Anti-crack glass fiber reinforced concrete composite pipe and manufacturing process thereof

Abstract

This invention relates to the field of building component technology, and more particularly to a crack-resistant glass fiber reinforced concrete composite pipe and its manufacturing process. The process includes: firstly, preparing a cylindrical reinforcing cage and configuring it with multi-scale glass fiber concrete containing a medium- and long fiber skeleton, short fibers, and fine fibers. Then, a pre-core pipe is formed by centrifugal casting, and after curing, the finished composite pipe is obtained. This method obtains the crack load by conducting an external pressure test on the finished product, and determines whether the product is qualified based on the comparison result with a preset threshold. For unqualified products, further diagnosis and automatic correction of the centrifugal speed are achieved by calculating the skeleton offset characterization value, or by analyzing the crack fluctuation characterization value to diagnose and automatically optimize the casting rate and curing time, thereby forming a closed-loop quality control. The composite pipe obtained by this invention combines the high toughness of steel reinforcement with the strong crack resistance of the multi-scale fiber network, and has a socket, anti-permeability coating, and anti-corrosion layer, resulting in enhanced durability.

Description

Technical Field

[0001] This invention relates to the field of building component technology, and in particular to a crack-resistant glass fiber reinforced concrete composite pipe and its manufacturing process. Background Technology

[0002] Concrete composite pipes are widely used in municipal, water conservancy, and construction fields due to their advantages such as low cost, readily available raw materials, and good load-bearing capacity. However, traditional concrete pipes, especially reinforced concrete pipes, have long faced the following key technical challenges in practical applications:

[0003] First, insufficient crack resistance is the core bottleneck restricting its service life and safety. Traditional reinforced concrete pipes are prone to cracking under external loads, especially external pressure loads, due to the brittle nature of concrete. Once cracks appear, external moisture and corrosive media can seep in along the cracks, causing the internal steel bars to corrode. Steel corrosion not only reduces its own strength but also exacerbates concrete cracking due to the volume expansion of corrosion products, creating a vicious cycle that ultimately seriously affects the structural integrity and durability of the pipe.

[0004] Secondly, to address the issue of steel reinforcement corrosion, the industry has tried various methods, such as applying anti-corrosion treatment to the steel surface or increasing the thickness of the concrete protective layer. However, these methods are either costly or have limited effectiveness. Furthermore, traditional processes rely on relatively crude control over the production process. For example, in the critical centrifugal forming process, improper speed control can cause the internal reinforcing cage to shift or deform under centrifugal force, resulting in uneven tube wall thickness, creating structural weak points, and significantly reducing the overall load-bearing capacity of the finished product.

[0005] Finally, the insufficient toughness of concrete also limits further improvement in its crack resistance. Although existing technologies have attempted to add short fibers to concrete to improve toughness, single short fibers mainly improve the early plastic shrinkage and microcracks of concrete, and have limited effect on inhibiting macroscopic structural cracks, making it difficult to form a multi-scale, synergistically enhanced crack-resistant system. Summary of the Invention

[0006] Therefore, the present invention provides a crack-resistant glass fiber reinforced concrete composite pipe and its manufacturing process to overcome the problem of insufficient crack resistance of concrete composite pipes in the prior art.

[0007] To achieve the above objectives, on the one hand, the present invention provides a manufacturing process for a crack-resistant glass fiber reinforced concrete composite pipe, comprising:

[0008] Step S1: Fix several longitudinal ribs onto several equally spaced circumferential ribs to complete the preparation of the cylindrical reinforcing cage;

[0009] Step S2: Prepare the target concrete by mixing glass fiber and concrete according to the preset ratio, wherein the glass fiber includes a medium and long fiber skeleton, short fibers and fine fibers.

[0010] Step S3: Fix the reinforcing cage in the centrifugal forming cavity, and pour the target concrete at a preset speed and a preset rate to prepare the pre-core tube.

[0011] Step S4: Place the pre-core tube in a curing room with preset temperature and preset humidity for a preset curing time to obtain the finished composite tube;

[0012] Step S5: Perform an external pressure test on the finished composite pipe to obtain the crack load of the finished composite pipe, and determine whether the composite pipe preparation meets the preset standard based on the crack load of the finished composite pipe.

