A permanent formwork with high durability for use in highly corrosive environments and its production process

Abstract

The present invention discloses a permanent formwork with high durability for highly corrosive environments and a production process, including a composite formwork body, which is composed of a fiber-reinforced cement-based composite material and a resin-based fiber-reinforced composite material grid; the present invention can be used as a permanent formwork for components such as beams, slabs, columns, shear walls, etc. of concrete structures in ocean engineering and highly corrosive environments, greatly simplifies the on-site construction steps, reduces labor costs, and shortens the construction period; due to the good ductility, toughness, excellent impermeability and crack control ability of the cured fiber-reinforced cement-based composite material, it also plays the role of a protective layer while serving as a permanent formwork, can effectively prevent the intrusion of external harmful substances, and thus has broad application prospects in highly corrosive environments such as ocean engineering, water conservancy projects, chemical plants, basements, etc.

Description

Technical Field

[0001] The present invention relates to the field of building precast formwork, and particularly to a permanent formwork with high durability for highly corrosive environments and a production process thereof. Background Art

[0002] When reinforced concrete structures are applied to highly corrosive environments such as marine engineering, hydraulic engineering, chemical plants, basements, etc., their durability is often difficult to guarantee. China is a major infrastructure country, and the number of structures with reinforced concrete as the main body in the country has always been in an absolute dominant position in the world. At present, many of the infrastructure facilities built in the early days in our country have entered or are about to enter the aging stage, and there may be a peak period of concrete repair and reconstruction in the next ten to twenty years, which will inevitably cause huge economic losses. Therefore, it is of great significance to take corresponding measures and methods to ensure the normal service life and durability requirements of the project and to ensure the normal operation of the structure. An effective way to solve the problem of insufficient structural durability is to use a permanent formwork made by compounding fiber-reinforced cement-based composite material (abbreviation: ECC) and resin-based fiber-reinforced composite material (FRP) grid to replace the traditional concrete protective layer. ECC is a kind of fiber-reinforced cement-based composite material made by mixing chopped polyvinyl alcohol fibers, cement, fly ash, quartz sand, water reducer and water. ECC has good ductility, toughness, impermeability and crack control ability. Its ultimate tensile strain can reach 1%-1.5%, which is 100-150 times that of ordinary concrete. When its tensile strain reaches 1%, the maximum crack width is only 60-70μm. Therefore, ECC has broad application prospects in industries such as marine engineering construction, cement-based product research and development, repair and strengthening of existing structures, and municipal engineering construction. Li Qinghua et al. applied pre-tensile strain to high-ductility cement-based composite materials and studied their water penetration performance under the working state with cracks. The test results show that UHTCC still has good impermeability performance when the crack width is 40-70μm, and when the average crack width is 42.45μm, its relative permeability coefficient is only about 10 times that of the uncracked C30 concrete. FRP grid is a kind of lightweight, high-strength and corrosion-resistant composite material made by weaving long fiber bundles into a net shape and then impregnating the surface with resin-like materials. FRP materials are widely used to replace the tensile reinforcement in concrete structures due to their lightweight, high-strength and corrosion-resistant characteristics, so as to improve the durability of the structure. Many countries have applied FRP materials to the bridge deck, FRP prestressed tendons and FRP cables in bridge engineering, the FRP profile-concrete composite structure and anti-cracking bars in marine engineering, the anchor bolts in geotechnical engineering, the slope reinforcement and fiber concrete pavement in traffic engineering, etc. Using the permanent formwork made by compounding FRP and ECC to replace the traditional concrete protective layer not only ensures the durability of the structure, but also significantly improves the overall mechanical performance of the formwork under uniaxial tension, and improves the ultimate bearing capacity and axial stiffness of the plate. Xu Jiaqi et al. carried out a study on the flexural performance of reinforced concrete beams strengthened with high-performance cement-based composite material-prestressed CFRP grid. The research shows that with the different numbers of grid layers and prestress levels in the strengthening layer, the improvement ranges of the cracking, yield and ultimate loads can reach 20%-55%, 15%-39% and 14%-45%.In addition, the application of permanent formwork can simplify on-site construction, shorten the construction period, and reduce labor costs. It has obvious advantages compared with traditional formwork both in terms of technology and economy. In 1997, researchers in Utah, USA, began to study the application of fiber-reinforced composite permanent formwork in small-span bridges. In 2007, the Black Bridge was built in Wisconsin, USA. The bridge uses a pultruded fiber-reinforced composite bridge deck formwork, and the main beam is a precast concrete T-beam with a spacing of 2.1 m. The spacing between the flanges of the main beam is 914 mm. The formwork is placed between the T-shaped main beams. The length of the formwork is taken as the spacing between the flanges of the main beam, and the width has two sizes: 305 mm and 610 mm. In 2014, the construction of the Comprehensive Station Building of Hohhot Automobile East Hub started. The project uses GRC permanent formwork for the beam-column reinforced concrete frame structure components of the outer enclosure and roof. The cross-section of the components is mainly a regular hexagon, with a part being arc-shaped and slanting upwards, and another part being an inverted cone-shaped slanting upwards with a smaller bottom and a larger top. Two frames are in a group and cross at the ±0 position. Based on the above background, the present invention provides a permanent formwork with high durability for high-corrosion environments and a production process. Summary of the Invention

