A UHPC anti-gravity pressure pouring device and its construction process

Abstract

The present invention relates to the field of construction engineering technology, and discloses a UHPC counter-gravity pressurized casting device and its construction process. The device includes: a formwork system, including an outer formwork placed on a bottom formwork platform, with an inner formwork fixedly provided in the outer formwork; pressurized grouting equipment, including a hopper for loading UHPC mixture, a propulsion cylinder for driving grouting, and a control module for controlling the grouting pressure and grouting speed of the propulsion cylinder grouting; the inlet end of the grouting connection hose is connected to the slurry outlet of the propulsion cylinder, and at least one outlet end of the grouting connection hose is connected to the bottom of the outer formwork, grouting into the cavity between the inner and outer formworks. The present invention addresses the problems of difficult casting, loose casting, and poor surface quality of existing UHPC thin-walled components and components with complex shapes. The invention adopts a vacuum pumping and vibration technology, which makes the casting process convenient and easy to operate, the casting is dense, and the surface quality is high, thereby achieving high-quality construction and forming of UHPC thin-walled components and components with complex shapes.

Description

Technical Field

[0001] The present invention relates to the technical field of construction engineering, and in particular to a UHPC anti-gravity pressure casting device and a construction process thereof. Background Art

[0002] At present, there are two traditional molding processes for the construction of ultra-high performance concrete (UHPC) components:

[0003] (1) For large concrete components with large casting surfaces, such as slabs, beams, and rectangular blocks, UHPC is generally transported to the top of the component mold using a pump truck or hopper for pouring. Gravity (sometimes requiring vibration) allows the UHPC to flow downward and become dense. This method is currently the most common forming process for concrete components.

[0004] (2) For hollow tubular components such as pipe piles, centrifugal molding can be used. This construction method rotates the component at high speed to generate huge centrifugal force, so that the UHPC inside the component is squeezed against the inside of the mold and excess water is discharged. This method is widely used in the production of tubular UHPC components, and the component molding quality is good.

[0005] The above two traditional UHPC casting methods have certain limitations, the main disadvantages are as follows:

[0006] (1) The method of using a pump truck or hopper to pour on the top of the component mold will become very difficult for thin-walled components (thin-walled hollow boxes, large-diameter round tubes) that need to be poured vertically. ① Due to the small pouring surface on the top, the insufficient pouring construction operation area will greatly extend the pouring time. Since the UHPC water-cement ratio is extremely low (generally not more than 0.2), the pouring surface is prone to water loss and forms a hard shell. The long interval between each batch of material pouring will cause multiple pouring cold joints in the component, seriously affecting the structural strength and durability; ② The amount of cementitious material in UHPC is roughly the amount of cementitious material used. The large adhesion between the mixture and the mold and steel mesh makes it difficult for reinforced UHPC structures, especially thin-walled structures, to achieve complete self-flowing density by relying solely on gravity or vibration, making the final product more likely to have quality problems such as voids and poor surface quality.

[0007] (2) Although the centrifugal method has better molding quality, it can only be applied to the construction and molding of tubular components, and is difficult to apply to components with complex shapes.

[0008] In response to the shortcomings of the above-mentioned traditional UHPC casting methods, some studies have proposed some innovative measures for improvement, which are listed as follows:

[0009] An existing Chinese patent, CN116104309A, discloses a UHPC thin-walled structure casting device. The device's main principle is to install a large hopper on top of the thin-walled component, thereby addressing the limited construction area and long construction time of thin-walled components. However, the patent fails to address the problem of UHPC's difficulty in flowing and compacting due to the small internal space of thin-walled components and relying solely on gravity or vibration.

[0010] The existing Chinese patent, published (announcement) number CN 117513642 B, provides a prefabricated UHPC-HPC composite hollow thin-walled component and its manufacturing method. The main principle is to use the HPC hollow thin-walled component as an inner mold to centrifuge the UHPC material based on traditional centrifugal construction equipment, thereby achieving a second layer of UHPC cast outside the HPC hollow thin-walled component. This centrifugal method achieves the formation of the UHPC-HPC composite hollow thin-walled component. This invention solves the construction difficulties of composite structural pipe piles, but it is still only applicable to the construction and formation of tubular components, and is difficult to apply to components with more complex shapes.

