A method for rapid and non-destructive reinforcement of existing structures using UHPC

Abstract

This invention discloses a method for rapid and non-destructive reinforcement of existing structures using UHPC, comprising the following steps: S1, prefabricating lightweight UHPC anchor blocks; S2, cleaning and wetting the surface of the existing structure to be reinforced, spraying high-viscosity UHPC, stopping spraying after reaching a predetermined thickness to form an adhesive layer; S3, installing lightweight UHPC anchor blocks onto the adhesive layer before the adhesive layer initially sets; S4, spraying early-strength UHPC onto the surface to be reinforced again until the required thickness is reached, completing the reinforcement of the existing structure. This method for rapid and non-destructive reinforcement of existing structures using UHPC facilitates construction on facades and roofs, improves the efficiency and quality of reinforcement of permanent and temporary structures without damaging the original structure, and shortens the reinforcement construction cycle, demonstrating good economic efficiency and application prospects.

Description

Technical Field

[0001] This invention relates to the field of existing structure reinforcement. More specifically, this invention relates to a method for rapid and non-destructive reinforcement of existing structures using UHPC. Background Technology

[0002] In the field of structural reinforcement, the main methods used are cross-section enlargement, steel plate bonding, fiber bonding, prestressed reinforcement, and shotcrete reinforcement. Cross-section enlargement is the most widely used, often employing ordinary grade concrete. After reinforcement, the structure's self-weight increases significantly, resulting in relatively poor reinforcement effectiveness. Steel plate bonding and fiber bonding require applying high-performance adhesives and bonding steel plates or fiber cloth. However, the adhesives have slow strength development and are prone to aging, while steel plates and fiber cloth are expensive and have poor durability. Prestressed reinforcement is generally only suitable for vertically loaded structures such as beam bridges and is not applicable to piers, building frames, foundation pit support, tunnel linings, etc., thus its application scope is relatively limited. Shotcrete UHPC reinforcement requires damaging the original structure through rebar installation and mesh reinforcement. The rebar installation process is cumbersome, time-consuming, and labor-intensive, and the rebar is susceptible to external corrosion, which can damage the overall structural strength of the concrete. Summary of the Invention

[0003] To achieve these objectives and other advantages according to the present invention, a preferred embodiment of the present invention provides a method for rapid and non-destructive reinforcement of existing structures using UHPC, comprising the following steps:

[0004] S1. Precast lightweight UHPC anchor block;

[0005] S2. Clean and wet the surface of the existing structure to be reinforced, spray high-viscosity UHPC, and stop spraying after reaching the predetermined thickness to form an adhesive layer;

[0006] S3. Install lightweight UHPC anchor blocks onto the adhesive layer before the adhesive layer initially sets;

[0007] S4. Spray early-strength UHPC onto the surface to be reinforced again until the required thickness is achieved, thus completing the reinforcement of the existing structure.

[0008] According to the above technical solution, in step S3, installing lightweight UHPC anchor blocks onto the adhesive layer specifically includes:

[0009] The lightweight UHPC anchor block is attached to the surface of the adhesive layer, and then the anchor is inserted through the lightweight UHPC anchor block into the adhesive layer, thereby firmly installing the lightweight UHPC anchor block on the surface of the existing structure to be reinforced.

[0010] According to the above technical solution, the high-viscosity UHPC is obtained by adding a thixotropic agent to UHPC, wherein the amount of the thixotropic agent is 0-6% of the weight of UHPC, and the fiber used in UHPC is steel fiber with a volume content of 1.5%.

[0011] According to the above technical solution, the lightweight UHPC anchor block is prepared using porous aggregate as raw material.

[0012] According to the above technical solution, the lightweight UHPC anchor block is a square mesh structure with an inner hole in the middle, and the side wall thickness of the square mesh structure is thinner at both ends and thicker in the middle. Solid anchors of different lengths are distributed on both sides of the lightweight UHPC anchor block, so that the side wall thickness of the lightweight UHPC anchor block is consistent everywhere, and it is also filled with UHPC.