[0013] Step S6: In response to the composite tube preparation not meeting the preset standard, verify whether the composite tube preparation meets the preset standard based on the skeleton offset characterization value, or determine the reason why the composite tube preparation does not meet the preset standard based on the crack fluctuation characterization value.

[0014] Furthermore, in response to the crack load being less than a first preset crack load threshold, it is determined that the composite pipe preparation does not meet the preset standard, and the reason for the composite pipe preparation not meeting the preset standard is determined based on the crack fluctuation characterization value;

[0015] In response to the crack load being greater than or equal to a first preset crack load threshold and less than a second preset crack load threshold, it is determined that the composite pipe preparation does not meet the preset standard, and the composite pipe preparation is verified according to the skeleton offset characterization value to determine whether it meets the preset standard.

[0016] In response to the crack load being greater than or equal to a second preset crack load threshold, it is determined that the composite pipe preparation meets the preset standard.

[0017] Furthermore, in response to the skeleton offset characterization value being less than a preset skeleton offset characterization threshold, the composite tube fabrication is verified to meet a preset standard;

[0018] In response to the skeleton offset characterization value being greater than or equal to a preset skeleton offset characterization threshold, it is verified that the composite tube preparation does not meet the preset standard, and the reason for the composite tube preparation not meeting the preset standard is that the preset speed of the centrifugal forming equipment is not up to standard, and the preset speed of the centrifugal forming cavity is increased according to the difference between the skeleton offset characterization value and the preset skeleton offset characterization threshold.

[0019] The skeleton offset characterization value is the average of the root square values ​​of the radial offset distances between each longitudinal rib and the central axis of the composite tube during the centrifugal forming process of the reinforcing cage.

[0020] Furthermore, the increase in the preset rotational speed of the centrifugal forming cavity is positively correlated with the difference between the skeleton offset characterization value and the preset skeleton offset characterization threshold.

[0021] Furthermore, in response to the crack fluctuation characterization value being less than the preset crack fluctuation characterization threshold, it is determined that the reason why the composite pipe preparation does not meet the preset standard is that the preset curing time is not up to standard, and the preset curing time is increased according to the difference between the preset crack fluctuation characterization threshold and the crack fluctuation characterization value.

[0022] In response to the crack fluctuation characterization value being greater than or equal to a preset crack fluctuation characterization threshold, it is determined that the reason why the composite pipe preparation does not meet the preset standard is that the preset casting rate is not up to standard, and the preset casting rate is increased according to the difference between the crack fluctuation characterization value and the preset crack fluctuation characterization threshold.

[0023] Furthermore, the crack fluctuation characterization value is determined by the crack length, crack width, and crack distribution density.

[0024] Furthermore, the increase in the preset maintenance duration is positively correlated with the difference between the preset crack fluctuation characterization threshold and the crack fluctuation characterization value.

[0025] Furthermore, the increase in the preset pouring rate is positively correlated with the difference between the crack fluctuation characterization value and the preset crack fluctuation characterization threshold.

[0026] On the other hand, the present invention provides a crack-resistant glass fiber reinforced concrete composite pipe manufactured by the aforementioned manufacturing process, which is provided with a socket for receiving two adjacent composite pipes.

[0027] Furthermore, the inner wall of the composite pipe is provided with an anti-permeability coating, which is an epoxy resin-based coating with a coating thickness of 0.5mm-1.5mm and a permeation pressure greater than or equal to 1.5MPa; the outer wall of the composite pipe is provided with an anti-corrosion layer, which is a polyurethane modified asphalt coating with a coating thickness of 1mm-3mm.

[0028] Furthermore, the preset ratio of the glass fiber is as follows:

[0029] Medium-length fibers have a length greater than or equal to 4 mm and less than 8 mm, and account for 50% of the total fiber mass.

[0030] Short fibers have a length greater than or equal to 2 mm and less than 4 mm, and a mass percentage of 30%.

[0031] The fine fibers are less than 2 mm in length and account for 20% of the total mass.

[0032] Furthermore, the volume content of the glass fiber in the target concrete is 0.1% to 5%.

[0033] Furthermore, the reinforcing cage has at least one layer.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows: by combining longitudinal and circumferential reinforcements to form a reinforcing cage, and using composite glass fiber concrete containing medium and long fiber skeleton, short fiber and fine fiber, the invention significantly improves the crack resistance and structural stability of the composite pipe by using centrifugal forming and graded curing processes.