[0011] The existing Chinese patent, with publication (announcement) number CN117247255A, provides single-layer pre-set coarse aggregate grouting UHPC panels, functionally gradient high-performance cement-based fiber composite panels, and preparation methods. Specifically, the panels are uniformly pre-filled with coarse aggregate in a mold, injected with UHPC through a grouting pipe, vibrated and compacted, and cured to obtain the functionally gradient high-performance cement-based fiber composite panels. This invention application addresses the difficulty in compacting pre-set coarse aggregate panels and functionally gradient high-performance cement-based fiber composite panels. However, the patent focuses more on the penetration resistance of single-layer pre-set coarse aggregate grouting UHPC panels and functionally gradient high-performance cement-based fiber composite panels, and does not propose relevant construction measures for thin-walled components. Summary of the Invention

[0012] To address the shortcomings of traditional UHPC casting methods and existing publicly available technologies, this invention proposes a UHPC counter-gravity pressure casting device and construction process. This process utilizes pressurized grouting at the bottom of the component mold, forcing the UHPC to flow upwards due to high pressure, thereby expelling air from the component. For components with extremely complex shapes, the component can be placed in a negative pressure sealed container and vibrated while grouting, further resolving the difficulty of air removal during the casting process. Furthermore, bottom-feeding avoids the formation of cold joints in the UHPC skin caused by multiple pours. The high grouting pressure further densifies the UHPC, resolving the casting difficulties, loose casting, and poor surface quality associated with traditional casting methods and existing improved methods for thin-walled and complex-shaped UHPC components.

[0013] The present invention provides the following technical solutions:

[0014] A UHPC counter-gravity pressure pouring device, comprising:

[0015] The template system includes an outer template placed on a bottom template platform, and an inner template is fixedly provided in the outer template;

[0016] Pressurized grouting equipment, including a hopper for loading UHPC mixture, a propulsion cylinder for driving grouting, and a control module for controlling the grouting pressure and grouting speed of the propulsion cylinder;

[0017] The inlet end of the grouting connection hose is connected to the slurry outlet of the propulsion cylinder, and at least one outlet end of the grouting connection hose is connected to the bottom of the outer template to grout the cavity between the inner and outer templates.

[0018] According to some embodiments, a high-frequency vibrator is provided on the outer formwork, the inner formwork or the bottom formwork platform.

[0019] According to some embodiments, an airtight sealing box is provided outside the outer mold plate and the bottom mold platform, and air is evacuated from the inside of the sealing box by a vacuum pump to form a negative pressure.

[0020] According to some embodiments, the grouting connection hose is connected to the bottom of the outer formwork via a connecting device.

[0021] According to some embodiments, lateral self-balancing is achieved by anchoring the inner and outer formworks by several pairs of tie rods; a bottom plate strip that bears the bottom pressure is provided at the bottom of the inner formwork; several tie rods are provided on the bottom formwork platform and outside the outer formwork, a top beam is provided between the tops of the tie rods, and at least one vertical pressure rod is provided between the top beam and the bottom plate strip to achieve anti-floating self-balancing of the bottom plate of the inner formwork; a plurality of inner formwork cross braces are provided in the inner formwork to achieve self-balancing of the formwork all around.

[0022] On the other hand, the present invention also provides a construction process of the above-mentioned UHPC counter-gravity pressure casting device, which comprises the following steps:

[0023] S1: Determine the anti-gravity pressure value:

[0024] Calculate the pressure value of the pressure grouting equipment. Based on the component to be cast, calculate its bottom pressure p1 = ρgh, where ρ, g, and h are the density, gravity constant, and component height of the UHPC, respectively. Calculate the adhesion stress p2 between the UHPC and the pipe of the pressure grouting equipment, that is, the actual output pressure value p = p1 + p2, where the adhesion force p2 = κS, where κ is the adhesion force generated by the 1m long pump pipe on the pipe wall of the flowing UHPC, determined by experiments or taken as 0.065MPa / ㎡; S is the expanded area of ​​the pipe of the pressure grouting equipment;

[0025] S2: Install the equipment:

[0026] Before making the formwork, a hole is pre-drilled at the installation position at the bottom of the outer formwork; the formwork is installed, and the outer and inner formwork vertical plates are fixed using tie rods; after the formwork is installed, the connecting device is connected to the bottom of the outer formwork; the panel of the connecting device and the outer formwork are sealed with a rubber gasket; the grouting connecting hose is locked with the propulsion cylinder and the connecting device;