[0013] According to the above technical solution, the anchor bolt adopts a double barb structure.

[0014] According to the above technical solution, the fibers used in the lightweight UHPC anchor block are steel fibers.

[0015] According to the above technical solution, the early-strength UHPC is obtained by adding an early-strength quick-setting agent to UHPC. In step S4, early-strength UHPC is sprayed onto the surface to be reinforced again. The amount of early-strength quick-setting agent added to the early-strength UHPC is such that the early-strength UHPC sprayed in step S4 and the high-viscosity UHPC sprayed in step S2 are hydrated synchronously.

[0016] According to the above technical solution, the fibers used in the early strength UHPC are non-metallic fibers.

[0017] According to the above technical solution, in step S4, an early-strength UHPC is sprayed onto the surface to be reinforced using a spraying mechanism. The spraying mechanism includes a concrete pump pipe, a swirl air inlet, a concrete nozzle, an air inlet pipe, a quick-setting agent feed pipe, an air-material mixer, and an air-material feed pipe. The air inlet pipe and the quick-setting agent feed pipe are both connected to the air-material mixer to respectively input air and quick-setting agent into the air-material mixer. The air-material mixer is connected to the swirl air inlet through two air-material feed pipes. The concrete pump pipe is also connected to the inlet end of the swirl air inlet, and the outlet end of the swirl air inlet is connected to the concrete nozzle.

[0018] The present invention has at least the following beneficial effects:

[0019] The UHPC rapid non-destructive reinforcement method for existing structures of the present invention is convenient for facade and top construction. It can improve the reinforcement efficiency and quality of permanent and temporary structures without damaging the original structure, and also shorten the reinforcement construction cycle. It has good economic benefits and application prospects.

[0020] ① The spraying angle is flexible, and it can be sprayed vertically, horizontally and obliquely. The sprayed UHPC has good adhesion to existing concrete, soil or rock surfaces. At the same time, the shape, size and thickness distribution of the anchor block can be adjusted at will according to the stress of the structure, which is highly designable. (The steel mesh is troublesome to make and has poor designability. The anchor block is directly prefabricated according to the actual stress.) It is suitable for permanent structures such as bridges (main beams, piers) and building frames, as well as temporary structures such as foundation pit support and tunnel lining, with a wider range of applications.

[0021] ② The shotcrete reinforcement process does not require the installation or removal of formwork, and the precast anchor block process does not require interface roughening and rebar installation, which minimizes damage to existing structures and saves the workload of roughening and rebar installation. In addition, the early strength UHPC has a fast strength development speed (compressive strength can reach more than 40MPa in 12 hours), and the construction time is shortened by more than 50% compared with conventional shotcrete reinforcement, with little impact on traffic along the route.

[0022] ③ The spraying equipment and anchor blocks can be moved and put into use at any time. The spraying pipe can be freely extended and flexibly adjusted. After the air and material are mixed, air and material are fed in both directions, and the accelerator is dispersed more evenly, which improves the overall spraying quality of early-strength UHPC. Combined with the fast hardening and early strength characteristics of early-strength UHPC, it is especially suitable for emergency repair projects after impact loads such as earthquakes, debris flows, and impacts.

[0023] ④ UHPC has high tensile and compressive strength. Under the same reinforcement effect, the thickness of its reinforcement layer is much smaller than that of ordinary concrete reinforcement layer. At the same time, lightweight UHPC is used as anchor blocks to minimize the impact of reinforcement work on the self-weight, size and appearance of the existing structure, thus achieving lightweight reinforcement.

[0024] ⑤ A large number of short and fine fibers are added to the UHPC matrix, which gives the tensile reinforcement layer excellent crack resistance and impact toughness, thereby significantly improving the bending reinforcement performance of the beam, the pier column's resistance to debris flow erosion and impact resistance.

[0025] ⑥ The surface early-strength sprayed UHPC uses non-metallic fibers to replace steel bars and steel fibers, avoiding the damage to concrete structures caused by the corrosion of steel bars and steel fibers. Combined with the density of the UHPC structure itself, it greatly slows down the deterioration process of the structure, thereby improving the structural life. It is suitable for the reinforcement of structures in various extreme environments, such as plateaus, saline-alkali land and marine environments.

