Gradient repair method and structure based on optimization of pore structure of repair interface transition zone

Abstract

The application belongs to the field of concrete durability, and provides a gradient repair method and structure based on optimization of repair interface transition zone pore structure, wherein the gradient repair method based on optimization of repair interface transition zone pore structure comprises sequentially pouring first gradient repair material and second gradient repair material on the surface of existing concrete to be repaired; the first gradient repair material and the second gradient repair material are subjected to flow state fusion treatment to form interface tortuosity of the first gradient repair material and the second gradient repair material, and mechanical interlocking of the interface is realized; the first gradient repair material and the second gradient repair material after the flow state fusion treatment are once solidified and molded to obtain a repaired concrete structure. The application can realize low porosity of the interface, increase the bonding area of the repair material and the existing concrete, repair the surface without roughness treatment, and significantly improve the bonding performance of the repair interface, thereby guaranteeing full play of the performance of the repair material.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of concrete life extension, and particularly relates to a gradient repair method and structure based on optimization of pore structure of an interface transition zone. BACKGROUND

[0002] The statements in this section merely provide background information related to the application and do not necessarily constitute prior art.

[0003] Concrete repair is a feasible way to ensure normal service or even long-term service of concrete structures. The interface between new and old concrete is similar to the transition zone between aggregates and cement stone, which is a weak area in the system. Since new and old concrete contains mortar, a water film is formed on the surface of the old concrete when the repair material is poured, the local water-binder ratio of the interface is high, the interface is affected by the "edge wall effect", calcium hydroxide is enriched and preferentially oriented, resulting in high porosity of the interface transition zone and weak repair interface.

[0004] Traditional concrete repair has low interface bonding performance, which is caused by the following reasons: lack of mortar at the interface, reduction of effective bonding area of the interface, high porosity of the interface transition zone due to the aggregation and preferential orientation of calcium hydroxide, high water-binder ratio of traditional repair materials, low interface bonding strength, and debonding phenomenon, which makes it difficult for the repair material to fully play its role in reinforcement and protection. In addition, the high porosity of the interface transition zone and the loose structure make the repair interface vulnerable to the erosion of harmful external media, thereby accelerating the deterioration of the repair interface and causing the repair material to fall off.

[0005] To solve the above problems, application publication CN 116675494 A provides a repair material with high interface bonding performance and low mortar aggregate ratio and a repair method, which adopts a two-layer repair design, the first layer is first paved with mortar and then pressed into gravel, and the second layer is first layered with gravel and then grouted from bottom to top. At the same time, in order to achieve high interface bonding performance between the repair material and the old concrete, the repair layer 1 adopts a low water-binder ratio, and the cementitious system is mixed with silica fume. In order to achieve high fatigue performance and wear resistance of the pavement, the repair layer 2 is mixed with steel fibers and nanomaterials. This technical solution needs two steps of mortar stirring for pouring and aggregate pressing or aggregate pouring and mortar stirring for pouring, and cannot be once-molded to realize repair layer material pouring. Moreover, the repair object in this technology is pavement concrete, i.e., the repair surface is a horizontal surface, if the repair surface is an inclined surface, the mortar wrapping of the aggregate will be uneven when the aggregate is pressed in. Moreover, the repair of pavement concrete needs to process the roughness of the repair surface to achieve a more ideal repair effect. SUMMARY

[0006] In order to solve the technical problems in the background art, the application provides a gradient repair method and structure based on optimization of pore structure of a repair interface transition zone, which can significantly improve the bonding performance of the repair interface and ensure full play of the performance of the repair material.

[0007] In order to achieve the above-mentioned purpose, the application adopts the following technical solutions:

[0008] The first aspect of the application provides a gradient repair method based on optimization of pore structure of a repair interface transition zone.