[0035] Furthermore, the medium and long fiber skeleton can enhance the toughness and flexural strength of concrete, while short and fine fibers can fill the internal pores of concrete and inhibit the generation and propagation of microcracks.

[0036] Furthermore, during the centrifugal forming process, precise control of the rotation speed and pouring rate ensures that the concrete is evenly distributed on the surface of the reinforcing cage, avoiding stress concentration caused by material accumulation or uneven density.

[0037] Furthermore, during the curing stage, the coordinated control of preset temperature and humidity promotes the full hydration reaction of cement, further optimizes the microstructure of concrete, and reduces the risk of drying shrinkage cracks.

[0038] Furthermore, the defined crack load detection and process parameter feedback mechanism can enable dynamic monitoring and adjustment of the composite pipe manufacturing process, ensuring the consistency of product quality.

[0039] Furthermore, the epoxy resin-based anti-permeability coating on the inner wall of the composite pipe and the polyurethane-modified asphalt anti-corrosion layer on the outer wall can effectively improve its impermeability and corrosion resistance, expanding the application scenarios of the product in complex environments.

[0040] Furthermore, through multi-dimensional process optimization, the composite pipe achieves a synergistic improvement in crack resistance and durability while maintaining high strength.

[0041] Furthermore, the gradient ratio design of the fiber skeleton creates a multi-layered stress support system inside the concrete. Medium and long fibers bear the main load transfer, while short and fine fibers prevent crack initiation at the microscopic level. The combined effect of these two factors increases the crack resistance threshold of the composite pipe.

[0042] Furthermore, the precise control of dual parameters in the centrifugal forming process, combined with the intelligent adjustment of temperature and humidity during the curing stage, further ensures the density and uniformity of the concrete structure. Attached Figure Description

[0043] Figure 1 This is a flowchart illustrating the manufacturing process of a crack-resistant glass fiber reinforced concrete composite pipe according to an embodiment of the present invention.

[0044] Figure 2 This is a flowchart illustrating the process of determining whether the composite pipe manufacturing process conforms to a preset standard based on the crack load of the finished composite pipe, as described in this embodiment of the invention.

[0045] Figure 3 This invention provides a flowchart for verifying whether the composite tube fabrication conforms to a preset standard based on the skeleton offset characterization value.

[0046] Figure 4 This is a flowchart illustrating the process of determining why the composite pipe fabrication does not meet the preset standards based on crack fluctuation characterization values, according to an embodiment of the present invention.

[0047] Figure 5 This is a schematic diagram of the overall structure of the crack-resistant glass fiber reinforced concrete composite pipe according to an embodiment of the present invention;

[0048] Figure 6 This is a schematic diagram of the overall structure of the cylindrical reinforcing cage according to an embodiment of the present invention;

[0049] In the diagram: 1. Longitudinal reinforcement; 2. Circumferential reinforcement; 3. Spigot and socket joint. Detailed Implementation

[0050] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0051] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0052] Please see Figure 1-6 The following are flowcharts illustrating the manufacturing process of a crack-resistant glass fiber reinforced concrete composite pipe according to an embodiment of the present invention: a flowchart for determining whether the composite pipe preparation meets a preset standard based on the crack load of the finished composite pipe; a flowchart for verifying whether the composite pipe preparation meets a preset standard based on the skeleton offset characterization value; a flowchart for determining the reasons why the composite pipe preparation does not meet the preset standard based on the crack fluctuation characterization value; a schematic diagram of the overall structure of the crack-resistant glass fiber reinforced concrete composite pipe according to an embodiment of the present invention; and a schematic diagram of the overall structure of the cylindrical reinforcing cage according to an embodiment of the present invention.

[0053] On one hand, an embodiment of the present invention provides a manufacturing process for a crack-resistant glass fiber reinforced concrete composite pipe, comprising:

[0054] Step S1: Fix several longitudinal ribs onto several equally spaced circumferential ribs to complete the preparation of the cylindrical reinforcing cage;

[0055] Step S2: Prepare the target concrete by mixing glass fiber and concrete according to the preset ratio, wherein the glass fiber includes a medium and long fiber skeleton, short fibers and fine fibers.