[0026] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the construction steps for rapid and non-destructive reinforcement of existing structures using UHPC in one embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of the spraying mechanism in one embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of the structure of an anchor pin in one embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of the spraying mechanism in one embodiment of the present invention. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0032] The following description is intended to disclose the present invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious modifications will occur to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0033] Those skilled in the art should understand that, in the disclosure of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting this invention.

[0034] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0035] like Figure 1-4 As shown, a preferred embodiment of the present invention provides a method for rapid and non-destructive reinforcement of existing structures using a UHPC, comprising the following steps:

[0036] S1, Precast lightweight UHPC anchor block 2;

[0037] S2. Clean and wet the surface of the existing structure 1 to be reinforced, spray high-viscosity UHPC, stop spraying after reaching the predetermined thickness, and form an adhesive layer 3.

[0038] S3. Install lightweight UHPC anchor blocks 2 onto the adhesive layer before the adhesive layer initially sets;

[0039] S4. Spray early-strength UHPC4 onto the surface to be reinforced again until the required thickness is achieved, thus completing the reinforcement of the existing structure 1.

[0040] The aforementioned technical solution abandons the traditional method of roughening the surface of the existing structure to be reinforced and inserting anchor bars, as this method inevitably causes damage to the existing structure and involves a large amount of work. This technical solution, however, sprays a layer of high-viscosity UHPC as an inorganic adhesive onto the surface of the existing structure to be reinforced. Before the adhesive layer initially sets, prefabricated lightweight UHPC mesh anchor blocks are fixed to the surface of the adhesive layer. After the adhesive layer initially sets, early-strength UHPC is sprayed onto the anchor blocks to form a covering layer. The covering layer, adhesive layer, and mesh anchor blocks form an integral structure, achieving rapid reinforcement of the structure. This technical solution eliminates the need for interface roughening and rebar installation, minimizing damage to the existing structure and saving the workload associated with roughening and rebar installation.

[0041] Based on the above technical solutions, a spray gun is used to spray the surface to be reinforced using a spraying device. The spraying angle is flexible and can be vertical, horizontal, and oblique. The sprayed UHPC has good adhesion to existing concrete, soil, or rock surfaces. At the same time, the shape, size, and thickness distribution of the lightweight UHPC anchor blocks can be adjusted at will according to the stress conditions of the structure, which is highly designable. The lightweight UHPC anchor blocks are directly prefabricated according to the actual stress conditions, which is suitable for permanent structures such as bridges (main beams, piers), building frames, as well as temporary structures such as foundation pit support and tunnel lining. The application range is wider. In contrast, traditional steel mesh is troublesome to produce and has poor design flexibility. Moreover, the spray reinforcement process does not require the installation and removal of formwork.

[0042] Based on the above technical solutions, the spraying equipment and lightweight UHPC anchor blocks can be moved independently and put into use at any time. The spraying equipment can be a spraying pipe, which can be freely extended and flexibly adjusted. Combined with the fast hardening and early strength characteristics of early-strength UHPC, it is especially suitable for emergency repair projects after impact loads such as earthquakes, debris flows, and impacts.

[0043] In another technical solution, step S3, installing a lightweight UHPC anchor block onto the adhesive layer, specifically includes:

[0044] The lightweight UHPC anchor block is attached to the surface of the adhesive layer, and then the anchor 5 is inserted through the lightweight UHPC anchor block 2 into the adhesive layer 3, thereby firmly installing the lightweight UHPC anchor block on the surface of the existing structure to be reinforced.

[0045] In the above technical solution, the anchor 5 is inserted into the adhesive layer instead of directly into the surface of the existing structure, which minimizes damage to the existing structure. The anchor can effectively fix the lightweight UHPC anchor block to the surface of the existing structure.

[0046] In another technical solution, the high-viscosity UHPC is obtained by adding a thixotropic agent to UHPC (which itself contains fibers), wherein the amount of the thixotropic agent is 0-6% of the weight of the UHPC, and the fibers used in the UHPC are steel fibers with a volume fraction of 1.5%.