[0027] S3: Flushing equipment and pipelines:

[0028] Before the formal counter-gravity pressure pouring, flush the pressure grouting equipment, hopper, grouting connection hose and connection device with water to ensure that the equipment does not affect the water-binder ratio of UHPC;

[0029] S4: Anti-gravity pressure pouring:

[0030] After setting the pressure and flow rates on the control module of the pressurized grouting equipment, pour the UHPC wet mix with a slump expansion of 700±100mm into the hopper of the pressurized grouting equipment. The propulsion cylinder pushes the UHPC mixture between the outer and inner formwork. The propulsion cylinder automatically controls the pouring flow rate through the control module, allowing the UHPC wet mix to fill the internal space of the formwork from bottom to top.

[0031] According to some embodiments, in step S2, a high-frequency vibrator is provided on the bottom formwork, the outer formwork, or the inner formwork to vibrate the formwork to accelerate the flow and remove part of the gas inside the UHPC mixture.

[0032] According to some embodiments, in step S2, an airtight sealing box is provided outside the outer formwork and the bottom formwork platform, and before pouring, the interior of the sealing box is pumped into a negative pressure state by a vacuum pump to remove the gas inside the UHPC mixture.

[0033] According to some embodiments, in step S4, the grouting speed is 1m 3 / h~10m 3 / h.

[0034] According to some embodiments, in step S4, the top surface concrete is poured 1-10 mm higher than the design height, higher than a specific value Δh=hε, where h is the component height and ε is the UHPC shrinkage strain.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The present invention proposes a UHPC counter-gravity pressurized casting device and its construction process. To address the problems of casting difficulties, loose casting, and poor surface quality existing in existing UHPC thin-walled components and components with complex shapes, the invention adopts a combined negative pressure pumping and vibration technology. The casting process is convenient and easy to operate, the casting is dense, and the surface quality is high, thereby achieving high-quality construction and forming of UHPC thin-walled components and components with complex shapes.

[0037] 1. Full coverage casting: This solution can achieve the situation where UHPC thin-walled components cannot be densely poured by traditional gravity casting, or even have large areas without slurry on the bottom plate.

[0038] 2. Good surface quality: The surface of UHPC thin-walled components is free of pores and other honeycomb-like phenomena (traditional gravity-cast UHPC components will have a large number of pores and other phenomena, mainly because UHPC is entirely powder and contains a lot of gas. Even if vibration is used in gravity casting, only part of the gas can be discharged).

[0039] 3. High pouring efficiency: The pouring speed of counter-gravity pressure is more than 10 times that of traditional gravity pouring. The reason is that UHPC is very viscous and has a high viscosity. Traditional gravity pouring has to overcome the viscosity, so the flow speed is slow. Counter-gravity pressure pouring relies on pressure to push UHPC to flow, so the pouring speed is relatively fast.

[0040] 4. Friendly to special-shaped components: Anti-gravity pressure casting can cast special-shaped components well, while traditional gravity casting is very difficult to construct special-shaped components. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Schematic diagram of the UHPC counter-gravity pressure casting device provided in an embodiment of the present invention.

[0042] Figure 2 A schematic diagram of a self-balancing template reinforcement solution provided by an embodiment of the present invention.

[0043] In the picture:

[0044] Outer formwork 1; inner formwork 2; bottom formwork platform 3; pressurized grouting equipment 4; hopper 5; propulsion cylinder 6; control module 7; grouting connecting hose 8; connecting device 9; rubber gasket 10; clamp 11; high-frequency vibrator 12; tie rod 13; sealing box 14; vacuum pump 15; wooden bottom plate strip 16; inner formwork cross brace 17; top beam 18; vertical pressure rod 19; pull rod 20. DETAILED DESCRIPTION

[0045] The present invention is described in detail below with reference to the embodiments and accompanying drawings. However, it should be understood that the embodiments and accompanying drawings are merely exemplary descriptions of the present invention and do not constitute any limitation on the scope of protection of the present invention. All reasonable variations and combinations within the scope of the inventive concept of the present invention fall within the scope of protection of the present invention.

[0046] The present invention will be further described below with reference to the accompanying drawings.

