Efficient construction method for rapidly repairing cement concrete bridge floor by using UHPC (Ultra High Performance Concrete)

Abstract

The invention relates to an efficient construction method for quickly repairing a cement concrete bridge floor by using UHPC, which belongs to the technical field of bridge repairing and comprises the following steps: step 1, damage assessment: judging the damage condition according to the damage range and depth of the bridge floor; step 2, surface treatment: dedusting and decontaminating the damaged surface, and cleaning a boundary crack area which is not communicated with the center of the damaged area by using a tool, so that the boundary crack area is communicated with the center of the damaged area to form a complete repair surface; 3, recording a damaged range and depth data after cleaning; 4, preparing a UHPC material, and preparing and manufacturing raw materials according to the data recorded in the step 3; 5, the prepared UHPC material is poured into the center of a damaged area, and a boundary crack area needs to be guided by a thin rod; 6, after repairing is completed, the damaged area is covered with a thin film for wet curing, and the method can improve the construction efficiency, relieve traffic pressure, shorten the repairing period and reduce the repairing cost.

Description

Technical Field

[0001] The invention belongs to the technical field of bridge repair, and specifically relates to an efficient construction method for quickly repairing a cement concrete bridge deck by using UHPC. Background Art

[0002] As a new type of high-performance concrete material, UHPC has the characteristics of high strength, high toughness, and high durability. Its compressive strength and tensile strength are much higher than those of ordinary concrete, and it has excellent wear resistance and corrosion resistance, which makes UHPC have significant advantages in bridge deck repair. In addition, UHPC also has good fluidity and self-compactness, which can effectively fill cracks and holes and improve the quality of repair.

[0003] With the continuous acceleration of infrastructure construction, the use of cement concrete bridge decks is becoming more and more frequent, so the need for bridge deck damage repair is becoming more and more urgent. Traditional repair methods often have problems such as long construction period and unsatisfactory repair effect, which cannot meet the needs of modern rapid construction.

[0004] Some bridge decks, as the main arterial roads in the city, need to carry a large amount of traffic. However, for the construction and repair on the bridge, in order to ensure the safety of the construction workers, it is usually necessary to divide the construction area, resulting in the inability of vehicles to pass normally, causing great traffic pressure in the entire city. Therefore, the repair work of the bridge deck needs to improve the construction efficiency during the construction period, restore the normal operation of the bridge deck, and speed up the normal passage of cars. At the same time, as a bridge that carries a lot of traffic, it is also necessary to ensure the durability of the repair and improve the quality of the bridge deck.

[0005] In the existing bridge deck repair construction method, a transport vehicle is usually required to transport the repair materials to the repair area. At the same time, for the safety of the construction workers, the entire bridge deck or even the entire lane needs to be divided into construction areas to interrupt the traffic on the bridge deck. At the same time, bridge deck repair involves complicated processes such as bridge deck assessment, repair, cleaning, maintenance and acceptance. The complicated construction process seriously affects traffic.

[0006] Therefore, there is an urgent need to develop a new and efficient bridge deck repair method. Summary of the invention

[0007] In order to solve the above problems existing in the prior art, the present invention provides an efficient construction method for quickly repairing cement concrete bridge decks using UHPC, which solves the problem of complicated construction process and low efficiency of existing repair methods, which increases traffic pressure.

[0008] The purpose of the present invention can be achieved through the following technical solutions:

[0009] An efficient construction method for quickly repairing a cement concrete bridge deck using UHPC includes the following steps: 1. Damage assessment, judging the damage according to the damage range and depth of the bridge deck;

[0010] Step 2: Surface treatment: if the damage is localized and large-scale, remove dust and dirt from the damaged surface and use tools to clean the boundary crack area that is not connected to the center of the damaged area, so that the boundary crack area is connected to the center of the damaged area to form a complete repair surface;

[0011] Step 3: Record the damage scope and depth data after cleaning;

[0012] Step 4: UHPC material preparation, prepare and make raw materials according to the data recorded in step 3;

[0013] Step 5: Pour the prepared UHPC material into the center of the damaged area. The boundary crack area needs to be guided by a thin rod to fill the boundary crack area with UHPC material.