[0047] In the above technical solution, the high-viscosity UHPC is prepared using a thixotropic agent as a tackifier, which serves to bond the working surface to the lightweight UHPC mesh anchor block. Adding the thixotropic agent to the UHPC gives the slurry good fluidity under pump pressure. After being sprayed onto the working surface and allowed to stand, it exhibits good cohesion and adhesion. Its thickness is 2-4 cm, and its initial setting time is 2-4 h. The setting time can be adjusted according to the size of the bonding surface and the spraying rate to meet the installation requirements of the anchor block.

[0048] The high-viscosity UHPC incorporates 8-13mm short-cut steel fibers, which effectively improve the toughness and destructive load of the reinforced structure. This gives the reinforced layer in the tension zone excellent crack resistance and impact toughness, thereby significantly improving the flexural strength of the beam, and the resistance of the piers to debris flow erosion and impact.

[0049] In another technical solution, the lightweight UHPC anchor block is prepared using porous aggregates and hollow vitrified microspheres as raw materials, effectively reducing the weight of the UHPC anchor block to a density as low as 1900-2100 kg / m³. 3 However, its strength is less than 100 MPa.

[0050] In another technical solution, the lightweight UHPC anchor block 2 is a square mesh structure 2-1 with an inner hole in the middle, and the sidewall thickness of the square mesh structure 2-1 is thinner at both ends and thicker in the middle. Solid anchor nails 5 of different lengths are distributed on both sides of the lightweight UHPC anchor block, so that the sidewall thickness of the lightweight UHPC anchor block is consistent everywhere.

[0051] Based on the above technical solution, a specific method for pouring UHPC into the anchor block is also provided. During installation, after placing the square mesh structure in the designed position, the whole structure is pushed inward so that the inner side of the square mesh structure is submerged in the concrete. The pushing is continued for about 1-2 hours until the bonded UHPC has initially set.

[0052] In another technical solution, the anchor 5 adopts a double barb structure, that is, the anchor 5 has two barbs, and the two barbs 5-1 are distributed in opposite directions and are respectively located on the left and right sides of the anchor, thereby increasing the contact area and adhesion force with the high-viscosity UHPC adhesive layer.

[0053] In another technical solution, the UHPC within the lightweight UHPC anchor block is also incorporating steel fibers. These steel fibers, with a length of 13-22mm, effectively improve the toughness and destructive load of the reinforced structure. This gives the reinforced layer in the tension zone excellent crack resistance and impact toughness, thereby significantly improving the beam's bending reinforcement performance, and the pier's resistance to debris flow erosion and impact.

[0054] In another technical solution, the early-strength UHPC is obtained by adding an early-strength quick-setting agent to UHPC. In step S4, early-strength UHPC is sprayed onto the surface to be reinforced again. The amount of early-strength quick-setting agent added to the early-strength UHPC is such that the early-strength UHPC sprayed in S4 and the high-viscosity UHPC sprayed in S2 are hydrated synchronously to reduce the interface difference and make the reinforcement layer form a unified whole, thus completing the reinforcement of the existing structure.

[0055] Among them, early-strength UHPC has a fast strength development speed (compressive strength can reach more than 40MPa in 12 hours), the construction time is shortened by more than 50% compared with conventional shotcrete reinforcement, and the impact on traffic along the route is small;

[0056] In step S4, an early-strength UHPC is sprayed onto the surface to be reinforced using a spraying mechanism 6. The spraying mechanism includes a concrete pump pipe 6-1, a swirl air inlet 6-2, a concrete nozzle 6-3, an air inlet pipe 6-4, a quick-setting agent feed pipe 6-5, an air-material mixer 6-6, and an air-material inlet pipe 4. The air inlet pipe 6-4 and the quick-setting agent feed pipe 6-5 are both connected to the air-material mixer 6-6 to respectively input air and quick-setting agent into the air-material mixer 6-6. The air-material mixer 6-6 is connected to the swirl air inlet 6-2 through two air-material inlet pipes. The concrete pump pipe 6-1 is also connected to the inlet end of the swirl air inlet 102, and the outlet end of the swirl air inlet 6-2 is connected to the concrete nozzle 6-3.

