A nanocomposite modified wet-sprayed concrete interface reinforcing admixture

Abstract

This invention relates to the field of interface strengthening admixtures for wet-mixed sprayed concrete, and discloses a nanocomposite modified interface strengthening admixture for wet-mixed sprayed concrete, comprising the following components in parts by weight: 5-15 parts nano-silica, 3-10 parts nano-calcium carbonate, 0.5-3 parts graphene oxide, 2-8 parts polyvinyl alcohol, 1-5 parts polyacrylamide, 0.5-5 parts AR glass fiber, 2-10 parts bentonite, 1-8 parts zeolite powder, 0.5-3 parts polycarboxylate superplasticizer, and 0.1-0.5 parts defoamer. This invention, through the synergistic effect of AR glass fiber, bentonite, and zeolite powder in the nanocomposite components, reduces the rebound rate of wet-mixed sprayed concrete and increases the thickness of a single spraying, while simultaneously improving interfacial bond strength. It utilizes the thixotropic properties of bentonite to balance pumpability and sprayability, achieves internal curing, inhibits shrinkage cracking, and results in better overall performance.

Description

Technical Field

[0001] This invention relates to the field of interface-reinforcing admixtures for wet-sprayed concrete, specifically a nano-composite modified interface-reinforcing admixture for wet-sprayed concrete. Background Technology

[0002] As the core regulating facility of the new power system, pumped storage power stations face multiple challenges during construction due to the characteristics of their underground powerhouse caverns, such as large spans, high sidewalls, and complex structures. These challenges include high rebound rate of wet-sprayed concrete, ventilation optimization, and structural stability control. Currently, the rebound rate of wet-sprayed concrete in hydraulic and transportation tunnels is generally 20% to 30%. In engineering practice, quality defects in wet-sprayed concrete are mostly caused by improper base treatment, excessively thin single layers, insufficient curing, or equipment defects. The rebound rate depends on the adhesion between the concrete and the rock mass and its own cohesion: a clean and moist base can enhance adhesion, while increased cohesion reduces detachment. Due to the high construction difficulty, the tunnel arch has become a key part of quality control.

[0003] Current research focuses primarily on the mechanical properties of cured shotcrete, with insufficient attention paid to the workability of freshly mixed concrete. Reducing rebound requires enhancing sprayability, but this may sacrifice pumpability; balancing these two aspects is a technical challenge. There is a need to develop a nanocomposite modifier that can simultaneously enhance interfacial adhesion, balance pumpability and sprayability, reduce rebound rate, and improve post-curing strength and durability. Therefore, we propose a nanocomposite modified wet-mix shotcrete interfacial strengthening admixture. Summary of the Invention

[0004] The purpose of this invention is to provide a nanocomposite modified wet sprayed concrete interface reinforcing admixture, which solves the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a nano-composite modified wet-sprayed concrete interface reinforcing admixture, comprising the following components in parts by weight: 5-15 parts nano-silica, 3-10 parts nano-calcium carbonate, 0.5-3 parts graphene oxide, 2-8 parts polyvinyl alcohol, 1-5 parts polyacrylamide, 0.5-5 parts AR glass fiber, 2-10 parts bentonite, 1-8 parts zeolite powder, 0.5-3 parts polycarboxylate superplasticizer, and 0.1-0.5 parts defoamer.

[0006] As a preferred embodiment of the present invention, the specific weight parts are: 10 parts of nano-silica, 6 parts of nano-calcium carbonate, 1.5 parts of graphene oxide, 5 parts of polyvinyl alcohol, 3 parts of polyacrylamide, 2.5 parts of AR glass fiber, 6 parts of bentonite, 4 parts of zeolite powder, 1.5 parts of polycarboxylate superplasticizer, and 0.3 parts of organosilicon defoamer.

[0007] As a preferred embodiment of the present invention, the specific weight parts are: 12 parts of nano-silica, 4 parts of nano-calcium carbonate, 2 parts of graphene oxide, 6 parts of polyvinyl alcohol, 2 parts of polyacrylamide, 4 parts of AR glass fiber, 8 parts of bentonite, 5 parts of zeolite powder, 2 parts of polycarboxylate superplasticizer, and 0.2 parts of organosilicon defoamer; the synthesized zeolite powder has a particle size of 800 mesh and a porosity of 55%.