[0003] The object of the present invention is to address the deficiencies of the prior art and provide a permanent formwork with high durability for high-corrosion environments and a production process to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solution: A permanent formwork with high durability for high-corrosion environments, including a composite formwork body, which is composed of a fiber-reinforced cementitious composite material and a resin-based fiber-reinforced composite material grid.

[0005] A production process of a permanent formwork with high durability for high-corrosion environments, the specific steps are as follows:

[0006] S1: Use anchor clamps to anchor and tension the resin-based fiber-reinforced composite material grid on the reaction frame to keep it in a horizontal load-holding state. The lower part of the resin-based fiber-reinforced composite material grid is a flat table surface, and the resin-based fiber-reinforced composite material grid is 1 / 2 of the plate thickness away from the table surface.

[0007] S2: Uniformly spread the fiber-reinforced cementitious composite material on the resin-based fiber-reinforced composite material grid, and use a rolling device to advance uniformly from one end to the other end of the reaction frame to push and flatten the fiber-reinforced cementitious composite material, compact it, and leave embossed patterns on the surface.

[0008] S3: Cure the fiber-reinforced cementitious composite material until it sets and hardens. Release the anchored resin-based fiber-reinforced composite material grid through the anchor clamps, trim off the excess fiber-reinforced cementitious composite material and resin-based fiber-reinforced composite material grid, and continue to cure until it reaches the design value of the tensile strength.

[0009] As a preferred technical solution of the present invention, the reaction frame is a rectangular frame, and anchor clamps are provided at both inner ends of the reaction frame. The anchor clamp at one end of the reaction frame is welded to the reaction frame, and the anchor clamp at the other end of the reaction frame is welded to the threaded rod on the reaction frame.

[0010] As a preferred technical solution of the present invention, the anchor clamp is composed of two fixing plates and a plurality of bolts, and a connecting hook is welded to the top of the anchor clamp at the other end of the reaction frame.

[0011] As a preferred technical solution of the present invention, the rolling device is composed of a front roller, a rear roller, a rolling plate and rollers. The front roller is installed at the bottom of one side of the rolling plate through a bearing, the rear roller is installed at the bottom of the other side of the rolling plate through a bearing, and rollers are installed at both ends of the front roller and the rear roller.

[0012] As a preferred technical solution of the present invention, the fiber-reinforced cement-based composite material is a fiber-reinforced cement-based composite material prepared by mixing chopped polyvinyl alcohol fibers, cement, fly ash, quartz sand, polycarboxylate water reducer and water.

[0013] As a preferred technical solution of the present invention, the cement is ordinary Portland cement with a strength grade not lower than P.O42.5; the fly ash is Class I fly ash; the particle size of the quartz sand is 80-120 mesh; the length of the polyvinyl alcohol fiber is 12 mm and the diameter is 39 μm; the water reduction rate of the polycarboxylate water reducer is 30%; the mass ratio of cement to fly ash is 1:3-1:3.5, the mass ratio of quartz sand to the cementitious material is 1:3-1:3.5, the mass ratio of water to the cementitious material is 1:3-1:3.5, the fiber accounts for 2% of the total volume of the fiber-reinforced cement-based composite material, and the polycarboxylate water reducer accounts for 0.5%-1% of the mass of the cementitious material.

[0014] As a preferred technical solution of the present invention, the composite template body is integrally cast with the concrete.