[0014] Step 6: After the repair is completed, cover the damaged area with a film for wet curing.

[0015] Preferably, in step 2, the independently split regions are connected to each other through openings, and the opening of the crack region close to the center of the damaged region is connected to the center of the damaged region.

[0016] Preferably, step four includes:

[0017] S401, selection and preparation of raw materials, including cement, ultrafine powder, fine aggregate and fine sand, steel fiber and chemical additives;

[0018] S402, the raw material ratio is determined, where the ratio of cement, ultrafine powder, fine aggregate, fine sand and steel fiber is 1:1:1:2.5;

[0019] S403, use a high-speed mixer to stir to ensure that the raw materials are evenly mixed.

[0020] Preferably, the water-to-binder ratio of the UHPC material is between 0.15 and 0.25.

[0021] Preferably, the chemical additive is a water reducing agent, and the dosage of the water reducing agent is 4%.

[0022] Preferably, when the damaged area is located in a steep slope section of a bridge, a positioning mechanism is installed in the damaged area, and the positioning mechanism is installed with a coating. From bottom to top of the steep slope, the coating covers 2 / 3 of the damaged area and fits the bridge deck.

[0023] Preferably, the positioning mechanism includes two horizontal components and two vertical components; both ends of any horizontal component are detachably connected to the vertical components; the horizontal components and the vertical components have the same structure, and the horizontal components include a fixed section and a telescopic section, and the telescopic section is sleeved on the fixed section and slidably connected to the fixed section.

[0024] Preferably, it also includes a transverse adjustment member and a vertical adjustment member, and both the transverse adjustment member and the vertical adjustment member are installed on one side of the fixed section of their respective components close to the telescopic section; the transverse adjustment member is used to adjust the length of the transverse component, and the vertical adjustment member is used to adjust the width of the vertical component. The structures of the transverse adjustment member and the vertical adjustment member are consistent, and the transverse adjustment member includes a rotating gear and a rack, the gear is installed in the fixed section, and a rotating member extending out of the fixed section is provided, the rotating member is used to rotate the gear, and the rack is installed in the telescopic section and meshes with the gear in the fixed section.

[0025] Preferably, it further comprises a latch pin, and the fixing section is further provided with a latch pin hole, and the latch pin cooperates with the latch pin hole to position the length and width of the positioning mechanism.

[0026] The beneficial effects of the present invention are:

[0027] The use of UHPC materials for repair can complete the repair work in a short time, reduce the impact on traffic, and shorten the repair cycle. UHPC materials have excellent mechanical properties and durability, which can ensure that the damaged area has a load-bearing capacity and service life similar to the original bridge deck. Through fast and efficient repairs, the service life of the bridge deck can be extended, the frequency of maintenance and reconstruction can be reduced, thereby reducing long-term maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0029] Figure 1 A schematic diagram of the installation structure of a positioning mechanism provided in one embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of the installation structure of the positioning mechanism provided in one embodiment of the present invention on an inclined bridge deck;

[0031] Figure 3 A schematic diagram of a connection structure of a lateral positioning assembly provided in one embodiment of the present invention;

[0032] Legend: 1. Damaged area; 11. Boundary crack area; 12. Opening; 21. Horizontal component; 22. Vertical component; 211. Fixed section; 212. Telescopic section; 3. Horizontal adjustment member; 31. Gear; 32. Rack. DETAILED DESCRIPTION

[0033] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0034] like Figure 1-Figure 3 As shown, an efficient construction method for quickly repairing cement concrete bridge decks using UHPC includes step 1: damage assessment, judging whether it is crack damage or local area damage according to the damage range and depth of the bridge deck; on a cement concrete bridge deck, a local damage area 1 with an area of ​​2 square meters and a depth of about 5 centimeters was found, accompanied by several small cracks; after evaluation, it was determined that the area was locally damaged and needed to be quickly repaired;

[0035] Step 2: Surface treatment. If the damage is local and large, remove dust and dirt from the damaged surface and use tools to clean the boundary crack area 11 that is not connected to the damaged area 1, so that the boundary crack area 11 is connected to the damaged area 1 to form a complete repair surface; use a high-pressure air gun to remove dust from the damaged area 1, and use a detergent to remove oil and other impurities; then, use special tools such as a chisel to open 12 the boundary crack area 11 that is not connected to the damaged area 1, until the crack is connected to the center of the damaged area 1, forming a flat and continuous repair surface.

