High-impermeability and high-disturbance-resistance cement-based repairing material for tunnel engineering and preparation method thereof

Abstract

The invention belongs to the technical field of material science, and discloses a high-impermeability and high-disturbance-resistance cement-based patching material for tunnel engineering and a preparation method thereof.The high-impermeability and high-disturbance-resistance cement-based patching material is prepared from, by mass, 426-480 parts of ordinary Portland cement, 90-100 parts of aluminate cement, 44-50 parts of semi-hydrated gypsum, 135-160 parts of mineral powder, 80-135 parts of fly ash and 1.35-1.8 parts of nano montmorillonite modified fiber. The mortar is prepared from the following components in parts by weight: 1.5 to 2 parts of redispersible latex powder, 0.9 to 1.35 parts of a water reducing agent, 0.9 to 1.35 parts of a defoaming agent, 800 to 900 parts of quartz sand and 240 to 270 parts of water. The cement-based repairing material provided by the invention has the advantages of good mechanical properties, high early strength, stable increase of later strength, no shrinkage phenomenon, high impermeability and crack resistance, good disturbance resistance, good volume stability, good new and old interface bonding performance, excellent durability, easy preparation and convenient construction.

Description

Technical Field

[0001] The present invention belongs to the technical field of materials science and specifically relates to a high impermeability and high anti-disturbance cement-based repair material for tunnel engineering and a preparation method thereof. Background Art

[0002] With the rapid and vigorous development of transportation infrastructure construction, tunnel engineering, as an important part of transportation infrastructure, is also developing rapidly. Due to its characteristics such as shortening mileage, saving time and economic costs, tunnel engineering is indispensable in fields such as railways, highways, and urban underground rail transit, playing an important role in alleviating ground traffic pressure and connecting different regions, and is a key node to ensure the efficient and convenient transportation.

[0003] Tunnels are usually in complex underground geological environments and are under the combined action of various factors such as groundwater, formation stress, and temperature changes for a long time. The erosiveness of groundwater, the dynamic changes of formation stress, and the periodic fluctuations of temperature cause continuous damage to the tunnel lining structure. At the same time, the vibration load generated by vehicle driving in the tunnel will also have an adverse impact on the lining structure. Under the long-term action of the above complex environments, various diseases inevitably occur in the tunnel lining structure, among which lining cracks are one of the most common and harmful diseases. The appearance of cracks not only destroys the integrity of the lining structure but also provides a channel for the intrusion of groundwater and other harmful media, thereby triggering a series of disease problems such as leakage, steel bar corrosion, concrete cracking, and spalling. The existence of these disease problems not only affects the normal operation of the tunnel, has huge potential safety hazards, but also reduces the bearing capacity of the structure and seriously affects the service life of the tunnel. Therefore, it is extremely urgent for tunnel engineering to develop a repair material that can both improve impermeability performance and effectively resist disturbance.

[0004] With the vigorous development of the materials industry, repair materials applicable to the lining cracks of tunnel engineering have also emerged one after another and entered the public eye. Currently, the main repair materials for the lining cracks of tunnel engineering are modified ultra-fine cement, magnesium phosphate cement, early-strength Portland cement, polymer cement slurry, and epoxy resin repair materials.

[0005] Chinese invention patent CN118598635A provides a magnesium phosphate cement for tunnel crack repair and its preparation method. The magnesium phosphate cement of this invention uses magnesia raw materials, phosphate materials, and mineral admixtures as the main components, and adds a retarder, a temperature control agent, and a viscosity reducer to extend the final setting time of the magnesium phosphate cement, improve the fluidity of the slurry, increase the hourly strength and interfacial bonding performance. It realizes the effective control of the setting time of the magnesium phosphate cement and the significant improvement of the working performance, and has excellent hourly strength and interfacial bonding performance, effectively solving the problems of insufficient bonding performance, easy aging, and strength regression of existing repair and reinforcement materials. However, the cost is relatively high, and the insufficient long-term durability of the magnesium phosphate cement will instead cause the repaired part to fail prematurely.

[0006] Chinese invention patent CN117069465A provides a high impermeability cement-based repair material for tunnel engineering and its preparation method. The invention includes the following raw material components: Portland cement, quartz sand, fly ash, inorganic bentonite, active catalyst, desulfurized gypsum, polycarboxylate superplasticizer, cellulose ether, polyacrylamide, wood fiber, defoamer, and water. The high impermeability cement-based repair material has the advantages of high flexural and compressive strength, high bonding strength, high impermeability grade, large impermeability pressure, low dry shrinkage rate, and durability; it can solve the problem of poor self-waterproof performance of tunnel lining concrete in tunnel engineering, and can also repair the tunnel lining structure that has been deteriorated by leakage water, solving the problem of tunnel leakage water. It not only solves the problems of insufficient density, shrinkage cracking, or temperature load stress cracking of traditional lining concrete, resulting in poor self-waterproof ability, but also can timely repair and maintain the deteriorated traditional lining concrete, solving the problem of tunnel engineering leakage water. However, the cost is relatively high, sensitive to the amount of materials used, and easily affects the performance of the repair material.