[0008] In a preferred embodiment of the present invention, the specific weight parts are as follows: 8 parts nano-silica, 8 parts nano-calcium carbonate, 1 part graphene oxide, 4 parts polyvinyl alcohol, 4 parts polyacrylamide, 3 parts AR glass fiber, 7 parts bentonite, 7 parts zeolite powder, 2.5 parts polycarboxylate superplasticizer, and 0.3 parts defoamer; the sodium-based modified bentonite is an organic intercalated modified bentonite with an interlayer spacing of not less than 1.8 nm; the natural clinoptilolite powder has a particle size of 1000 mesh and a porosity of 50%.

[0009] In a preferred embodiment of the present invention, the AR glass fiber has a length of 3-12 mm, a single filament diameter of 10-20 μm, and a zirconium oxide content of ≥16.5%; the bentonite has a fineness of ≥200 mesh; and the zeolite powder has a fineness of 200-1200 mesh and a porosity of ≥30%.

[0010] In a preferred embodiment of the present invention, the bentonite is sodium-based bentonite, calcium-based bentonite, or organically modified bentonite.

[0011] In a preferred embodiment of the present invention, the zeolite powder is natural clinoptilolite powder or synthetic zeolite powder.

[0012] In a preferred embodiment of the present invention, the additive is in powder form and is prepared by the following method: nano-silica, nano-calcium carbonate, graphene oxide, polyvinyl alcohol, and polyacrylamide are dry-mixed at 1000-1500 rpm for 10-15 min to obtain premixed powder A; AR glass fiber, bentonite, zeolite powder, polycarboxylate superplasticizer, and defoamer are dry-mixed at 300-500 rpm for 8-12 min to obtain mixture B; A and B are mixed at 20-40 rpm for 15-30 min and then passed through a 60-80 mesh sieve.

[0013] In a preferred embodiment of the present invention, the admixture is added to wet-sprayed concrete at a dosage of 5%-7% of the mass of the cementitious material.

[0014] In a preferred embodiment of the present invention, the admixture is used in combination with an alkali-free liquid quick-setting agent, wherein the amount of quick-setting agent is 6%-6.5% of the mass of the cementitious material.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] 1. This invention reduces the rebound rate of wet-sprayed concrete and increases the thickness of a single spraying by using AR glass fiber, bentonite and zeolite powder as synergistic nanocomposite components. At the same time, it improves the interfacial bonding strength, balances pumpability and sprayability by utilizing the thixotropic properties of bentonite, achieves internal curing, inhibits shrinkage cracking, and has better overall performance.

[0017] 2. The AR glass fiber of this invention forms a three-dimensional randomized network to resist jet impact, bentonite reduces viscosity during pumping and restores viscosity after spraying, and zeolite powder with a porous structure adsorbs the slurry and forms a mechanical interlock with the rock wall. The three components, together with the nanocomposite components, can reduce the rebound rate of the arch, increase the thickness of a single spray, enhance the bond strength between concrete and rock wall, effectively reduce plastic shrinkage cracks, and the water absorption and expansion characteristics of bentonite can slowly release water during hydration, playing an internal curing role and inhibiting drying shrinkage cracking. Detailed Implementation

[0018] To make the technical means, creative features, achieved objectives and effects of this invention easily understood, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention. The core improvement of this invention lies in providing a nanocomposite modified wet-mixed sprayed concrete interface reinforcing admixture. This admixture introduces AR glass fiber, bentonite, and porous materials into the nanocomposite modified components. AR glass fiber reduces the spray rebound rate; the water absorption, expansion, and thixotropic properties of bentonite balance pumpability and sprayability while achieving internal curing; and the adsorption and mechanical interlocking effects of porous materials enhance the interfacial adhesion between wet-mixed sprayed concrete and the rock wall. Simultaneously, the fibers and bentonite powder form a fiber-clay composite network, reducing the rebound rate and inhibiting cracking. The following embodiments are all based on the scope of protection of the claims of this invention, detailing the admixture formulation, preparation process, application method, and performance testing to ensure that those skilled in the art can completely reproduce the technical solution of this invention.