[0036] Step 3: Record the damage scope and depth data after cleaning; record the damage scope and depth after cleaning in detail as reference data for subsequent UHPC material preparation.

[0037] Step 4: UHPC material preparation. Prepare and make the raw materials according to the data recorded in step 3 to ensure that the repair material has excellent fluidity, adhesion and self-stability. Calculate the volume of the repair space according to the recorded damage range and depth data, and determine the formula ratio of the UHPC material to prepare the corresponding raw materials. During the stirring process, ensure that the materials are mixed evenly to obtain excellent fluidity, adhesion and self-stability.

[0038] Step 4: Pour the prepared UHPC material into the center of the damaged area 1. The boundary crack area needs to be guided by a thin rod so that the boundary crack area is filled with UHPC material. The prepared UHPC material can completely fill the damaged area 1 and form a strong bond with the original bridge deck.

[0039] Step 5: After the repair is completed, the damaged area 1 is covered with a film for wet curing; After the repair is completed, the damaged area 1 is immediately covered with a plastic film for wet curing, and the integrity of the film is regularly checked to ensure that the damaged area 1 always remains moist. Wet curing can effectively promote the hardening and strength development of the UHPC material, ensuring that the damaged area 1 forms a solid whole with the original bridge deck.

[0040] Based on the above construction steps, compared with the existing bridge deck repair process, such as asphalt, its construction method is to use a cutting tool to cut off the damaged part - clean up dust and debris - spray adhesive layer asphalt - preheat the asphalt repair material evenly on the damaged area 1 - asphalt compaction treatment - maintenance; among them, because the fluidity of asphalt is poor, in order to ensure the durability of asphalt, it is usually necessary to completely remove the damaged boundary crack area 11 until only a dense concrete bridge deck is left, and after the boundary crack area 11 is chiseled out, the concrete needs to be cleaned and collected, and at the same time, it is cleaned with a high-pressure water gun to clean the damaged area 1, and before paving the asphalt material, it is necessary to wait for it to dry, and then apply the adhesive layer to increase the bonding strength between the asphalt material and the bridge deck to ensure the durability of the asphalt. It can be seen that compared with the asphalt material repair method, more tools are needed, and the construction process for the damaged area 1 is more complicated and takes a longer time, and the efficiency is not high; but if the bridge deck is repaired, the asphalt material needs to be repaired. As the main arterial road in the city, it needs to carry a large amount of traffic. The multi-lane bridge deck has been turned into a single lane due to repair. If the bridge deck repair time is too long and the efficiency is too low, vehicles cannot pass normally, resulting in the original multi-lane only being able to achieve single lane traffic, causing great traffic pressure in the entire city; therefore, the present application uses UHPC material as a repair material, and controls the fluidity of UHPC by proportioning the UHPC material, so that when repairing, UHPC can automatically fill the crack area at the edge through its own fluidity. At the same time, the crack area has openings 12, which can ensure the repair effect of the boundary crack area 11, and there is no need to chisel out the boundary crack area 11, thereby improving construction efficiency and entering the maintenance stage as soon as possible. In the maintenance stage, the damaged area 1 is enclosed, and the construction area enclosed during construction is shortened, so that the space for vehicle passage is increased, the time for normal vehicle passage is accelerated, and the traffic pressure caused by bridge deck repair is alleviated.

[0041] In summary, the use of UHPC materials for repair can complete the repair work in a short time, reduce the impact on traffic, and shorten the repair cycle. In addition, UHPC materials have excellent mechanical properties and durability, which can ensure that the damaged area 1 has a bearing capacity and service life similar to the original bridge deck; through fast and efficient repairs, the service life of the bridge deck can be extended, the frequency of maintenance and reconstruction can be reduced, thereby reducing long-term maintenance costs.

