Reinforced concrete components of seawater and sea sand based on dual intervention and preparation method thereof

Abstract

The present invention provides a seawater sea-sand reinforced concrete member based on dual intervention and a preparation method thereof. The reinforced concrete member includes a fiber-reinforced cement substrate folded into a U shape. At least one layer of continuous conductive carbon fiber cloth is provided inside the fiber-reinforced cement substrate. The conductive carbon fiber cloth is arc-shaped at the U-shaped corner, and there is a cementitious void at the U-shaped corner. Concrete is filled in the U-shaped cavity of the fiber-reinforced cement substrate, and a steel cage or multiple steel bars are embedded in the concrete. The steel cage or multiple steel bars extend out of the concrete and are used for electrically connecting to the negative electrode of a power source. The continuous conductive carbon fiber cloth extends out of the outside of the cement substrate and is used for electrically connecting to the positive electrode of the power source. By adopting the technical solution of the present invention, not only can the corrosion of steel bars be delayed from the inside, but also the strength and durability of the structure can be improved from the outside, effectively improving the mechanical properties, durability and service life of the reinforced concrete structure.

Description

Technical Field

[0001] The present invention belongs to the technical field of reinforced concrete structures, and particularly relates to a seawater and sea sand reinforced concrete member based on dual intervention and a preparation method thereof. Background Art

[0002] Seawater and sea sand reinforced concrete is beneficial to locally obtain materials in coastal areas, alleviating the dilemma of resource shortage and effectively saving construction costs. However, seawater and sea sand contain a large amount of erosive ions such as SO4 2- , Cl - etc., resulting in a rapid decline in the strength and stiffness of the structure. Domestic and foreign scholars have studied various solutions, among which the impressed current cathodic protection (ICCP) technology and the structural strengthening (SS) technology are widely applied and highly recognized. However, the ICCP technology cannot restore the bearing capacity that the member has already lost, and the SS technology cannot prevent further corrosion of the steel bars. Therefore, aiming at the limitations of the ICCP technology and the SS technology used alone, scholars have further proposed the ICCP-SS dual intervention technology, which can effectively solve the corrosion problem of seawater and sea sand reinforced concrete. In the ICCP-SS dual intervention system, carbon fiber reinforced cementitious composites (C-FRCM) are used as both the auxiliary anode material of the ICCP technology and the strengthening material of the SS technology to improve the corrosion resistance of the seawater and sea sand reinforced concrete structure. This technology generally uses a conductive fiber grid. Although the fiber grid has the functions of reinforcement and conduction, its texture is soft, making it extremely difficult to shape and position in new buildings. To ensure the mechanical properties of the fiber grid, the fiber grid at the corners of the member needs to be continuous without interruption, and to ensure its electrical conductivity, epoxy resin cannot be used for shaping treatment. Therefore, how to balance conductivity and shaping in the structure has become a difficult problem in the application of the ICCP-SS dual intervention system. Summary of the Invention

[0003] Aiming at the above technical problems, the present invention discloses a seawater and sea sand reinforced concrete member based on dual intervention and a preparation method thereof.

[0004] For this, the technical solution adopted by the present invention is as follows:

[0005] A seawater and sea sand reinforced concrete member based on dual intervention, comprising a fiber reinforced cement substrate folded into a U shape, and at least one layer of continuous conductive carbon fiber cloth is arranged in the fiber reinforced cement substrate. The conductive carbon fiber cloth is arc-shaped at the U-shaped corner, and there is a cementitious vacancy at the U-shaped corner;

[0006] The U-shaped cavity of the fiber-reinforced cement substrate is filled with concrete, and a steel reinforcement cage or multiple steel bars are embedded in the concrete. The steel reinforcement cage or multiple steel bars extend out of the concrete and are used for electrically connecting to the negative electrode of the power supply; the continuous conductive carbon fiber cloth extends out of the cement substrate and is used for electrically connecting to the positive electrode of the power supply.

[0007] For the seawater and sea sand reinforced concrete member based on dual intervention adopting this technical solution, this structure can take into account conductivity and shaping, enabling the fiber-reinforced cement substrate and the main body of the concrete member to form an integral part that jointly bears force. It can play the role of improving the durability of the structure and enhancing the mechanical properties of the member from the initial stage of structure use, thereby increasing the overall service life of the structure. It can be used in newly built seawater and sea sand reinforced concrete members and has high engineering application value. Among them, the conductive carbon fiber cloth is arc-shaped at the U-shaped corner, avoiding the problem of stress concentration.