[0057] The following provides the operating procedure for the injection mechanism 6:

[0058] S1. After the concrete is mixed, it is transported to the site by a tanker truck and put into the spraying machine. The concrete is then delivered to the spray gun head 6-3 by the concrete pump pipe 6-1.

[0059] S2. The quick-setting agent enters the air-material mixer 6-6 through the quick-setting agent feed pipe 6-5 under the action of air inlet. In the air-material mixer 6-6, it is atomized under the action of high air pressure, and then enters the cyclone air inlet 6-2 together with the air through the feed pipes at both ends.

[0060] S3. The concrete is subjected to the air pressure from the swirl air inlet 6-2 at the spray gun head 6-3, and is mixed with the atomized quick-setting agent before being sprayed onto the working surface.

[0061] In the above technical solution, the concrete pump pipe 6-1, the accelerator material pipe 6-4, and the air inlet pipe 6-3 can be freely extended and flexibly adjusted. After the air and material are mixed, air and material are fed in both directions, the accelerator is more evenly dispersed, and the overall spraying quality of early-strength UHPC is improved. Combined with the fast-hardening and early-strength characteristics of early-strength UHPC, it is especially suitable for emergency repair projects after impact loads such as earthquakes, debris flows, and impacts.

[0062] According to the above technical solution, the early-strength UHPC also contains non-metallic fibers, which are 8-13cm in length and include polypropylene, polyoxymethylene, basalt, etc. In this application, non-metallic fibers are used to replace steel bars and steel fibers, avoiding the damage to concrete structures caused by the corrosion of steel bars and steel fibers. Combined with the compactness of the UHPC structure itself, the deterioration process of the structure is greatly slowed down, thereby improving the service life of the structure. It can be used for the reinforcement of structures in various extreme environments, such as plateaus, saline-alkali land and marine environments.

[0063] To further verify the effectiveness of the embodiments of the present invention, they are compared with Comparative Examples 1 and 2. Comparative Example 1 uses conventional vertical formwork casting. Specifically, S1, the surface of the existing structure to be reinforced is cleaned, and anchoring steel bars are inserted into the cleaned surface and welded to the original steel bars for fixation; S2, a wooden or steel vertical formwork model is made according to the design shape, and the gaps in the vertical formwork are sealed; S3, repair concrete is injected into the vertical formwork from a height, and the concrete is gently tamped with a vibrator; S4, the concrete is cured until the strength meets the requirements, the vertical formwork is removed, and curing is carried out to ensure the stable growth of the concrete strength.

[0064] Comparative Example 2 uses existing rebar spraying technology. Specifically, S1, the surface of the existing structure to be reinforced is cleaned, and anchor bars with hook structures are inserted into the cleaned surface; S2, a spraying pipe is installed, and UHPC is sprayed onto the surface to be reinforced using the spraying pipe. Spraying is stopped after the sprayed UHPC reaches the set thickness; S3, a steel mesh is made, and the steel mesh is hung on the anchor bars and fixed using the hook structure; S4, conventional UHPC is sprayed onto the surface to be reinforced again until the required thickness is reached; S5, steps S2 to S4 are repeated sequentially until the surface to be reinforced is completed. The reinforced surface is then corrected and cured to complete the reinforcement of the existing structure. Examples 1-4 use the anchor block spraying process of this invention, only with different amounts of thickening thixotropic agent and early-strength quick-setting agent added.

