Carbon fiber reinforced polymer tendon prestressed concrete cylinder pipe

Abstract

The utility model provides a kind of carbon fiber tendon prestressed steel cylinder concrete pipe.The carbon fiber tendon prestressed steel cylinder concrete pipe includes: steel cylinder, the inside of the steel cylinder is provided with inner layer concrete pipe core, the outside of the steel cylinder is provided with outer layer concrete pipe core;The outer layer concrete pipe core is wound carbon fiber tendon and forms carbon fiber layer with the outer periphery of the steel cylinder being deviated, wherein, wherein, the minimum clear distance between adjacent carbon fiber tendon is greater than or equal to the diameter of carbon fiber tendon, and the maximum center distance between adjacent carbon fiber tendon is less than or equal to 38mm;The carbon fiber layer is provided with mortar protective layer with the side being deviated from the outer layer concrete pipe core.

Description

Technical Field

[0001] This application relates to the field of pipeline engineering technology, and more specifically, to a carbon fiber reinforced prestressed steel cylinder concrete pipe. Background Technology

[0002] In related technologies, cold-drawn steel wire is a commonly used prestressing tendon material in prestressed concrete cylinder pipes (PCCP). In the structural system of prestressed concrete cylinder pipes, steel wire is the most critical load-bearing component, and its performance is closely related to the service life and load-bearing safety of the pipeline, directly determining whether the pipeline can operate safely and stably within the specified design life.

[0003] However, prestressed concrete cylinder pipes are mostly used in harsh environments, such as underground environments. The groundwater commonly found in underground environments, and the corrosive chemical media such as acids and alkalis they may contain, will cause long-term corrosion of the steel wires. Under this long-term corrosion, the steel wires are highly susceptible to rust. Once the steel wires rust, their mechanical properties will significantly decrease, specifically manifested in a reduction in the stress they can withstand, and even the possibility of wire breakage. The reduced stress and wire breakage problems will further weaken the overall structural strength of the pipeline, posing a serious threat to its structural safety, and will also significantly shorten the actual service life of the pipeline.

[0004] In view of this, a new technical solution is needed to solve the above-mentioned technical problems. Utility Model Content

[0005] The purpose of this application is to provide a new technology solution for prestressed steel cylinder concrete pipe to solve the technical problems existing in using cold-drawn steel wire as the prestressing tendon material for prestressed steel cylinder concrete pipe.

[0006] According to an embodiment of this application, a carbon fiber reinforced prestressed steel cylinder concrete pipe is provided. The carbon fiber reinforced prestressed steel cylinder concrete pipe includes:

[0007] A steel cylinder, wherein an inner concrete core is provided on the inner side of the steel cylinder and an outer concrete core is provided on the outer side of the steel cylinder.

[0008] The outer concrete core is wrapped with carbon fiber reinforcement to form a carbon fiber layer away from the outer periphery of the steel cylinder. The minimum net distance between adjacent carbon fiber reinforcements is greater than or equal to the diameter of the carbon fiber reinforcement, and the maximum center-to-center distance between adjacent carbon fiber reinforcements is less than or equal to 38 mm.

[0009] A mortar protective layer is provided on the side of the carbon fiber layer facing away from the outer concrete core.

[0010] Optionally, a modified cement slurry covering layer is provided between the carbon fiber layer and the mortar protective layer.

[0011] Optionally, the fiber volume content of the carbon fiber reinforcement is greater than or equal to 60%.

[0012] Optionally, the carbon fiber reinforcement is a thermosetting carbon fiber reinforcement.

[0013] Optionally, the outer concrete core forms multiple carbon fiber layers away from the outer periphery of the steel cylinder, wherein a mortar protective layer is provided between adjacent carbon fiber layers in the multiple carbon fiber layers, and the outer periphery of the outermost carbon fiber layer in the multiple carbon fiber layers is provided with the mortar protective layer.

[0014] Optionally, a modified cement slurry covering layer is provided between the carbon fiber layer and the mortar protective layer.

[0015] Optionally, the water-cement ratio of the modified cement slurry coating is 0.6–0.7, and the coating amount is controlled at 0.4 L / m². 2 ~0.5L / m 2 .

[0016] Optionally, if multiple carbon fiber layers are formed on the outer concrete core away from the outer periphery of the steel cylinder, the thickness of the mortar protective layer is at least the diameter of the carbon fiber reinforcement, and the thickness of the outermost mortar protective layer away from the outer concrete core should be greater than or equal to 25 mm.

[0017] Optionally, the carbon fiber layer is formed by winding the carbon fiber reinforcement for the Nth time around the outer concrete core away from the outer periphery of the steel cylinder, wherein N>1, the cubic compressive strength of the mortar protective layer is higher than or equal to 32MPa, the compressive strength of the mortar protective layer specimen at 28 days is higher than or equal to 45MPa, and the water absorption rate of the mortar protective layer is less than or equal to 10%.