[0007] Chinese invention patent CN105439506A provides a waterborne epoxy resin modified cement mortar repair material and its preparation method. The addition of waterborne epoxy resin and additives effectively improves the flexibility and bonding performance of the cement mortar, and the addition of calcium-magnesium expansive agent effectively improves the impermeability of the cement mortar. The expansion effect can compensate for the self-shrinkage of the modified mortar and reduce the shrinkage deformation. The waterborne epoxy resin modified cement mortar of this invention has the characteristics of short setting time, good fluidity, high compressive and flexural strength, earthquake resistance, low shrinkage deformation, durability, good waterproof performance, simple production, and convenient construction, and has extremely high bonding strength and excellent durability. However, it is greatly affected by changes in environmental temperature and humidity and is not very suitable for the repair of tunnel engineering.

[0008] Chinese Invention Patent CN110627445A provides a high impermeability cement-based repair material for tunnel engineering and its preparation method. This invention belongs to the technical field of building materials and is composed of portland cement, fly ash, silica fume, steel slag powder, rock powder, tailings sand, quartz sand, attapulgite clay, acrylate emulsion, cellulose ether, polyacrylamide, PVA fiber, PET fiber, polycarboxylate superplasticizer, and defoamer. It has the characteristics of easy construction, good workability, good water retention, high compressive strength, high impermeability grade, high toughness and adhesiveness, and excellent durability; it can be applied to the initial protection of lining concrete during the construction of tunnel engineering or the maintenance and repair in the later stage of the project. However, the cost is relatively high, and the fibers incorporated are not easily stirred evenly, affecting the overall compactness of the specimens. Summary of the Invention

[0009] To solve the problems existing in the prior art, the purpose of the present invention is to provide a high impermeability and high anti-disturbance cement-based repair material for tunnel engineering and its preparation method. The cement-based repair material provided by the present invention has good mechanical properties, high early strength, stable growth of later strength without reverse shrinkage, high impermeability and crack resistance, good anti-disturbance performance, good volume stability, good bonding performance between new and old interfaces, excellent durability, and is easy to prepare and convenient for construction.

[0010] To achieve the above purpose, the technical solutions adopted by the present invention are as follows: A high impermeability and high anti-disturbance cement-based repair material for tunnel engineering, in parts by mass, includes the following raw materials: 426 - 480 parts of ordinary portland cement, 90 - 100 parts of aluminate cement, 44 - 50 parts of hemihydrate gypsum, 135 - 160 parts of mineral powder, 80 - 135 parts of fly ash, 1.35 - 1.8 parts of nano-montmorillonite modified fiber, 1.5 - 2 parts of redispersible latex powder, 0.9 - 1.35 parts of superplasticizer, 0.9 - 1.35 parts of defoamer, 800 - 900 parts of quartz sand, and 240 - 270 parts of water.

[0011] Preferably, the ordinary portland cement uses P·O 42.5 ordinary portland cement with an SO 3 content of less than 5%, and the aluminate cement uses CA-50 aluminate cement.

[0012] Preferably, the mineral powder uses S95 grade granulated blast furnace slag powder, and the fly ash uses Class II fly ash.

[0013] Preferably, the superplasticizer uses a high-efficiency polycarboxylate powdered superplasticizer, and the defoamer uses P803 type powdered silicone defoamer.

[0014] Preferably, the dispersant uses sodium hexametaphosphate.

[0015] Preferably, the quartz sand used is graded quartz sand with a high purity and a particle size of 15 to 40 mesh, and the particle gradation meets the requirements of medium sand of Grade II.

[0016] The present invention also provides a preparation method of the high impermeability and high anti-disturbance cement-based repair material for tunnel engineering as described above, including the following processes: Mix ordinary Portland cement, aluminate cement, hemihydrate gypsum, mineral powder, fly ash, redispersible latex powder, nano-montmorillonite modified fiber, water reducing agent, defoaming agent and quartz sand evenly to obtain a dry material mixture; Add water to the dry material mixture and continuously stir. After the dry material mixture is mixed evenly with water, the high impermeability and high anti-disturbance cement-based repair material for tunnel engineering is obtained.

[0017] Preferably: when mixing ordinary Portland cement, aluminate cement, hemihydrate gypsum, mineral powder, fly ash, redispersible latex powder, nano-montmorillonite modified fiber, water reducing agent, defoaming agent and quartz sand evenly, the mixing time is 2 to 3 minutes; When adding water to the dry material mixture and continuously stirring, first add all the water to the dry material mixture within 1 to 2 minutes, and then continuously stir for 1 to 2 minutes to mix the dry material mixture evenly with water, and obtain the high impermeability and high anti-disturbance cement-based repair material for tunnel engineering.