[0019] The nanocomposite modified wet-mixed sprayed concrete interface reinforcing admixture used in this invention has the following basic formula range by weight: 5-15 parts nano-silica, 3-10 parts nano-calcium carbonate, 0.5-3 parts graphene oxide, 2-8 parts polyvinyl alcohol, 1-5 parts polyacrylamide, 0.5-5 parts AR glass fiber, 2-10 parts bentonite, 1-8 parts zeolite powder, 0.5-3 parts polycarboxylate superplasticizer, and 0.1-0.5 parts defoamer. The AR glass fiber has a length of 3-12 mm, a single filament diameter of 10-20 μm, and a zirconium oxide content ≥16.5%; the bentonite is sodium-based bentonite, calcium-based bentonite, or modified bentonite, with a fineness ≥200 mesh; the zeolite powder is natural clinoptilolite powder or synthetic zeolite powder, with a fineness of 200-1200 mesh and a porosity ≥30%. Each component is made into a powder admixture through dry mixing or spray drying processes. When used on site, it is added to the wet sprayed concrete mixture at 5%-7% of the mass of the cementitious materials.

[0020] The above-mentioned additive is prepared by dry mixing, and the specific steps are as follows: Nano silica, nano calcium carbonate, graphene oxide, polyvinyl alcohol, and polyacrylamide are weighed according to the proportion and put into a high-speed mixer and dry mixed at 1000-1500 rpm for 10-15 min to obtain nano-composite premixed powder A; AR glass fiber, bentonite, zeolite powder, polycarboxylate superplasticizer, and defoamer are put into another mixer and dry mixed at 300-500 rpm for 8-12 min to obtain powder mixture B; A and B are combined and put into a three-dimensional motion mixer and mixed at 20-40 rpm for 15-30 min, and then passed through a 60-80 mesh sieve to obtain powdered additive, which is then sealed and packaged for later use.

[0021] The present invention will be further illustrated by the following three specific embodiments.

[0022] Example 1

[0023] This embodiment provides a nanocomposite modified wet-mixed sprayed concrete interface reinforcing admixture, prepared by dry mixing method, with the specific formulation as follows:

[0024] Nano silica: 10 parts; nano calcium carbonate: 6 parts; graphene oxide: 1.5 parts; polyvinyl alcohol: 5 parts; polyacrylamide: 3 parts; AR glass fiber: 2.5 parts; sodium bentonite: 6 parts; zeolite powder: 4 parts; polycarboxylate superplasticizer: 1.5 parts; silicone defoamer: 0.3 parts.

[0025] The preparation method is as follows:

[0026] Nano-silica, nano-calcium carbonate, graphene oxide, polyvinyl alcohol, and polyacrylamide were weighed according to the above proportions and then dry-mixed in a high-speed mixer at 1500 rpm for 10 minutes to obtain nano-composite premixed powder A. AR glass fiber, sodium bentonite, zeolite powder, polycarboxylate superplasticizer, and defoamer were added to another mixer and dry-mixed at 500 rpm for 8 minutes to obtain powder mixture B. A and B were combined and added to a three-dimensional motion mixer and mixed at 30 rpm for 20 minutes to ensure uniform distribution of each component. The mixture was then passed through a 60-mesh sieve to obtain the powdered additive, which was then sealed and packaged for later use.

[0027] When wet-sprayed concrete construction is required, the concrete should be prepared according to the following mix proportions:

[0028] Cement: PO42.5 ordinary Portland cement, 450 kg / m³; Sand: medium sand with a fineness modulus of 2.7, 850 kg / m³; Crushed stone: 5-10 mm continuous gradation, 750 kg / m³; Water: 180 kg / m³, water-cement ratio 0.40; Accelerating agent: alkali-free liquid accelerating agent, dosage is 6% of the mass of cementitious materials; Admixture of this invention: dosage is 5% of the mass of cementitious materials.

[0029] Construction method: Pre-mix cement, sand, crushed stone, and the admixture of this invention dry for 30 seconds, add 70% mixing water and mix for 60 seconds, then add the remaining 30% mixing water and quick-setting agent, and continue mixing for 90 seconds to obtain the wet-sprayed concrete mixture. Apply the wet-spraying process, with a spraying distance of 1.0-1.5m, a spraying angle of 80°-90°, and an air pressure of 0.4-0.6MPa.