[0056] Step S3: Fix the reinforcing cage in the centrifugal forming cavity, and pour the target concrete at a preset speed and a preset rate to prepare the pre-core tube.

[0057] Step S4: Place the pre-core tube in a curing room with preset temperature and preset humidity for a preset curing time to obtain the finished composite tube;

[0058] Step S5: Perform an external pressure test on the finished composite pipe to obtain the crack load of the finished composite pipe, and determine whether the composite pipe preparation meets the preset standard based on the crack load of the finished composite pipe.

[0059] Step S6: In response to the composite tube preparation not meeting the preset standard, verify whether the composite tube preparation meets the preset standard based on the skeleton offset characterization value, or determine the reason why the composite tube preparation does not meet the preset standard based on the crack fluctuation characterization value.

[0060] Specifically, a preset ratio of the glass fibers is set:

[0061] Medium-length fibers have a length of 4mm-8mm and a mass percentage of 50%.

[0062] The short fibers have a length of 2mm-4mm and a mass percentage of 30%.

[0063] The fine fibers are less than 2mm in length and comprise 20% of the total fiber mass. This configuration allows the medium-length fibers to form a continuous support skeleton within the concrete matrix, effectively enhancing the overall structural stability and bending resistance of the composite pipe. The short fibers fill the gaps between the medium-length fibers, strengthening the bond strength between the fiber and concrete interface and reducing stress concentration. The fine fibers further refine micro-cracks within the concrete, preventing crack propagation. The synergistic effect of these three components significantly improves the crack resistance and durability of the composite pipe. During concrete pouring, this proportion of glass fiber ensures uniform dispersion, preventing fiber agglomeration and guaranteeing consistent performance across all parts of the composite pipe. This lays a solid foundation for structural stability during subsequent curing and use.

[0064] Specifically, the preset rotation speed is set to 1500 r / min-2000 r / min, and this invention selects 1750 r / min. This rotation speed range allows the concrete to adhere tightly to the inner wall of the reinforcing cage under centrifugal force, forming a uniform and dense structural layer, while avoiding the separation of aggregate and cementitious material in the concrete due to excessive rotation speed. The preset speed is set to 2 m³ / h-5 m³ / h, and this invention selects 3.5 m³ / h. This speed ensures that the concrete is evenly distributed in the centrifugal forming cavity, preventing local accumulation that causes density differences. Combined with the rotation speed parameters, this ensures the uniformity of the wall thickness and the structural integrity of the pre-core tube. The preset temperature is set to 20℃-35℃, and this invention selects 23℃. This temperature range can promote the appropriate progress of cement hydration reaction, avoiding slow hydration rate due to excessively low temperature or excessively high temperature causing excessive water evaporation. The preset humidity is set to 70%-80%, and this invention selects 75%. This humidity condition can effectively prevent the concrete surface from developing shrinkage cracks due to excessive water loss, providing a stable environment for the formation of cement gel and strength growth. Working in synergy with the temperature parameter, it ensures that the pre-core tube achieves steady strength improvement and structural densification during the curing stage.

[0065] Specifically, in response to the crack load being less than a first preset crack load threshold, it is determined that the composite pipe preparation does not meet the preset standard, and the reason for the composite pipe preparation not meeting the preset standard is determined based on the crack fluctuation characterization value.

[0066] In response to the crack load being greater than or equal to a first preset crack load threshold and less than a second preset crack load threshold, it is determined that the composite pipe preparation does not meet the preset standard, and the composite pipe preparation is verified according to the skeleton offset characterization value to determine whether it meets the preset standard.

[0067] In response to the crack load being greater than or equal to a second preset crack load threshold, it is determined that the composite pipe preparation meets the preset standard.

[0068] Specifically, the first preset crack load threshold is set to 1.2 MPa, and the second preset crack load threshold is set to 2.5 MPa. By setting these two thresholds, the crack resistance performance of the composite pipe can be graded and evaluated. When the crack load is in different ranges, targeted quality judgment and process adjustment measures are taken to ensure that the product quality meets the needs of different application scenarios. For example, when the crack load is less than 1.2 MPa, it indicates that the crack resistance performance of the composite pipe is poor, and it is necessary to start by looking at the crack fluctuation characterization value to find the cause, which may involve factors such as curing time or pouring rate; while when the crack load is between 1.2 MPa and 2.5 MPa, the focus is on checking whether the position of the reinforcing cage is accurate through the skeleton offset characterization value and whether the centrifugal speed meets the standard, thereby achieving refined control and quality assurance of the production process.

