FRP composite pipe

Abstract

The utility model discloses a fiber reinforced plastic (FRP) composite pipe, which comprises an FRP pipe and an adhesion layer adhered on the inner wall of the FRP pipe, and a steel wire is arranged between the FRP pipe and the adhesion layer. Wherein the tensile strength of the steel wire is greater than or equal to 1400 MPa. The FRP composite pipe provided by the utility model has excellent lateral pressure resistance, material ductility, circumferential tensile strength and the like, has good adhesive property with concrete, and is suitable for being used as a permanent template in road facilities, bridges, tunnels, industrial buildings, civil buildings and the like. Meanwhile, the FRP composite pipe also has excellent corrosion resistance, can effectively resist air, moisture, chloride ion permeation and the like, and is also suitable for being applied to a marine environment concrete structure.

Description

TECHNICAL FIELD

[0001] The utility model relates to civil engineering, ocean engineering technical field especially, it relates to a FRP composite pipe. BACKGROUND

[0002] Formwork engineering is one of the key links in the construction process of concrete structure, and has a significant impact on the quality, safety, progress and economic benefits of construction engineering. The cost of traditional formwork engineering in conventional concrete structure accounts for about 20%-30% of the total cost. Compared with the traditional formwork, the fiber reinforced resin (referred to as "composite material", English Fiber Reinforced Polymer, English abbreviation "FRP") formwork has superior performance such as light weight, high strength, corrosion resistance, etc., and has been more and more widely used in new road engineering, bridge and tunnel engineering, industrial and civil building engineering. The FRP pipe can effectively improve the service performance and durability of the concrete structure when used as a permanent formwork in the concrete structure; in addition, the FRP pipe can produce a constraint effect on the concrete, thereby improving the bearing capacity and ductility of the concrete structure. The FRP pipe as a permanent formwork has been preliminarily applied in new concrete structure engineering and has achieved remarkable social and economic benefits. Moreover, the FRP pipe also has excellent corrosion resistance and can effectively resist the penetration of air, moisture and chloride ions. According to the literature, a 3mm thick resin-rich layer can effectively prevent chloride ion penetration for 50 years. Therefore, in the marine environment, the FRP pipe is particularly suitable for use as a permanent formwork for concrete structures.

[0003] At present, the FRP pipe is mainly used in compression and bending members such as concrete beams, slabs, columns and concrete arch structures, as a common bearing material to improve the long-term and short-term performance and bearing capacity of the concrete structure. The hoop tensile strength of the pure FRP pipe as a permanent formwork has certain advantages compared with ordinary steel formwork, and in compression and bending members, it mainly provides concrete constraint effect and anti-permeation effect. However, in large members, the constraint effect and anti-permeability of the pure FRP pipe do not match the wall thickness requirement, resulting in waste of the FRP pipe and reducing the economic advantage of the FRP pipe in the application of large members.

[0004] Therefore, the prior art still needs to be improved and developed. INVENTION CONTENTS

[0005] In view of the above shortcomings of the prior art, the present utility model provides a FRP composite pipe to solve the problem that the constraint effect and anti-permeability of the existing pure FRP pipe do not match the wall thickness requirement, resulting in waste of the pure FRP pipe and reducing the economic advantage of the pure FRP pipe in the application of large members.

[0006] The technical scheme adopted by the utility model to solve the above technical problems is as follows:

[0007] The utility model discloses a first aspect provides a kind of FRP composite pipe, the FRP composite pipe includes FRP pipe and the adhesion layer being bonded in the inner wall of the FRP pipe, steel wire is also provided between the FRP pipe and the adhesion layer;

[0008] Wherein, the tensile strength of the steel wire is greater than or equal to 1400MPa.

[0009] Preferably, the thickness of the FRP pipe is less than or equal to 6mm.

[0010] Preferably, the steel wire is arranged along the axial direction of the FRP pipe, and the steel wire is distributed in a spiral shape.

[0011] Preferably, the steel wire is a spiral steel wire, and the cross-sectional diameter of the spiral steel wire is less than or equal to 12mm.

[0012] Preferably, the starting end of the steel wire is fixedly connected to the inner wall of one end of the FRP pipe, and the terminal end of the steel wire is fixedly connected to the inner wall of the other end of the FRP pipe.