[0009] A gradient repair method based on optimization of pore structure of a repair interface transition zone, comprising:

[0010] Pouring a first gradient repair material and a second gradient repair material on a surface of an existing concrete structure to be repaired in sequence;

[0011] Performing flow state fusion treatment on the first gradient repair material and the second gradient repair material to form an interface fold of the first gradient repair material and the second gradient repair material, so as to realize mechanical interlocking of the interface;

[0012] After the flow state fusion treatment, the first gradient repair material and the second gradient repair material are solidified once to form a repaired concrete structure.

[0013] As an embodiment, the flow state fusion treatment on the first gradient repair material and the second gradient repair material is performed by an insertion guide process.

[0014] As an embodiment, the process of performing flow state fusion treatment on the first gradient repair material and the second gradient repair material by the insertion guide process is as follows:

[0015] Inserting a vibrating rod into the interface of the first gradient repair material and the second gradient repair material, keeping the vibrating rod and the interface at a constant angle and moving the vibrating rod up and down, and making the first gradient repair material and the second gradient repair material fuse by disturbing the flow state of the first gradient repair material and the second gradient repair material.

[0016] The above-mentioned technical solution has the advantage that the interface of the first gradient repair material and the second gradient repair material is fully vibrated, so that the first gradient repair material and the second gradient repair material are in a flow state and fully fused, forming strong mechanical interlocking without adding a new repair interface transition zone.

[0017] As an embodiment, the thickness of the second gradient repair material is 4-20 times the thickness of the first gradient repair material.

[0018] The advantages of the above technical solution are that when the load on the existing concrete is transmitted to the first gradient repair material through the interface and then to the second gradient repair material, the second gradient repair material can provide stable load support capacity.

[0019] As an implementation form, before pouring the first gradient repair material on the surface of the existing concrete to be repaired, the method further comprises:

[0020] The surface of the existing concrete to be repaired is cleaned and dried.

[0021] The advantages of the above technical solution are that the impurities on the surface of the existing concrete can be avoided to affect the stability of the overall repair result.

[0022] As an implementation form, the first gradient repair material at least comprises three components of carbon nanofiber, steel fiber and silica fume.

[0023] The advantages of the above technical solution are that the steel fiber and the carbon nanofiber can realize multi-scale crack resistance, enhance the mechanical properties of the repair material at the interface, enhance the mechanical interlocking force at the interface, and improve the bonding strength of the repair interface; the silica fume component can play the effect of volcanic ash, absorb calcium hydroxide in the interface transition zone, prevent the preferred orientation of calcium hydroxide, and reduce the porosity of the interface transition zone.

[0024] As an implementation form, the first gradient repair material at least comprises three components of carbon fiber, carbon nanotube and silica fume.

[0025] The advantages of the above technical solution are that the carbon nanofiber or the carbon nanotube regulates the distribution of the hydration product at the repair interface, promotes the hydration of cement, grows dense calcium silicate gel at the repair interface, reduces the porosity of the repair interface transition zone, and plays the role of bridging the microcracks at the repair interface; the silica fume component can play the effect of volcanic ash, absorb calcium hydroxide in the interface transition zone, prevent the preferred orientation of calcium hydroxide, and reduce the porosity of the interface transition zone.

[0026] As an implementation form, the second gradient repair material at least comprises components of cement, sand and gravel.

[0027] As an implementation form, the second gradient repair material at least comprises components of cement, sand, tailings sand, gravel, recycled aggregate and water reducing agent.

[0028] The second aspect of the present application provides a concrete structure.

[0029] A concrete structure comprises:

[0030] The existing concrete part and the repair part;

[0031] The repair part is obtained by the gradient repair method based on optimization of the pore structure of the repair interface transition zone as described above.

[0032] Compared with the prior art, the present application has the following advantages:

[0033] (1) The gradient repair method based on optimization of the pore structure of the repair interface transition zone of the present application adopts the first gradient repair material and the second gradient repair material after flow state fusion treatment and solidification once forming, without the need for pipe embedding and pouring, and the repair surface does not need to be subjected to roughness treatment process, which can realize low porosity of the interface, thereby increasing the bonding area of the repair material and the existing concrete, thereby enhancing the mechanical interlocking force, and the repair surface does not need roughness treatment, which significantly improves the bonding performance of the repair interface, and ensures the full play of the performance of the repair material.

