 224 nm, a diameter of 16 nm, and a tensile strength of 5810 MPa.

[0157] In the preparation method of grouting material based on carbon nanofiber toughening:

[0158] In step S2, the amount of the catalyst used is 0.6 parts by mass.

[0159] After testing, the final setting time of the grouting material based on carbon nanofiber toughening in this embodiment is 82 minutes, and the impact resistance is 6.2 J / cm 2 The flexural strength is 16.2MPa and the compressive strength is 51MPa.

[0160] Example 4 (the amount of catalyst used is 2 wt% of the carbon source)

[0161] This embodiment is basically the same as Embodiment 1, except that:

[0162] Grouting materials based on carbon nanofiber toughening:

[0163] The carbon nanofibers have a length of 229 nm, a diameter of 16 nm, and a tensile strength of 5682 MPa.

[0164] In the preparation method of grouting material based on carbon nanofiber toughening:

[0165] In step S2, the amount of the catalyst used is 0.4 parts by mass.

[0166] After testing, the final setting time of the grouting material based on carbon nanofiber toughening in this embodiment is 82 minutes, and the impact resistance is 5.9 J / cm 2 The flexural strength is 16.0MPa and the compressive strength is 48MPa.

[0167] Example 5 (the amount of catalyst used is 1 wt% of the carbon source)

[0168] This embodiment is basically the same as Embodiment 1, except that:

[0169] Grouting materials based on carbon nanofiber toughening:

[0170] The carbon nanofibers have a length of 241 nm, a diameter of 14 nm, and a tensile strength of 5564 MPa.

[0171] In the preparation method of grouting material based on carbon nanofiber toughening:

[0172] In step S2, the amount of the catalyst used is 0.2 parts by mass.

[0173] After testing, the final setting time of the grouting material based on carbon nanofiber toughening in this embodiment is 82 minutes, and the impact resistance is 5.8 J / cm 2 The flexural strength is 15.7MPa and the compressive strength is 46MPa.

[0174] Example 6 (100 parts of sulphoaluminate cement clinker, same as Example 1, other components are at the lower limit)

[0175] This embodiment is basically the same as Embodiment 1, except that:

[0176] Grouting materials based on carbon nanofiber toughening:

[0177] The grouting material based on carbon nanofiber toughening is composed of the following components in parts by weight: 100 parts of sulphoaluminate cement clinker, 8 parts of carbon nanofiber, 1.2 parts of early strength agent, 0.4 parts of accelerator, 1.6 parts of toughening agent, 0.24 parts of defoaming agent and 0.4 parts of water retaining agent.

[0178] In the preparation method of grouting material based on carbon nanofiber toughening:

[0179] In step S3, 8 parts of carbon nanofibers, 1.2 parts of early strength agent, 0.4 parts of accelerator, 1.6 parts of toughening agent, 0.24 parts of defoaming agent and 0.4 parts of water retaining agent obtained in step S2 are weighed by mass and added to 100 parts of sulphoaluminate cement clinker gelling material, and mixed in a dry powder mixer for 15 minutes to obtain the grouting material toughened by carbon nanofibers in this embodiment.

[0180] After testing, the final setting time of the grouting material based on carbon nanofiber toughening in this embodiment is 77 minutes, and the impact resistance is 5.3 J / cm 2 The flexural strength is 13.5MPa and the compressive strength is 58MPa.

[0181] Example 7 (100 parts of sulphoaluminate cement clinker, same as Example 1, other components are all upper limits)

[0182] This embodiment is basically the same as Embodiment 1, except that:

[0183] Grouting materials based on carbon nanofiber toughening:

[0184] The grouting material based on carbon nanofiber toughening is composed of the following components in parts by weight: 100 parts of sulphoaluminate cement clinker, 12 parts of carbon nanofiber, 1.8 parts of early strength agent, 0.6 parts of accelerator, 2.4 parts of toughening agent, 0.36 parts of defoaming agent and 0.6 parts of water retaining agent.