[0013] Preferably, the steel wire extends along the inner wall of the FRP pipe in a spiral trajectory.

[0014] Preferably, the adjacent spiral turns of the steel wire maintain uniform spacing.

[0015] Preferably, the thickness of the adhesion layer is greater than or equal to 1mm and less than or equal to 1 / 2 of the cross-sectional diameter of the steel wire.

[0016] Beneficial effects:

[0017] The utility model discloses a kind of FRP composite pipes, traditional pure FRP pipe is composed of long fiber and resin. Among them, resin has the chemical properties of corrosion resistance and anti-permeation, but the mechanical property of itself is poor. The mechanical property of long fiber is superior, and can provide restraint effect for concrete in mechanics. But multiple long fibers need to be bonded under the adhesion of resin matrix, and can bear stress together, so the volume ratio of resin and long fiber in pure FRP pipe is basically maintained at about 1:1. To meet the chemical corrosion resistance, anti-permeation function, 3mm thick pure FRP pipe can effectively prevent chloride ion permeation within 50 years. To achieve the concrete restraint effect in mechanics, the diameter-thickness ratio of pure FRP pipe should not be greater than 200, and in large components, the wall thickness of pure FRP pipe will far exceed the wall thickness required by anti-permeability. The mismatch between the concrete restraint effect and anti-permeability in the requirement of FRP pipe wall thickness causes the waste of FRP pipe. Compared with the traditional pure FRP pipe, the FRP pipe in the FRP composite pipe provided by the utility model mainly plays the role of fixing steel wire, corrosion resistance, anti-permeability and improving the performance of concrete structure as a permanent form, and no longer mainly bears the restraint effect, and the steel wire in the FRP composite pipe replaces the long fiber in the pure FRP pipe to provide the main restraint effect.

[0018] In the FRP composite pipe provided by the utility model, the wall thickness of the FRP pipe is no longer limited by the diameter-thickness ratio required by the restraint effect, and the thickness is relatively thin. The FRP composite pipe successfully solves the problem that the restraint effect and anti-permeability in the traditional pure FRP pipe do not match in the requirement of wall thickness, and has significant economic advantages. In addition, the tensile strength of the steel wire is not less than 1400MPa, the elastic modulus reaches about 200GPa, and the ductility is high, which can effectively reduce stress concentration, further develop the strength of the fiber material in the FRP composite pipe, and significantly improve the circumferential stress performance of the composite pipe. The steel wire as the inner ring rib of the FRP pipe effectively improves the lateral pressure resistance of the FRP composite pipe. Finally, in the FRP composite pipe provided by the utility model, the inner steel wire can provide restraint effect, reduce the use amount of the FRP pipe, the FRP pipe can provide anti-permeability effect to prevent the inner steel wire from being corroded by external environment, and the adhesive layer can firmly bond the inner steel wire and the FRP pipe, so that the FRP pipe and the inner steel wire act as a whole.

[0019] The FRP composite pipe provided by the utility model has excellent lateral pressure resistance, material ductility, circumferential tensile performance and good adhesion performance with concrete, and is suitable for being used as a permanent form in road facilities, bridges and tunnels, industrial buildings, civil buildings and the like. Meanwhile, the FRP composite pipe also has excellent corrosion resistance, can effectively resist air, moisture and chloride ion permeation, and is also suitable for application in marine environment concrete structure. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1is a structure schematic view of a circular FRP composite pipe provided by the embodiment 1 of the utility model;

[0021] Figure 2 is a longitudinal section structure schematic view of the circular FRP composite pipe provided by the embodiment 1 of the utility model;

[0022] Figure 3 is a structure schematic view of a square FRP composite pipe provided by the embodiment 2 of the utility model;

[0023] Figure 4 is a structure schematic view of an elliptical FRP composite pipe provided by the embodiment 3 of the utility model;

[0024] Figure 5 is a structure schematic view of a circular truncated cone FRP composite pipe provided by the embodiment 4 of the utility model;

[0025] Figure 6 is a structure schematic view of a ladder FRP composite pipe provided by the embodiment 5 of the utility model.