[0030] Performance tests were conducted on the cured shotcrete, and a control group without the admixture of this invention was also tested. The control group used the same concrete mix proportions but without the admixture of this invention. The test results are shown in Table 1 below:

[0031]

[0032] As shown in Table 1, the rebound rate of the wet-sprayed concrete in this embodiment is only 11.5% at the arch crown, which is much lower than the 27.5% of the control group, demonstrating a significant effect in reducing rebound. The slump loss after 1 hour is only 15 mm, indicating excellent slump retention and good pumpability. The maximum thickness of a single spray can reach 155 mm, which is much higher than the 90 mm of the control group, indicating a significant enhancement in the adhesion between the concrete and the rock wall. The 28-day compressive strength and splitting tensile strength are increased by 14.5% and 32.3% respectively, the bond strength is increased by 52.9%, and the plastic shrinkage crack area ratio is reduced by 71.0%. The reasons are as follows: AR glass fibers form a three-dimensional randomly distributed network, resisting particle shedding caused by jet impact; the thixotropic properties of bentonite reduce viscosity during pumping shearing and restore viscosity after spraying, balancing pumpability and sprayability; simultaneously, the adsorbed water in its interlayer is gradually released during the hydration exothermic stage, achieving internal curing function and effectively inhibiting shrinkage cracking; the porous structure of zeolite powder adsorbs slurry moisture and polymer molecules, forming a suction cup effect and mechanical interlock with the micro-rough structure of the rock wall, significantly improving interfacial adhesion. Therefore, the overall performance of this embodiment is significantly better than the control group.

[0033] Example 2

[0034] This embodiment provides a nanocomposite modified wet-mixed sprayed concrete interface reinforcing admixture, prepared by dry mixing. The formulation increases the content of AR glass fiber and uses calcium-based bentonite and zeolite powder with a finer particle size. The specific formulation is as follows:

[0035] Nano silica: 12 parts; nano calcium carbonate: 4 parts; graphene oxide: 2 parts; polyvinyl alcohol: 6 parts; polyacrylamide: 2 parts; AR glass fiber: 4 parts; calcium-based bentonite: 8 parts; zeolite powder: 5 parts (synthetic zeolite powder with a particle size of 800 mesh and a porosity of 55%); polycarboxylate superplasticizer: 2 parts; silicone defoamer: 0.2 parts.

[0036] The preparation method is as follows:

[0037] Nano-silica, nano-calcium carbonate, graphene oxide, polyvinyl alcohol, and polyacrylamide were weighed according to a certain ratio and then dry-mixed in a high-speed mixer at 1500 rpm for 10 minutes to obtain nano-composite premixed powder A. AR glass fiber, calcium-based bentonite, zeolite powder, polycarboxylate superplasticizer, and defoamer were added to another mixer and dry-mixed at 500 rpm for 8 minutes to obtain powder mixture B. A and B were combined and added to a three-dimensional motion mixer and mixed at 30 rpm for 20 minutes to ensure that the fibers were evenly distributed in the powder. The mixture was then passed through a 60-mesh sieve to obtain the powdered additive, which was then sealed and packaged for later use.

[0038] The mix proportion and application method of wet sprayed concrete are the same as in Example 1, except that: the admixture dosage of this invention is adjusted to 6.5% of the mass of cementitious materials, the spraying distance is adjusted to 1.2 to 1.8 meters, and the wind pressure is 0.45 to 0.55 MPa.

[0039] Performance tests were conducted on the cured sprayed concrete, and a control group was also tested, identical to that in Example 1. The test results are shown in Table 2 below:

[0040]

[0041] As shown in Table 2, the rebound rate of the wet-sprayed concrete in this embodiment was further reduced to 9.8%, a decrease of 64.4% compared to the control group; the maximum thickness of a single spraying reached 180 mm, the bond strength increased by 70.6%, the 28-day compressive strength increased by 24.2%, and the plastic shrinkage cracks were completely eliminated. Compared with Example 1, the rebound rate control effect was better due to the increase of AR glass fiber content from 2.5 parts to 4 parts; the water absorption rate of calcium-based bentonite was milder than that of sodium-based bentonite, which was beneficial to controlling the initial fluidity of the mixture; the synthetic zeolite powder had a finer particle size and higher porosity, forming a better mechanical interlocking effect with the fiber, further enhancing the interfacial adhesion. This embodiment adopted a dry-mixing process, with lower equipment investment and energy consumption, suitable for industrial mass production. However, attention should be paid to the slight impact of the increased fiber content on pumpability. The initial slump of 195 mm is still within a good range, and the formula can be selected according to the actual construction conditions.