[0018] Optionally, the outer concrete core is further provided with a pre-embedded anchor, and the tensile force that the pre-embedded anchor can withstand is at least 65% of the ultimate tensile strength of the carbon fiber reinforcement.

[0019] Optionally, the steel cylinder is formed with a weld, which is a spiral circumferential weld.

[0020] This application provides a carbon fiber reinforced prestressed steel cylinder concrete pipe. By controlling the net spacing and center-to-center distance between the carbon fiber reinforcing bars, this application ensures that stress is evenly distributed across the concrete core, improving the pipe's crack resistance and load-bearing capacity, and enhancing its stability under complex working conditions. Furthermore, by controlling the net spacing and center-to-center distance between the carbon fiber reinforcing bars, this application ensures that the mortar protective layer forms uniformly and is less prone to detachment. The mortar protective layer enhances the pipe's impermeability and corrosion resistance, effectively protecting the outer concrete core and carbon fiber reinforcing bars from environmental erosion.

[0021] Other features and advantages of this specification will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of this specification and, together with their description, serve to explain the principles of this specification.

[0023] Figure 1 The diagram shown is a structural diagram of the carbon fiber reinforced prestressed steel cylinder concrete pipe provided in an embodiment of this application.

[0024] Figure 2 The diagram shown is a structural schematic of a single-layer carbon fiber prestressed steel cylinder concrete pipe provided in an embodiment of this application.

[0025] Figure 3 The diagram shown is a structural schematic of a multi-layer carbon fiber reinforced prestressed steel cylinder concrete pipe provided in an embodiment of this application.

[0026] Explanation of reference numerals in the attached figures:

[0027] 1. Steel cylinder; 11. Socket steel ring; 12. Spiral steel ring; 13. Sealing ring; 14. Water inlet hole;

[0028] 2. Inner concrete core; 3. Outer concrete core; 4. Carbon fiber layer; 5. Mortar protective layer; 6. Modified cement slurry covering layer; 31. Embedded anchor. Detailed Implementation

[0029] Various exemplary embodiments of this application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of this application.

[0030] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0031] Technologies and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such technologies and equipment should be considered part of the specification.

[0032] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0033] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0034] This application provides a carbon fiber reinforced prestressed steel cylinder concrete pipe. This carbon fiber reinforced prestressed steel cylinder concrete pipe can be used in pressure pipeline projects such as long-distance water transmission and diversion pipelines, urban water supply and drainage trunk lines, industrial water transmission pipelines, farmland irrigation, factory pipe networks, power plant water supply pipes, and cooling water circulation systems. It is particularly suitable for complex and corrosive groundwater and soil environments such as coastal areas and high-salinity areas.

[0035] Reference Figure 1 The carbon fiber reinforced prestressed steel cylinder concrete pipe includes: a steel cylinder 1, an inner concrete core 2 on the inner side of the steel cylinder 1, and an outer concrete core 3 on the outer side of the steel cylinder 1.

[0036] The outer concrete core 3 is wrapped with carbon fiber reinforcement to form a carbon fiber layer 4 away from the outer periphery of the steel cylinder 1. The minimum net distance between adjacent carbon fiber reinforcements is greater than or equal to the diameter of the carbon fiber reinforcement, and the maximum center-to-center distance between adjacent carbon fiber reinforcements should not be greater than 38 mm.

[0037] A mortar protective layer 5 is provided on the side of the carbon fiber layer 4 facing away from the outer concrete core 3.

[0038] In this embodiment, the provided carbon fiber reinforced prestressed steel cylinder concrete pipe mainly includes a steel cylinder 1, an inner concrete core 2, an outer concrete core 3, a carbon fiber layer 4, and a mortar protective layer 5. That is, the carbon fiber reinforced prestressed steel cylinder concrete pipe includes an inner concrete core 2 made of concrete and an outer concrete core 3 made of concrete located outside it. A steel cylinder 1 is disposed between the inner concrete core 2 and the outer concrete core 3. A carbon fiber layer 4 is formed on the outside of the outer concrete core 3 by winding carbon fiber reinforcement, and a mortar protective layer 5 is disposed on the surface of the carbon fiber layer 4.

[0039] Specifically, the steel cylinder 1 is made by spirally winding thin steel plates. The welds on the steel cylinder 1 are spiral circumferential welds to enhance the overall structural integrity and strength of the steel cylinder 1.

[0040] In one specific embodiment, refer to Figure 1 The steel cylinder 1 includes a socket end and a spigot end. A socket steel ring 11 is welded to the opening of the socket end, and a spigot steel ring 12 is welded to the opening of the spigot end. The socket steel ring 11 and the spigot steel ring 12 are inserted together to form a complete steel cylinder 1. A sealing ring 13 is installed at the connection between the socket steel ring 11 and the spigot steel ring 12. There is at least one sealing ring 13 to ensure good sealing performance. A test water inlet hole 14 is provided in the middle of the two sealing rings 13 for convenient water inlet sealing tests.