[0015] As a preferred technical solution of the present invention, the resin-based fiber-reinforced composite material grid can be stacked in multiple layers, but at most no more than 3 layers.

[0016] The beneficial effects of the present invention are as follows: First, the resin matrix fiber-reinforced composite material grid is anchored and tensioned by a long-line pedestal to keep it in a horizontal load-bearing state. Then, a composite plate formwork is erected on the resin matrix fiber-reinforced composite material grid. Next, the fiber-reinforced cement-based composite material is laid in layers on the resin matrix fiber-reinforced composite material grid and compacted and leveled. After curing the fiber-reinforced cement-based composite material until it sets and hardens, the resin matrix fiber-reinforced composite material grid is relaxed, and the excess grid and fiber-reinforced cement-based composite material are trimmed off. Then, it is continuously cured until it reaches the design value of the tensile strength, forming a qualified product.

[0017] Compared with the prior art, the present invention solves the problem of insufficient durability of components; simplifies the manufacturing and construction processes of components; the grid size and performance are flexible and variable, which can meet the needs of different projects.

[0018] The present invention can be used as a permanent formwork for components such as beams, slabs, columns, and shear walls of concrete structures in marine engineering and highly corrosive environments, and greatly simplifies the on-site construction steps, reduces labor costs, and shortens the construction period. Since the cured fiber-reinforced cement-based composite material has good ductility, toughness, excellent impermeability and crack control ability, it also plays the role of a protective layer while serving as a permanent formwork, which can effectively prevent the intrusion of external harmful substances, so it has a broad application prospect in marine engineering, water conservancy projects, chemical plants, basements and other highly corrosive environments. The present invention can select appropriate types of resin matrix fiber-reinforced composite material grids (such as carbon fiber CFRP, basalt fiber BFRP, glass fiber GFRP, etc.) and different reinforcement ratios according to project requirements to adjust and improve the performance of the permanent formwork. While ensuring the durability of the structure, it significantly improves the overall mechanical properties of the formwork under uniaxial tension, increases the ultimate bearing capacity and axial stiffness of the plate. The present invention can be prefabricated in a factory, using a special long-line pedestal to tension the resin matrix fiber-reinforced composite material grid and a roll forming process, with high production efficiency. At the construction site, the size can be adjusted by cutting with an ordinary cutting machine to adapt to the requirements of the project site. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is the overall schematic diagram after splicing of the present invention;

[0020] Figure 2 is the overall schematic diagram of the present invention;

[0021] Figure 3 is the schematic diagram of the grid tensioning device of the present invention;

[0022] Figure 4 is the schematic diagram of the composition of the rolling device of the present invention;

[0023] Figure 5 is the simplified dimension diagram of the rear roller of the rolling device of the present invention;

[0024] Figure 6 Schematic diagram of the surface embossing of the present invention.

[0025] In the figure: composite template body 1, concrete 2, fiber-reinforced cement-based composite material 3, resin-based fiber-reinforced composite material grid 4, reaction frame 5, anchor clamp 6, connecting hook 7, loading bolt 8, rolling device 9, front roller 91, rear roller 91, rolling plate 93, roller 94. Specific embodiments

[0026] The following elaborates on the preferred embodiments of the present invention in conjunction with the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0027] Embodiment: Please refer to Figure 1 and Figure 2 , the present invention provides a technical solution: a permanent template with high durability for high-corrosion environments, including a composite template body 1, which is composed of a fiber-reinforced cement-based composite material 3 and a resin-based fiber-reinforced composite material grid 4.

[0028] Please refer to Figures 3 - 6 , the production process of a permanent template with high durability for high-corrosion environments is as follows:

[0029] S1: Anchor and tension the resin-based fiber-reinforced composite material grid 4 on the reaction frame 5 using the anchor clamp 6 to keep it in a horizontal load-bearing state. The lower part of the resin-based fiber-reinforced composite material grid 4 is a flat tabletop, and the resin-based fiber-reinforced composite material grid 4 is at a distance of 1 / 2 plate thickness from the tabletop.

[0030] S2: Uniformly spread the fiber-reinforced cement-based composite material 3 on the resin-based fiber-reinforced composite material grid 4, and use the rolling device 9 to advance uniformly from one end to the other end of the reaction frame 5 to push and flatten the fiber-reinforced cement-based composite material 3 and compact it, leaving embossments on the surface.

