A rapid and efficient method for emergency repair of concrete cracks and its application.

Abstract

This invention provides a rapid and efficient emergency repair method for concrete cracks, applicable to emergency repairs of cracks in concrete structures such as dams, roads, and bridges. This method utilizes the aluminothermic reaction of aluminum and sulfate to melt excess aluminum and alloying agents, which then flow into the concrete cracks. The resulting aluminum alloy serves as the repair material. This aluminum alloy repair material features high strength, high plasticity, good fluidity, and rapid cooling, allowing for thorough repair of all corners of the crack, shortening the repair cycle, enhancing the corrosion resistance of reinforcing steel, improving the load-bearing capacity of the crack, and preventing secondary cracking. Furthermore, the continuous aluminothermic reaction of aluminum and sulfate does not require external energy, significantly reducing energy consumption. It also reduces repair time from tens of hours in traditional crack repair methods to tens of minutes in this invention, enabling emergency crack repair in situations where external energy is unavailable during field rescue and disaster relief operations.

Description

Technical Field

[0001] This invention belongs to the field of concrete crack repair technology, specifically relating to a rapid and efficient emergency repair method for concrete cracks, and also relating to the application of the above-mentioned emergency repair method in the repair of structures with concrete cracks such as dams, roads, and bridges. Background Technology

[0002] In recent decades, with the rapid development of my country's infrastructure industry, concrete, due to its advantages such as easy availability, good integrity, durability, and high strength, has been used to construct numerous dams, roads, bridges, and other facilities. During their service life, these facilities are highly susceptible to cracking due to factors such as weather changes and continuous load-bearing. These cracks expose the reinforcing steel, leading to corrosion and further crack propagation, reducing the strength and stability of dams and other facilities, thus shortening their lifespan and safety. Therefore, timely repair of concrete cracks to improve the lifespan and safety of these facilities is extremely important.

[0003] Currently, most crack repair methods involve pouring cement-based materials. Patent 201010120894.X discloses a DBB concrete pavement crack repair material, which uses cement as a matrix material and adds water, styrene-butadiene emulsion, JS waterproof emulsion, polycarboxylate superplasticizer, CaCl2, U-shaped expansion agent, crystalline sodium sulfate, and tributyl phosphate to the cement. Patent 201911213651.8 discloses an underground engineering concrete crack repair material, formulated from the following raw materials in weight percentages: 25-45% cement, 30-50% sand, 20-30% slag powder, 8-15% desulfurized gypsum, 1-10% silica fume, 1-2% sodium silicate, 0.5-5% mixed fiber, and 0.4-1.8% superabsorbent resin.

[0004] Although these cement-based repair methods have played a certain role in improving the strength and impermeability of cracks, these conventional repair methods also have certain drawbacks: (1) These concrete crack repair materials are only mechanically mixed and do not react, so their fluidity is poor and they are difficult to flow to a distance from the crack, so they cannot achieve 100% repair; (2) These concrete crack repair materials have a slow solidification speed, which makes it difficult to meet the needs of rapid crack repair in emergency situations; (3) The preparation, transportation and storage of these concrete crack repair materials require professional equipment and processes, which greatly increases the cost of use; (4) After these materials solidify, their plasticity is still very low, and they are prone to secondary cracks during subsequent service.

[0005] Therefore, a novel emergency repair method for concrete cracks is proposed, which uses a lower cost and a simpler and faster process to achieve in-situ and efficient repair of concrete cracks in dams, roads, bridges and other facilities. This is a technical problem that urgently needs to be solved. Summary of the Invention

[0006] One of the objectives of this invention is to provide a method for emergency repair of concrete cracks that is efficient, fast, low-cost, and has a short process in situ.

[0007] The second objective of this invention is to provide a rapid and efficient emergency repair method for concrete cracks, applicable to the repair of concrete cracks in dams, roads, bridges, and other structures.

[0008] One of the technical solutions adopted to achieve the objective of this invention is to provide a rapid and efficient emergency repair method for concrete cracks, comprising the following steps:

[0009] S1. Create a pouring groove on the surface of the concrete crack and clean it.

[0010] S2. Based on the volume of the crack and the casting trough, prepare a corresponding mass of self-propagating sealant and fill it into a cavity container; the components of the self-propagating sealant include an exothermic agent, a slag-forming agent, and an alloying agent; the exothermic agent is composed of aluminum and sulfate;

[0011] S3. Place the cavity container above one end of the casting tank, ignite the self-propagating sealant, move the cavity container so that the molten aluminum alloy formed by melting aluminum and alloying agent flows into the crack through the outlet of the cavity container and the casting tank, and fills the crack and the casting tank.