[0069] Specifically, in response to the skeleton offset characterization value being less than a preset skeleton offset characterization threshold, the composite tube preparation is verified to meet a preset standard;

[0070] In response to the skeleton offset characterization value being greater than or equal to a preset skeleton offset characterization threshold, it is verified that the composite tube preparation does not meet the preset standard, and the reason for the composite tube preparation not meeting the preset standard is that the preset speed of the centrifugal forming equipment is not up to standard, and the preset speed of the centrifugal forming cavity is increased according to the difference between the skeleton offset characterization value and the preset skeleton offset characterization threshold.

[0071] The skeleton offset characterization value is the average of the root square values ​​of the radial offset distances between each longitudinal rib and the central axis of the composite tube during the centrifugal forming process of the reinforcing cage.

[0072] Specifically, the preset skeleton offset characterization threshold is set to 0.8 mm. This threshold is set based on the structural stability requirements of the reinforcing cage during centrifugal forming. When the skeleton offset characterization value is less than 0.8 mm, it indicates that the radial offset between the longitudinal reinforcement and the central axis is within an acceptable range, and the overall positional accuracy of the reinforcing cage meets the design standards. At this time, it can be determined that the composite pipe preparation meets the preset requirements in the skeleton positioning stage. If the offset value reaches or exceeds 0.8 mm, it indicates that the centrifugal speed is insufficient to provide enough centrifugal force to maintain the stability of the reinforcing cage. It is necessary to increase the speed to reduce the radial offset, ensure the accurate stress position of the reinforcing cage in the concrete, and avoid insufficient local strength or uneven stress distribution of the composite pipe due to skeleton offset.

[0073] Specifically, the increase in the preset rotational speed of the centrifugal forming cavity is positively correlated with the difference between the skeleton offset characterization value and the preset skeleton offset characterization threshold. It is understood that the positive correlation can be linear or nonlinear, and is not specifically limited. The slope of the linear positive correlation is also not specifically limited and can be set according to the actual preparation conditions, as long as the larger the difference between the skeleton offset characterization value and the preset skeleton offset characterization threshold, the larger the increase in the preset rotational speed of the centrifugal forming cavity. For example, if the increase in the preset rotational speed of the centrifugal forming cavity is set to ΔM, and the difference between the skeleton offset characterization value and the preset skeleton offset characterization threshold is set to Δμ, then ΔM = γ × (Δμ + μ0), where γ is the rotational speed adjustment coefficient, set to 1.06, and μ0 is a constant.

[0074] Specifically, in response to the crack fluctuation characterization value being less than the preset crack fluctuation characterization threshold, it is determined that the reason why the composite pipe preparation does not meet the preset standard is that the preset curing time is not up to standard, and the preset curing time is increased according to the difference between the preset crack fluctuation characterization threshold and the crack fluctuation characterization value.

[0075] In response to the crack fluctuation characterization value being greater than or equal to a preset crack fluctuation characterization threshold, it is determined that the reason why the composite pipe preparation does not meet the preset standard is that the preset casting rate is not up to standard, and the preset casting rate is increased according to the difference between the crack fluctuation characterization value and the preset crack fluctuation characterization threshold.

[0076] Specifically, the preset crack fluctuation characterization threshold is set to 0.3. This threshold comprehensively considers the crack control requirements of composite pipes in practical applications. By quantifying and integrating the length, width, and distribution density of cracks, a standard for judging the overall degree of crack fluctuation is formed. When the crack fluctuation characterization value is below 0.3, it indicates that the overall impact of cracks is relatively small. In this case, priority should be given to promoting more complete cement hydration by extending the curing time, reducing microcracks caused by uneven water distribution or incomplete hydration inside the concrete. When the crack fluctuation characterization value reaches or exceeds this threshold, it indicates that there may be problems with the flow and distribution of concrete during the pouring process. It is necessary to increase the pouring rate to optimize the filling effect of concrete in the centrifugal forming cavity and avoid structural defects caused by untimely or slow local pouring. The setting of this threshold provides a clear judgment basis for the dynamic adjustment of composite pipe manufacturing process parameters, which helps to accurately control the crack resistance of the product while ensuring production efficiency.