[0031] S3: Cure the fiber-reinforced cement-based composite material 3 until it sets and hardens, release the anchored resin-based fiber-reinforced composite material grid 4 through the anchor clamp 6, trim off the excess fiber-reinforced cement-based composite material 3 and resin-based fiber-reinforced composite material grid 4, and continue to cure until it reaches the designed value of the tensile strength.

[0032] The reaction frame 5 is a rectangular frame. Anchor clamps 6 are provided at both inner ends of the reaction frame 5. The anchor clamp 6 at one end of the reaction frame 5 is welded to the reaction frame 5, and the anchor clamp 6 at the other end of the reaction frame 5 is welded to the threaded rod on the reaction frame 5; the anchor clamp 6 is composed of two fixing plates and several bolts, and a connecting hook 7 is welded to the top of the anchor clamp 6 at the other end of the reaction frame 5.

[0033] The rolling device 9 is composed of a front roller 91, a rear roller 92, a rolling flat plate 93 and rollers 94. The front roller 91 is installed at the bottom of one side of the rolling flat plate 93 through a bearing, and the rear roller 92 is installed at the bottom of the other side of the rolling flat plate 93 through a bearing. Rollers 94 are installed at both ends of the front roller 91 and the rear roller 92.

[0034] The fiber-reinforced cementitious composite material 3 is a fiber-reinforced cementitious composite material made by mixing and stirring chopped polyvinyl alcohol fibers, cement, fly ash, quartz sand, polycarboxylate water reducer and water; the cement is ordinary Portland cement with a strength grade not lower than P.O42.5; the fly ash is Class 1 fly ash; the particle size of the quartz sand is 80 - 120 mesh; the length of the polyvinyl alcohol fiber is 12 mm and the diameter is 39 μm; the water reduction rate of the polycarboxylate water reducer is 30%; the mass ratio of cement to fly ash is 1:3 - 1:3.5, the mass ratio of quartz sand to the cementitious material is 1:3 - 1:3.5, the mass ratio of water to the cementitious material is 1:3 - 1:3.5, the fiber accounts for 2% of the total volume of the fiber-reinforced cementitious composite material 3, and the polycarboxylate water reducer accounts for 0.5% - 1% of the mass of the cementitious material.

[0035] The composite template body 1 is integrally cast with the concrete 2; the resin-based fiber-reinforced composite material grid 4 can be stacked in multiple layers, but at most no more than 3 layers.

[0036] Working principle: A high-durability permanent formwork and production process applicable to high-corrosion environments. The fiber-reinforced cementitious composite material and the resin-based fiber-reinforced composite material grid are compounded to make a plate, which can be used as both the formwork of the component and the protective layer of the component, simplifying the on-site construction steps while greatly improving the durability of the structure, making it widely applicable to concrete structures in high-corrosion environments such as ocean engineering, water conservancy projects, chemical plants, basements, etc.

[0037] The present invention is made by compounding a fiber-reinforced cementitious composite material and a resin-based fiber-reinforced composite material grid. The fiber-reinforced cementitious composite material is a fiber-reinforced cementitious composite material made by mixing and stirring chopped polyvinyl alcohol fibers, cement, fly ash, quartz sand, water reducer and water. The fiber-reinforced cementitious composite material has good ductility, toughness, impermeability and crack control ability. Its ultimate tensile strain can reach 1% - 1.5%, and its ultimate tensile strength can reach 3.5 - 4.0 MPa. Even when reaching its ultimate tensile strength, the crack width is only 60 - 70 μm. Such a small crack width can effectively prevent the intrusion of external harmful substances. Using the resin-based fiber-reinforced composite material grid to reinforce the permanent formwork can significantly improve the overall mechanical properties of the formwork under uniaxial tension, and improve the ultimate bearing capacity and axial stiffness of the plate.

[0038] During the production of the product of the present invention, the grid needs to be tensioned to keep it in a horizontal load-holding state until the fiber-reinforced cementitious composite material wrapping the grid sets and hardens. The purpose of tensioning the grid here is to tighten the grid and eliminate its bending so as to give full play to the performance of the grid. Therefore, too high a tensile force is not required.