[0012] S4. After the cracks and the filling material in the casting trough have cooled, the repaired cracks should be trimmed.

[0013] The general idea of ​​the rapid and efficient emergency repair method for concrete cracks provided by this invention is as follows:

[0014] This invention addresses the problems of poor fluidity, inadequate filling of narrow cracks, slow setting speed, and susceptibility to secondary cracking in conventional concrete crack repair using cement-based repair materials. It proposes a concrete crack repair method based on a self-propagating reaction system. The self-propagating sealant of this invention comprises an exothermic agent composed of aluminum and sulfate. Compared to other common reaction systems using CuO, Fe2O3, etc., which involve vigorous reactions requiring diluents to reduce the degree of reaction, the self-propagating reaction system of this invention offers advantages such as safe and stable reaction, adjustable composition, pure and fluid high-temperature aluminum alloy liquid, and rapid cooling. This allows for the filling and repair of concrete cracks. The product, after cooling, exhibits good elasticity and plasticity, as well as high strength and hardness, enabling not only rapid and thorough crack repair but also effectively preventing secondary cracking.

[0015] In the aforementioned emergency repair method, firstly, a casting groove is created on the surface of the irregular crack to facilitate the smooth entry of molten aluminum alloy into the crack. Secondly, the amount of self-propagating sealant is determined based on the volume of the crack and the casting groove, enabling rapid one-time filling and repair of the crack. The self-propagating sealant comprises an exothermic agent composed of aluminum and sulfate, a slagging agent, and an alloying agent. When the sealant is ignited, the exothermic system of aluminum and sulfate reacts with the alloying agent to generate high-temperature molten aluminum alloy, which rapidly flows and fills the fine corners of the crack. The addition of the slagging agent ensures more thorough slag-liquid separation, guaranteeing the purity of the molten aluminum alloy filling material. Further, during the repair process, the cavity container is moved along the length of the casting groove, allowing the molten aluminum alloy to flow sequentially into the crack through the outlet of the cavity container and the casting groove, filling both the crack and the groove. Finally, the filling material in the crack and the casting groove cools down within just a few minutes to tens of minutes. By surface finishing of the crack and the casting groove, the emergency repair is complete.

[0016] Furthermore, in step S1, the cross-section of the pouring trough is funnel-shaped, which increases the opening area on the crack surface to ensure that the repair material flows smoothly into and fills the crack. The crack can be cleaned using a blower or a wind-powered fire extinguisher.

[0017] Further, in step S2, the length, width, and depth of the crack can be measured using equipment such as a tape measure, measuring tape, or ultrasonic testing instrument, and then the volume of the crack can be calculated, thereby determining the required mass of self-propagating crack sealant. Preferably, the formula for calculating the mass m of the self-propagating crack sealant is:

[0018] ;

[0019] Where m is the required mass of self-propagating sealant, s is the correction factor, a is the density coefficient, ρ is the density of aluminum, V is the volume of the crack, k is the aluminum utilization rate, W is the mass fraction of aluminum in the self-propagating sealant, and V0 is the groove volume.

[0020] Preferably, the density coefficient a = 0.9~1.0 and the aluminum utilization rate k = 0.7~0.8.

[0021] In the above calculation formula, the density coefficient 'a' is introduced to account for the fact that after aluminum and alloying agent form an aluminum alloy, its density will be slightly lower than that of aluminum (the specific value depends on the proportion of alloying agent). 'aρ' represents the density of this aluminum alloy, and 'aρV' represents the mass of aluminum alloy required for the sealant. Furthermore, in this invention, a portion of the aluminum in the self-propagating sealant raw material participates in the self-propagating reaction, while another portion of the molten aluminum does not separate from the slag and solidifies with the slag on the inner wall of the cavity container. Since the aluminum used for sealant is only a part of the total aluminum content, the amount of aluminum used, 'k', needs to be introduced. In addition, considering that the mass of aluminum alloy required for sealant, 'aρV', is an approximation and the calculated result will be too small, a coefficient 's' is added here for optimization. The value of 's' ranges from 1 to 1.1. The introduction of these three parameters allows for more precise control of the amount of self-propagating sealant used, avoiding significant waste or insufficient use during application.