[0047] Example 1

[0048] This embodiment provides a UHPC counter-gravity pressure casting device and its construction process. The schematic diagram of the UHPC counter-gravity pressure casting device is shown in the attached Figure 1 The UHPC counter-gravity pressure pouring device includes: an outer formwork 1, an inner formwork 2, a bottom formwork platform 3, a pressurized grouting device 4, a hopper 5, a propulsion cylinder 6, a control module 7, a grouting connection hose 8, a connecting device 9, a rubber gasket 10, a clamp 11, a high-frequency vibrator 12, a tie rod 13, a sealing box 14, and an air pump 15 (the sealing box 14, the air pump 15, and the high-frequency vibrator 12 are optional). The bottom of the sealing box 14 is provided with a bottom formwork platform 3, and a U-shaped or other configuration outer formwork 1 and inner formwork 2 are arranged above the bottom formwork platform 3. The side of the outer formwork 1 is provided with a high-frequency vibrator 12 for vibration and a plurality of tie rods 13 for fixing the inner and outer formworks. A pressurized grouting device 4 is provided on one side of the sealed box 14. The pressurized grouting device 4 includes a hopper 5 for loading UHPC material. The control module 7 on the pressurized grouting device 4 controls the propulsion cylinder 6 to adjust the grouting to a specific pressure value and grouting speed. One end of the grouting connection hose 8 is connected to the slurry outlet of the propulsion cylinder 6 through a clamp 11, and the other end is connected to the bottom of the grouting cavity in the inner and outer templates through a connecting device 9 and a rubber gasket 10, and is locked with a clamp 11. The sealed box 14 is also connected to an air pump 15 for exhausting air from the sealed box 14 to form a negative pressure environment. The control module 7 is selected from a PLC controller.

[0049] Attachment Figure 1 The component shown is a thin-walled open box. This figure is only for schematic illustration of the anti-gravity pressure molding construction process. The mold can also be changed to other shapes and structures as needed. The sealed box 14 can be installed as needed or not.

[0050] The UHPC counter-gravity pressurized pouring device provided in this embodiment uses a pressurized pouring equipment control module 7 to adjust the pressure value and grouting speed respectively. The pressure value and grouting speed can be adjusted and controlled separately, while existing conventional concrete pumps can only adjust the flow rate. The device needs to be connected to the bottom of the inner and outer formwork through a connecting device 9 to achieve counter-gravity grouting, while conventional concrete pumps use free fall to flow from the top of the component where there is no formwork.

[0051] The process includes the following steps:

[0052] S1: Determine the anti-gravity pressurization value: Calculate the pressure value of the pressure grouting equipment 4: Based on the component to be cast, calculate its bottom pressure p1 = ρgh (ρ, g, h are the density of UHPC, gravity constant and component height, respectively), and consider the adhesion stress p2 between the UHPC and the pipeline of the pressure grouting equipment 4, that is, the actual output pressurization value p = p1 + p2, where the adhesion force p2 = κS (κ is the pipe wall adhesion force generated by a 1m long pump pipe on the flowing UHPC, which can be determined based on experiments. If no experiments are performed, it can be taken as 0.065MPa / ㎡; S is the expanded area of ​​the pipeline).

[0053] S2: Install the equipment: Place the connecting device 9 on the outer formwork 1: Before making the formwork, pre-drill a hole at the installation position of the outer formwork 1; install the formwork, and use the tie rods 13 to fix the outer formwork 1 and the inner formwork 2 vertical plates; after the formwork is installed, connect the connecting device 9 to the outer formwork 1 (if the outer formwork 1 is a steel formwork, the connecting device 9 and the outer formwork 1 are connected by bolts; if the outer formwork 1 is a wooden formwork, a tie rod 13 is required to connect the connecting device 9 to the outer formwork 1 and the inner formwork 2 to form a whole); in order to prevent leakage of slurry, the panel of the connecting device 9 and the outer formwork 1 are sealed with a rubber gasket 10; the grouting connecting hose 8 and the thrust cylinder 6 and the connecting device 9 are all locked with a clamp 11.

[0054] S3: Flushing equipment and pipelines: Before the formal counter-gravity pressure pouring, flush the pressure grouting equipment 4, hopper 5, grouting connecting hose 8, connecting device 9, etc. with water to ensure that the equipment will not affect the water-cement ratio of UHPC.