[0008] As a further improvement of the present invention, the continuous conductive carbon fiber cloth is coated on the top of the concrete member, and cement bases are provided on both the upper and lower surfaces of the conductive carbon fiber cloth. That is, a layer of cement-based material is applied to the top of the concrete member, and then the conductive carbon fiber cloth on both sides is coated on the top of the concrete, and finally a layer of cement-based material is poured above the conductive carbon fiber cloth for protection.

[0009] As a further improvement of the present invention, a keyway layer is provided on the U-shaped inner wall of the fiber-reinforced cement substrate, and the keyways in the keyway layer extend along the U-shaped direction; the keyway layer is formed by casting strip-shaped cement-based blocks through a template. Adopting this technical solution can improve the shear resistance of the fiber-reinforced cement substrate.

[0010] As a further improvement of the present invention, the fiber-reinforced cement substrate includes a first outer vertical cement substrate, a second outer vertical cement substrate, a bottom outer cement substrate, a first inner vertical cement substrate, a second inner vertical cement substrate, and a bottom inner cement substrate. The conductive carbon fiber cloth is folded into a U shape. The first outer vertical cement substrate, the second outer vertical cement substrate, and the bottom outer cement substrate are located outside the conductive carbon fiber cloth, and the first inner vertical cement substrate, the second inner vertical cement substrate, and the bottom inner cement substrate are located inside the conductive carbon fiber cloth.

[0011] As a further improvement of the present invention, the conductive carbon fiber cloth is a carbon fiber grid cloth.

[0012] The present invention also discloses a preparation method of the seawater and sea sand reinforced concrete member based on dual intervention as described above, which includes the following steps:

[0013] Step S1, fix the first-layer cement-based mold in a grid shape on the bottom plate and pour the first-layer cement substrate layer;

[0014] Step S2: Lay the conductive carbon fiber cloth on the surface of the first layer of cement substrate layer, and press it tightly with a pressing plate to embed it into the first layer of cement substrate layer;

[0015] Step S3: Place the second-layer cement-based mold in the shape of a Chinese character "mu" above the conductive carbon fiber cloth, align it with the first-layer cement-based mold and fix it to the first-layer cement-based mold, and pour the second layer of cement substrate layer; the shape and size of the second-layer cement-based mold are the same as those of the first-layer cement-based mold;

[0016] Step S4: After removing the first-layer cement-based mold and the second-layer cement-based mold, fold the obtained fiber-reinforced cement substrate into a U shape, place chamfering molds on both sides of the bottom inside the outer mold, put the U-shaped fiber-reinforced cement substrate into the outer mold, and make the U-shaped corners of the fiber-reinforced cement substrate adhere to the chamfering molds;

[0017] Step S5: Place the steel cage or multiple steel bars into the U-shaped cavity, place spacers around the steel cage or multiple steel bars, and then pour concrete;

[0018] Step S6: Cover the surface of the concrete with plastic wrap and place it in a cool place indoors to harden.

[0019] With this technical solution, the mold structure is simple, easy to assemble, easy to construct, and the mold can be reused repeatedly, reducing the cost; the above method solves the problem that the conductive carbon fiber cloth is difficult to shape and position, and the conductive carbon fiber cloth is in a continuous state in the fiber-reinforced cement substrate, improving the mechanical properties of the concrete member and having a longer service life. By using the chamfering mold, the corners of the conductive carbon fiber cloth are made into an arc shape, solving the problem of stress concentration at the corners.

[0020] As a further improvement of the present invention, the chamfering mold can be made of arc-shaped wooden strips, which mainly play a role in guiding the conductive carbon fiber cloth to form an arc shape at the corners, solving the problem of stress concentration of the conductive carbon fiber cloth at the corners.

[0021] As a further improvement of the present invention, the preparation method further includes Step S7: Remove the outer mold, trim the excess conductive carbon fiber cloth, and repair the chamfers of the component with high-strength mortar;

[0022] Or after the concrete reaches the initial setting in Step S6, apply a layer of fiber-reinforced cement-based material, lay the conductive carbon fiber cloth on both sides on the surface of the cement-based material, press it tightly with a pressing plate, pour another layer of cement-based material above the conductive carbon fiber cloth, then cover the surface of the specimen with plastic wrap and place it in a cool place indoors to harden. Remove the mold after 48 hours, and repair the chamfers of the component with high-strength mortar.