[0042] Example 3

[0043] This embodiment provides a nano-composite modified wet-mixed sprayed concrete interface reinforcing admixture, prepared by a dry-mixing method. It further incorporates organically modified bentonite to enhance internal curing effects, and uses a high dosage of zeolite powder supplemented with a fly ash cementitious system. The formulation balances cost control and environmental friendliness. The specific formulation is as follows:

[0044] Nano-silica: 8 parts; Nano-calcium carbonate: 8 parts; Graphene oxide: 1 part; Polyvinyl alcohol: 4 parts; Polyacrylamide: 4 parts; AR glass fiber: 3 parts; Sodium-modified bentonite: 7 parts, organically intercalated, interlayer spacing not less than 1.8 nm; Zeolite powder: 7 parts, natural clinoptilolite powder, particle size 1000 mesh, porosity 50%; Polycarboxylate superplasticizer: 2.5 parts; Defoamer: 0.3 parts; Preparation method is as follows:

[0045] Nano-silica, nano-calcium carbonate, graphene oxide, polyvinyl alcohol, and polyacrylamide were weighed according to the specified ratio and then dry-mixed in a high-speed mixer at 1500 rpm for 12 minutes to obtain nano-composite premixed powder A. AR glass fiber, sodium-modified bentonite, zeolite powder, polycarboxylate superplasticizer, and defoamer were added to another mixer and dry-mixed at 500 rpm for 10 minutes to obtain powder mixture B. A and B were combined and added to a three-dimensional motion mixer and mixed at 30 rpm for 25 minutes to ensure uniform dispersion of each component. The mixture was then passed through an 80-mesh sieve to obtain the powdered additive, which was then sealed and packaged for later use.

[0046] The mix proportion and application method of wet sprayed concrete are the same as in Example 1, except that: a cementitious system of 420 kg of cement per cubic meter and 60 kg of fly ash per cubic meter is used. The admixture dosage of this invention is 7% of the mass of cementitious materials, the water-cement ratio is 0.40, and the accelerator dosage is 6.5%.

[0047] Performance tests were conducted on the cured shotcrete, and the control group and long-term durability indicators were also tested. The control group was the same as in Example 1. The test results are shown in Table 3 below:

[0048]

[0049] As shown in Table 3, the rebound rate of the wet-sprayed concrete in this embodiment was 10.5%, which was 61.8% lower than that of the control group; the 28-day splitting tensile strength increased by 45.2%, and the bond strength increased by 62.4%; the sulfate erosion resistance coefficient increased from 0.78 to 0.92, and the durability was significantly improved. The unique advantages of this embodiment are: the zeolite powder content was increased to 7 parts, and its rich and regular pore structure not only provides stronger water storage and release capacity, but also forms a synergistic internal curing network with modified bentonite. The auto-shrinkage was reduced by about 35% after 7 days according to comparative tests. Moreover, the hardness of zeolite powder means that the volume does not shrink after water release, effectively supporting the coating structure and avoiding pitting; the interlayer spacing of the organic modified bentonite was increased, the water absorption expansion ratio was reduced but the water retention capacity was enhanced, making it more suitable for composite use with fibers and avoiding loss of slurry fluidity due to excessive expansion. In addition, by using fly ash to replace part of the cement, this embodiment can meet the performance requirements while having significant low-carbon characteristics. The amount of cement used can be reduced by about 30 kg per cubic meter of concrete, and carbon dioxide emissions can be reduced by about 24 kg, which meets the requirements of green environmental protection.

[0050] Example 4

[0051] To verify the synergistic effect of the present invention, a comparative example was set up: containing only the nanocomposite modified components, specifically 10 parts nano-silica, 6 parts nano-calcium carbonate, 1.5 parts graphene oxide, 5 parts polyvinyl alcohol, 3 parts polyacrylamide, 1.5 parts polycarboxylate superplasticizer, and 0.3 parts defoamer, without adding AR glass fiber, bentonite, and zeolite powder. Using the same concrete mix proportion and spraying process conditions as Example 1, the performance test results of the comparative example are shown in Table 4 below:

[0052]

[0053] As can be seen from the comparative examples, without AR glass fiber, bentonite, and zeolite powder, the rebound rate increased significantly to 24.3%, the bond strength decreased significantly to 0.92 MPa, and the slump loss reached 65 mm in 1 hour, indicating poor slump retention. A comparison with Example 1 demonstrates that there is a significant synergistic effect among the components of this invention, and none can be omitted: AR glass fiber provides macroscopic physical reinforcement, bentonite achieves rheological regulation and internal curing, and zeolite powder provides porous adsorption and interfacial interlocking. These three components, together with the nanocomposite modified components, construct a multi-layered synergistic system of chemical, physical, and rheological properties, enabling the achievement of the comprehensive performance goals of low rebound, high adhesion, and excellent pumpability.