[0018] Preferably, the preparation method of the nano-montmorillonite modified fiber includes: Soak the fiber in an anhydrous ethanol solution for 235 - 245 minutes, then wash it, and dry it at a constant temperature of 42 - 48 °C to constant weight to obtain the pretreated fiber; Mix deionized water: anhydrous ethanol: silane coupling agent according to the mass ratio of (0.9 - 1.1):(2.9 - 3.1):(0.1 - 0.3), adjust the pH to 4 - 5 with acetic acid, and then perform ultrasonic dispersion. After uniform dispersion, a silane coupling agent solution is obtained; Soak the pretreated fiber in the silane coupling agent for 115 - 125 minutes, wherein the mass ratio of the pretreated fiber to the deionized water in the silane coupling agent is 0.08:(0.9 - 1.1), then separate the fiber, and wash the fiber with a mixed solution of deionized water and anhydrous ethanol until neutral, and dry it to constant weight after washing to obtain the fiber treated with the silane coupling agent; Mix deionized water: sodium hexametaphosphate: nano-montmorillonite according to the mass ratio of (398 - 402):(1.4 - 1.6):(6 - 8), add acetic acid to adjust the pH to 5 - 6, quickly stir at 57 - 63 °C for 18 - 22 minutes, and then perform ultrasonic dispersion for 28 - 32 minutes to obtain a nano-montmorillonite solution; Add the fibers treated with silane coupling agent into the nano-montmorillonite solution, stir magnetically, and react at 57 - 63 °C for 175 - 185 min. Among them, the mass ratio of deionized water in the nano-montmorillonite solution treated with silane coupling agent is 5:(398 - 402); after the magnetic stirring ends, separate the fibers and wash them alternately with absolute ethanol and deionized water. After washing to neutrality, dry the fibers in vacuum at 57 - 63 °C for 355 - 365 min to obtain nano-montmorillonite modified fibers.

[0019] Preferably, The fibers are at least one of basalt fibers, PVA fibers, PP fibers, carbon fibers, and steel fibers; The silane coupling agent is KH-550 type silane coupling agent.

[0020] The present invention has the following beneficial effects: In the high anti-seepage and high anti-disturbance cement-based repair material for tunnel engineering of the present invention, mineral powder and fly ash can not only improve the fluidity and cohesion of the system, but also fill the voids between cement particles, refine the pore structure of the system, make the system more dense, and thus improve the anti-seepage property of the repair material. At the same time, they can undergo pozzolanic reactions with substances such as calcium hydroxide in cement to generate more hydrated calcium silicate gels, further improving the mechanical strength and durability of the mortar; the nano-montmorillonite modified fiber material can significantly improve the mechanical strength, bonding strength, anti-seepage property, and anti-disturbance property of the repair material. The main reason is that on the one hand, nano-montmorillonite has a large specific surface area and a layered structure, which can effectively block the penetration of moisture and harmful ions, improve the anti-seepage property of the repair material, and the layered structure can slip when the material is stressed, absorbing part of the energy, thus improving the toughness of the material; at the same time, the active components (such as SiO 2 and Al 2 O 3 in nano-montmorillonite can react with Ca(OH) 2The secondary hydration reaction occurs, generating new hydration products. These new hydration products fill the pores in the cement matrix, further enhancing the microstructure of the material. On the other hand, after the modified fibers are uniformly dispersed within the cement matrix, a three-dimensional network structure can be formed, which can effectively disperse stress and reduce the generation of cracks; at the same time, it enhances the toughness and anti-disturbance ability of the repair material, enabling it to withstand dynamic loads and vibrations in the tunnel environment; finally, montmorillonite nanoparticles adhere to the fiber surface to form a rougher structure, improving the mechanical bite force and thus enhancing the bonding performance between the repair material and the matrix. By adding redispersible latex powder, the bonding strength and cohesion of the cement-based repair material under temperature and humidity changes, ion erosion, and dynamic load effects can be significantly improved, and the impermeability and waterproofness of the repair material can also be enhanced. This is because the redispersible latex powder can fill the pores in the system to form a denser structure, and the latex powder can form a polymer film in the system, which can block water penetration while enhancing the interfacial bonding property, thereby improving the overall cohesion of the system and making the repair material bond more firmly to the concrete matrix; also, due to the polymer film formed by the latex powder having a certain elasticity, it can absorb part of the stress, enabling the repair material to have a certain deformation ability and further improving the anti-disturbance ability of the repair material. Specific embodiments

[0021] The technical solutions of the present invention are described in detail below in conjunction with specific embodiments. Each embodiment is an experimental example and provides real performance test data.