[0023] As a further improvement of the present invention, the preparation method further includes step S8. After connecting and fixing the protruding steel bars with wires and then performing insulation treatment, epoxy resin glue is subsequently applied to the outside of the connection joint for protection. The wire is used to connect to the negative pole of the DC power supply. A wire is used to connect to the exposed conductive carbon fiber cloth, and the wire is used to connect to the positive pole of the DC power supply to form an impressed current cathodic protection circuit.

[0024] As a further improvement of the present invention, between step S3 and step S4, step S3-1 is included:

[0025] Place the keyway mold above the second-layer cement substrate layer and fixedly connect it to the second-layer cement substrate layer. Then pour the cement-based material and remove the keyway mold to form a cement-based shear keyway layer.

[0026] Among them, the keyway mold includes a frame identical to the second-layer cement-based mold. In each empty slot within the frame, a number of strip-shaped members are arranged side by side at intervals, and the strip-shaped members divide each empty slot into several keyways.

[0027] As a further improvement of the present invention, in step S1, step S3, and step S3-1, a release agent is respectively applied to the inner sides of the first-layer cement-based mold, the second-layer cement-based mold, and the keyway mold, and the edges of the first-layer cement-based mold, the second-layer cement-based mold, and the keyway mold are respectively blocked with a foaming agent or rubber and then poured. During the pouring process, continuous vibration is carried out to ensure the pouring density.

[0028] As a further improvement of the present invention, after step S3, steps S2 to S3 can be repeated to produce a fiber-reinforced cement substrate containing multiple layers of conductive carbon fiber cloth.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] First, by adopting the technical solution of the present invention, the ICCP-SS dual intervention system can be applied to seawater sea-sand reinforced concrete beam and column members with different thicknesses, layers, and lengths. The fiber-reinforced cement substrate therein serves both as an auxiliary anode material for ICCP technology and as a reinforcing material for SS technology. It can not only delay the corrosion of steel bars from the inside but also improve the strength and durability of the structure from the outside. Moreover, the fiber-reinforced cement substrate and the reinforced concrete member form an integral structure that jointly bears the load, effectively improving the mechanical properties, durability, and service life of the reinforced concrete structure.

[0031] Second, in the technical solution of the present invention, the fiber grids on each side of the reinforced concrete member are in a continuous and unbroken state, which has good effects on enhancing the flexural and shear resistance of the beam and the circumferential constraint of the column.

[0032] Thirdly, for the preparation method adopting the technical solution of the present invention, the mold structure is simple, easy to assemble and disassemble, solving the problem that the fiber grid is difficult to shape and position in a newly built building. At the same time, it ensures that the fiber grid on all sides of the component is continuous without interruption, greatly improving the mechanical enhancement effect. Making the corner of the conductive carbon fiber cloth into an arc solves the problem of stress concentration at the corner. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the external shape of a reinforced concrete beam and column based on dual intervention according to an embodiment of the present invention.

[0034] Figure 2 It is a schematic diagram of a U-shaped fiber-reinforced cement substrate according to Embodiment 1 of the present invention.

[0035] Figure 3 It is a schematic diagram of a U-shaped fiber-reinforced cement substrate according to Embodiment 2 of the present invention.

[0036] Figure 4 It is a schematic diagram of connecting a power supply according to Embodiments 1 and 2 of the present invention.

[0037] Figure 5 It is a schematic diagram of the structure of the bottom plate according to Embodiment 3 of the present invention.

[0038] Figure 6 It is a schematic diagram of the structure of the first layer of cement-based mold according to Embodiment 3 of the present invention.

[0039] Figure 7 It is a schematic diagram of the structure of the carbon fiber grid cloth according to Embodiment 3 of the present invention.

[0040] Figure 8 It is a schematic diagram of the structure of the second layer of cement-based mold according to Embodiment 3 of the present invention.

[0041] Figure 9 It is a schematic diagram of the structure of the keyway mold according to Embodiment 3 of the present invention.

[0042] Figure 10 It is a schematic diagram of the structure of the outer mold according to Embodiment 3 of the present invention.