[0185] In the preparation method of grouting material based on carbon nanofiber toughening:

[0186] In step S3, 12 parts of carbon nanofibers, 1.8 parts of early strength agent, 0.6 parts of accelerator, 2.4 parts of toughening agent, 0.36 parts of defoaming agent and 0.6 parts of water retaining agent obtained in step S2 are weighed according to mass and added to 100 parts of sulphoaluminate cement clinker gelling material, and mixed in a dry powder mixer for 15 minutes to obtain the grouting material based on carbon nanofiber toughening of this embodiment.

[0187] After testing, the final setting time of the grouting material based on carbon nanofiber toughening in this embodiment is 85 minutes, and the impact resistance is 7.7 J / cm 2 The flexural strength is 17.9MPa and the compressive strength is 52MPa.

[0188] Example 8 (the contents of other components are the same as those in Example 1, and the content of sulphoaluminate cement clinker is the lower limit)

[0189] This embodiment is basically the same as Embodiment 1, except that:

[0190] Grouting materials based on carbon nanofiber toughening:

[0191] The grouting material based on carbon nanofiber toughening is composed of the following components in parts by weight: 80 parts of sulphoaluminate cement clinker, 10 parts of carbon nanofiber, 1.5 parts of early strength agent, 0.5 parts of accelerator, 2 parts of toughening agent, 0.3 parts of defoaming agent and 0.5 parts of water retaining agent.

[0192] In the preparation method of grouting material based on carbon nanofiber toughening:

[0193] In step S3, 10 parts of carbon nanofibers, 1.5 parts of early strength agent, 0.5 parts of accelerator, 2 parts of toughening agent, 0.3 parts of defoaming agent and 0.5 parts of water retaining agent obtained in step S2 are weighed according to mass and added to 80 parts of sulphoaluminate cement clinker gelling material, and mixed in a dry powder mixer for 15 minutes to obtain the grouting material toughened by carbon nanofibers in this embodiment.

[0194] After testing, the final setting time of the grouting material based on carbon nanofiber toughening in this embodiment is 86 minutes, and the impact resistance is 7.4 J / cm 2 The flexural strength is 17.2MPa and the compressive strength is 41MPa.

[0195] Example 9 (the contents of other components are the same as those in Example 1, and the content of sulphoaluminate cement clinker is the upper limit)

[0196] This embodiment is basically the same as Embodiment 1, except that:

[0197] Grouting materials based on carbon nanofiber toughening:

[0198] The grouting material toughened based on carbon nanofibers is composed of the following components in parts by weight: 120 parts of sulphoaluminate cement clinker, 10 parts of carbon nanofibers, 1.5 parts of early strength agent, 0.5 parts of accelerator, 2 parts of toughening agent, 0.3 parts of defoaming agent and 0.5 parts of water retaining agent.

[0199] In the preparation method of grouting material based on carbon nanofiber toughening:

[0200] In step S3, 10 parts of carbon nanofibers, 1.5 parts of early strength agent, 0.5 parts of accelerator, 2 parts of toughening agent, 0.3 parts of defoaming agent and 0.5 parts of water retaining agent obtained in step S2 are weighed according to mass and added to 120 parts of sulphoaluminate cement clinker gelling material, and mixed in a dry powder mixer for 15 minutes to obtain the grouting material toughened by carbon nanofibers in this embodiment.

[0201] After testing, the final setting time of the grouting material based on carbon nanofiber toughening in this embodiment is 77 minutes, and the impact resistance is 5.2 J / cm 2 The flexural strength is 16.5MPa and the compressive strength is 57MPa.

[0202] Example 10 (the contents of other components are the same as those in Example 1, and the content of carbon nanofibers is the lower limit)

[0203] This embodiment is basically the same as Embodiment 1, except that:

[0204] Grouting materials based on carbon nanofiber toughening:

[0205] The grouting material based on carbon nanofiber toughening is composed of the following components in parts by weight: 100 parts of sulphoaluminate cement clinker, 8 parts of carbon nanofiber, 1.5 parts of early strength agent, 0.5 parts of accelerator, 2 parts of toughening agent, 0.3 parts of defoaming agent and 0.5 parts of water retaining agent.