[0039] To prevent the occurrence of bonding slip between the resin matrix fiber-reinforced composite material grid and the fiber-reinforced cementitious composite material during loading, after the fiber-reinforced cementitious composite material is evenly spread, a special rolling device is required to roll and form it to ensure that the fiber-reinforced cementitious composite material can tightly wrap the grid. The resin matrix fiber-reinforced composite material grid 4 needs to be arranged in the center in the horizontal and thickness directions. It can be stacked in multiple layers according to the actual situation, but at most no more than 3 layers.

[0040] The product of the present invention is integrally cast with the concrete member. Since both are cement-based materials, they have good compatibility, excellent interfacial bonding performance, and the same coefficient of linear thermal expansion. At the same time, there is good interfacial bonding, similar coefficients of linear expansion, and similar ultimate tensile strains between the resin matrix fiber-reinforced composite material grid and the fiber-reinforced cementitious composite material, which provides a guarantee for the grid and the fiber-reinforced cementitious composite material to work together. In actual projects, resin matrix fiber-reinforced composite material grids with appropriate materials (such as GFRP, CFRP, BFRP, etc.) and mesh sizes can be selected according to the project needs.

[0041] The fiber-reinforced cementitious composite material includes cement, fly ash, quartz sand, polyvinyl alcohol fiber, polycarboxylate water reducer, and water; the cement is ordinary Portland cement with a strength grade not lower than P.O42.5; the fly ash is Class 1 fly ash; the particle size of the quartz sand is 80 - 120 mesh; the length of the polyvinyl alcohol fiber is 12 mm and the diameter is 39 μm; the water reduction rate of the polycarboxylate water reducer is 30%; the mass ratio of cement to fly ash is 1:3 - 1:3.5, the mass ratio of quartz sand to the cementitious material is 1:3 - 1:3.5, the mass ratio of water to the cementitious material is 1:3 - 1:3.5, the fiber accounts for 2% of the total volume of the fiber-reinforced cementitious composite material, and the water reducer accounts for 0.5% - 1% of the mass of the cementitious material.

[0042] The template can be prefabricated in the factory to make qualified products, which is easy to control the quality. During the product production process, on the surface layer combined with concrete, a certain depth of texture (1-2 mm deep) is formed through a special rolling process, which can strengthen its combination with the post-poured concrete. The other side contacts with a smooth tabletop to form a smooth, clean and dense surface, which can greatly improve the surface density, flatness and aesthetics of the later structural members, and avoid the secondary plastering of the structural members in the later stage. By adopting a special long-line pedestal tensioning resin-based fiber-reinforced composite grille and rolling forming process, the production efficiency is high, and a cutting machine can be used to adjust the size of the board to adapt to the engineering requirements.

[0043] In the present invention, a complete template can be first formed by cutting, trimming and splicing, and then the prepared concrete is poured into the template to make a component. At this time, the side formwork will be subjected to the lateral pressure of the concrete, but the phenomenon of formwork bulging will not occur. When the beam component made by the present invention bears a load and the tensile steel bar stress at the bottom reaches the yield strength, the strain of the ECC-FRP composite permanent formwork is only 0.5%-0.6%, which is far less than its ultimate strain of 1%. Therefore, the surface crack width of the component is less than 60 μm at this time.

[0044] Clamp the resin-based fiber-reinforced composite grille tightly by using the anchor fixture 6 (fiber cloth can be laid between two clamping plates to fill the pores between the grille and the clamping plates to increase the friction force); refer to Figure 3 , calculate the required tensile force according to the uniform load generated by the self-weight of the grille, and tension the resin-based fiber-reinforced composite grille 4 by tightening the loading bolt at the tensioning end to ensure that the grille is in a horizontal axially tensioned state; refer to Figure 3 , erect a mold on the tensioned resin-based fiber-reinforced composite grille 4, fix the FRP bars at the axial position of the mold, then evenly spread the fiber-reinforced cementitious composite material 3 and use a rolling device to roll the spread fiber-reinforced cementitious composite material 3, and finally cover the mold with a plastic wrap and wait for the fiber-reinforced cementitious composite material 3 to set and harden; refer to Figure 4 、 Figure 5 , the rolling device 9 is composed of a front roller 91, a rear roller 91 and a rolling plate 93. The diameters of the front and rear rollers are the same as the thickness of the rolling plate93. The distance from the bottom of the rolling plate to the bottom of the wheel is the thickness of the template plate. The surface of the rear roller is provided with a plurality of strip-shaped protrusions with a height of 1-2 mm, which leave embossments on the surface while compacting and leveling the fiber-reinforced cementitious composite material 3 to enhance the adhesion between the template and the concrete; after 24 hours, the fiber-reinforced cementitious composite material 3 has set and hardened. At this time, the resin-based fiber-reinforced composite grille 4 can be relaxed, the external mold can be removed, and the composite formwork can be continuously cured until it reaches the designed tensile strength; refer to Figure 1Calculate the total volume of the required formwork according to the engineering requirements and pour it into a whole slab, and then use a cutting machine to cut and assemble the slab into a complete formwork; the above process can be adjusted according to different engineering requirements, for example, the resin-based fiber-reinforced composite material grid 4 can be arranged in 2-3 layers. The present invention is integrally cast with the component, eliminating the processes of formwork erection and removal, simplifying the on-site construction, reducing the labor cost, and saving the construction period.