[0041] Preferably, the thickness of the thin steel plate is 1.5 mm. For example, if the inner diameter of the inner concrete core 2 is in the range of 1000 mm to 4000 mm, preferably, the thickness of the steel cylinder 1 is 1.5 mm.

[0042] Both the inner concrete core 2 and the outer concrete core 3 are made of concrete. The core concrete includes fine and coarse aggregates. The fine aggregate for the core concrete should preferably be medium-coarse sand, and the quality requirements of the sand should comply with GB / T14684, with a mud content not exceeding 2%. The coarse aggregate for the core concrete should be crushed stone or gravel, with a maximum particle size not exceeding 31.5 mm and not exceeding 2 / 5 of the concrete layer thickness. The quality requirements of the gravel should comply with GB / T14685.

[0043] Optionally, admixtures may be used in the concrete raw materials of the inner concrete core 2 and the outer concrete core 3. When admixtures are used, they should not have a harmful effect on the steel cylinder 1 or the water quality.

[0044] Optionally, finished fly ash, ground slag, or silica fume may be added during the batching of the core concrete.

[0045] In this embodiment, the inner concrete core 2 is in direct contact with the transported medium, which can prevent the medium from corroding the inner wall of the steel cylinder 1 and extend the service life of the steel cylinder 1. The outer concrete core 3 wraps around the outside of the steel cylinder 1, providing physical protection for the steel cylinder 1 and preventing the steel cylinder 1 from being subjected to mechanical damage and chemical corrosion from the external environment.

[0046] The inner and outer concrete core 3 works together with the steel cylinder 1 to form a composite structure. This composite structure can fully utilize the tensile strength of the steel cylinder 1 and the compressive strength of the concrete, significantly improving the overall rigidity and load-bearing capacity of the pipeline, enabling the pipeline to withstand greater internal and external pressures and soil pressure.

[0047] It should be emphasized that in this embodiment, carbon fiber reinforcement is wound around the outer periphery of the outer concrete core 3 to form a carbon fiber layer 4. The number of carbon fiber layers 4 wound around the outer periphery of the outer concrete core 3 varies depending on the pipe specifications, load conditions, installation parameters, and geological conditions. Generally, refer to... Figure 1 and Figure 2 A single-layer carbon fiber layer 4 is formed around the outer periphery of the outer concrete core 3, and a mortar protective layer 5 is applied to the outer surface of the single-layer carbon fiber layer 4. In special cases, refer to... Figure 3 Multiple carbon fiber layers 4 are formed around the outer periphery of the outer concrete core 3. While forming the multiple carbon fiber layers 4, multiple mortar protective layers 5 are also formed, with the carbon fiber layers 4 and mortar protective layers 5 spaced apart. Taking two carbon fiber layers 4 as an example: Outer concrete core 3 → Single-layer (first layer) carbon fiber layer 4 → Mortar protective layer 5 → Single-layer (second layer) carbon fiber layer 4 → Mortar protective layer 5.

[0048] Regardless of whether a single carbon fiber layer 4 is formed outside the outer concrete core 3 or multiple carbon fiber layers 4 are formed outside the outer concrete core 3, the spacing between adjacent carbon fiber reinforcements in the same carbon fiber layer 4 must meet the following requirements: the minimum clear distance between adjacent carbon fiber reinforcements should be greater than or equal to the diameter of the carbon fiber reinforcement, and the maximum center-to-center distance between adjacent carbon fiber reinforcements should be less than or equal to 38 mm. In other words, the minimum clear distance between adjacent carbon fiber reinforcements should not be less than the diameter of the carbon fiber reinforcement, and the maximum center-to-center distance between adjacent carbon fiber reinforcements should not be greater than 38 mm.

[0049] The "clear distance" refers to the shortest distance between two adjacent carbon fiber reinforcements, excluding the space occupied by the carbon fiber reinforcements themselves. It measures the size of the gap between the outer edges of the carbon fiber reinforcements, which is the actual usable space and does not involve the diameter or thickness of the carbon fiber reinforcements themselves.

[0050] For example, the diameter range of carbon fiber reinforcement bars is 3.4mm to 7mm. For instance, the diameters of carbon fiber reinforcement bars are 3.4mm, 5mm, 6mm, and 7mm. In carbon fiber reinforced prestressed steel cylinder concrete tube structures, the selection of the carbon fiber reinforcement bar diameter needs to comprehensively consider prestress loss, anchorage performance, and the overall structural stress requirements. A diameter range of 3.4-7mm can meet the reinforcement requirements of most engineering scenarios.

[0051] For example, in the same layer of carbon fiber, the minimum clear distance between adjacent carbon fiber tendons can be: 3.4mm, 3.5mm, 3.6mm, 3.7mm, 3.8mm, 3.9mm, 4.0mm, 4.5mm, 5.0mm, 5.5mm, 6.0mm, 6.5mm, 7.0mm.