[0206] In the preparation method of grouting material based on carbon nanofiber toughening:

[0207] In step S3, 8 parts of carbon nanofibers, 1.5 parts of early strength agent, 0.5 parts of accelerator, 2 parts of toughening agent, 0.3 parts of defoaming agent and 0.5 parts of water retaining agent obtained in step S2 are weighed by mass and added to 100 parts of sulphoaluminate cement clinker gelling material, and mixed in a dry powder mixer for 15 minutes to obtain the grouting material toughened by carbon nanofibers in this embodiment.

[0208] According to the test, the final setting time of the grouting material based on carbon nanofiber toughening in this embodiment is 80 minutes, and the impact resistance is 5.2 J / cm 2 The flexural strength is 15.2MPa and the compressive strength is 56MPa.

[0209] Example 11 (the contents of other components are the same as those in Example 1, and the content of carbon nanofibers is the upper limit)

[0210] This embodiment is basically the same as Embodiment 1, except that:

[0211] Grouting materials based on carbon nanofiber toughening:

[0212] The grouting material toughened based on carbon nanofibers is composed of the following components in parts by weight: 100 parts of sulphoaluminate cement clinker, 12 parts of carbon nanofibers, 1.5 parts of early strength agent, 0.5 parts of accelerator, 2 parts of toughening agent, 0.3 parts of defoaming agent and 0.5 parts of water retaining agent.

[0213] In the preparation method of grouting material based on carbon nanofiber toughening:

[0214] In step S3, 12 parts of carbon nanofibers, 1.5 parts of early strength agent, 0.5 parts of accelerator, 2 parts of toughening agent, 0.3 parts of defoaming agent and 0.5 parts of water retaining agent obtained in step S2 are weighed according to mass and added to 100 parts of sulphoaluminate cement clinker gelling material, and mixed in a dry powder mixer for 15 minutes to obtain the grouting material toughened by carbon nanofibers in this embodiment.

[0215] After testing, the final setting time of the grouting material based on carbon nanofiber toughening in this embodiment is 84 minutes, and the impact resistance is 7.5 J / cm 2 The flexural strength is 17.4MPa and the compressive strength is 49MPa.

[0216] Example 13 (Carbon nanofiber is a commercially available product)

[0217] This embodiment is basically the same as Embodiment 1, except that:

[0218] In the grouting material toughened based on carbon nanofibers, the carbon nanofibers are H2550 carbon nanofibers produced by Korea's Hyosung Group.

[0219] The method for preparing a grouting material toughened by carbon nanofibers does not include step S1 and step S2, and the carbon nanofibers in step S3 are H2550 carbon nanofibers produced by Korea Hyosung Group.

[0220] After testing, the final setting time of the grouting material in this embodiment is 90 minutes, and the impact resistance is 4.5 J / cm 2 The flexural strength is 11.4MPa and the compressive strength is 37MPa.

[0221] Embodiment 14

[0222] This embodiment is basically the same as Embodiment 1, except that:

[0223] In the grouting material toughened based on carbon nanofibers, the carbon nanofibers are GS2023 carbon nanofibers produced by Toray New Materials (Guangdong) Co., Ltd.

[0224] The preparation method of the grouting material toughened by carbon nanofibers does not include step S1 and step S2, and the carbon nanofibers in step S3 are GS2023 carbon nanofibers produced by Toray New Materials (Guangdong) Co., Ltd.

[0225] According to tests, the final setting time of the carbon nanofiber-toughened grouting material of this embodiment is 89 minutes, the impact resistance is 4.5 J / cm2, the flexural strength is 11.7 MPa, and the compressive strength is 35 MPa.

[0226] Comparative Example 1 (Grouting Slurry Does Not Contain Carbon Nanofibers at All)

[0227] This comparative example is basically the same as Example 1, except that:

[0228] The carbon nanofiber-reinforced grouting material does not contain carbon nanofibers.