[0045] The above embodiments only represent several implementation manners of the present invention, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A permanent formwork with high durability for use in highly corrosive environments, comprising a composite formwork body (1), characterized in that: The composite formwork body (1) is composed of a fiber-reinforced cementitious composite material (3) and a resin-based fiber-reinforced composite material grid (4). The production process of the permanent formwork with high durability and applicable to high-corrosion environments is as follows: S1: Anchor and tension the resin-based fiber-reinforced composite material grid (4) on the reaction frame (5) using the anchor clamp (6) to keep it in a horizontal load-holding state. The lower part of the resin-based fiber-reinforced composite material grid (4) is a flat tabletop, and the resin-based fiber-reinforced composite material grid (4) is at a distance of 1 / 2 of the plate thickness from the tabletop. S2: Uniformly spread the fiber-reinforced cementitious composite material (3) on the resin-based fiber-reinforced composite material grid (4). Use the rolling device (9) to move uniformly from one end to the other end of the reaction frame (5) to push and flatten the fiber-reinforced cementitious composite material (3), compact it, and leave embossments on the surface. S3: Cure the fiber-reinforced cementitious composite material (3) until it sets and hardens. Release the anchored resin-based fiber-reinforced composite material grid (4) through the anchor clamp (6), trim off the excess fiber-reinforced cementitious composite material (3) and resin-based fiber-reinforced composite material grid (4), and continue to cure until it reaches the designed value of the tensile strength. The reaction frame (5) is a rectangular frame. Anchor clamps (6) are provided at both inner ends of the reaction frame (5). The anchor clamp (6) at one end of the reaction frame (5) is welded to the reaction frame (5), and the anchor clamp (6) at the other end of the reaction frame (5) is welded to the threaded rod on the reaction frame (5). The anchor clamp (6) is composed of two fixed plates and several bolts. A connecting hook (7) is welded to the top of the anchor clamp (6) at the other end of the reaction frame (5). The rolling device (9) is composed of a front roller (91), a rear roller (92), a rolling plate (93), and rollers (94). One side bottom of the rolling plate (93) is installed with the front roller (91) through a bearing, and the other side bottom of the rolling plate (93) is installed with the rear roller (92) through a bearing. Rollers (94) are installed at both ends of the front roller (91) and the rear roller (92). The fiber-reinforced cementitious composite material (3) is a fiber-reinforced cementitious composite material made by mixing chopped polyvinyl alcohol fibers, cement, fly ash, quartz sand, polycarboxylate water reducer, and water. The cement is ordinary Portland cement with a strength grade not lower than P.O42.5; the fly ash is Class 1 fly ash; the particle size of the quartz sand is 80 - 120 mesh; the length of the polyvinyl alcohol fiber is 12 mm, and the diameter is 39 μm; the water reduction rate of the polycarboxylate water reducer is 30%; the mass ratio of cement to fly ash is 1:1.5 - 1:2, the mass ratio of quartz sand to the cementitious material is 1:3 - 1:3.5, the mass ratio of water to the cementitious material is 1:3 - 1:3.5, the fiber accounts for 2% of the total volume of the fiber-reinforced cementitious composite material (3), and the polycarboxylate water reducer accounts for 0.5% - 1% of the mass of the cementitious material. The composite formwork body (1) is integrally cast with the concrete (2). The resin-based fiber-reinforced composite material grid (4) can be stacked in multiple layers, but at most no more than 3 layers.

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