[0077] Specifically, the crack fluctuation characterization value is determined jointly by the crack length, crack width, and crack distribution density. Its specific calculation method is as follows:

[0078]

[0079] Where D represents the crack fluctuation characterization value, A represents the crack length, B represents the crack width, C represents the crack distribution density, A' represents the preset crack length, B' represents the preset crack width, C' represents the preset crack distribution density, α represents the weighting coefficient for crack length, β represents the weighting coefficient for crack width, and λ represents the weighting coefficient for crack distribution density. In this embodiment, the preset crack length is set to 5 mm, the preset crack width to 0.2 mm, and the preset distribution density to 3 cracks / m². The weighting coefficients α, β, and λ are set to 0.2, 0.1, and 0.1, respectively, to highlight the influence of crack length on overall fluctuation while also considering the synergistic effect of width and distribution density. The D value calculated using this formula can comprehensively reflect the integrated characteristics of the crack in both macroscopic size and microscopic distribution, providing a quantitative basis for judging process problems. For example, when the crack length of a certain composite pipe is 6mm, the width is 0.15mm, and the distribution density is 4 cracks / m², substituting into the formula, we can get D=(0.2×(6 / 5)+0.1×(0.15 / 0.2)+0.1×(4 / 3))≈0.2×1.2+0.1×0.75+0.1×1.33=0.448. This value is greater than the preset threshold of 0.3. At this time, it can be determined that the crack fluctuation is mainly caused by the substandard pouring rate, and the pouring rate needs to be increased accordingly to optimize the concrete filling effect.

[0080] Specifically, the increase in the preset curing time is directly related to the difference between the preset crack fluctuation characterization threshold and the crack fluctuation characterization value. It is understood that the parameter adjustment method for the preset curing time can refer to the parameter adjustment method for the preset rotation speed of the centrifugal forming chamber, and will not be elaborated here.

[0081] Specifically, the increase in the preset casting rate is directly related to the difference between the crack fluctuation characterization value and the preset crack fluctuation characterization threshold. It is understood that the parameter adjustment method for the preset casting rate can refer to the parameter adjustment method for the preset rotation speed of the centrifugal forming cavity, and will not be elaborated here.

[0082] On the other hand, the crack-resistant glass fiber reinforced concrete composite pipe manufactured according to the present invention has a socket for connecting two adjacent composite pipes. The socket can be made of different materials such as steel, fiberglass, or concrete, and can have different sealing types such as no rubber ring, single rubber ring, or double rubber ring. This embodiment uses a single rubber ring concrete socket. The single rubber ring seal is made of EPDM rubber, which has excellent elastic recovery and aging resistance, maintaining a good sealing effect during the thermal expansion and contraction of the composite pipe. Combined with the epoxy resin-based anti-seepage coating at the joint, the impermeability of the socket is further improved, ensuring that the composite pipe will not leak during long-term use.

[0083] Specifically, the inner wall of the composite pipe is provided with an anti-permeability coating, which is an epoxy resin-based coating with a thickness of 0.5mm-1.5mm and a permeation pressure greater than or equal to 1.5MPa. The outer wall of the composite pipe is provided with an anti-corrosion layer, which is a polyurethane-modified asphalt coating with a thickness of 1mm-3mm. This epoxy resin-based anti-permeability coating on the inner wall, with its excellent chemical stability and dense molecular structure, can effectively block the intrusion of media such as moisture and corrosive ions. The 0.5mm-1.5mm coating thickness and the design of a permeation pressure greater than 1.5MPa ensure the reliability of the coating under complex working conditions. The polyurethane-modified asphalt coating anti-corrosion layer on the outer wall, with a thickness of 1mm-3mm, forms a solid barrier. Its good weather resistance and anti-aging properties can resist the erosion of the composite pipe by external environmental factors. The synergistic effect of the inner and outer protective structures significantly improves the overall durability and service life of the composite pipe.