[0229] In the preparation method of grouting material based on carbon nanofiber toughening:

[0230] Step S1 and step S2 are not included, and step S3 does not contain carbon nanofibers.

[0231] After testing, the final setting time of the grouting material in this comparative example is 89 minutes, and the impact resistance is 3.1 J / cm 2 The flexural strength is 9.1MPa and the compressive strength is 31MPa.

[0232] Comparative Example 2 (the carbon nanofiber content of the grouting slurry is lower than the lower limit of this application)

[0233] This comparative example is basically the same as Example 1, except that:

[0234] Grouting materials based on carbon nanofiber toughening:

[0235] The grouting material based on carbon nanofiber toughening is composed of the following components in parts by weight: 100 parts of sulphoaluminate cement clinker, 7 parts of carbon nanofiber, 1.5 parts of early strength agent, 0.5 parts of accelerator, 2 parts of toughening agent, 0.3 parts of defoaming agent and 0.5 parts of water retaining agent.

[0236] After testing, the final setting time of the grouting material based on carbon nanofiber toughening in this comparative example is 81min, and the impact resistance is 4.5J / cm 2 The flexural strength is 15.0MPa and the compressive strength is 57MPa.

[0237] Comparative Example 3 (the carbon nanofiber content of the grouting slurry is higher than the upper limit of this application)

[0238] This comparative example is basically the same as Example 1, except that:

[0239] Grouting materials based on carbon nanofiber toughening:

[0240] The grouting material based on carbon nanofiber toughening is composed of the following components in parts by weight: 100 parts of sulphoaluminate cement clinker, 13 parts of carbon nanofiber, 1.5 parts of early strength agent, 0.5 parts of accelerator, 2 parts of toughening agent, 0.3 parts of defoaming agent and 0.5 parts of water retaining agent.

[0241] After testing, the final setting time of the grouting material based on carbon nanofiber toughening in this comparative example is 87 minutes, and the impact resistance is 7.6 J / cm 2 The flexural strength is 17.7MPa and the compressive strength is 47MPa.

[0242] Comparative Example 4

[0243] The grouting slurry of this comparative example is common grouting material, i.e. cement.

[0244] The grouting slurries of Example 1 and Comparative Example 4 were impacted for 30 seconds at an impact force of 100 KN, and their structural changes were numerically simulated. The results were as follows: Figure 2 and Figure 1 shown.

[0245] contrast Figure 1 and Figure 2 It can be seen that the ordinary grouting slurry of comparative example 4 breaks upon impact, while the grouting slurry of Example 1 of the present application introduces carbon nanofibers. When impacted, the carbon nanofibers act as stress concentration points, produce a large number of micro-nano-scale silver shear bands, absorb impact energy, and can significantly improve the toughness of the grouting material.

[0246] In the present application, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0247] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A grouting material based on carbon nanofiber toughening, characterized in that: The invention comprises the following components in parts by weight: 80-120 parts of sulphoaluminate cement clinker, 8-12 parts of carbon nanofibers, 1.2-1.8 parts of early strength agent, 0.4-0.6 parts of coagulant, 1.6-2.4 parts of toughening agent, 0.24-0.36 parts of defoamer, and 0.4-0.6 parts of water retaining agent; The early strength agent is composed of sodium metaaluminate, sodium aluminate and nano zeolite powder in a mass ratio of 1:1:(3-5); The coagulant is composed of m-phenylenediamine and 1,3-diaminobenzene in a mass ratio of 1:(4-6); The toughening agent is composed of polystyrene-acrylonitrile-butadiene block copolymer nanoparticles, polystyrene-isoprene-styrene block copolymer nanoparticles, and polystyrene and methyl methacrylate block copolymer nanoparticles in a mass ratio of (2.4-3.6): (1.6-2.4): (1.6-2.4); The defoamer is composed of dimethyl silicone oil, stearic acid and alkylphenol polyoxyethylene ether in a mass ratio of (1.6-2.4):1:(5.6-8.4); The water retaining agent is composed of potassium polyacrylate, sodium pyrophosphate and sodium hexametaphosphate in a mass ratio of 1: (2.4-3.6):

1.