[0043] Figure 11 It is a schematic diagram of the structure of the chamfering mold according to Embodiment 3 of the present invention.

[0044] Figure 12 It is a schematic diagram of the construction process of the first layer of cement-based according to Embodiment 3 of the present invention.

[0045] Figure 13 It is a schematic diagram of the construction process of the fiber grid according to Embodiment 3 of the present invention.

[0046] Figure 14It is a schematic diagram of the construction process of the second layer of cement-based in Embodiment 3 of the present invention.

[0047] Figure 15 It is a schematic diagram of the keyway construction process in Embodiment 3 of the present invention.

[0048] Figure 16 It is a schematic diagram of placing the U-shaped C-FRCM plate into the outer mold in Embodiment 3 of the present invention.

[0049] Figure 17 It is a schematic diagram of the structure before pouring the beam and column in Embodiment 3 of the present invention, where (a) is the seawater and sea sand reinforced concrete beam based on double intervention in Embodiment 1, and (b) is the seawater and sea sand reinforced concrete column based on double intervention in Embodiment 2.

[0050] Figure 18 It is a schematic diagram of the subsequent process of pouring the beam in Embodiment 3 of the present invention.

[0051] Figure 19 It is a schematic diagram of the subsequent process of pouring the column in Embodiment 3 of the present invention.

[0052] Reference numerals include:

[0053] 1 - fiber-reinforced cement substrate, 2 - steel reinforcement cage, 3 - concrete, 4 - wire, 5 - conductive clip, 6 - regulated DC power supply;

[0054] 11 - carbon fiber grid cloth, 12 - first outer vertical cement substrate, 13 - second outer vertical cement substrate, 14 - bottom outer cement substrate, 15 - first inner vertical cement substrate, 16 - second inner vertical cement substrate, 17 - bottom inner cement substrate, 18 - keyway layer;

[0055] 21 - bottom plate, 22 - first layer cement-based mold, 23 - second layer cement-based mold, 24 - keyway mold, 25 - outer mold, 26 - chamfer mold, 27 - first layer cement-based, 28 - second layer cement-based. Detailed implementation manners

[0056] The following further elaborates on the preferred embodiments of the present invention.

[0057] Embodiment 1

[0058] As Figure 1 and Figure 2As shown in the figure, a reinforced concrete beam made of seawater and sea sand based on dual intervention includes a fiber-reinforced cement substrate 1 folded into a U shape. A continuous carbon fiber grid cloth 11 is provided inside the fiber-reinforced cement substrate 1. The carbon fiber grid cloth 11 is arc-shaped at the U-shaped corner, and there is a cement-based vacancy at the U-shaped corner. The fiber-reinforced cement substrate 1 includes a first outer vertical cement substrate 12, a second outer vertical cement substrate 13, a bottom outer cement substrate 14, a first inner vertical cement substrate 15, a second inner vertical cement substrate 16, and a bottom inner cement substrate 17. The carbon fiber grid cloth 11 is folded into a U shape. The first outer vertical cement substrate 12, the second outer vertical cement substrate 13, and the bottom outer cement substrate 14 are located outside the carbon fiber grid cloth 11. The first inner vertical cement substrate 15, the second inner vertical cement substrate 16, and the bottom inner cement substrate 17 are located inside the carbon fiber grid cloth 11. A keyway layer 18 is provided on the U-shaped inner wall of the fiber-reinforced cement substrate 1. The keyways in the keyway layer 18 extend along the U-shaped direction. The keyway layer 18 is formed by casting strip-shaped cement-based blocks through a template. The U-shaped cavity of the fiber-reinforced cement substrate 1 is filled with concrete 3, and a steel reinforcement cage 2 is embedded in the concrete 3. One or more steel bars of the steel reinforcement cage 2 extend out of the concrete 3 and are connected to a wire 4, and are electrically connected to the negative electrode of a power source through the wire 4. The continuous carbon fiber grid cloth 11 is connected to a conductive clip 5 and is electrically connected to the positive electrode of the power source through the conductive clip 5.

[0059] Example 2

[0060] As Figure 1 and Figure 3 shown in the figure, a reinforced concrete column made of seawater and sea sand based on dual intervention, on the basis of Example 1, a layer of cement-based material is smeared on the top of the concrete 3. After leveling, the continuous carbon fiber grid cloth 11 on both sides is covered on the top surface of the cement-based material, and then another layer of cement-based material is smeared and leveled above the carbon fiber grid cloth 11.