[0084] Specifically, the volume content of the glass fiber in the target concrete is 0.1% to 5%. This setting allows for precise control of the dispersion and reinforcing effect of the glass fiber in the concrete matrix. When the volume content is in the range of 0.1% to 5%, the glass fiber can fully exert its bridging and crack-preventing effects while avoiding fiber agglomeration caused by excessive content, ensuring that the fluidity and formability of the concrete are not significantly affected. Lower volume contents, such as 0.1% to 1%, can effectively inhibit the generation of early drying shrinkage cracks in concrete; medium contents, such as 1% to 3%, can significantly improve the flexural strength and toughness of the composite pipe; and higher contents, such as 3% to 5%, further enhance the material's impact resistance and fatigue durability. This wide range of volume contents design allows the composite pipe to be flexibly adjusted according to the differentiated requirements of strength, toughness, and crack resistance in different engineering scenarios, while balancing production costs and material performance. This provides reliable material performance guarantees for the application of composite pipes in various fields such as municipal engineering, water conservancy construction, and underground pipe corridors.

[0085] Specifically, the reinforcing cage has at least one layer. This arrangement allows for flexible adjustment of the cage structure based on the design pressure rating and pipe diameter of the composite pipe, meeting the load-bearing requirements of different engineering scenarios. When the composite pipe is used in low-pressure transportation scenarios or small-diameter applications, a single-layer reinforcing cage structure can be used. By rationally arranging the spacing and diameter of the longitudinal and circumferential reinforcing bars, production costs can be effectively controlled while ensuring structural stability. For high-pressure transportation or large-diameter composite pipes, two or more layers of reinforcing cages can be used, with connecting bars between layers forming an overall load-bearing system, further enhancing the circumferential compressive strength and deformation resistance of the composite pipe. In addition, the multi-layer reinforcing cage design can achieve a precise balance between strength, stiffness, and toughness of the composite pipe by adjusting the material and specifications of the reinforcing bars in each layer. For example, high-strength glass fiber reinforcement can be used in the inner layer to improve local compressive strength, while high-toughness steel bars can be used in the outer layer to enhance overall impact resistance, enabling the composite pipe to adapt to various construction environments such as underground laying or overhead installation under complex geological conditions.

[0086] The glass-reinforced concrete composite pipe manufactured according to the example of the present invention, after undergoing an external pressure test, yielded the following parameters based on its load-bearing capacity compared with other control groups.

[0087] Table 1 Crack Load

[0088]

[0089] Table 2 Comparison of Crack Loads

[0090]

[0091] Based on the comparison table above, the conclusions are as follows: Under the same reinforcement area, the crack load of reinforced concrete pipe with short fibers (B2) is 1.15 times that of reinforced concrete pipe (B1); the crack load of reinforced concrete pipe with short fibers (C1) is 1.02 times that of reinforced concrete pipe (B1); the crack load of reinforced concrete pipe with short fibers (C2) is 1.13 times that of reinforced concrete pipe (B1); and the crack load of reinforced concrete pipe with short fibers (C1) is 1.10 times that of glass reinforced concrete pipe with short fibers (C2).

[0092] The parameters of the glass-reinforced concrete composite pipe sample prepared according to the above method are as follows:

[0093]

[0094] The external pressure test data of the glass-reinforced concrete composite pipe specimens prepared according to the above method are as follows:

[0095]

[0096] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

[0097] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A manufacturing process for a crack-resistant glass fiber reinforced concrete composite pipe, characterized in that, It includes, Step S1: Fix several longitudinal ribs onto several equally spaced circumferential ribs to complete the preparation of the cylindrical reinforcing cage; Step S2: Prepare the target concrete by mixing glass fiber and concrete according to the preset ratio, wherein the glass fiber includes a medium and long fiber skeleton, short fibers and fine fibers. Step S3: Fix the reinforcing cage in the centrifugal forming cavity, and pour the target concrete at a preset speed and a preset rate to prepare the pre-core tube. Step S4: Place the pre-core tube in a curing room with preset temperature and preset humidity for a preset curing time to obtain the finished composite tube; Step S5: Perform an external pressure test on the finished composite pipe to obtain the crack load of the finished composite pipe, and determine whether the composite pipe preparation meets the preset standard based on the crack load of the finished composite pipe. Step S6: In response to the composite tube preparation not meeting the preset standard, verify whether the composite tube preparation meets the preset standard based on the skeleton offset characterization value, or determine the reason why the composite tube preparation does not meet the preset standard based on the crack fluctuation characterization value. In response to the skeleton offset characterization value being less than a preset skeleton offset characterization threshold, the composite tube preparation is verified to meet a preset standard; In response to the skeleton offset characterization value being greater than or equal to a preset skeleton offset characterization threshold, it is verified that the composite tube preparation does not meet the preset standard, and the reason for the composite tube preparation not meeting the preset standard is that the preset speed of the centrifugal forming equipment is not up to standard, and the preset speed of the centrifugal forming cavity is increased according to the difference between the skeleton offset characterization value and the preset skeleton offset characterization threshold. The skeleton offset characterization value is the average of the root square values ​​of the radial offset distances between each longitudinal rib and the central axis of the composite tube during the centrifugal forming process of the reinforcing cage. The increase in the preset rotational speed of the centrifugal forming cavity is positively correlated with the difference between the skeleton offset characterization value and the preset skeleton offset characterization threshold.