[0034] (2) The present application performs flow state fusion treatment on the first gradient repair material and the second gradient repair material, so that the first gradient repair material and the second gradient repair material are fully fused in the flow state, forming strong mechanical interlocking, without increasing new repair interface transition zone, so that the compactness of the repair material-concrete matrix interface is improved, thereby reducing the deterioration speed of the repair interface under freeze-thaw, salt dry-wet cycle durability environment, delaying the time of the repair material falling off from the existing structure, and improving the service period of the repair material in severe environment.

[0035] (3) The first gradient repair material containing steel fibers and nanofiber components of the present application utilizes the multiscale synergistic effect of steel fibers and nanofibers to regulate the hydration products of the interface transition zone, enhances the macro-scale mechanical interlocking force and micro-nano-scale mechanical interlocking force of the interface, improves the solid-liquid repair interface transition zone, and realizes the reduction of the porosity of the pore structure of the repair interface transition zone, and even eliminates the edge wall effect.

[0036] (4) The first gradient repair material of the present application contains carbon fibers, carbon nanotubes and silica ash, wherein the steel fibers and carbon nanofibers can realize multiscale crack resistance, enhance the mechanical properties of the repair material at the interface, enhance the mechanical interlocking force of the interface, and improve the bonding strength of the repair interface; the silica ash component can play the effect of volcanic ash, absorb calcium hydroxide in the interface transition zone, prevent the preferential orientation of calcium hydroxide, and reduce the porosity of the interface transition zone.

[0037] The advantages of the additional aspects of the present application will be partially given in the following description, partially will become obvious from the following description, or will be understood by the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0038] The drawings accompanying the specification of the present application form a part thereof, serve to provide further understanding of the present application, and together with the description of the exemplary embodiments of the present application and the explanation thereof serve to explain the present application, and do not constitute an improper limitation of the present application.

[0039] Figure 1 is a gradient repair method flowchart based on optimizing the pore structure of the interface transition zone of the repair according to an embodiment of the present application;

[0040] Figure 2 is the experimental result of experimental example 1 of the present application;

[0041] Figure 3 is the experimental result of experimental example 2 of the present application. DETAILED DESCRIPTION

[0042] The present application will be further described below in conjunction with the accompanying drawings and embodiments.

[0043] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0044] It should be noted that the terms used herein are only intended to describe specific embodiments and are not intended to limit exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise, and it should also be understood that when the terms "comprise" and / or "include" are used in the specification, they refer to the presence of a feature, step, operation, device, component, and / or combinations thereof.

[0045] According to Figure 1 , the present embodiment provides a gradient repair method based on optimizing the pore structure of the interface transition zone of the repair, which comprises:

[0046] Step 1: Pouring first gradient repair material and second gradient repair material on the existing concrete surface to be repaired in turn.

[0047] In the specific implementation process, before pouring the first gradient repair material on the existing concrete surface to be repaired, it further comprises:

[0048] Washing and air-drying the existing concrete surface to be repaired. This can avoid impurities on the existing concrete surface affecting the stability of the overall repair result.

[0049] In order to optimize the pore structure of the interface transition zone of the repair and transfer the load on the existing concrete through the interface to the first gradient repair material and then to the second gradient repair material, and to avoid the risk of the first gradient repair material being too thin and possibly failing to debond during load transfer, preferably, the thickness of the first gradient repair material is 4mm-20mm.

[0050] The second gradient repair material thickness is 4-20 times of the first gradient repair material thickness. In this way, when the load on the existing concrete is transmitted to the first gradient repair material through the interface and then to the second gradient repair material, the second gradient repair material can provide stable load support capacity.

[0051] It should be noted here that the pouring direction of the gradient repair material can be parallel to the repair surface, perpendicular to the repair surface, or other inclined angles.

[0052] In some optional embodiments, the first gradient repair material contains at least three components of carbon nanofiber, steel fiber and silica fume.