[0022] By improving the workability, mechanical properties, and bonding properties of the repair material, and at the same time fully solving the technical solutions of high impermeability and high anti-disturbance required for tunnel engineering repairs, through the combined action of composite mineral admixtures, nano-montmorillonite modified fiber materials, and redispersible latex powder, a high impermeability and high anti-disturbance cement-based repair material for tunnel engineering is obtained. The specific solutions of the present invention are as follows: The high impermeability and high anti-disturbance cement-based repair material for tunnel engineering of the present invention is made from raw materials including the following parts by mass: 426 - 480 parts of ordinary Portland cement, 90 - 100 parts of aluminate cement, 44 - 50 parts of hemihydrate gypsum, 135 - 160 parts of mineral powder, 80 - 135 parts of fly ash, 1.35 - 1.8 parts of nano-montmorillonite modified fiber, 1.5 - 2 parts of redispersible latex powder, 0.9 - 1.35 parts of water reducer, 0.9 - 1.35 parts of defoamer, 800 - 900 parts of quartz sand, and 240 - 270 parts of water.

[0023] In the above solution of the present invention, the ordinary Portland cement can adopt SO 3Ordinary Portland cement P·O 42.5 with a content less than 5%. The aluminate cement that can be used is aluminate cement of type CA-50. The hemihydrate gypsum that can be used is industrial-grade hemihydrate gypsum with a purity higher than 99.0%. The blast furnace slag powder that can be used is S95-grade granulated blast furnace slag powder. The fly ash that can be used is Class II fly ash. The water reducer that can be used is a highly efficient polycarboxylate powdered water reducer. The defoamer that can be used is P803-type powdered silicone defoamer. The dispersant that can be used is sodium hexametaphosphate. The quartz sand that can be used is high-purity quartz sand with a particle size of 15 - 40 mesh, and the particle size distribution meets the requirements of Class II medium sand.

[0024] The nano-montmorillonite modified fiber used in the above solution of the present invention is obtained by surface treating the fiber with nano materials and a silane coupling agent. Among them, the fiber can be at least one of basalt fiber, PVA fiber, PP fiber, carbon fiber, and steel fiber. The nano material is nano-montmorillonite. The silane coupling agent that can be used is KH-550 type silane coupling agent.

[0025] The preparation method of the high impermeability and high anti-disturbance cement-based repair material for tunnel engineering of the present invention includes the following steps: Step 1: First, soak the fiber in an anhydrous ethanol solution for 4h ± 5min, wash it, and then dry it at a constant temperature of 45 ± 3°C until constant weight to obtain the pretreated fiber; then mix deionized water: anhydrous ethanol: silane coupling agent in a mass ratio of 1 ± 0.1: 3 ± 0.1: 0.2 ± 0.1 in a beaker, adjust the pH to 4 - 5 using acetic acid, put the beaker into an ultrasonic disperser for ultrasonic dispersion, and obtain a silane coupling agent solution after uniform dispersion. Here, the dispersion time is related to the dosage of the raw materials, and the present invention does not make specific limitations; then take a certain amount of the aforementioned pretreated fiber and soak it in the prepared silane coupling agent for 2h ± 5min, take out the fiber, wash and filter it 2 - 3 times with a mixed solution of deionized water and anhydrous ethanol (at this time, it can be ensured that the washing is to neutral), and dry it in a vacuum oven at 80 ± 3°C for 6h ± 5min, cool it to room temperature, and then put the fiber into a drying dish and dry it until constant weight. Among them, the mass ratio of the pretreated fiber to the deionized water in the silane coupling agent is 0.08: 1 ± 0.1.

[0026] Step 2: Mix deionized water, sodium hexametaphosphate, and nano-montmorillonite at a mass ratio of 400±2:1.5±0.1:7±1. Then add an appropriate amount of acetic acid to adjust the pH to 5 - 6, and rapidly stir at 60±3°C for 20±2 min. Subsequently, ultrasonically disperse for 30±2 min using an ultrasonic disperser to obtain a nano-montmorillonite solution. Weigh a certain amount of the fibers treated with a silane coupling agent and put them into the prepared nano-montmorillonite solution. React using a magnetic stirrer at 60±3°C for 3 h±5 min. Fish out the reacted fibers and wash them alternately with anhydrous ethanol and deionized water three times (this can ensure washing to neutrality). After filtration, vacuum dry at 60±3°C for 6 h±5 min to obtain the final nano-montmorillonite modified fibers. Among them, the mass ratio of deionized water in the nano-montmorillonite solution treated with a silane coupling agent is 5:400±2.