[0026] Wherein, the various reference signs in the drawing: 1, FRP pipe; 2, attached layer; 3, steel wire. DETAILED DESCRIPTION

[0027] The utility model provides a kind of FRP composite pipe and its application, to make the purpose, technical scheme and effect of the utility model more clear, explicit, the following is further detailed to the utility model of the utility model.It should be understood that the specific embodiments described herein are merely used to explain the utility model, and are not used to limit the utility model.

[0028] The embodiment of the utility model provides a kind of FRP composite pipe, such as Figure 1 And Figure 2 As shown, the FRP composite pipe includes FRP pipe 1 and the attached layer 2 of the adhesion in the inner wall of the FRP pipe 1, the FRP pipe 1 and the attached layer 2 between still be provided with steel wire 3;Wherein, the tensile strength of the steel wire 3 is greater than or equal to 1400MPa.

[0029] Firstly, the FRP pipe 1 in the FRP composite pipe mainly provides the functions of fixing the inner steel wire 3, preventing corrosion, resisting permeation, and improving the performance of the concrete structure as a permanent form, and the wall thickness of the FRP pipe 1 is not limited by the requirement of the ratio of diameter to thickness caused by the restraint effect. Thus, the FRP composite pipe provided by the embodiment of the present application has a significant economic advantage. In addition, the steel wire 3 in the FRP composite pipe replaces the long fiber in the pure FRP pipe to provide the main restraint effect, reduce the resin usage, and reduce the cost. Meanwhile, the tensile strength of the steel wire 3 is not less than 1400 MPa and the elastic modulus reaches about 200 GPa, and the steel wire has high ductility, which can effectively reduce stress concentration, further exert the strength of the fiber material in the FRP pipe 1, and significantly improve the performance of the ring force. Specifically, the steel wire 3 is made of super-high-strength steel wire, and the super-high tensile strength and good ductility of the super-high-strength spiral steel wire can not only effectively provide restraint effect for the concrete, but also can serve as the inner rib of the FRP pipe 1 to significantly improve the lateral pressure resistance of the FRP composite pipe as a form during the construction process. The steel wire 3 serves as the inner ring rib of the FRP pipe 1 to effectively improve the lateral pressure resistance of the FRP pipe 1. In addition, the adhesive layer 2 in the FRP composite pipe can firmly fix the FRP pipe 1 and the inner steel wire 3 to ensure the working reliability of the FRP composite pipe. The adhesive layer 2 cooperates with the steel wire 3 to effectively ensure the common stress of the FRP composite pipe and the concrete, and inhibit the relative slip between them and the shrinkage of the concrete.

[0030] In some embodiments, the size of the FRP pipe 1, the adhesive layer 2 and the steel wire 3 in the FRP composite pipe can be selected according to common specifications, and the mechanical properties, corrosion resistance and permeation resistance required can be adjusted.

[0031] In some specific embodiments, the thickness of the FRP pipe 1 in the FRP composite pipe is not greater than 6 mm, the steel wire section diameter of the steel wire 3 is not greater than 12 mm, and the thickness of the adhesive layer 2 is not greater than 1 / 2 of the steel wire section diameter of the steel wire 3.

[0032] In some embodiments, the inner contour of the FRP pipe 1 is the same as the outer contour of the steel wire 3. These different outer contour shapes help the FRP composite pipe as a permanent form to meet the demand for the shape of the concrete structure engineering.

[0033] In some embodiments, the FRP pipe 1 is prepared from long fibers and a first resin, and the first resin is one of an epoxy resin, a vinyl resin and a polyester resin. These resins are used as the matrix material of the FRP pipe 1 to play a role in bonding the long fibers. The long fibers include at least one of glass fiber, carbon fiber, basalt fiber and aramid fiber, which can all improve the strength of the FRP pipe 1, reduce the weight, improve the corrosion resistance, and improve the tensile and shear resistance.

[0034] In some embodiments, the mass fraction of long fibers in the FRP pipe 1 is greater than 40%. The mass fraction of long fibers ensures the mechanical properties of the FRP pipe 1.