[0055] S4: Counter-gravity pressure pouring: After the control module 7 on the pressure grouting equipment 4 sets the pressure value p and flow value, the UHPC wet material with a slump expansion of 700±100mm is poured into the hopper 5 of the pressure grouting equipment 4. The propulsion cylinder 6 propels the UHPC mixture between the outer formwork 1 and the inner formwork 2. The propulsion cylinder 6 is automatically servo-controlled by the control module 7 to control the pouring flow rate, so that the UHPC wet material fills the internal space of the formwork from bottom to top under counter-gravity.

[0056] Casting process of special-shaped components: For components with more complex shapes, in order to allow the air inside the mold to be discharged more smoothly, a high-frequency vibrator 12 can be installed on the bottom mold platform 3, the outer mold 1 or the inner mold 2 to vibrate the mold to accelerate the flow and discharge some of the gas inside the UHPC mixture.

[0057] Casting process of components with special requirements: For components with strict requirements on surface finish and honeycomb surface, a sealing box 14 can be installed on the periphery of the component. Before casting, the inside of the sealing box 14 is evacuated to a negative pressure state of 5-10Pa by an air pump 15. During casting, the high-frequency vibrator 13 vibrates the formwork and evacuates the gas inside the sealing box 14, thereby completely eliminating the gas inside the UHPC mixture and further improving the casting quality of the component.

[0058] The specific technical parameters and requirements of this process are as follows:

[0059] (1) The slump expansion range of the UHPC mixture used in this process is generally 600mm to 800mm. The specific value needs to be determined by testing based on the complexity of the component's shape and the appearance quality requirements;

[0060] (2) The pressurized grouting equipment 4 consists of three parts: a hopper 5, a propulsion cylinder 6, and a control module 7. The hopper 5 must have a stirring function. The maximum pressure output of the pressurized grouting equipment 4 is not less than twice the required pressure value. The pressurized grouting equipment 4 can be mobile or fixed.

[0061] (3) The adhesion force κ of the UHPC mixture is the adhesion force generated by the 1 m long pump pipe on the flowing UHPC pipe wall, which can be determined based on experiments. If no experiment is performed, it can be taken as 0.065 MPa / ㎡.

[0062] (4) Grouting speed is generally 1m 3 / h~10m 3 / h, which needs to be determined according to factors such as the complexity of the mold shape and the volume of the component. On-site technicians can adjust it appropriately according to the pouring situation;

[0063] (5) The grouting connection hose 8, the connection device 9 and the rubber gasket 10 need to be installed at the bottom of the template. The installation position should allow the UHPC to flow smoothly throughout the entire internal space of the mold. Multiple feed ports can also be set according to the casting speed requirements;

[0064] (6) Since the shrinkage strain of UHPC is not less than 400 με, the top surface of the component will collapse by 1-10 mm due to shrinkage after the curing is completed. Therefore, during the counter-gravity pressure pouring process, the top surface concrete must be 1-10 mm higher than the design height, which is higher by a specific value Δh = hε (h is the component height, ε is the UHPC shrinkage strain).

[0065] Example 2

[0066] Based on Example 1, this example provides another self-balancing formwork solution that increases the pressure range. Since the pressure on the formwork in the pressurized forming construction process is greater than that in the traditional casting process, the formwork bearing capacity and rigidity must be strictly calculated before casting. In addition, the bottom plate of the inner formwork 2 will be damaged due to the large buoyancy generated during the casting of the surrounding UHPC side panels. Therefore, the bottom pressure plate of the inner formwork 2 needs to be separately designed for anti-floating. Figure 2 An optional self-balancing formwork solution is provided, and the specific implementation process is as follows: the outer formwork 1 is directly fixed on the bottom formwork platform 3, and the outer formwork 1 and the inner formwork 2 vertical plates are anchored by tension rods 13 to achieve self-balancing of the side plates; the bottom plate of the inner formwork 2 requires an anti-floating device due to the large buoyancy at the bottom, and a plurality of wooden bottom plate pressure strips 16 are set to press the bottom plate of the inner formwork 2, and then a plurality of steel vertical pressure rods 19 are set to press the wooden bottom plate pressure strips 16, and the vertical pressure rods 19 are pressed by the top beam 18, and the top beam 18 is connected to the bottom formwork platform 3 through the tension rod 20, thereby achieving self-balancing of the bottom plate of the inner formwork 2 against floating; in order to ensure the stability of the outer formwork 1 and the inner formwork 2 vertical plates, a plurality of inner formwork cross braces 17 can be set to achieve self-balancing of the formwork around the component.