[0042] In one embodiment, in step 2, the openings 12 between the independently split regions are connected to each other, and the openings 12 of the boundary crack regions 11 closer to the damaged region 1 are connected to the center of the damaged region 1; UHPC materials are known for their excellent fluidity and can fill small gaps and holes. By connecting the scattered crack openings 12 and connecting them to the damaged region 1, it can be ensured that the UHPC material can smoothly flow into each boundary crack region 11 during pouring, thereby making full use of the fluidity characteristics of the material; in traditional repair methods, it may be necessary to chisel or clean the cracks at the edge first, and integrate them with the damaged region 1, which is easier to fill; however, this method increases the complexity and time cost of the construction operation, and in this embodiment, according to the fluidity characteristics of UHPC, the cracks at the edge are not chiseled but directly connected by the openings 12, which not only simplifies the construction steps, but also improves the construction efficiency; in addition, by connecting multiple scattered crack openings 12 and connecting them to the damaged region 1, a continuous damaged region 1 can be formed; in this way, when the UHPC material is filled and hardened, a more solid overall structure will be formed, thereby improving the strength and durability of the damaged region 1. When pouring the repair material, the operation can also be distributed. First, the UHPC material is poured into the crack area so that the crack area is not filled through the opening 12, but the UHPC material poured into the crack area penetrates from the crack area to the center of the damaged area 1. Secondly, the main UHPC material is poured into the center of the damaged area 1 so that the repair material poured at the edge of the crack is fully integrated with the repair material poured in the center of the damaged area 1. At the same time, the crack opening 12 is connected and connected to the damaged area 1, which can disperse stress, reduce the occurrence of stress concentration, and improve the overall stability of the bridge deck. By making full use of the fluidity characteristics of the UHPC material for efficient repair, the long-term maintenance cost of the bridge can be reduced, because the continuous structure formed in the damaged area 1 has high strength and durability, which can reduce the need for future repairs and reinforcement work due to damage.

[0043] In summary, according to the fluidity characteristics of UHPC, the strategy of not chiseling the cracks at the edges but directly connecting them with the openings 12 can make full use of the performance characteristics of the material, improve the repair efficiency and quality, and reduce the construction cost and maintenance cost.

[0044] In one embodiment, step 4 includes:

[0045] S401, selection and preparation of raw materials, including cement, ultrafine powder, fine aggregate and fine sand, steel fiber and chemical additives; for the selection of raw materials, ultrafine powder uses highly active ultrafine mineral powder, such as silica fume, slag powder, etc., to improve the microstructure and mechanical properties of the material; select fine aggregate and fine sand with reasonable particle size distribution and stable quality to provide the skeleton and filling effect required by UHPC materials; add appropriate steel fiber to increase the tensile strength and toughness of UHPC and improve the overall performance of the repair layer;

[0046] S402, the raw material ratio is determined, wherein the ratio of cement, ultrafine powder, fine aggregate, fine sand and steel fiber is 1:1:1:2.5; according to the actual situation of bridge deck damage and the performance requirements of UHPC materials, the raw material ratio is determined, wherein the ratio of cement, ultrafine powder, fine aggregate, fine sand and steel fiber is 1:1:1:2.5. Such a ratio can provide excellent fluidity, adhesion and self-stability, and is suitable for the rapid repair of bridge decks.

[0047] S403, use a high-speed mixer to stir to ensure that the raw materials are evenly mixed; put the prepared raw materials into the high-speed mixer according to the determined ratio. Because steel fibers play a vital role, it is necessary to ensure that the steel fibers are evenly distributed in the UHPC material, so that the repaired bridge deck has strong compressive and tensile properties; turn on the mixer, adjust the stirring speed and time, and ensure that the raw materials are fully mixed and evenly dispersed; during the stirring process, add an appropriate amount of water or other liquid additives to adjust the consistency and fluidity of UHPC; after the stirring is completed, the prepared UHPC materials are transported to the construction site for subsequent repair work.

[0048] In one embodiment, the water-cement ratio of the UHPC material is between 0.15 and 0.25, which means that the amount of mixing water required for each portion of cement is lower, which helps to reduce the porosity in the concrete and improve the density, thereby enhancing the strength and durability of the concrete; due to the low water-cement ratio, the pores in the concrete are reduced, which helps to reduce the possibility of harmful ion and gas penetration and improve the concrete's impermeability.