[0061] As Figure 4 shown in the figure, when the reinforced concrete beam made of seawater and sea sand based on dual intervention in Example 1 and the reinforced concrete column made of seawater and sea sand based on dual intervention in Example 2 are in use, the wire 4 is wound around the steel bar surface and fixed with insulating tape, and then epoxy resin glue is applied outside the tape for protection, and the wire 4 is connected to the negative electrode of a regulated DC power supply 6. Stainless steel sheets are used to clamp the extended carbon fiber grid cloth 11, and the wire 4 is connected to the positive electrode of the regulated DC power supply 6 to form an impressed current cathodic protection circuit. The regulated DC power supply 6 provides electrical energy for the entire closed circuit, and after power-on, an open-circuit potential detector is used to monitor the open-circuit potential and current density of the steel bar. The regulated DC power supply 6 is turned on to provide power protection for the specimen, and at the same time, a detector can be set for the specimen to monitor the open-circuit potential of the steel bar.

[0062] Example 3

[0063] The preparation methods of Example 1 and Example 2 both include: the production of carbon fiber reinforced cement substrate (abbreviated as C-FRCM board) and concrete pouring.

[0064] Among them, the production process of the C-FRCM board includes the production of the first layer of cement-based material, the fixing of carbon fiber grid cloth, the production of the second layer of cement-based material, and the production of the keyway layer. The process of beam concrete pouring in Example 1 includes placing the C-FRCM board into the outer mold, concrete pouring, trimming of carbon fiber grid cloth, chamfer repair, natural curing, and demolding. The process of column concrete pouring in Example 2 includes placing the C-FRCM board into the outer mold, concrete pouring, pressing of carbon fiber grid cloth, cement-based pouring, chamfer repair, natural curing, and demolding; the impressed current cathodic protection process includes the connection of the cathode and the anode, power-on protection, and potential monitoring.

[0065] The molds required for the production process of the C-FRCM board include a bottom plate 21, a first-layer cement-based mold 22, a second-layer cement-based mold 23, and a keyway mold 24. The bottom plate 21, the first-layer cement-based mold 22, the second-layer cement-based mold 23, and the keyway mold 24 can be made into steel molds according to the required dimensions, and positioning holes are set at the same time. The first-layer cement-based mold 22, the second-layer cement-based mold 23, and the keyway mold 24 are fixed to the bottom plate 21 through bolts and nuts. The first-layer cement-based mold 22 and the second-layer cement-based mold 23 are eye-shaped molds with the same shape and size. The keyway mold 24 includes a frame with the same shape and size as the second-layer cement-based mold 23. A number of strip-shaped members are arranged side by side at intervals in each empty slot within the frame. The strip-shaped members divide each empty slot into several keyways, and the keyways extend along a U shape.

[0066] The bottom plate 21 is a whole piece of steel plate with openings, and bolt holes for fixing the upper mold are provided therein. By connecting with the first-layer cement-based mold 22, the whole upper mold is fixed, and at the same time, it also serves as the bottom plate 21 of the first-layer cement-based material, as Figure 5 shown.

[0067] The first-layer cement-based mold 22 is surrounded by strip-shaped steel plates. Bolt holes are provided at the ends and the middle of the steel plates. The outer bolt holes are connected to the bottom plate 21, and the middle bolt holes are used to fix the keyway mold 24. The thickness of the strip-shaped steel plates is the same as the thickness of the required cement-based material layer. After the cement-based mold is fixed to the bottom plate 21 according to the outer dimensions required for the beam and column, a cement-based mold is formed, as Figure 6 shown.

[0068] The carbon fiber grid cloth 11 is cut according to the required dimensions of the beam and column. After the pouring of the first layer of cement-based material is completed, it is fixed on the formwork through the second-layer cement-based mold 23. The schematic diagram of the carbon fiber grid cloth 11 is asFigure 7 as shown

[0069] The second - layer cement - based mold 23 is surrounded by strip steel plates, and the thickness of the strip steel plates is the same as that of the required cement - based material layer. Multiple bolt holes are provided at the ends and the middle of the steel plates. By bolt connection, the keyway mold 24 above and the first - layer cement - based mold 22 below are connected simultaneously, and at the same time, it plays a role in fixing the carbon fiber grid cloth 11, as Figure 8 shown