[0027] Step 3: Moisten the mixer, and uniformly stir ordinary Portland cement, aluminate cement, hemihydrate gypsum, mineral powder, fly ash, redispersible latex powder, nano-montmorillonite modified fibers, water reducer, defoamer, and quartz sand in the mixer according to the ratio to form a dry material mixture. The stirring time is 2 - 3 min. Step 4: Sequentially add water to the dry material mixture obtained in Step 3 and stir slowly (140±5 r / min) for 1 - 2 min. Subsequently, increase the mixer speed to fast stirring (285±10 r / min) until the fibers are uniformly dispersed in the slurry without agglomeration, and then stop stirring. The stirring time is 1 - 2 min to obtain the high anti-seepage and high anti-disturbance cement-based repair material for tunnel engineering of the present invention.

[0028] In the above preparation method, the number after "±" of the parameter value is the allowable deviation of the corresponding parameter. Within the corresponding deviation range, the technical solutions of the present invention are all feasible.

[0029] The present invention uses a compound of ordinary Portland cement, aluminate cement, and hemihydrate gypsum, and incorporates mineral powder, fly ash, nano-montmorillonite modified fiber material, and redispersible latex powder, ensuring that the cement-based repair material has high early strength and steadily developing late strength. The specimens after disturbance also have high mechanical strength, and the anti-seepage and anti-cracking properties of the repair material are further improved. At the same time, the cement-based repair material of the present invention has good volume stability, good new-old interface bonding performance, good durability, is easy to prepare, and is convenient for construction. Compared with the prior art, the present invention has the following beneficial effects: The cement-based repair material of the present invention is composed of ordinary Portland cement, aluminate cement and hemihydrate gypsum as the matrix. The ternary system formed can quickly set and harden, shorten the repair time, have high early strength and stable growth of late strength, have a certain anti-disturbance property, and have a certain micro-expansibility, enabling the repair material to be closely combined with the concrete matrix, enhancing the bonding performance of the interface, having good impermeability and good durability. The main reason is that a large amount of ettringite and calcium aluminate hydrate can be generated in the early stage of the hydration of the ternary system, filling the voids inside the system, improving the porosity of the system, thereby increasing the density of the system and obtaining higher mechanical strength. At the same time, ettringite contains a large amount of crystal water and has a certain expansion property for the system, and can form a good bond with the base concrete; The added mineral powder and fly ash can not only improve the fluidity and cohesiveness of the system, but also fill the voids between cement particles, refine the pore structure of the system, make the system more dense, thereby improving the impermeability of the repair material. At the same time, it can undergo a pozzolanic reaction with substances such as calcium hydroxide in the cement to generate more calcium silicate hydrate gel, further improving the mechanical strength and durability of the mortar; The added nano-montmorillonite modified fiber material can significantly improve the mechanical strength, bonding strength, impermeability and anti-disturbance property of the repair material. The main reason is that on the one hand, nano-montmorillonite has a large specific surface area and a layered structure, which can effectively block the penetration of moisture and harmful ions, improve the impermeability of the repair material, and the layered structure can slip when the material is stressed, absorbing part of the energy, thereby improving the toughness of the material; at the same time, the active components in nano-montmorillonite (such as SiO 2 and Al 2 O 3 ) can undergo a secondary hydration reaction with Ca(OH) 2 in the cement hydration products to generate new hydration products, and these new hydration products fill the pores in the cement matrix, further enhancing the microstructure of the material. On the other hand, after the modified fibers are uniformly dispersed in the cement matrix, a three-dimensional network structure can be formed, which can effectively disperse stress and reduce the generation of cracks; at the same time, it enhances the toughness and anti-disturbance property of the repair material, enabling it to withstand the dynamic load and vibration in the tunnel environment; finally, the montmorillonite nano-particles adhere to the surface of the fibers to form a rougher structure, improving the mechanical bite force, and further improving the bonding performance between the repair material and the matrix.

[0030] The incorporated redispersible latex powder can significantly improve the bonding strength and cohesion of cement-based repair materials under temperature and humidity changes, ion erosion, and dynamic load, and can also improve the impermeability and waterproofness of the repair materials. This is because the redispersible latex powder can fill the pores in the system to form a denser structure, and the latex powder can form a polymer film in the system, which can block water penetration while enhancing the interfacial adhesion, thereby improving the overall cohesion of the system and making the repair material bond more firmly to the concrete matrix. Also, due to the polymer film formed by the latex powder having a certain elasticity, it can absorb part of the stress, enabling the repair material to have a certain deformation ability and further improving the anti-disturbance property of the repair material.

[0031] By adding defoaming agents, the internal bubbles of the cement-based repair material are significantly reduced, the pore structure of the system is improved, and the density of the repair material is further increased. This can not only improve the mechanical properties of the repair material but also improve its impermeability. By adding water reducers, the setting and hardening time of the repair material can be adjusted according to engineering requirements, and the fluidity of the slurry is increased, which is conducive to on-site construction.