[0052] For example, in the same carbon fiber layer 4, the center-to-center spacing between adjacent carbon fiber ribs satisfies the following condition: greater than 6.8 mm and less than or equal to 38 mm. For example, the spacing between adjacent carbon fiber ribs can be: 8 mm, 10 mm, 12 mm, 14 mm, 15 mm, 16 mm, 18 mm, 20 mm, 22 mm, 24 mm, 26 mm, 28 mm, 30 mm, 32 mm, 34 mm, 36 mm, 37 mm, 38 mm.

[0053] Specifically, carbon fiber reinforcement features high strength and high modulus of elasticity. By wrapping carbon fiber reinforcement around the outer periphery of the outer concrete core 3 and applying prestress, the pipeline can be under compression before bearing load, thereby improving the pipeline's crack resistance and load-bearing capacity. Compared with traditional cold-drawn steel wire, carbon fiber reinforcement has better corrosion resistance, effectively avoiding problems such as stress reduction and wire breakage caused by steel wire corrosion, thus extending the pipeline's service life.

[0054] For example, the mechanical performance indicators of the carbon fiber reinforcement used in the embodiments of this application meet the requirements of Table 1:

[0055] Table 1:

[0056]

[0057] The minimum clear distance between adjacent carbon fiber reinforcing bars is specified to be no less than the diameter of the reinforcing bar, ensuring that the reinforcing bars are not overly dense during winding. When the pipeline is subjected to complex loads such as internal and external pressures and soil pressure, each carbon fiber reinforcing bar can independently and fully exert its high strength and high modulus of elasticity. This avoids interference such as mutual compression and friction between adjacent reinforcing bars caused by overly dense winding. Such interference may damage the internal fiber structure of the carbon fiber reinforcing bar, reducing its tensile strength and modulus of elasticity. The reasonable spacing fundamentally eliminates this hidden danger, ensuring the stable performance of the mechanical properties of the carbon fiber reinforcing bars and providing reliable and durable prestressed support for the pipeline.

[0058] Meanwhile, the maximum center-to-center spacing is specified to be no greater than 38mm. This ensures that the carbon fiber layer 4 can be uniformly prestressed, improving the prestress transfer efficiency and allowing the pipeline to distribute stress more evenly under load, thus enhancing the overall stability of the pipeline. Appropriate spacing facilitates uniform distribution of the carbon fiber reinforcement during winding, enabling the prestress to be transferred more evenly to the outer concrete core 3. When the pipeline is under load, the uniformly distributed prestress can effectively offset some of the tensile stress, preventing stress concentration areas on the concrete core. Stress concentration can easily lead to concrete cracking, thereby affecting the overall structural safety and service life of the pipeline.

[0059] Furthermore, the embodiments of this application specify that the minimum clear distance between adjacent carbon fiber reinforcements shall not be less than the diameter of the carbon fiber reinforcements, and the maximum center-to-center distance between adjacent carbon fiber reinforcements shall not be greater than 38mm, which has a good effect on the construction of mortar protective layer 5 and pipeline performance.

[0060] Specifically, the not-too-dense winding method of the carbon fiber reinforcement provides favorable working conditions for the construction of the mortar protective layer 5. During mortar spraying, workers can more smoothly and evenly cover the outer concrete core 3 and the surface of the carbon fiber reinforcement, avoiding problems such as difficulty in filling the mortar, voids, or uneven thickness caused by overly dense carbon fiber reinforcement. The uniform and dense mortar protective layer 5 not only improves the appearance quality of the pipeline but also enhances its impermeability and corrosion resistance, effectively protecting the outer concrete core 3 and carbon fiber reinforcement from environmental erosion.

[0061] Furthermore, the reasonable spacing of the carbon fiber reinforcements allows the mortar to better contact and bond with the outer concrete core 3 and the surface of the carbon fiber reinforcements during the solidification process. This excellent bonding performance ensures that the mortar protective layer 5 will not easily fall off or crack during pipeline use, and can play a stable protective role for a long time.

[0062] When the mortar completely and evenly covers the outer concrete core 3, a continuous and dense protective layer is formed. This protective layer can effectively block the intrusion of groundwater, acids, alkalis, and other corrosive media, preventing them from corroding and damaging the concrete core and carbon fiber reinforcement. At the same time, the mortar protective layer 5 also provides heat insulation and fireproofing, reducing the impact of external temperature changes and fires on the pipeline, and improving the pipeline's adaptability and reliability in various harsh environments.

[0063] This embodiment of the application controls the net spacing and center-to-center spacing of the carbon fiber reinforcing bars, enabling stress to be evenly distributed on the concrete core, thereby improving the pipe's crack resistance and load-bearing capacity, and enhancing its stability under complex working conditions. Furthermore, by controlling the net spacing and center-to-center spacing of the carbon fiber reinforcing bars, this embodiment of the application ensures that the mortar protective layer 5 is uniformly formed and not easily detached. The mortar protective layer 5 enhances the pipe's impermeability and corrosion resistance, effectively protecting the outer concrete core 3 and the carbon fiber reinforcing bars from external environmental erosion.