[0022] Furthermore, in step S2, a movable component is provided at the bottom of the cavity container, and the movable component is symmetrically arranged on both sides of the crack. With the aid of the movable component, the cavity container can move along the length of the crack, ensuring that the repair process is continuous, rapid, and stable. In this invention, the movable component can be a wheel directly mounted on the bottom of the cavity container, or it can be a mechanism detachably assembled below the cavity container to assist in its movement.

[0023] Furthermore, in step S2, the cavity container is made of a high-melting-point, stable material, including graphite, boron nitride, zirconium oxide, yttrium oxide, etc., and has an internal cavity for filling with self-propagating sealant. A self-fusing sheet is provided at the outlet at the bottom of the cavity. During use, the self-fusing sheet is first placed at the bottom of the cavity container to block the outlet, and then the self-propagating sealant is filled.

[0024] Preferably, the material of the self-fusing sheet is selected from one or more combinations of aluminum, tin, and magnesium, or other low-melting-point metals, and its thickness is 1-2 mm. The self-fusing sheet seals the outlet of the cavity container before the reaction begins. When the self-propagating sealant is ignited and the high-temperature liquid aluminum alloy flows to the outlet where the self-fusing sheet is located, the self-fusing sheet will automatically melt, thereby opening the discharge channel.

[0025] Preferably, the outer wall of the cavity container is also provided with an insulating shell.

[0026] Further, in step S2, the components of the self-propagating sealant, by weight fraction, include:

[0027] Exothermic agents: Al: 50wt.%~70wt.%; CaSO4: 2wt.%~4wt.%; BaSO4: 1wt.%~3wt.%; MgSO4: 10wt.%~30wt.%;

[0028] Slagging agent: CaF2: 5wt.%~6wt.%, BaCl2: 0.5wt.%~1wt.%, MgF2: 0.25wt.%~1wt.%, CaS: 2wt.%~3wt.%;

[0029] Alloying agent: Sn: 3wt.%~10wt.%, Si: 0.5wt.%~2wt.%, Mg: 1wt.%~1.5wt.%, Cu: 0.5wt.%~2wt.%.

[0030] In this invention, the sulfate in the exothermic agent is composed of CaSO4, BaSO4, and MgSO4. CaSO4 has a fast reaction rate, which can drive other reactions and make the reaction more complete; BaSO4 has stable reaction, making the operation safer; MgSO4 has a small relative molecular mass, resulting in more thorough slag-liquid separation and a higher proportion of aluminum alloy liquid used for seam repair.

[0031] Preferably, in the composition of the self-propagating sealant, Al: 55wt.%~65wt.%; MgSO4: 15wt.%~25wt.%; more preferably, Al: 52wt.%~62wt.%; MgSO4: 18wt.%~23wt.%.

[0032] The addition of Sn in the alloying agent helps to improve the fluidity of the alloy liquid, ensuring that the aluminum alloy liquid can fill every detail and corner of the crack in a short time and efficiently; the addition of Si, Mg and Cu gives the aluminum alloy a certain strength and hardness, which can better cope with various external loads during the service of the facility.

[0033] This invention also employs a multi-component slag-forming system, which has excellent protective effects, thorough slag-liquid separation, and ensures that the liquid flowing into the cracks is a single aluminum alloy liquid.

[0034] Specifically, the reaction equation for the heat generated by the exothermic agent is as follows:

[0035]

[0036]

[0037]

[0038] The heat generated by the above reaction melts excess aluminum and alloying agent to form aluminum alloy. At the same time, slag-forming agent and products (sulfides + Al2O3) generate eutectic material (slag) with low melting point, low density and good fluidity. Based on the above three characteristics, these eutectic material will easily float on the aluminum alloy, making the aluminum alloy liquid pure, and the liquid flowing down for filling the gap is pure aluminum alloy liquid.

[0039] Furthermore, in this invention, to ensure rapid reaction and prevent heat loss, the particle size of the aluminum powder should not be too coarse; simultaneously, considering the safety of the repair process, the particle size of the aluminum powder should not be too fine. Taking all these factors into account, the mesh size of the aluminum powder is set to 80-250 mesh. Correspondingly, to match the particle size of the aluminum powder for reaction, the mesh size of other raw materials is also controlled to be between 50-300 mesh.

[0040] Furthermore, CaSO4, BaSO4, and MgSO4 undergo drying pretreatment before use and are sealed and stored in a dry environment. These sulfates typically have a certain degree of hygroscopicity, meaning they absorb moisture from the air. The presence of moisture can cause pores to form during the sealing process, reducing the sealing effect. Drying pretreatment of the sulfates can prevent this problem from occurring.