2. The grouting material based on carbon nanofiber toughening according to claim 1, characterized in that: The invention comprises the following components in parts by weight: 90-110 parts of sulphoaluminate cement clinker, 9-11 parts of carbon nanofibers, 1.35-1.65 parts of early strength agent, 0.45-0.55 parts of coagulant, 1.8-2.2 parts of toughening agent, 0.27-0.33 parts of defoaming agent and 0.45-0.55 parts of water retaining agent.

3. The grouting material based on carbon nanofiber toughening according to claim 2, characterized in that: The invention comprises the following components in parts by weight: 100 parts of sulphoaluminate cement clinker, 10 parts of carbon nanofibers, 1.5 parts of early strength agent, 0.5 parts of coagulant, 2 parts of toughening agent, 0.3 parts of defoamer and 0.5 parts of water retaining agent.

4. The grouting material based on carbon nanofiber toughening according to any one of claims 1 to 3, characterized in that: The carbon nanofiber has a length of 200-250 nm, a diameter of 10-20 nm, and a tensile strength of 5000-5910 MPa.

5. The grouting material based on carbon nanofiber toughening according to claim 4, characterized in that: In the early strength agent, the mass ratio of sodium aluminate, sodium aluminate and nano zeolite powder is 1:1:4; And / or, in the coagulant, the mass ratio of m-phenylenediamine to 1,3-diaminobenzene is 1:5; and / or, in the toughening agent, the mass ratio of polystyrene-acrylonitrile-butadiene block copolymer nanoparticles, polystyrene-isoprene-styrene block copolymer nanoparticles, and polystyrene and methyl methacrylate block copolymer nanoparticles is 3:2:2; And / or, in the defoaming agent, the mass ratio of dimethyl silicone oil, stearic acid and alkylphenol polyoxyethylene ether is 2:1:7; And / or, in the water-retaining agent, the mass ratio of potassium polyacrylate, sodium pyrophosphate and sodium hexametaphosphate is 1:3:

1.

6. A method for preparing a grouting material based on carbon nanofiber toughening according to any one of claims 1 to 5, characterized in that: include: The carbon nanofibers, the early strength agent, the coagulant, the toughening agent, the defoamer and the water retaining agent in the formula amount are added to the sulphoaluminate cement clinker gelling material and mixed evenly to obtain the grouting material toughened by the carbon nanofibers.

7. The preparation method according to claim 6, characterized in that: The preparation method further comprises the step of preparing the carbon nanofibers; the preparation method of the carbon nanofibers comprises: dissolving the carbon source in a solvent to obtain a uniform solution; At least a portion of the uniform solution is subjected to electrostatic spinning, and then subjected to a carbonization reaction under the action of a catalyst to obtain the carbon nanofibers.

8. The preparation method according to claim 7, characterized in that: The carbon source comprises at least one of polyacrylonitrile, lignin, hydroxypropyl methylcellulose, hydroxyethyl cellulose, and cellulose ether; And / or, the solvent includes at least one of tetrahydrofuran, N-methylpyrrolidone, dimethylacetamide, and carbon tetrachloride; And / or, the method of dissolving the carbon source in the solvent includes at least one of ultrasonic dispersion, heating, stirring, and ball milling; and / or, the catalyst comprises at least one of cobalt, nickel, manganese, gallium, platinum and palladium; And / or, the amount of the catalyst is 1-5wt% of the amount of the carbon source; And / or, the carbonization reaction is carried out in a protective gas atmosphere; And / or, the temperature of the carbonization reaction is 650-700° C., and the time of the carbonization reaction is 100-120 min.

9. Application of the carbon nanofiber-toughened grouting material as described in any one of claims 1 to 5 or the carbon nanofiber-toughened grouting material prepared by the preparation method of the carbon nanofiber-toughened grouting material as described in any one of claims 6 to 8 in the field of grouting reinforcement of coal mine rock burst tunnels.

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