[0064] In this embodiment of the application, when the outer concrete core 3 is wrapped with carbon fiber reinforcement, the cubic compressive strength of the outer concrete core 3 should not be less than 28d, which is 70% of the compressive strength, thus ensuring that the outer concrete core 3 has sufficient strength during the carbon fiber reinforcement winding stage.

[0065] Meanwhile, the initial compressive stress established in the outer concrete core 3 during the winding process should not exceed 50% of the compressive strength of the outer concrete core 3 during the winding process. This restriction is to prevent the concrete core from brittle failure due to excessive initial compressive stress during the winding of carbon fiber reinforcement.

[0066] When wrapping the reinforcing bars, the surface temperature of the outer concrete core 3 must not be lower than 2℃. This ensures the bonding quality between the modified cement slurry and the core concrete, and reduces the prestress loss of the carbon fiber reinforcement caused by temperature changes, thus providing a guarantee for the long-term stable operation of the pipeline.

[0067] In addition, when wrapping carbon fiber reinforcement around the outer concrete core 3, the surface of the outer concrete core 3 needs to be kept flat. For example, holes with a diameter or depth exceeding 10mm on the outer surface of the outer concrete core 3 must be repaired, and the concrete edges should be ground smooth.

[0068] According to the embodiments of this application, refer to Figure 1 and Figure 2 A modified cement slurry covering layer 6 is provided between the carbon fiber layer 4 and the mortar protective layer 5. For example, in a single-layer carbon fiber reinforced prestressed steel cylinder concrete pipe, a modified cement slurry covering layer 6 is provided between the carbon fiber layer 4 and the mortar protective layer 5.

[0069] In the production of carbon fiber reinforced prestressed steel cylinder concrete pipe in this embodiment, the mortar protective layer 5 is formed by spraying. Since the spraying pressure generated during the spraying operation will affect the carbon fiber reinforcement, and the stability of the carbon fiber reinforcement's performance is crucial as a key component of the reinforcing structure, it is essential to address the potential impact of the spraying pressure on the carbon fiber reinforcement. Therefore, a modified cement slurry covering layer 6 is introduced between the carbon fiber layer 4 and the mortar protective layer 5. Specifically, after completing the winding process of the carbon fiber reinforcement, a layer of modified cement slurry is uniformly coated onto the surface of the carbon fiber reinforcement by controlling the coating process. The water-cement ratio of the modified cement slurry should preferably be 0.6–0.7, and the coating amount should preferably be controlled at 0.4 L / m². 2 ~0.5L / m 2 This forms a reliable protective layer, ensuring that the carbon fiber reinforcement is not affected by adverse factors such as spraying pressure during subsequent production and use, thus ensuring the overall performance and quality of the carbon fiber reinforced prestressed steel cylinder concrete pipe.

[0070] According to the embodiments of this application, the fiber volume content of the carbon fiber reinforcement is greater than or equal to 60%, that is, the fiber volume content of the carbon fiber reinforcement is not less than 60%.

[0071] In this embodiment, the carbon fiber reinforcement should be prepared using a pultrusion process, with a fiber volume content of not less than 60%. This ensures the reinforcement maintains a consistently high tensile strength, effectively resisting the tensile stress in the carbon fiber reinforced prestressed steel cylinder concrete pipe under internal and external pressures, soil pressure, and other loads, thus preventing structural cracking or failure. The high fiber content also ensures less deformation and lower prestress loss under stress. In carbon fiber reinforced prestressed steel cylinder concrete pipes, this helps maintain the initial prestress of the pipe, improving crack resistance and load-bearing stability. Furthermore, the high fiber content reduces the proportion of the resin matrix, lowering the risk of performance degradation due to resin aging or corrosion. In carbon fiber reinforced prestressed steel cylinder concrete pipes, this characteristic extends the pipe's service life and reduces maintenance costs.

[0072] For example, the fiber volume content of the carbon fiber reinforcement is not less than 60%, the tensile strength of the carbon fiber reinforcement is typically ≥1800MPa, and the tensile modulus of the carbon fiber reinforcement is typically ≥160GPa.

[0073] For example, the fiber volume content of carbon fiber reinforcement is typically in the range of 60% to 75%, such as 60%, 65%, 70%, and 75%.

[0074] According to an embodiment of this application, the carbon fiber reinforcement is a thermosetting carbon fiber reinforcement.