[0041] Furthermore, in step S3, the method of igniting the self-propagating sealant includes: sprinkling an igniter on top of the self-propagating sealant and igniting it with an ignition strip. The igniter can be gunpowder, and the ignition strip can be a magnesium strip, etc.

[0042] The second technical solution adopted by the present invention to achieve the objective is to provide an application of the method described in the first objective of the present invention in the repair of concrete cracks in dams, roads and bridges.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] (1) The rapid and efficient emergency repair method for concrete cracks provided by this invention uses molten aluminum alloy liquid generated by a self-propagating reaction as a filler for concrete cracks. The aluminum alloy liquid has excellent fluidity and can smoothly enter the details and corners of the cracks. At the same time, the aluminum alloy cools quickly at room temperature, and its solidification time is only a few minutes to tens of minutes, thus achieving efficient and rapid repair of concrete cracks. In addition, the high-temperature metal liquid generated by this invention has strong burning and scouring properties, which can clean up weeds, gravel and other debris in the cracks during the flow process, and has even better filling performance.

[0045] (2) The rapid and efficient emergency repair method for concrete cracks provided by this invention uses aluminum alloy to fill the concrete cracks. The aluminum alloy liquid can effectively coat the exposed steel reinforcement surface. During corrosion, the aluminum alloy will be preferentially sacrificed, thereby slowing down the corrosion of the steel reinforcement and extending the service life of the facility. In addition, compared with cement-based materials, aluminum alloy has very good elasticity and plasticity, which can effectively prevent secondary cracking at the crack.

[0046] (3) The rapid and efficient emergency repair method for concrete cracks provided by this invention is powered by a self-propagating reaction and does not require external energy, thus meeting the development needs of energy conservation and emission reduction. Compared with traditional cement-based crack repair methods that require large-scale mixing equipment, have complex processes and cumbersome procedures, the raw materials used in this invention are all commercially available conventional materials that can be used simply by mixing. At the same time, the method is simple to operate and can be completed without professional personnel or professional training.

[0047] (4) The method for emergency repair of concrete cracks provided by the present invention is applicable to the repair of concrete cracks in dams, roads, bridges and other structures. The present invention reduces the repair time from tens of hours in traditional crack repair methods to tens of minutes in the present invention. In the case of field rescue and disaster relief and no external energy, it can quickly and efficiently complete the emergency repair of concrete cracks and has broad prospects for promotion and application. Attached Figure Description

[0048] Figure 1 A flowchart illustrating a rapid and efficient emergency repair method for concrete cracks provided by this invention;

[0049] Figure 2 This is a schematic diagram of the cross-sectional structure of the cavity container used in an embodiment of the present invention;

[0050] Figure 3 This is a schematic diagram of the side cross-sectional structure of the cavity container used in an embodiment of the present invention;

[0051] Among them, 1-concrete crack; 2-pouring trough; 3-cavity container; 4-moving component; 5-insulating shell; 6-cavity; 7-self-fusing sheet; 8-self-propagating sealant; 9-ignition agent. Detailed Implementation

[0052] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0053] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0054] Figure 1 This is a schematic flowchart of the emergency repair method for concrete cracks used in various embodiments of the present invention; Figure 2 and Figure 3 This is a schematic diagram of the front and side sections of the cavity-shaped container used in various embodiments of the present invention.

[0055] like Figure 2 and 3 As shown, a pouring groove 2 is first opened on the surface of the concrete crack 1, and then the cavity container 3 is placed above the crack 1 and the pouring groove 2. The bottom of the cavity container 3 is equipped with a moving component 4. In this embodiment, the moving component 4 is a trolley that is detachably installed on the bottom of the cavity container 3. The bottom plate of the trolley has a hole corresponding to the outlet of the cavity container 3. Rollers are installed under the bottom plate of the trolley. The rollers are steerable tires, which facilitates flexible adjustment of the position of the cavity container 3. The trolley is also equipped with a handle for the operator to push and pull. The main body of the cavity container 3 is made of graphite. It has an outer heat-insulating shell 5 and an inner cavity 6 for filling with self-propagating sealant 8. The bottom of the cavity 6 is funnel-shaped and has an outlet. A self-melting sheet 7 is first placed at the outlet, and then the self-propagating sealant 8 is filled in, compacted and flattened. Finally, ignition powder 9 is sprinkled on top of the self-propagating sealant 8.