[0032] In the following embodiments of the present invention, two kinds of nano-montmorillonite modified fibers are used. In one kind of nano-montmorillonite modified fiber, the fiber is a PP fiber, and this nano-montmorillonite modified fiber is denoted as nano-montmorillonite modified PP fiber; in the other kind of nano-montmorillonite modified fiber, the fiber is a PVA fiber, and this nano-montmorillonite modified fiber is denoted as nano-montmorillonite modified PVA fiber.

[0033] The preparation method of the nano-montmorillonite modified PP fiber includes the following steps: Step 1: First, soak the PP fiber in an anhydrous ethanol solution for 4 h, wash it, and then dry it at a constant temperature of 45 °C until constant weight; then mix deionized water: anhydrous ethanol: KH-550 silane coupling agent in a mass ratio of 1:3:0.2 in a beaker, adjust the pH to 4 - 5 with acetic acid, put the beaker into an ultrasonic disperser for ultrasonic dispersion for 15 min to obtain a silane coupling agent solution; then take a certain amount of PP fiber and soak it in the prepared silane coupling agent for 2 h, take out the fiber, wash and filter it 3 times with a mixed solution of deionized water and anhydrous ethanol, and dry it in a vacuum oven at 80 °C for 6 h, cool it to room temperature, and then put the fiber into a drying dish to dry until constant weight. Among them, the mass ratio of the pretreated fiber to the deionized water in the silane coupling agent is 8:100.

[0034] Step 2: Mix deionized water, sodium hexametaphosphate, and nano-montmorillonite in a mass ratio of 400:1.5:7. Then add an appropriate amount of acetic acid to adjust the pH to 5 - 6. Stir at a high speed (2000 r / min) with a magnetic stirrer at 60 °C for 20 min, and then ultrasonically disperse for 30 min using an ultrasonic disperser. Weigh a certain amount of fibers treated with a silane coupling agent and put them into the prepared nano-montmorillonite solution. React with a magnetic stirrer at 60 °C for 3 h. Take out the reacted fibers and wash them alternately with anhydrous ethanol and deionized water 3 times. After filtration, dry them in a vacuum at 60 °C for 6 h to obtain the final nano-montmorillonite modified PP fibers. Among them, the mass ratio of deionized water in the nano-montmorillonite solution treated with a silane coupling agent is 5:400.

[0035] The preparation method of nano-montmorillonite modified PVA fibers is the same as that of nano-montmorillonite modified PP fibers. The only difference is the fibers used. The fibers used in the preparation of nano-montmorillonite modified PVA fibers are PVA fibers.

[0036] In the following examples and comparative examples of the present invention, ordinary Portland cement uses P·O 42.5 ordinary Portland cement with an SO 3 content of less than 5%. The aluminate cement uses aluminate cement of type CA-50. The mineral powder uses S95 grade granulated blast furnace slag powder. The fly ash uses grade II fly ash. The water reducer uses a high-performance polycarboxylate powder water reducer. The defoamer uses P803 type powdered silicone defoamer. The dispersant uses sodium hexametaphosphate. The quartz sand uses high-purity quartz sand with a particle size of 15 - 40 mesh, and the particle size distribution meets the requirements of grade II medium sand.

[0037] Example 1 By mass, the raw materials of the high anti-seepage and high anti-disturbance cement-based repair material for tunnel engineering in this example include: 480 g of ordinary Portland cement, 100 g of aluminate cement, 50 g of hemihydrate gypsum, 135 g of mineral powder, 135 g of fly ash, 270 g of water, 1.35 g of nano-montmorillonite modified PP fibers, 1.08 g of high-performance polycarboxylate water reducer, 1.08 g of P803 type powdered defoamer, and 900 g of quartz sand.

[0038] Prepare the above raw materials into a high anti-seepage and high anti-disturbance cement-based repair material for tunnel engineering according to the following steps: Step 1: Wet the mixer. According to the ratio, mix ordinary Portland cement, aluminate cement, hemihydrate gypsum, mineral powder, fly ash, redispersible latex powder, nano-montmorillonite modified PP fibers, water reducer, defoamer, and quartz sand in the mixer and stir well to form a dry material mixture. The stirring time is 3 min; Step 2: Add water to the dry material mixture obtained in Step 1 and stir slowly for 2 minutes; then increase the rotational speed of the mixer to fast stirring until the PP fibers are evenly dispersed in the slurry without agglomeration, and stop stirring after 2 minutes to obtain the high anti-seepage and high anti-disturbance cement-based repair material for tunnel engineering in this example.

[0039] Example 2 By mass, the raw materials of the high anti-seepage and high anti-disturbance cement-based repair material for tunnel engineering in this example include: 480 g of ordinary Portland cement, 100 g of aluminate cement, 50 g of hemihydrate gypsum, 135 g of mineral powder, 135 g of fly ash, 270 g of water, 1.8 g of nano-montmorillonite modified PP fiber, 1.26 g of high-efficiency polycarboxylate water reducer, 1.26 g of P803 type powder defoamer, and 900 g of quartz sand.