[0067] The sealed box 14 can be formed by welding Q235 steel plates to form a closed box body, and the steel plates have a thickness of 1-4 mm.

[0068] The above embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions that fall within the scope of protection of the present invention are within the scope of protection of the present invention. It should be noted that improvements and modifications that can be made by a person skilled in the art without departing from the principles of the present invention are also considered to be within the scope of protection of the present invention.

Claims

1. A construction process for a UHPC counter-gravity pressure casting device, characterized by: The UHPC counter-gravity pressure pouring device includes: The template system includes an outer template placed on a bottom template platform, and an inner template is fixedly provided in the outer template; Pressurized grouting equipment, including a hopper for loading UHPC mixture, a propulsion cylinder for driving grouting, and a control module for controlling the grouting pressure and grouting speed of the propulsion cylinder; The inlet end of the grouting connection hose is connected to the slurry outlet of the propulsion cylinder, and at least one outlet end of the grouting connection hose is connected to the bottom of the outer template to grout the cavity between the inner and outer templates; The inner and outer formworks are anchored by several pairs of tie rods to achieve lateral self-balancing; the bottom of the inner formwork is provided with a bottom plate strip that bears the bottom pressure; several tie rods are provided on the bottom formwork platform and outside the outer formwork, a top beam is provided between the tops of the tie rods, and at least one vertical pressure rod is provided between the top beam and the bottom plate strip to achieve anti-floating self-balancing of the bottom plate of the inner formwork; a plurality of inner formwork cross braces are provided inside the inner formwork to achieve self-balancing of the formwork on all sides; The construction process of the UHPC counter-gravity pressure casting device includes the following steps: S1: Determine the anti-gravity pressure value: Calculate the pressure value of the pressure grouting equipment. Based on the component to be cast, calculate its bottom pressure p1 = ρgh, where ρ, g, and h are the density, gravity constant, and component height of the UHPC, respectively. Calculate the adhesion stress p2 between the UHPC and the pipe of the pressure grouting equipment, that is, the actual output pressure value p = p1 + p2, where the adhesion force p2 = κS, where κ is the adhesion force generated by the 1m long pump pipe on the pipe wall of the flowing UHPC, determined by experiments or taken as 0.065MPa / ㎡; S is the expanded area of ​​the pipe of the pressure grouting equipment; S2: Install the equipment: Before making the formwork, a hole is pre-drilled at the installation position at the bottom of the outer formwork; the formwork is installed, and the outer and inner formwork vertical plates are fixed using tie rods; after the formwork is installed, the connecting device is connected to the bottom of the outer formwork; the panel of the connecting device and the outer formwork are sealed with a rubber gasket; the grouting connecting hose is locked with the propulsion cylinder and the connecting device; S3: Flushing equipment and pipelines: Before the formal counter-gravity pressure pouring, flush the pressure grouting equipment, hopper, grouting connection hose and connection device with water to ensure that the equipment does not affect the water-binder ratio of UHPC; S4: Anti-gravity pressure pouring: After setting the pressure value p and flow value in the control module of the pressure grouting equipment, the collapse expansion is set to 700± 100mm thick UHPC wet material is poured into the hopper of the pressurized grouting equipment. The propulsion cylinder pushes the UHPC mixture between the outer and inner formwork. The propulsion cylinder automatically controls the pouring flow through the control module, allowing the UHPC wet material to fill the internal space of the formwork from bottom to top due to anti-gravity.

2. The construction process according to claim 1, characterized in that: In step S2, a high-frequency vibrator is installed on the bottom formwork, the outer formwork or the inner formwork to vibrate the formwork to accelerate the flow and remove part of the gas inside the UHPC mixture.

3. The construction process according to claim 2, characterized in that: In step S2, an airtight sealing box is provided outside the outer formwork and the bottom formwork platform, and before pouring, the interior of the sealing box is pumped into a negative pressure state by a vacuum pump to remove the gas inside the UHPC mixture.

4. The construction process according to claim 1, characterized in that: In step S4, the grouting speed is 1m 3 / h~10m 3 / h.

5. The construction process according to claim 1, characterized in that: In step S4, the top surface concrete is poured 1-10 mm higher than the design height, which is higher by a specific value Δh=hε, where h is the component height and ε is the UHPC shrinkage strain.

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