[0053] For example, the first gradient repair material includes 800-900 parts of cement, 110-260 parts of silica fume, 240-280 parts of water, 21-32 parts of water reducing agent, 800-1000 sand, 1-4 parts of carbon nanofiber, and 100-160 parts of steel fiber.

[0054] The cement is ordinary portland cement; the silica fume has a silicon content of 85-92% and an average particle size of 0.1-0.3 μm; the water is deionized water or tap water; the water reducing agent is polycarboxylic acid water reducing agent with a solid content of about 40%; the sand is river sand with a particle size of not more than 2.36 mm, or quartz sand powder with a particle size of not more than 630 μm; the carbon nanofiber has a length of 30-100 μm and a purity of more than 90%; and the steel fiber is copper-plated straight steel fiber with a length of not more than 13 mm.

[0055] The first gradient repair material is prepared as follows: the cement, silica fume and sand are dry mixed and stirred for 4-5 min, then the mixture of water and water reducing agent is added and stirred for 6-10 min, the carbon nanofiber is added and stirred for 3-5 min, and finally the steel fiber is added and stirred for 4-6 min. The prepared mixture has the characteristics of low porosity, with a porosity of less than 7.2%.

[0056] The steel fiber and carbon nanofiber can achieve multi-scale crack resistance, enhance the mechanical properties of the repair material at the interface, enhance the mechanical interlocking force at the interface, and improve the bonding strength of the repair interface; the silica fume component can play the role of volcanic ash effect, absorb calcium hydroxide in the interface transition zone, prevent preferential orientation of calcium hydroxide, and reduce the porosity of the interface transition zone.

[0057] In other optional embodiments, the first gradient repair material contains at least three components of carbon fiber, carbon nanotube and silica fume.

[0058] For example, the first gradient repair material includes 720-810 parts of cement, 80-90 parts of fly ash, 80-100 parts of slag, 50-160 parts of silica fume, 240-280 parts of water, 24-36 parts of water reducing agent, 150-300 parts of garbage bottom ash, 600-800 parts of sand, 100-150 parts of crushed stone, 1-3 parts of carbon nanotubes, and 100-160 parts of carbon fibers. Among them, the first gradient repair material mixed with an appropriate amount of garbage bottom ash can improve the compressive strength of UHPC due to its internal solidification effect. From the microstructure analysis, the addition of garbage bottom ash promotes the hydration of the repair material, making the hydration degree of the slurry higher, and the microstructure is more dense than the reference sample.

[0059] The cement is ordinary portland cement; the fly ash has an average particle size of 45 μm, an activity index greater than 70%, and a specific surface area of slag 425 m 2 / g, a loss on ignition less than 6%, a silicon content of silica fume of 85-92%, and an average particle size of 0.1-0.3 μm; the water is deionized water or tap water; the water reducing agent is a polycarboxylic acid water reducing agent with a solid content of about 40%; the garbage bottom ash has a particle size of not more than 400 μm, is soaked in water for 24 h, and then the surface is dried; the sand is river sand with a particle size of not more than 2.36 mm or quartz sand powder with a particle size of not more than 630 μm; the crushed stone has a particle size of 5 mm, and the crushed stone is basalt or limestone crushed stone; the carbon nanotube has a length of 10-30 μm, a diameter of 20-40 nm, and a purity of greater than 95%; and the carbon fiber has a diameter of 10 μm, a length of 10 mm, and a breaking elongation of 1.6%.

[0060] The preparation process of the first gradient repair material is as follows:

[0061] The cement, fly ash, silica fume, slag, garbage bottom ash, sand, and crushed stone are dry mixed and stirred for 4-5 min, then the mixture of water and water reducing agent is added and stirred for 6-10 min, the carbon nanotube is added and stirred for 3-5 min, and finally the carbon fiber is added and stirred for 4-6 min. The prepared mixture has the characteristics of low porosity, and the porosity is less than 7.2%.