[0056] Ignite the ignition powder 9 with an ignition stick, which in turn ignites the self-propagating sealant 8. The self-propagating reaction causes excess aluminum and alloying agents to melt, forming molten aluminum alloy, which in turn melts the self-melting sheet 7. The remaining products and slag-forming agents form slag that floats on the surface of the molten aluminum and adheres to the inner wall of the cavity container 3. The molten aluminum alloy flows out of the outlet of the cavity container 3 and falls into the casting tank 2, subsequently seeping into the crack 1. During the repair process, allow the trolley to stand until the molten aluminum alloy is about to overflow the crack 1. Then, slowly move the trolley, allowing the steerable tires to roll to a short distance above the opening of the casting tank 2. Allow it to stand until the molten aluminum alloy is about to overflow the crack 1. Repeat this step until the repair is complete.

[0057] The present invention will be further described below with reference to specific embodiments, but these are not intended to limit the scope of the invention.

[0058] Example 1

[0059] This embodiment provides a rapid and efficient emergency repair method for bridge cracks, as detailed below:

[0060] The volume of a crack in a bridge was measured to be 0.15 m³. 3 The calculated mass of self-propagating sealant required is 1132 kg.

[0061] The exothermic agents are: Al: 52 wt.%, 200 mesh; CaSO4: 2 wt.%, 180 mesh; BaSO4: 1 wt.%, 180 mesh; MgSO4: 23 wt.%, 180 mesh.

[0062] Slagging agent: CaF2: 5wt.%, 100 mesh, BaCl2: 0.5wt.%, 100 mesh, MgF2: 1wt.%, 100 mesh, CaS: 2wt.%, 100 mesh;

[0063] Alloying agents: Sn: 8wt.%, 200 mesh, Si: 2wt.%, 200 mesh, Mg: 1.5wt.%, 200 mesh, Cu: 2wt.%, 200 mesh.

[0064] Follow these steps: First, cut a groove along the crack and clean it with a blower. Then, place an aluminum sheet into a cavity container to block the outlet. Next, thoroughly mix the sealant and pour it into the cavity container, pressing it down firmly. Insert magnesium strips onto the surface. Push the cart carrying the cavity container above the crack, aligning the outlet with the crack groove. Ignite the magnesium strips. Wait for molten aluminum alloy to drip from the outlet, then let it stand until it overflows the crack. Push the cart a short distance above the groove, letting it stand until the molten aluminum alloy overflows the crack. Repeat this step until the crack is repaired. After 6 minutes, the molten aluminum alloy has completely cooled. Trim the crack to a smooth surface. The sealant bonds tightly to the concrete substrate, resulting in excellent crack repair.

[0065] Example 2

[0066] This embodiment provides a rapid and efficient emergency repair method for road cracks, as detailed below:

[0067] The volume of a crack in a road was measured to be 0.5 m³. 3 The calculated mass of self-propagating sealant required is approximately 3255 kg.

[0068] The exothermic agents are: Al: 62 wt.%, 180 mesh; CaSO4: 2.7 wt.%, 150 mesh; BaSO4: 2.3 wt.%, 150 mesh; MgSO4: 18 wt.%, 150 mesh.

[0069] Slagging agent: CaF2: 6wt.%, 80 mesh, BaCl2: 0.55wt.%, 80 mesh, MgF2: 0.3wt.%, 80 mesh, CaS: 2.15wt.%, 80 mesh;

[0070] Alloying agent: Sn: 4wt.%, 180 mesh, Si: 0.5wt.%, 180 mesh, Mg: 1wt.%, 180 mesh, Cu: 0.5wt.%, 180 mesh.

[0071] Follow these steps: First, cut a groove along the crack and clean it with a blower. Then, place an aluminum sheet into a cavity container to block the outlet. Next, thoroughly mix the sealant and pour it into the cavity container, pressing it down firmly. Insert magnesium strips onto the surface. Push the cart carrying the cavity container above the crack, aligning the outlet with the crack groove. Ignite the magnesium strips. Wait for molten aluminum alloy to drip from the outlet, then let it stand until it overflows the crack. Push the cart a short distance above the groove, letting it stand until the molten aluminum alloy overflows the crack. Repeat this step until the crack is repaired. After 14 minutes, the molten aluminum alloy will have completely cooled. Trim the crack to a smooth surface. The sealant bonds tightly to the concrete substrate, resulting in excellent crack repair.

[0072] Example 3

[0073] This embodiment provides a rapid and efficient emergency repair method for cracks in dam bodies, as detailed below:

[0074] The volume of a crack in a dam was measured to be 0.4 m³. 3 The calculated mass of self-propagating sealant required is approximately 2708 kg.