2. The manufacturing process of the crack-resistant glass fiber reinforced concrete composite pipe according to claim 1, characterized in that, In response to the crack load being less than a first preset crack load threshold, it is determined that the composite pipe preparation does not meet the preset standard, and the reason for the composite pipe preparation not meeting the preset standard is determined based on the crack fluctuation characterization value; In response to the crack load being greater than or equal to a first preset crack load threshold and less than a second preset crack load threshold, it is determined that the composite pipe preparation does not meet the preset standard, and the composite pipe preparation is verified according to the skeleton offset characterization value to determine whether it meets the preset standard. In response to the crack load being greater than or equal to a second preset crack load threshold, it is determined that the composite pipe preparation meets the preset standard.

3. The manufacturing process of the crack-resistant glass fiber reinforced concrete composite pipe according to claim 2, characterized in that, In response to the crack fluctuation characterization value being less than the preset crack fluctuation characterization threshold, it is determined that the reason why the composite pipe preparation does not meet the preset standard is that the preset curing time is not up to standard, and the preset curing time is increased according to the difference between the preset crack fluctuation characterization threshold and the crack fluctuation characterization value. In response to the crack fluctuation characterization value being greater than or equal to a preset crack fluctuation characterization threshold, it is determined that the reason why the composite pipe preparation does not meet the preset standard is that the preset casting rate is not up to standard, and the preset casting rate is increased according to the difference between the crack fluctuation characterization value and the preset crack fluctuation characterization threshold. The crack fluctuation characterization value is determined by the crack length, crack width, and crack distribution density.

4. The manufacturing process of the crack-resistant glass fiber reinforced concrete composite pipe according to claim 3, characterized in that, The increase in the preset maintenance duration is positively correlated with the difference between the preset crack fluctuation characterization threshold and the crack fluctuation characterization value. The increase in the preset pouring rate is positively correlated with the difference between the crack fluctuation characterization value and the preset crack fluctuation characterization threshold.

5. A crack-resistant glass fiber reinforced concrete composite pipe manufactured using the manufacturing process described in any one of claims 1-4, characterized in that, The composite pipe includes a socket for receiving two adjacent composite pipes.

6. The crack-resistant glass fiber reinforced concrete composite pipe according to claim 5, characterized in that, The inner wall of the composite pipe is provided with an anti-permeability coating, which is an epoxy resin-based coating with a coating thickness of 0.5mm-1.5mm and a permeation pressure greater than or equal to 1.5MPa; the outer wall of the composite pipe is provided with an anti-corrosion layer, which is a polyurethane modified asphalt coating with a coating thickness of 1mm-3mm.

7. The crack-resistant glass fiber reinforced concrete composite pipe according to claim 6, characterized in that, The preset ratio of the glass fiber: Medium-length fibers have a length greater than or equal to 4 mm and less than 8 mm, and account for 50% of the total fiber mass. Short fibers have a length greater than or equal to 2 mm and less than 4 mm, and a mass percentage of 30%. The fine fibers are less than 2 mm in length and account for 20% of the total mass.

8. The crack-resistant glass fiber reinforced concrete composite pipe according to claim 7, characterized in that, The glass fiber content in the target concrete is 0.1% to 5% by volume.

9. The crack-resistant glass fiber reinforced concrete composite pipe according to claim 8, characterized in that, The reinforcing cage has at least one layer.

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