[0062] The carbon nanofiber or carbon nanotube here regulates the distribution of hydration products at the repair interface, promotes cement hydration, grows dense calcium silicate gel at the repair interface, reduces the porosity of the transition zone at the repair interface, and plays a role in bridging microcracks at the repair interface; the silica fume component can play a pozzolanic effect, absorb calcium hydroxide in the interface transition zone, prevent preferential orientation of calcium hydroxide, and reduce the porosity of the interface transition zone.

[0063] It should be noted that the components of the first gradient repair material can be specifically set by the person skilled in the art according to the actual situation, which will not be described in detail here.

[0064] In some embodiments, the second gradient repair material comprises at least cement, sand, and gravel.

[0065] For example, the second gradient repair material comprises 320-440 parts of cement, 600-750 parts of sand, 1000-1210 parts of gravel, and 191-221 parts of water.

[0066] The cement is ordinary Portland cement, the sand is river sand with a particle size of no more than 5 mm, the gravel is basalt or limestone gravel with a particle size of 10-16 mm, and the water is deionized water or tap water.

[0067] In other embodiments, the second gradient repair material comprises at least cement, sand, tailings sand, gravel, recycled aggregate, and water reducing agent.

[0068] For example, the second gradient repair material comprises 320-440 parts of cement, 530-710 parts of sand, 70-140 parts of tailings sand, 850-970 parts of gravel, 150-240 parts of recycled aggregate, 191-221 parts of water, and 3-10 parts of water reducing agent.

[0069] The cement is ordinary Portland cement, the sand is river sand with a particle size of no more than 5 mm, the tailings sand is with a particle size of no more than 5 mm, the gravel is basalt or limestone gravel with a particle size of 10-16 mm, the recycled aggregate is concrete removed by crushing and screening to a particle size of 10-16 mm, and the water is deionized water or tap water.

[0070] The preparation process of the second gradient repair material is as follows:

[0071] The cement, sand, tailings sand, gravel, and recycled aggregate are dry mixed and stirred for 3-5 min, and then water and water reducing agent are added and stirred for 6-8 min. The prepared mixture has a high porosity after curing, and the porosity is 12.5%-17.5%. The interface between the first gradient repair material and the concrete matrix is a solid-liquid interface, and the interface transition zone between the traditional repair material and the concrete matrix has high porosity. The porosity of the interface transition zone of this method is low, and even the interface barrier effect is eliminated. Before the solid-liquid interface is formed, only the surface is cleaned with water, and the liquid gradient repair material is poured.

[0072] It should be noted that the components of the first gradient repair material can be specifically set by those skilled in the art according to actual conditions, which will not be described in detail here.

[0073] Step 2: The first gradient repair material and the second gradient repair material are subjected to flow state fusion treatment to form an interface zigzag of the first gradient repair material and the second gradient repair material, so as to realize mechanical interlocking of the interface.

[0074] In the embodiment, the first gradient repair material and the second gradient repair material are subjected to flow state fusion treatment through the insertion guide process.

[0075] Specifically, the process of subjecting the first gradient repair material and the second gradient repair material to flow state fusion treatment through the insertion guide process is as follows:

[0076] The vibration rod (or steel rod) is inserted into the interface between the first gradient repair material and the second gradient repair material, the vibration rod is kept at a constant angle with the interface and is moved up and down, the first gradient repair material and the second gradient repair material in the gradient flow state are disturbed, and the first gradient repair material and the second gradient repair material are fused.

[0077] In this way, the interface between the first gradient repair material and the second gradient repair material is fully vibrated, so that the first gradient repair material and the second gradient repair material are fully fused in the flow state, a strong mechanical interlocking is formed, and a new repair interface transition zone is not increased.

[0078] It should be noted that the vibration rod (or steel rod) can be parallel to the interface or form an angle less than or equal to 90 degrees with the interface.