[0040] The preparation method of the high anti-seepage and high anti-disturbance cement-based repair material for tunnel engineering in this example is the same as that of Example 1.

[0041] Example 3 By mass, the raw materials of the high anti-seepage and high anti-disturbance cement-based repair material for tunnel engineering in this example include: 426 g of ordinary Portland cement, 90 g of aluminate cement, 44 g of hemihydrate gypsum, 160 g of mineral powder, 80 g of fly ash, 240 g of water, 1.8 g of nano-montmorillonite modified PP fiber, 2 g of renewable latex powder, 1.35 g of high-efficiency polycarboxylate water reducer, 1.35 g of P803 type powder defoamer, and 800 g of quartz sand.

[0042] The preparation method of the high anti-seepage and high anti-disturbance cement-based repair material for tunnel engineering in this example is the same as that of Example 1.

[0043] Example 4 By mass, the raw materials of the high anti-seepage and high anti-disturbance cement-based repair material for tunnel engineering in this example include: 426 g of ordinary Portland cement, 90 g of aluminate cement, 44 g of hemihydrate gypsum, 160 g of mineral powder, 80 g of fly ash, 240 g of water, 1.35 g of nano-montmorillonite modified PVA fiber, 2 g of renewable latex powder, 1.26 g of high-efficiency polycarboxylate water reducer, 1.26 g of P803 type powder defoamer, and 800 g of quartz sand.

[0044] The preparation method of the high anti-seepage and high anti-disturbance cement-based repair material for tunnel engineering in this example is the same as that of Example 1.

[0045] Example 5 By mass fraction, the raw materials of the high anti-seepage and high anti-disturbance cement-based repair material for tunnel engineering in this embodiment include: 480 g of ordinary Portland cement, 100 g of aluminate cement, 50 g of hemihydrate gypsum, 135 g of mineral powder, 135 g of fly ash, 270 g of water, 1.35 g of nano-montmorillonite modified PVA fiber, 1.5 g of renewable latex powder, 1.35 g of high-efficiency polycarboxylate water reducer, 1.35 g of P803 type powder defoamer, and 900 g of quartz sand.

[0046] The preparation method of the high anti-seepage and high anti-disturbance cement-based repair material for tunnel engineering in this embodiment is the same as that in Example 1.

[0047] Comparative example; By mass fraction, the raw materials of the repair material in this comparative example include: 480 g of ordinary Portland cement, 100 g of aluminate cement, 50 g of hemihydrate gypsum, 135 g of mineral powder, 135 g of fly ash, 270 g of water, 0.9 g of high-efficiency polycarboxylate water reducer, 0.9 g of P803 type powder defoamer, and 900 g of quartz sand.

[0048] The preparation method of the repair material in this comparative example is the same as that in Example 1.

[0049] The various performance tests of the specimens of the materials obtained in the above Examples 1 to 5 and the comparative example under different conditions are shown in the following Table 1: Table 1

[0050] It can be seen from the test results in Table 1 that the initial setting and final setting times of the embodiments of the present invention are appropriate, and the time interval between the initial setting time and the final setting time is relatively low, so that the disturbed period of the repair material is short, reducing the probability of the repair material being disturbed; the early strength and late strength performance are excellent, the 1-day compressive strength after being disturbed is above 40 MPa, the 1-day flexural strength is greater than 9 MPa, the 28-day compressive strength is above 72 MPa, and the 28-day flexural strength is greater than 15 MPa; the bond strength is much improved compared with the comparative example, and the bond strength loss after being disturbed also becomes smaller, indicating that the repair material has a high anti-disturbance ability and can improve the negative impact of disturbance on the cement-based repair material. At the same time, it can also be seen from Table 1 that the anti-seepage performance of the mortar specimens prepared in each embodiment is also excellent.

[0051] In summary, the high anti-seepage and high anti-disturbance cement-based repair material for tunnel engineering provided by the present invention has good mechanical properties, bond properties, anti-seepage properties and anti-disturbance properties, and can be well used for the repair of tunnel engineering concrete structures.

[0052] Obviously, the described embodiments are only partial embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent replacements can still be made to the specific implementation manners of the present invention, and any modification or equivalent replacement without departing from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A high-permeability and high-disturbance cement-based repair material for tunnel engineering, characterized in that: In parts by mass, it includes the following raw materials: 426~480 parts of ordinary Portland cement, 90~100 parts of aluminate cement, 44~50 parts of hemihydrate gypsum, 135~160 parts of mineral powder, 80~135 parts of fly ash, 1.35~1.8 parts of nano-montmorillonite modified fiber, 1.5~2 parts of redispersible latex powder, 0.9~1.35 parts of water reducer, 0.9~1.35 parts of defoaming agent, 800~900 parts of quartz sand, and 240~270 parts of water.