[0075] In this embodiment, the carbon fiber reinforcement is thermosetting carbon fiber reinforcement. Compared to thermoplastic carbon fiber reinforcement, thermosetting carbon fiber reinforcement has higher strength and stiffness, providing excellent mechanical properties and making it suitable for engineering scenarios with high strength requirements. In carbon fiber reinforced prestressed steel cylinder concrete pipes, this high strength and stiffness helps to improve the pipe's load-bearing capacity and resistance to deformation. Furthermore, thermosetting carbon fiber reinforcement maintains good strength and stiffness under high-temperature environments and is not prone to softening or deformation. This characteristic allows thermosetting carbon fiber reinforcement in carbon fiber reinforced prestressed steel cylinder concrete pipes to better cope with the challenges of high-temperature environments, ensuring the safety and stability of the pipeline.

[0076] According to the embodiments of this application, refer to Figure 3 The outer concrete core 3 forms multiple carbon fiber layers 4 away from the outer periphery of the steel cylinder 1. A mortar protective layer 5 is provided between adjacent carbon fiber layers 4, and the outermost carbon fiber layer 4 in the multiple carbon fiber layers 4 is provided with the mortar protective layer 5 on its outer periphery.

[0077] In this embodiment, a prestressed steel cylinder concrete pipe with multiple carbon fiber layers 4 is provided. For example, in applications such as deep-sea water pipelines, nuclear power plant cooling water pipelines, and urban integrated pipe corridors, prestressed steel cylinder concrete pipes with multiple carbon fiber layers 4 can be used to withstand extremely high internal and external pressures.

[0078] In the structure of the prestressed steel cylinder concrete pipe with carbon fiber reinforcement in multiple carbon fiber layers 4, the outer concrete core 3 is separated from the outer periphery of the steel cylinder 1 to form multiple carbon fiber layers 4. A mortar protective layer 5 is provided between adjacent carbon fiber layers 4 in the multiple carbon fiber layers 4, and a mortar protective layer 5 is provided on the outer periphery of the outermost carbon fiber layer 4 in the multiple carbon fiber layers 4.

[0079] In this embodiment, in the structure of the prestressed steel cylinder concrete pipe with carbon fiber reinforcement in the multi-layer carbon fiber layer 4, the outer concrete core 3 forms a multi-layer carbon fiber layer 4 away from the outer periphery of the steel cylinder 1. A mortar protective layer 5 is provided between adjacent carbon fiber layers 4 in the multi-layer carbon fiber layer 4. The mortar protective layer 5 prevents direct friction between fiber layers and protects the integrity of the fibers. The mortar layer has a dense structure, which can effectively block corrosive media such as water, oxygen, and chloride ions from penetrating the carbon fiber layer 4, delaying the oxidative degradation of fibers and the aging of the resin matrix.

[0080] In addition, a mortar protective layer 5 is provided on the outermost carbon fiber layer 4 of the multilayer carbon fiber layer 4 to resist mechanical damage and external corrosive media; and the mortar layer has a dense structure, which can effectively block corrosive media such as water, oxygen, and chloride ions from penetrating the carbon fiber layer 4, delaying fiber oxidative degradation and resin matrix aging.

[0081] Similarly, refer to Figure 3 In the structure of a prestressed steel cylinder concrete pipe with carbon fiber reinforcement in multiple carbon fiber layers 4, a modified cement slurry covering layer 6 is provided between the carbon fiber layers 4 and the mortar protective layer 5. The function of the modified cement slurry covering layer 6 is the same as that in the single-layer carbon fiber layer 4 prestressed steel cylinder concrete pipe, and will not be repeated here.

[0082] According to the embodiments of this application, refer to Figure 3 Specifically, in the structure of a prestressed steel cylinder concrete pipe with multiple carbon fiber layers 4, the water-cement ratio of the modified cement slurry covering layer 6 should preferably be 0.6–0.7, and the coating amount should preferably be controlled at 0.4 L / m. 2 ~0.5L / m 2 .

[0083] In this embodiment, the modified cement slurry covering layer 6 needs to cover the surface of the carbon fiber reinforcement to ensure that the carbon fiber layer 4 is completely embedded in the modified cement slurry covering layer 6, so as to avoid fiber wear or scratching due to local exposure.

[0084] Specifically, the water-cement ratio of the modified cement slurry covering layer 6 is set in the range of 0.6 to 0.7. For example, the water-cement ratio of the modified cement slurry covering layer 6 is 0.60, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69, or 0.70.

[0085] By limiting the water-cement ratio of the modified cement slurry coating layer 6 to this range, the fluidity and hardening performance of the modified cement slurry can be precisely controlled. Within this range, the modified cement slurry exhibits good fluidity, ensuring uniform and thorough coating of the carbon fiber reinforcement and the surface of the steel cylinder concrete pipe during the coating process, avoiding localized weak points caused by uneven coating. Furthermore, after hardening, it forms a structure with suitable strength and density, effectively preventing the intrusion of external moisture and other substances, thereby significantly improving the durability of the carbon fiber reinforced prestressed steel cylinder concrete pipe and extending its service life.