[0054] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

[0055] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A nano-composite modified wet-sprayed concrete interface reinforcing admixture, characterized in that: It comprises the following components in parts by weight: 5-15 parts nano-silica, 3-10 parts nano-calcium carbonate, 0.5-3 parts graphene oxide, 2-8 parts polyvinyl alcohol, 1-5 parts polyacrylamide, 0.5-5 parts AR glass fiber, 2-10 parts bentonite, 1-8 parts zeolite powder, 0.5-3 parts polycarboxylate superplasticizer, and 0.1-0.5 parts defoamer.

2. The nanocomposite modified wet-sprayed concrete interface reinforcing admixture according to claim 1, characterized in that: The specific weight parts are as follows: 10 parts nano silica, 6 parts nano calcium carbonate, 1.5 parts graphene oxide, 5 parts polyvinyl alcohol, 3 parts polyacrylamide, 2.5 parts AR glass fiber, 6 parts bentonite, 4 parts zeolite powder, 1.5 parts polycarboxylate superplasticizer, and 0.3 parts organosilicon defoamer.

3. The nanocomposite modified wet-sprayed concrete interface reinforcing admixture according to claim 1, characterized in that: The specific weight parts are: 12 parts nano silica, 4 parts nano calcium carbonate, 2 parts graphene oxide, 6 parts polyvinyl alcohol, 2 parts polyacrylamide, 4 parts AR glass fiber, 8 parts bentonite, 5 parts zeolite powder, 2 parts polycarboxylate superplasticizer, and 0.2 parts organosilicon defoamer. The synthesized zeolite powder has a particle size of 800 mesh and a porosity of 55%.

4. The nanocomposite modified wet-sprayed concrete interface reinforcing admixture according to claim 1, characterized in that: The specific weight parts are: 8 parts nano-silica, 8 parts nano-calcium carbonate, 1 part graphene oxide, 4 parts polyvinyl alcohol, 4 parts polyacrylamide, 3 parts AR glass fiber, 7 parts bentonite, 7 parts zeolite powder, 2.5 parts polycarboxylate superplasticizer, and 0.3 parts defoamer; the sodium-based modified bentonite is an organic intercalated modified bentonite with an interlayer spacing of not less than 1.8 nm; the natural clinoptilolite powder has a particle size of 1000 mesh and a porosity of 50%.

5. The nanocomposite modified wet-sprayed concrete interface reinforcing admixture according to claim 1, characterized in that: The AR glass fiber has a length of 3-12 mm, a single filament diameter of 10-20 μm, and a zirconium oxide content of ≥16.5%; the bentonite has a fineness of ≥200 mesh; the zeolite powder has a fineness of 200-1200 mesh and a porosity of ≥30%.

6. The nanocomposite modified wet-sprayed concrete interface reinforcing admixture according to claim 1, characterized in that: The bentonite is sodium-based bentonite, calcium-based bentonite, or organically modified bentonite.

7. The nanocomposite modified wet-sprayed concrete interface reinforcing admixture according to claim 1, characterized in that: The zeolite powder is either natural clinoptilolite powder or synthetic zeolite powder.

8. The nanocomposite modified wet-sprayed concrete interface reinforcing admixture according to claim 1, characterized in that: The additive is in powder form and is prepared by the following method: nano silica, nano calcium carbonate, graphene oxide, polyvinyl alcohol, and polyacrylamide are dry-mixed at 1000-1500 rpm for 10-15 min to obtain premixed powder A; AR glass fiber, bentonite, zeolite powder, polycarboxylate superplasticizer, and defoamer are dry-mixed at 300-500 rpm for 8-12 min to obtain mixture B; A and B are mixed at 20-40 rpm for 15-30 min and then passed through a 60-80 mesh sieve.

9. The nanocomposite modified wet-sprayed concrete interface reinforcing admixture according to claim 1, characterized in that: The admixture is added to wet-mixed shotcrete at a rate of 5%-7% of the mass of the cementitious material.

10. The nanocomposite modified wet-sprayed concrete interface reinforcing admixture according to claim 9, characterized in that: The admixture is used in conjunction with an alkali-free liquid accelerator, with the accelerator dosage being 6%-6.5% of the mass of the cementitious material.

Images