2. The high-permeability and high-disturbance cement-based repair material for tunnel engineering according to claim 1, characterized in that: The ordinary Portland cement is P·O 42.5 ordinary Portland cement with a SO3 content of less than 5%, and the aluminate cement is CA-50 aluminate cement.

3. The high-permeability and high-disturbance cement-based repair material for tunnel engineering according to claim 1, characterized in that: The mineral powder is S95 grade granulated blast furnace slag powder, and the fly ash is grade II fly ash.

4. The high-permeability and high-disturbance cement-based repair material for tunnel engineering according to claim 1, characterized in that: The water reducing agent is a high-efficiency polycarboxylic acid powdered water reducing agent, and the defoaming agent is a P803 type powdered organic silicon defoaming agent.

5. The high-permeability and high-disturbance cement-based repair material for tunnel engineering according to claim 1, characterized in that: The dispersant is sodium hexametaphosphate.

6. The high-permeability and high-disturbance cement-based repair material for tunnel engineering according to claim 1, characterized in that: The quartz sand is high-purity graded quartz sand with a particle size of 15-40 meshes, and the particle grading meets the requirements of Grade II medium sand.

7. A method for preparing a high-permeability and high-disturbance cement-based repair material for tunnel engineering according to any one of claims 1 to 6, characterized in that: The process includes the following: Ordinary Portland cement, aluminate cement, semi-hydrated gypsum, mineral powder, fly ash, redispersible latex powder, nano-montmorillonite modified fiber, water reducing agent, defoaming agent and quartz sand are uniformly mixed to obtain a dry material mixture; Water is added to the dry material mixture and stirred continuously. After the dry material mixture and the water are evenly mixed, the high-impermeability and high-disturbance-resistant cement-based repair material for tunnel engineering is obtained.

8. The method for preparing a high-impermeability and high-disturbance cement-based repair material for tunnel engineering according to claim 7, characterized in that: When ordinary Portland cement, aluminate cement, hemihydrate gypsum, mineral powder, fly ash, redispersible latex powder, nano-montmorillonite modified fiber, water reducing agent, defoaming agent and quartz sand are mixed evenly, the mixing time is 2-3 minutes; When adding water to the dry material mixture and continuously stirring, first add all the water to the dry material mixture within 1 to 2 minutes, and then continue stirring for 1 to 2 minutes to mix the dry material mixture and water to obtain the high-permeability and high-disturbance cement-based repair material for tunnel engineering.

9. The method for preparing a high-impermeability and high-disturbance cement-based repair material for tunnel engineering according to claim 8, characterized in that: The preparation method of the nano-montmorillonite modified fiber comprises: The fiber is immersed in an anhydrous ethanol solution for 235-245 minutes, then washed, and dried at a constant temperature of 42-48° C. to a constant weight to obtain a pretreated fiber; Deionized water: anhydrous ethanol: silane coupling agent are mixed in a mass ratio of (0.9-1.1): (2.9-3.1): (0.1-0.3), and the pH is adjusted to 4-5 with acetic acid, and then ultrasonically dispersed to obtain a silane coupling agent solution after uniform dispersion; The pretreated fiber is immersed in a silane coupling agent for 115-125 minutes, wherein the mass ratio of the pretreated fiber to the deionized water in the silane coupling agent is 0.08:(0.9-1.1), and then the fiber is separated and washed with a mixture of deionized water and anhydrous ethanol until neutral, and then dried to constant weight after washing to obtain the fiber treated with the silane coupling agent; Deionized water: sodium hexametaphosphate: nano-montmorillonite are mixed in a mass ratio of (398-402): (1.4-1.6): (6-8), and acetic acid is added to adjust the pH to 5-6, and the mixture is rapidly stirred at 57-63°C for 18-22 minutes, and then ultrasonically dispersed for 28-32 minutes to obtain a nano-montmorillonite solution; The fiber treated with silane coupling agent is added to the nano-montmorillonite solution, and reacted at 57-63°C for 175-185 minutes using magnetic stirring, wherein the mass ratio of deionized water in the nano-montmorillonite solution treated with silane coupling agent is 5:(398-402); after the magnetic stirring, the fiber is separated and washed alternately with anhydrous ethanol and deionized water, and after washing to neutrality, the fiber is vacuum dried at 57-63°C for 355-365 minutes to obtain nano-montmorillonite modified fiber.

10. The method for preparing a high-impermeability and high-disturbance cement-based repair material for tunnel engineering according to claim 9, characterized in that: The fiber is at least one of basalt fiber, PVA fiber, PP fiber, carbon fiber and steel fiber; The silane coupling agent used is KH-550 silane coupling agent.

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