[0086] Meanwhile, the coating amount of modified cement slurry cover layer 6 is controlled at 0.4 L / m. 2 ~0.5L / m 2 For example, the coating amount of modified cement slurry cover layer 6 is controlled at 0.4 L / m. 2 0.41L / m 2 0.42L / m 2 0.43L / m 2 0.44L / m 2 0.45L / m 2 0.46L / m 2 0.47L / m 2 0.48L / m 2 0.49L / m 2 0.5L / m 2 .

[0087] Controlling the coating amount of modified cement slurry covering layer 6 within the above-mentioned range ensures, on the one hand, that the modified cement slurry forms a continuous and complete covering layer, fully exerting its protective function and preventing corrosion and aging of carbon fiber reinforcement due to direct contact with the external environment, thus ensuring the stability of the mechanical properties of the carbon fiber reinforcement and ensuring the safety and reliability of the entire carbon fiber reinforcement prestressed steel cylinder concrete pipe structure during long-term use. On the other hand, reasonable control of the coating amount also avoids waste of modified cement slurry, reduces production costs, and improves economic efficiency, meeting the requirements of efficient material utilization and cost control in engineering practice.

[0088] According to the embodiments of this application, refer to Figure 3When multiple layers of carbon fiber layers 4 are formed on the outer periphery of the outer concrete core 3 away from the outer periphery of the steel cylinder 1, the thickness of the mortar protective layer 5 provided between adjacent carbon fiber layers 4 is at least the diameter of the carbon fiber reinforcement, and the thickness of the outermost mortar protective layer 5 away from the outer concrete core is greater than or equal to 25 mm.

[0089] In this embodiment, the thickness of the mortar protective layer 5 between adjacent carbon fiber layers 4 is set to be at least the diameter of the carbon fiber reinforcement. Such a thickness provides sufficient space for isolation between adjacent carbon fiber layers 4, effectively preventing stress concentration caused by mutual contact and friction during the stress process.

[0090] Preferably, the thickness of the outermost mortar protective layer 5, which is away from the outer concrete core, is less than 30 mm and greater than or equal to 25 mm.

[0091] In this embodiment, appropriately increasing the thickness of the mortar protective layer 5 can provide sufficient wear resistance while avoiding cracking of the mortar layer due to excessive thickness. When the thickness exceeds 30mm, the mortar layer may crack due to increased self-weight and shrinkage stress, which would reduce the protective effect; while when the thickness is less than 25mm, it cannot effectively block external impacts or wear.

[0092] According to the embodiments of this application, refer to Figure 3 The carbon fiber layer 4 is formed by winding the carbon fiber reinforcement for the Nth time around the outer concrete core 3 away from the outer periphery of the steel cylinder 1, where N > 1. In this case, the cubic compressive strength of the mortar protective layer 5 is higher than or equal to 32 MPa, the compressive strength of the mortar protective layer 5 specimen at 28 days is higher than or equal to 45 MPa, and the water absorption rate of the mortar protective layer 5 is less than or equal to 10%. That is, the cubic compressive strength of the mortar protective layer 5 should not be lower than 32 MPa, the compressive strength of the mortar protective layer 5 specimen at 28 days should not be lower than 45 MPa, and the water absorption rate of the mortar protective layer should not be greater than 10%.

[0093] In this embodiment, particularly in the structure of a prestressed steel cylinder concrete pipe with multiple carbon fiber layers 4, after a mortar protective layer 5 is provided outside the modified cement slurry covering layer 6, a carbon fiber layer 4 needs to be provided outside the mortar protective layer 5. That is, a carbon fiber layer 4 needs to be wound again outside the mortar protective layer 5 outside the modified cement slurry covering layer 6. When winding the reinforcement again, the cubic compressive strength of the mortar protective layer 5 should not be less than 32 MPa to withstand the tensile stress and construction load generated during the winding process of the carbon fiber layer 4. If the mortar strength is insufficient, it may lead to interlayer debonding or cracking of the mortar layer, thereby affecting the stress transfer of the carbon fiber layer 4 and the overall structural performance.

[0094] Furthermore, the compressive strength of the mortar protective layer 5 specimens at 28 days of age is specified to be no less than 45 MPa, fully considering the strength development law of mortar during the hardening process. 28 days is a critical time point for mortar strength development; at this time, the mortar has basically completed the main hardening process and possesses relatively stable mechanical properties. Reaching or exceeding a compressive strength of 45 MPa means that the mortar protective layer 5 can quickly develop sufficient strength in the early stages, effectively resisting external impacts, compression, and other forces, reducing the risk of damage to the structure during construction and the initial stages of use.

[0095] Furthermore, the mortar protective layer 5 has a low water absorption rate, which can effectively prevent water penetration, reduce the intrusion pathways of harmful substances, delay the deterioration process of the structure, extend the service life of the carbon fiber reinforced prestressed steel cylinder concrete pipe, reduce maintenance costs, and improve the economic and social benefits of the project.