[0049] In one embodiment, the chemical additive is a water reducer, and the dosage of the water reducer is 4%. The addition of the water reducer can effectively improve the fluidity of UHPC, making it easier to pour and reducing the difficulty of construction. The addition of the water reducer also helps to reduce pores and cracks in the concrete, further improving its durability and impermeability.

[0050] In one embodiment, when the damaged area 1 is located in the steep slope section of the bridge, the damaged area 1 is installed with a positioning mechanism, and the positioning mechanism is installed with a coating. From the bottom to the top of the steep slope, the coating covers 2 / 3 of the damaged area 1 and fits the bridge deck, ensuring that the damaged area 1 located in the upper steep slope area can be fully filled with UHPC materials; in the steep slope section, due to gravity and the high fluidity of the UHPC material, the material can easily flow to the lower part. By covering the damaged area 1, 2 / 3 of the coating, the UHPC material can be effectively prevented from excessively flowing to the lower part, ensuring sufficient repair of the high area. Due to the effect of the coating, the damaged area 1 located in the upper steep slope area can be fully filled with UHPC materials, ensuring the integrity and strength of the damaged area 1. This is crucial to restore the structural integrity and safety of the bridge.

[0051] In one embodiment, the positioning mechanism includes two transverse components 21 and two vertical components 22; the two ends of any transverse component 21 are detachably connected to the vertical component 22; the transverse component 21 and the vertical component 22 have the same structure, the transverse component 21 includes a fixed section 211 and a telescopic section 212, the telescopic section 212 is sleeved on the fixed section 211 and slidably connected to the fixed section 211; the transverse component 21 and the vertical component 22 have the same structure, both consisting of a fixed section 211 and a telescopic section 212. The telescopic section 212 is sleeved on the fixed section 211 and slidably connected to the fixed section 211. This design enables the positioning mechanism to be adjusted according to different sizes of the damaged area 1. When the size of the positioning mechanism needs to be adjusted, its length can be changed by sliding the telescopic section 212 to adapt to damaged areas 1 of different sizes; in actual operation, the size of the positioning mechanism is first determined according to the specific size of the damaged area 1 of the bridge. Then, the length of the transverse component 21 and the vertical component 22 is adjusted by sliding the telescopic section 212 to match the damaged area 1. Next, the two ends of the transverse component 21 are detachably connected to the vertical component 22 to form a complete positioning mechanism. Finally, the positioning mechanism is placed on the damaged area 1 to ensure that it fits tightly with the bridge deck and provides stable support for the subsequent UHPC material repair; both the transverse component 21 and the vertical component 22 of the positioning mechanism use telescopic sections 212, so they can be adjusted according to the size of the damaged area 1, and have strong adaptability, so that the positioning mechanism can be widely used in the repair of various bridge damaged areas 1, improving its use value and practicality. The transverse component 21 and the vertical component 22 of the positioning mechanism are detachably connected, so that the positioning mechanism can be disassembled for cleaning and maintenance after completing a repair work, in preparation for the next use.

[0052] In one embodiment, it also includes a transverse adjustment member 3 and a vertical adjustment member, which are both installed on the side of the fixed section 211 of each component close to the telescopic section 212; the transverse adjustment member 3 is used to adjust the length of the transverse component 21, and the vertical adjustment member is used to adjust the width of the vertical component 22. The transverse adjustment member 3 and the vertical adjustment member have the same structure. The transverse adjustment member 3 includes a rotating gear 31 and a rack 32. The gear 31 is installed in the fixed section 211, and a rotating member extending out of the fixed section 211 is provided. The rotating member is used to rotate the gear 31. The rack 32 is installed in the telescopic section 212 and is in contact with the fixed section 211. The gear 31 is meshed; when the length or width of the horizontal component 21 or the vertical component 22 needs to be adjusted, the gear 31 is driven to rotate by rotating the rotating member, and the rotation of the gear 31 drives the rack 32 meshed with it to move linearly, thereby pushing the telescopic section 212 to slide in the fixed section 211. By controlling the rotation direction and amount of the gear 31, the extension or retraction length of the telescopic section 212 can be accurately adjusted, thereby adjusting the length or width of the entire component; by adjusting the length and width of the horizontal component 21 and the vertical component 22, the positioning mechanism can adapt to damaged areas 1 of different sizes and shapes, thereby improving its scope of application and flexibility.