[0065] Table 1 Comparison of the anchor block spraying process of this application and the traditional process

[0066]

[0067]

[0068] As shown in Table 1, the construction processes of Comparative Example 1 and Comparative Example 2 are different. After the reinforcement treatment using the spraying method of the present invention in Examples 1-4, the bond strength and breaking load increased by 47.6% and 7.0%, respectively. Compared with Example 3 and Comparative Example 2, the anchor block spraying process reduced the rebound rate by 69.5%, increased the bond strength by 59.0%, reduced the chloride ion permeability coefficient by 67.0%, saved 55.1% of the labor time, and the breaking load was similar to that of rebar spraying. However, Example 5 only added a quick-setting agent, which resulted in a decrease in bond strength compared with Example 3. Example 6 only added a thixotropic agent, which also resulted in a decrease in bond strength and breaking load compared with Example 3. Based on the above test results, this invention provides a new method and process for reinforcing existing structures through high-viscosity sprayed UHPC, lightweight UHPC anchor blocks, and early-strength sprayed UHPC technology. The use of this new method and process effectively improves the adhesion of the reinforcing material, thereby reducing the rebound rate and increasing the density. Combined with the use of non-metallic fibers, it greatly improves the corrosion resistance and durability of marine structures, while shortening the construction time and improving the reinforcement efficiency.

[0069] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for the rapid non-destructive reinforcement of existing structures with UHPC, characterized in that, Includes the following steps: S1. Precast lightweight UHPC anchor block; S2. Clean and wet the surface of the existing structure to be reinforced, spray high-viscosity UHPC, and stop spraying after reaching the predetermined thickness to form an adhesive layer; S3. Install lightweight UHPC anchor blocks onto the adhesive layer before the adhesive layer initially sets; S4. Spray early-strength UHPC onto the surface to be reinforced again until the required thickness is achieved, thus completing the reinforcement of the existing structure. In step S3, installing lightweight UHPC anchor blocks onto the adhesive layer specifically includes: The lightweight UHPC anchor block is attached to the surface of the adhesive layer, and then the anchor is inserted through the lightweight UHPC anchor block into the adhesive layer, thereby firmly installing the lightweight UHPC anchor block on the surface of the existing structure to be reinforced. The high-viscosity UHPC is obtained by adding a thixotropic agent to UHPC, wherein the amount of the thixotropic agent is less than 6% of the weight of UHPC, and the fiber used in UHPC is steel fiber with a volume content of 1.5%. The lightweight UHPC anchor block is prepared using porous aggregate as raw material; the lightweight UHPC anchor block has a square mesh structure with an inner hole in the middle, and the side wall thickness of the square mesh structure is thinner at both ends and thicker in the middle. Solid anchors of different lengths are distributed on both sides of the lightweight UHPC anchor block, so that the side wall thickness of the lightweight UHPC anchor block is consistent everywhere, and it is also filled with UHPC. The anchor bolt adopts a double barb structure.

2. The method of fast non-destructive reinforcement of existing structures with UHPC according to claim 1, characterized in that, The fibers used in the lightweight UHPC anchor block are steel fibers.

3. The method of fast non-destructive reinforcement of existing structures with UHPC according to claim 1, characterized in that, The early-strength UHPC is obtained by adding an early-strength quick-setting agent to UHPC. In step S4, early-strength UHPC is sprayed onto the surface to be reinforced again. The amount of early-strength quick-setting agent added to the early-strength UHPC is such that the early-strength UHPC sprayed in step S4 and the high-viscosity UHPC sprayed in step S2 are hydrated synchronously.

4. The method of fast non-destructive reinforcement of existing structures with UHPC according to claim 3, characterized in that, The fibers used in the early-strength UHPC are non-metallic fibers.

5. The method of fast non-destructive reinforcement of existing structures with UHPC according to claim 1, characterized in that, In step S4, an early-strength UHPC is sprayed onto the surface to be reinforced using a spraying mechanism. The spraying mechanism includes a concrete pump pipe, a swirl air inlet, a concrete nozzle, an air inlet pipe, a quick-setting agent feed pipe, an air-material mixer, and an air-material feed pipe. The air inlet pipe and the quick-setting agent feed pipe are both connected to the air-material mixer to input air and quick-setting agent into the air-material mixer, respectively. The air-material mixer is connected to the swirl air inlet through two air-material feed pipes. The concrete pump pipe is also connected to the inlet end of the swirl air inlet, and the outlet end of the swirl air inlet is connected to the concrete nozzle.

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