[0079] The first gradient repair material and the second gradient repair material of the embodiment are both once-poured and formed, and the flow state slurry or mortar contains coarse aggregate. By vibrating at the interface between the first gradient repair material and the second gradient repair material, the aggregate in the second gradient repair material will be keyed into the first gradient repair material, so that the aggregate in the second gradient repair material exists at the interface. Due to the irregularity of the surface of the aggregate, the tortuosity at the interface between the first gradient repair material and the second gradient repair material is increased, so that a dog-tooth interlocking shape is formed, and a macroscopic strong mechanical interlocking is realized. Since the traditional technology does not have this interface, the interface area of the embodiment needs to be inserted and guided, so that the liquid-liquid interface is dog-tooth interlocked, and the mechanical interlocking is enhanced, so that the risk of potential weakness of the interface is eliminated.

[0080] The interface between the first gradient repair material and the concrete matrix of the embodiment has a low porosity feature, and the interface structure is dense, breaking the phenomenon of calcium hydroxide enrichment at the repair interface. In the traditional technology, the interface between the repair material and the concrete matrix has a lack of slurry phenomenon, calcium hydroxide is enriched in the interface transition zone, the interface transition zone is loose and porous, and a gap is formed.

[0081] Step 3: The first gradient repair material and the second gradient repair material after the flow state fusion treatment are once-solidified and formed to obtain a repaired concrete structure.

[0082] The following gives specific experimental examples to illustrate the effect of the gradient repair method based on optimizing the pore structure of the repair interface transition zone of the application in detail:

[0083] Experimental Example 1:

[0084] The gradient repair method based on optimizing the pore structure of the repair interface transition zone of the application is used to repair the concrete, wherein the concrete matrix is composed of 328 parts of cement, 715 parts of river sand, 1167 parts of gravel, and 190 parts of water.

[0085] The cured concrete matrix is a prism, and the surface to be repaired is an inclined surface with an angle of 60° to the horizontal plane. The surface to be repaired is then washed with clean water, and the first gradient repair material is poured. The first gradient repair material is composed of 823 parts of cement, 1032 parts of sand, 208 parts of silica fume, 212 parts of water, 150 parts of steel fiber, and 24 parts of water reducing agent.

[0086] The thickness of the first gradient repair material is 9mm. After pouring the first gradient repair material, the second gradient repair material is poured. The second gradient repair material is composed of 396 parts of cement, 689 parts of sand, 1125 parts of stone, and 190 parts of water. The interface between the first and second gradient repair materials is inserted and guided to form a good mechanical interlocking.

[0087] The repaired concrete matrix forms a prism, and is cured and placed in a press to verify the effect.

[0088] The control group uses the traditional repair method, and only the second gradient repair material is poured on the surface of the concrete matrix. The repaired prism specimen is placed in a press to verify the effect.

[0089] The experimental results are shown in Table 1. Figure 2 The repaired specimen interface of the present experiment has no failure, and the concrete matrix failure specimen is damaged, with a failure load of 211.3kN.

[0090] The repaired specimen prepared by the traditional repair technique has an interface failure, with a failure load of 183.5kN. The repair interface performance is improved by 20%, and the failure mode of the repaired specimen is changed.

[0091] The concrete at the repair interface is analyzed for porosity, and the porosity analysis results are shown in Table 1.

[0092] The porosity of the transition zone of the repaired specimen prepared in the present experiment is less than 7%, indicating that the transition zone is dense. The porosity at a distance of 9mm from the repair interface increases to 12.8%, but the region forms a good mechanical interlocking due to sufficient insertion and guidance during pouring, so that failure does not occur.

[0093] The porosity of the interface transition zone of the repaired specimen prepared by the conventional technique gradually transits from 26.5% to 12.8%, without porosity mutation, and the interface has high porosity, and the calcium hydroxide is enriched at the repaired interface, which causes the interface transition zone to be loose and porous, and thus the interface is weak and easy to fail.

[0094] Table 1: Porosity distribution of the interface transition zone (%)

[0095]

[0096] Experimental Example 2:

[0097] On the basis of Experimental Example 1, only the inclination angle of the repaired surface is changed, the repaired surface is perpendicular to the horizontal surface, the concrete substrate is in the shape of a prism, the repaired surface is cleaned with water, a baffle is placed at a position 9 mm away from the repaired surface, the first gradient repair material is poured close to the repaired interface, the second gradient repair material is placed on the other side of the baffle, and the baffle is removed while vibrating. The control group does not need to place a baffle, and only the second gradient repair material needs to be poured in the empty position of the mold containing the concrete substrate.