[0070] The keyway mold 24 is also surrounded by strip steel plates. Bolt holes are provided at the ends of the steel plates. It is connected to the second - layer cement - based mold 23 through the bolt holes, playing a role in fixing, as Figure 9 shown

[0071] The molds required for pouring the beam and column concrete 3 include two parts: an outer mold 25 and a chamfer mold 26. Among them, the outer mold 25 can be a steel mold, an aluminum mold or a wooden mold according to the actual engineering requirements, and its internal dimensions are determined according to the dimensions of the required beams and columns. The schematic diagram is as Figure 10 shown. The chamfer mold 26 is a strip steel plate with an arc cut. After the fiber - reinforced cement substrate 1 is prepared, it is arranged at the bottom of the outer mold 25 of the beam and column members, playing a role in forming a chamfer at the corner of the member and reducing the stress concentration of the carbon fiber grid cloth 11, as Figure 11 shown

[0072] The specific preparation steps are as follows:

[0073] (1) Fix the first - layer cement - based mold 22 on the bottom plate 21 with bolts, and use a foaming agent or rubber to seal the edges of the mold to prevent slurry leakage during the pouring process. After the sealing is completed, evenly apply a release agent to the bottom plate 21 and the inner side of the cement - based mold, and then pour the first - layer cement 27. During the pouring process, continuous vibration is required to ensure the pouring density, as Figure 12 shown

[0074] (2) After the first - layer cement 27 is poured, cut the carbon fiber grid cloth 11 to the required size, lay it on the surface of the first - layer cement 27, and use a pressing plate to press it tightly and embed it into the first - layer cement 27 to ensure a strong bonding effect between the carbon fiber grid cloth 11 and the first - layer cement 27, as Figure 13 shown

[0075] (3) After the carbon fiber grid cloth 11 is fixed, evenly apply a release agent to the inner side of the second - layer cement - based mold 23. Align the edges of the mold and fix the second - layer cement - based mold 23 above the first - layer cement - based mold 22 with bolts, and use a foaming agent or rubber to seal the edges of the mold to prevent slurry leakage during the pouring process. Then pour the second - layer cement 28. During the pouring process, continuous vibration is required to ensure the pouring density, asFigure 14 as shown

[0076] (4)According to requirements, a C-FRCM board containing multiple layers of carbon fiber grid cloth can be fabricated, and steps (2) and (3) can be repeated.

[0077] (5)Evenly apply a release agent inside the keyway mold 24, align the edge of the keyway mold 24 with the edge of the second-layer cement-based mold 23, then fix the keyway mold 24 to the second-layer cement-based mold 23 with bolts, and seal the mold edge with foaming agent or rubber, and then pour the cement-based keyway layer 18. During the pouring process, continuous vibration is also required to ensure the pouring density, as Figure 15 as shown

[0078] (6)After pouring the second-layer cement-based 28 and the keyway layer 18, wait for about 24 hours, then sequentially remove the fixing bolts of the keyway mold 24 and the second-layer cement-based mold 23 in order, and remove the foaming agent or rubber used for sealing at the mold edge to complete the fabrication of the fiber-reinforced cement-based board 1.

[0079] (7)First, place the chamfering mold 26 on both sides of the bottom of the outer mold 25, transfer the fabricated fiber-reinforced cement-based board 1 into the outer mold 25, and place the fiber-reinforced cement-based board 1 closely against the inner wall of the outer mold 25. The layout form is as Figure 16 as shown

[0080] (8)Place the steel reinforcement cage 2 into the outer mold 25, place cushion blocks around the steel reinforcement cage 2 to ensure the thickness of the component protective layer, and then pour the concrete 3. During the pouring process, continuous vibration is carried out to ensure the density of the concrete 3.

[0081] (9)For the beam component of Example 1, as Figure 17 shown in (a), cover the surface of the specimen with plastic wrap and place it in a cool place indoors for hardening. After 48 hours, remove the mold. After removing the mold, trim the excess carbon fiber grid cloth 11 flush with the cement-based composite material, and repair the chamfer of the component with high-strength mortar, as Figure 18 shown. For the column component of Example 2, as Figure 17 shown in (b), after pouring the concrete 3, it is necessary to wait for the concrete 3 to reach the initial setting (1 - 2 hours), apply a layer of cement-based material on the top of the concrete 3, level it, lay the two-sided carbon fiber grid cloth 11 on the surface of the cement-based material, and press it tightly with a pressing plate, and then pour another layer of cement-based material above the carbon fiber grid cloth 11, as Figure 19 shown. Then stick plastic wrap on the surface of the specimen and place it in a cool place indoors for hardening. After 48 hours, remove the mold, and repair the chamfer of the component with high-strength mortar.