[0053] In one embodiment, a latch is also included, and the fixed section 211 and the telescopic section 212 are also provided with a latch hole. The latch cooperates with the latch hole to position the length and width of the positioning mechanism. After the positioning mechanism is adjusted to a suitable position, the telescopic section 212 is fixed to the fixed section 211 by the latch, ensuring that the positioning mechanism can be stably maintained at the desired position. The insertion and removal of the latch are simple and convenient, and the positioning and release operations can be performed quickly.

[0054] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. An efficient construction method for quickly repairing cement concrete bridge decks using UHPC, characterized in that: It includes step 1: damage assessment, judging the damage according to the damage scope and depth of the bridge deck; Step 2: Surface treatment: if the damage is localized and large-scale, remove dust and dirt from the damaged surface and use tools to clean the boundary crack area that is not connected to the center of the damaged area, so that the boundary crack area is connected to the center of the damaged area to form a complete repair surface; Step 3: Record the damage scope and depth data after cleaning; Step 4: UHPC material preparation, prepare and make raw materials according to the data recorded in step 3; Step 5: Pour the prepared UHPC material into the center of the damaged area. The boundary crack area needs to be guided by a thin rod to fill the boundary crack area with UHPC material. Step 6: After the repair is completed, cover the damaged area with a film for wet curing.

2. According to claim 1, a high-efficiency construction method for quickly repairing cement concrete bridge decks using UHPC is characterized in that: In step 2, the independently split regions are connected to each other through openings, and the openings of the crack regions close to the center of the damaged region are connected to the center of the damaged region.

3. According to claim 1, a high-efficiency construction method for quickly repairing cement concrete bridge decks using UHPC is characterized in that: Step 4 includes: S401, selection and preparation of raw materials, including cement, ultrafine powder, fine aggregate and fine sand, steel fiber and chemical additives; S402, the raw material ratio is determined, where the ratio of cement, ultrafine powder, fine aggregate, fine sand and steel fiber is 1:1:1:2.5; S403, use a high-speed mixer to stir to ensure that the raw materials are evenly mixed.

4. The method of claim 1 for rapidly repairing cement concrete bridge decks using UHPC is characterized in that: The water-to-binder ratio of UHPC materials is between 0.15-0.

25.

5. The method of claim 3 for quickly repairing cement concrete bridge decks using UHPC is characterized in that: The chemical additive is a water reducing agent, and the dosage of the water reducing agent is 4%.

6. The method of claim 1 for rapidly repairing cement concrete bridge decks using UHPC is characterized in that: When the damaged area is located at a steep slope section of a bridge, a positioning mechanism is installed at the damaged area, and the positioning mechanism is installed with a covering film. From bottom to top of the steep slope, the covering film covers 2 / 3 of the damaged area and fits the bridge deck.

7. The method of claim 6 for quickly repairing cement concrete bridge decks using UHPC is characterized in that: The positioning mechanism includes two horizontal components and two vertical components; the two ends of any horizontal component are detachably connected to the vertical components; the horizontal component and the vertical component have the same structure, and the horizontal component includes a fixed section and a telescopic section, and the telescopic section is sleeved on the fixed section and slidably connected to the fixed section.

8. The method of claim 7 for quickly repairing cement concrete bridge decks using UHPC is characterized in that: It also includes a transverse adjustment member and a vertical adjustment member, both of which are installed on one side of the fixed section of their respective components close to the telescopic section; the transverse adjustment member is used to adjust the length of the transverse component, and the vertical adjustment member is used to adjust the width of the vertical component. The structures of the transverse adjustment member and the vertical adjustment member are consistent. The transverse adjustment member includes a rotating gear and a rack, the gear is installed in the fixed section, and a rotating member extending out of the fixed section is provided, the rotating member is used to rotate the gear, the rack is installed in the telescopic section, and is meshed with the gear in the fixed section.

9. The method of claim 8 for quickly repairing cement concrete bridge decks using UHPC is characterized in that: It also includes a latch pin, and the fixing section is also provided with a latch pin hole. The latch pin cooperates with the latch pin hole to position the length and width of the positioning mechanism.

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