[0098] After curing, the repaired specimen is cored, the coring direction is perpendicular to the repaired surface, and the cored specimen is subjected to a pull-out test, and the experimental results are shown in Table 2: Figure 3

[0099] The repaired specimen prepared in this experiment has no failure at the interface, the concrete substrate fails, and the failure tensile load is 6.2 kN; the repaired specimen prepared by the conventional repair technique has an interface failure, and the failure load is 3.8 kN. The performance of the repaired interface is improved by 63%, and the failure mode of the repaired specimen is changed.

[0100] In one or more embodiments, a concrete structure is also provided, which includes:

[0101] The existing concrete part and the repaired part;

[0102] The repaired part is obtained by using the gradient repair method based on the optimized porosity structure of the repair interface transition zone as described above.

[0103] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Those skilled in the art can make various modifications and changes to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.​

Claims

1. A gradient repair method based on optimizing the pore structure of the interface transition region, characterized in that, include: First-gradient repair material and second-gradient repair material are poured sequentially onto the existing concrete surface to be repaired; The first-gradient repair material and the second-gradient repair material are subjected to fluid fusion treatment to form an interface tortuous between the first-gradient repair material and the second-gradient repair material, so as to achieve mechanical interlocking of the interface; After the first and second gradient repair materials are treated with fluid fusion, they solidify in one step to form the repaired concrete structure.

2. The gradient repair method based on optimizing and repairing the pore structure of the interface transition region as described in claim 1, characterized in that, The first and second gradient repair materials are fluidized and fused using an intercalation process.

3. The gradient repair method based on optimizing and repairing the pore structure of the interface transition region as described in claim 2, characterized in that, The process of fluidizing the first-gradient repair material and the second-gradient repair material using an intercalation process is as follows: A vibratory rod is inserted into the interface between the first gradient repair material and the second gradient repair material. The angle between the vibratory rod and the interface remains unchanged, and the vibratory rod is moved up and down. By disturbing the gradient flow state of the first gradient repair material and the second gradient repair material, the first gradient repair material and the second gradient repair material are fused together.

4. The gradient repair method based on optimizing and repairing the pore structure of the interface transition region as described in claim 1, characterized in that, The thickness of the second-gradient repair material is 4-20 times that of the first-gradient repair material.

5. The gradient repair method based on optimizing and repairing the pore structure of the interface transition region as described in claim 1, characterized in that, Before pouring the first-gradient repair material onto the existing concrete surface to be repaired, the following steps are also included: Clean and dry the existing concrete surface to be repaired.

6. The gradient repair method based on optimizing and repairing the pore structure of the interface transition region as described in claim 1, characterized in that, The first gradient repair material contains at least three components: carbon nanofibers, steel fibers, and silica fume.

7. The gradient repair method based on optimizing and repairing the pore structure of the interface transition region as described in claim 1, characterized in that, The first gradient repair material contains at least three components: carbon fiber, carbon nanotubes, and silica fume.

8. The gradient repair method based on optimizing and repairing the pore structure of the interface transition region as described in claim 1, characterized in that, The second gradient repair material contains at least the components of cement, sand and gravel.

9. The gradient repair method based on optimizing and repairing the pore structure of the interface transition region as described in claim 1, characterized in that, The second-gradient repair material contains at least the following components: cement, sand, tailings sand, crushed stone, recycled aggregate, and water-reducing agent; the sand is river sand with a particle size not exceeding 5 mm; the recycled aggregate is demolished concrete that has been crushed and screened to obtain a particle size of 10 mm-16 mm.

10. A concrete structure, characterized in that, include: Existing concrete sections and repaired sections; The repair portion is obtained using the gradient repair method based on the optimized repair interface transition zone pore structure as described in any one of claims 1-9.

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