[0082] After checking the surface flatness of the component, cover the specimen with geotextile and cure it naturally for 28 days to complete the production of the entire component.

[0083] (11)Clean the first-layer cement-based mold 22, the second-layer cement-based mold 23, the keyway mold 24, the chamfer mold 26, the bottom plate 21, the outer mold 25, etc. removed for reuse.

[0084] When applying the ICCP technology, as Figure 4 shown, it includes:

[0085] (12)Wind the wire 4 around the surface of the steel bar and fix it with insulating tape. Then, apply epoxy resin glue on the outside of the tape for protection, and connect the wire 4 to the negative pole of the regulated DC power supply 6; clamp the protruding carbon fiber grid cloth 11 with the conductive clamp 5, and connect the wire 4 to the positive pole of the regulated DC power supply 6 to form an impressed current cathodic protection circuit. Further, the conductive clamp 5 is a stainless steel clamp.

[0086] (13)Turn on the regulated DC power supply 6 to apply power protection to the specimen, and at the same time set a detector for the specimen to monitor the open-circuit potential of the steel bar.

[0087] Further, in the above preparation process, during the assembly of each layer of molds, try to ensure that the top surfaces of the molds are on the same horizontal plane, and ensure that the top surfaces of the molds are flush and the dimensions are accurate during the pouring process. After each layer of cement-based material is poured, it is flush with the top surface of the mold, and ensure that the surfaces of each layer of cement-based material and the keyway are flat to ensure the accurate positioning of the carbon fiber grid cloth 11 in the component. When laying the carbon fiber grid cloth 11 flat, press the carbon fiber grid cloth 11 tightly into the cement-based material, and the fiber grid can be pressed in combination with the keyway mold 24. When disassembling the inner mold, the filler in the middle gap should be removed first, and then the mold should be removed to ensure that there is no damage to the cement-based board. When arranging the plastic film on the inner side of the bottom plate 21 and the cement-based mold, it is necessary to apply a mold release agent to both the mold and the plastic film, and ensure that the plastic film is fixed firmly, the surface is flat and tight during the pouring of the cement-based material, and avoid situations such as scratching and tearing of the plastic film.

[0088] The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions or substitutions can still be made, which should all be regarded as belonging to the protection scope of the present invention.

Claims

1. A preparation method for a seawater-sea sand reinforced concrete member based on dual intervention, characterized in that: The reinforced concrete member of seawater and sea sand based on dual intervention includes a fiber-reinforced cement substrate folded into a U shape. At least one layer of continuous conductive carbon fiber cloth is provided inside the fiber-reinforced cement substrate. The conductive carbon fiber cloth is arc-shaped at the U-shaped corner, and there is a cement-based vacancy at the U-shaped corner. The U-shaped cavity of the fiber-reinforced cement substrate is filled with concrete, and a steel cage or multiple steel bars are embedded in the concrete. The steel cage or multiple steel bars extend out of the concrete for electrically connecting to the negative electrode of a power source. The continuous conductive carbon fiber cloth extends out of the outer side of the cement substrate for electrically connecting to the positive electrode of the power source. The preparation method of the reinforced concrete member of seawater and sea sand based on dual intervention includes the following steps: Step S1, fix the first-layer cement-based mold in the shape of a mesh on the bottom plate, and pour the first-layer cement substrate layer. Step S2, lay the conductive carbon fiber cloth on the surface of the first-layer cement substrate layer, and press it tightly with a pressing plate to embed it into the first-layer cement substrate layer. Step S3, place the second-layer cement-based mold in the shape of a mesh above the conductive carbon fiber cloth, align it with the first-layer cement-based mold and fix it to the first-layer cement-based mold, and pour the second-layer cement substrate layer. The shape and size of the second-layer cement-based mold are the same as those of the first-layer cement-based mold. Step S4, after removing the first-layer cement-based mold and the second-layer cement-based mold, fold the obtained fiber-reinforced cement substrate into a U shape, place chamfering molds on both sides of the bottom inside the outer mold, put the U-shaped fiber-reinforced cement substrate into the outer mold, and make the U-shaped corner of the fiber-reinforced cement substrate adhere to the chamfering mold. Step S5, place the steel cage or multiple steel bars into the U-shaped cavity, place spacers around the steel cage or multiple steel bars, and then pour concrete. Step S6, cover the surface of the concrete with plastic wrap and place it in a cool place indoors to harden.