[0096] According to the embodiments of this application, refer to Figure 1 The outer concrete core 3 is also provided with a pre-embedded anchor 31, and the tensile force that the pre-embedded anchor 31 can withstand is at least 65% of the standard tensile strength of the carbon fiber reinforcement.

[0097] In this embodiment, when winding carbon fiber reinforcement, the carbon fiber reinforcement is spirally wound onto the core according to the designed pitch under tension control stress. The starting and ending ends of the carbon fiber reinforcement should be firmly fixed. The pre-embedded anchors 31 at both ends of the core (the pre-embedded anchors 31 must be tightly bonded to the core concrete) should be able to withstand a tensile force of at least 65% of the standard tensile strength of the carbon fiber reinforcement, thus forming a double safety guarantee.

[0098] During the construction phase, the pre-embedded anchor 31 bears the instantaneous load during the tensioning of the carbon fiber reinforcement, preventing construction interruption due to anchor failure. During the operation phase, it resists extreme loads such as internal and external pressure from pipelines and earthquakes, preventing structural collapse caused by anchor failure.

[0099] The above embodiments mainly describe the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, they will not be elaborated here.

[0100] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A carbon fiber reinforced prestressed steel cylinder concrete pipe, characterized in that, include: A steel cylinder (1) is provided with an inner concrete core (2) on the inner side and an outer concrete core (3) on the outer side of the steel cylinder (1). The outer concrete core (3) is wrapped with carbon fiber reinforcement to form a carbon fiber layer (4) away from the outer periphery of the steel cylinder (1), wherein the minimum net distance between adjacent carbon fiber reinforcements is greater than or equal to the diameter of the carbon fiber reinforcement, and the maximum center distance between adjacent carbon fiber reinforcements is less than or equal to 38mm. A mortar protective layer (5) is provided on the side of the carbon fiber layer (4) facing away from the outer concrete core (3).

2. The carbon fiber reinforced prestressed steel cylinder concrete pipe according to claim 1, characterized in that, A modified cement slurry covering layer (6) is provided between the carbon fiber layer (4) and the mortar protective layer (5).

3. The carbon fiber reinforced prestressed steel cylinder concrete pipe according to claim 1, characterized in that, The fiber volume content of the carbon fiber reinforcement is greater than or equal to 60%.

4. The carbon fiber reinforced prestressed steel cylinder concrete pipe according to claim 1, characterized in that, The carbon fiber reinforcement is a thermosetting carbon fiber reinforcement.

5. The carbon fiber reinforced prestressed steel cylinder concrete pipe according to claim 1, characterized in that, The outer concrete core (3) forms multiple carbon fiber layers (4) away from the outer periphery of the steel cylinder (1), wherein the mortar protective layer (5) is provided between adjacent carbon fiber layers (4) in the multiple carbon fiber layers (4), and the outer periphery of the outermost carbon fiber layer (4) in the multiple carbon fiber layers (4) is provided with the mortar protective layer (5).

6. The carbon fiber reinforced prestressed steel cylinder concrete pipe according to claim 5, characterized in that, A modified cement slurry covering layer (6) is provided between the carbon fiber layer (4) and the mortar protective layer (5).

7. The carbon fiber reinforced prestressed steel cylinder concrete pipe according to claim 2 or 6, characterized in that, The modified cement slurry covering layer (6) has a water-cement ratio of 0.6 to 0.7, and the coating amount is controlled at 0.4 L / m. 2 ~0.5L / m 2 .

8. The carbon fiber reinforced prestressed steel cylinder concrete pipe according to claim 5, characterized in that, When multiple carbon fiber layers (4) are formed on the outer periphery of the outer concrete core (3) away from the outer periphery of the steel cylinder (1), the thickness of the mortar protective layer (5) provided between adjacent carbon fiber layers (4) is at least the diameter of the carbon fiber reinforcement and the thickness of the outermost mortar protective layer (5) away from the outer concrete core is greater than or equal to 25 mm.

9. The carbon fiber reinforced prestressed steel cylinder concrete pipe according to claim 8, characterized in that, The carbon fiber layer (4) is formed by wrapping the carbon fiber reinforcement around the outer concrete core (3) away from the outer periphery of the steel cylinder (1) for the Nth time. When N>1, the cubic compressive strength of the mortar protective layer (5) is higher than or equal to 32MPa, the compressive strength of the mortar protective layer (5) specimen at 28 days is higher than or equal to 45MPa, and the water absorption rate of the mortar protective layer (5) is less than or equal to 10%.

10. The carbon fiber reinforced prestressed steel cylinder concrete pipe according to claim 1, characterized in that, The outer concrete core (3) is also provided with a pre-embedded anchor, and the tensile force that the pre-embedded anchor can withstand is at least 65% of the standard tensile strength of the carbon fiber reinforcement.

11. The carbon fiber reinforced prestressed steel cylinder concrete pipe according to claim 1, characterized in that, The steel cylinder (1) has a weld seam, which is a spiral circumferential weld seam.

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