[0075] The exothermic agents are: Al: 58 wt.%, 175 mesh; CaSO4: 2 wt.%, 100 mesh; BaSO4: 2 wt.%, 100 mesh; MgSO4: 20 wt.%, 100 mesh.

[0076] Slagging agent: CaF2: 5.5wt.%, 100 mesh, BaCl2: 1wt.%, 100 mesh, MgF2: 1wt.%, 100 mesh, CaS: 2.5wt.%, 100 mesh;

[0077] Alloying agent: Sn: 3wt.%, 175 mesh, Si: 2wt.%, 175 mesh, Mg: 1wt.%, Cu: 2wt.%, 175 mesh.

[0078] Follow these steps: First, cut a groove along the crack and clean it with a blower. Then, place an aluminum sheet into a cavity container to block the outlet. Next, thoroughly mix the sealant and pour it into the cavity container, pressing it down firmly. Insert magnesium strips onto the surface. Push the cart carrying the cavity container above the crack, aligning the outlet with the crack groove. Ignite the magnesium strips. Wait for molten aluminum alloy to drip from the outlet, then let it stand until it overflows the crack. Push the cart a short distance above the groove, letting it stand until the molten aluminum alloy overflows the crack. Repeat this step until the crack is repaired. After 10 minutes, the molten aluminum alloy will have completely cooled. Trim the crack to a smooth surface. The sealant bonds tightly to the concrete substrate, resulting in excellent crack repair.

[0079] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the content of this specification should be included within the protection scope of the present invention.

Claims

1. A rapid and efficient method for emergency repair of concrete cracks, characterized in that, Includes the following steps: S1. Create a pouring groove on the surface of the concrete crack and clean it. S2. Based on the volume of the crack and the casting trough, prepare a corresponding mass of self-propagating sealant and fill it into a cavity container; the components of the self-propagating sealant include a heat-releasing agent, a slag-forming agent, and an alloying agent; the heat-releasing agent is composed of aluminum and sulfate; the formula for calculating the mass m of the self-propagating sealant is: ； Where m is the required mass of self-propagating sealant, s is the correction factor, a is the density factor, ρ is the density of aluminum, V is the volume of the crack, k is the aluminum utilization rate, W is the mass fraction of aluminum in the self-propagating sealant, and V0 is the groove volume. S3. Place the cavity container above one end of the casting tank, ignite the self-propagating sealant, move the cavity container so that the aluminum alloy liquid formed by melting aluminum and alloying agent flows into the crack through the outlet of the cavity container and the casting tank, and fills the crack and the casting tank. S4. After the cracks and the filling material in the casting trough have cooled, the repaired cracks should be trimmed.

2. The method according to claim 1, characterized in that, In step S1, the cross-section of the casting trough is funnel-shaped.

3. The method according to claim 1, characterized in that, In step S2, a movable component is provided at the bottom of the cavity container.

4. The method according to claim 1, characterized in that, In step S2, the cavity container is made of graphite and has an internal cavity for filling with self-propagating sealant. A self-melting sheet is provided at the outlet at the bottom of the cavity.

5. The method according to claim 4, characterized in that, The material of the self-fusing sheet is selected from one or more combinations of aluminum, tin, and magnesium, and the thickness of the self-fusing sheet is 1~2mm.

6. The method according to claim 1, characterized in that, In step S2, the components of the self-propagating sealant, by weight fraction, include: Exothermic agents: Al: 50wt.%~70wt.%; CaSO4: 2wt.%~4wt.%; BaSO4: 1wt.%~3wt.%; MgSO4: 10wt.%~30wt.%; Slagging agent: CaF2: 5wt.%~6wt.%, BaCl2: 0.5wt.%~1wt.%, MgF2: 0.25wt.%~1wt.%, CaS: 2wt.%~3wt.%; Alloying agent: Sn: 3wt.%~10wt.%, Si: 0.5wt.%~2wt.%, Mg: 1wt.%~1.5wt.%, Cu: 0.5wt.%~2wt.%.

7. The method according to claim 6, characterized in that, In the self-propagating sealant, Al has a mesh size of 80-250 mesh; the other components have a mesh size of 50-300 mesh.

8. The method according to claim 1, characterized in that, In step S3, the method of igniting the self-propagating sealant includes: sprinkling an igniter on top of the self-propagating sealant and igniting it with an ignition strip.

9. The application of a method according to any one of claims 1-8 in the repair of concrete cracks.

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