2. The preparation method of the seawater sea-sand reinforced concrete member based on double intervention according to claim 1, characterized in that: The continuous conductive carbon fiber cloth is coated on the top of the concrete, and the upper and lower surfaces of the conductive carbon fiber cloth located on the top of the concrete are leveled with fiber-reinforced cement-based material.

3. The preparation method of the seawater sea sand reinforced concrete member based on dual intervention according to claim 2, characterized in that: The fiber-reinforced cement substrate includes a first outer vertical cement substrate, a second outer vertical cement substrate, a bottom outer cement substrate, a first inner vertical cement substrate, a second inner vertical cement substrate, and a bottom inner cement substrate. The conductive carbon fiber cloth is folded into a U shape. The first outer vertical cement substrate, the second outer vertical cement substrate, and the bottom outer cement substrate are located on the outer side of the conductive carbon fiber cloth. The first inner vertical cement substrate, the second inner vertical cement substrate, and the bottom inner cement substrate are located on the inner side of the conductive carbon fiber cloth.

4. The preparation method of the seawater sea-sand reinforced concrete member based on dual intervention according to claim 3, characterized in that The conductive carbon fiber cloth is a carbon fiber grid cloth.

5. The preparation method of the seawater sea-sand reinforced concrete member based on dual intervention according to any one of claims 1 to 4, characterized in that: It also includes step S7, remove the outer mold, trim the redundant conductive carbon fiber cloth, and repair the chamfer of the member with high-strength mortar. Alternatively, after the concrete reaches the initial setting in step S6, apply a layer of fiber-reinforced cementitious material, lay the conductive carbon fiber cloths on both sides on the surface of the cementitious material, press them tightly with a pressing plate, then pour another layer of cementitious material above the conductive carbon fiber cloths, cover the surface of the specimen with plastic wrap and place it in a cool place indoors to harden. After 48 hours, remove the mold and repair the chamfer of the component with high-strength mortar.

6. The preparation method of the seawater sea-sand reinforced concrete member based on dual intervention according to claim 5, characterized in that: It further includes step S8. After connecting and fixing with the protruding steel bars using wires and then performing insulation treatment, epoxy resin glue is applied to the outside of the connection joint for protection. The wire is used to connect to the negative pole of the DC power supply; connect with the exposed conductive carbon fiber cloth using a wire, and the wire is connected to the positive pole of the DC power supply to form an impressed current cathodic protection circuit.

7. The preparation method of the seawater sea sand reinforced concrete member based on dual intervention according to claim 6, characterized in that, The U-shaped inner wall of the fiber-reinforced cement substrate is provided with a keyway layer, and the keyways in the keyway layer extend along the U-shaped direction; the keyway layer is formed by pouring strip-shaped cementitious blocks through a template; between step S3 and step S4, step S3-1 is included: Place the keyway mold above the second layer of cement substrate layer and fixedly connect it to the second layer of cement substrate layer, then pour the cementitious material, and remove the keyway mold to form a cementitious shear keyway layer; Among them, the keyway mold includes a frame identical to the second layer of cementitious mold. Each empty slot in the frame is provided with a number of strip-shaped members arranged side by side at intervals, and the strip-shaped members divide each empty slot into several keyways.

8. The preparation method of the seawater sea-sand reinforced concrete member based on double intervention according to claim 7, wherein: In step S1, step S3, and step S3-1, release agent is respectively applied to the inner sides of the first layer of cementitious mold, the second layer of cementitious mold, and the keyway mold, and the edges of the first layer of cementitious mold, the second layer of cementitious mold, and the keyway mold are respectively blocked with foaming agent or rubber and then poured. During the pouring process, continuous vibration is carried out to ensure the pouring compactness; After step S3, repeat step S2 to step S3 to fabricate a fiber-reinforced cement substrate containing multiple layers of conductive carbon fiber cloths.

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