[0035] In some embodiments, the steel wire 3 is a spiral steel wire with a cross-sectional diameter less than or equal to 12 mm. The starting end of the spiral steel wire is fixedly connected to the inner wall of one end of the FRP pipe 1, and then the spiral steel wire extends along the inner wall of the FRP pipe 1 in a spiral track, maintaining a uniform spacing between adjacent spiral turns to ensure the formation of a stable and continuous spiral structure inside the FRP pipe 1. The end of the spiral steel wire is fixedly connected to the inner wall of the other end of the FRP pipe 1, so that the entire spiral steel wire structure is stably installed and positioned inside the pipe, forming an organic whole assembly with the pipe body.

[0036] In some embodiments, the attachment layer 2 is prepared by mixing quartz sand and a second resin; the second resin is one of epoxy resin, vinyl resin, and polyester resin. The quartz sand particles in the attachment layer 2 can increase the mechanical interlocking force and adhesion between the attachment layer and the concrete. Through the synergistic effect of quartz sand and the second resin, the FRP pipe 1 and the steel wire 3 are firmly fixed to form a whole. In addition, these synthetic resins are used as the matrix material of the attachment layer 2, which plays a role in bonding the FRP pipe 1 and the steel wire 3, and also has the effect of improving the corrosion resistance of the steel wire 3.

[0037] In some embodiments, the thickness of the attachment layer is greater than or equal to 1 mm and less than or equal to 1 / 2 of the cross-sectional diameter of the strong spiral steel wire. The minimum thickness requirement of the attachment layer 2 ensures the firmness between the FRP pipe 1 and the steel wire 3, and the maximum thickness requirement ensures the uneven profile of the inner surface of the FRP composite pipe.

[0038] In some embodiments, the mass fraction of quartz sand in the attachment layer 2 is not less than 70%. This mass fraction ensures a sufficient degree of unevenness in the attachment layer 2.

[0039] In some embodiments, the maximum particle size of the quartz sand in the attachment layer 2 is not greater than the spiral pitch of the steel wire 3 and not less than the thickness of the attachment layer 2. The upper limit of the maximum particle size of the quartz sand ensures that the quartz sand can be distributed on the inner wall of the FRP pipe 1, and the lower limit of the maximum particle size of the quartz sand ensures that the quartz sand is not completely covered by the resin of the attachment layer 2.

[0040] In some embodiments, the preparation steps of the FRP composite pipe include: first, preparing the FRP pipe 1 and the steel wire 3 respectively, wherein the FRP pipe 1 is made by a fiber bundle winding process or a fiber cloth wet laying process, and the steel wire 3 is made by cold rolling of ultra-high strength steel wire and then processing; the prepared FRP pipe 1 and the steel wire 3 are assembled and fixed into an assembly, then the resin mortar is sprayed in the FRP pipe 1, the assembly is rotated around the axis of the FRP pipe 1, so that the resin mortar is uniformly distributed on the inner wall of the FRP pipe 1 and the surface of the steel wire 3 by the centrifugal force, and after the resin mortar is completely cured, the FRP pipe 1 and the steel wire 3 are finally formed by the bonding effect of the completely cured resin mortar.

[0041] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments, and are only used to explain the present application, but not to limit the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0042] Embodiment 1

[0043] A circular FRP composite pipe, a structural diagram of which is shown in Figure 1 , a longitudinal section structural diagram of which is shown in Figure 2 The circular FRP composite pipe comprises: an FRP pipe 1, a spiral steel wire 3, and an adhesive layer 2 for fixing the steel wire 3 on the inner side of the FRP pipe 1. The length of the FRP pipe 1 is 450 mm, the inner diameter is 150 mm, the sectional diameter of the steel wire of the spiral steel wire 3 is 3 mm, the spiral clear distance is 3 mm, and the thickness of the adhesive layer 2 is 1.5 mm.

[0044] Embodiment 2

[0045] An oval FRP composite pipe, a structural diagram of which is shown in Figure 3 . The difference between it and the embodiment 1 is that the cross-sectional shape is square.

[0046] Embodiment 3

[0047] A square FRP composite pipe, a structural diagram of which is shown in Figure 4 . The difference between it and the embodiment 1 is that the cross-sectional shape is oval.

[0048] Embodiment 4

[0049] A circular truncated cone FRP composite pipe, a structural diagram of which is shown in Figure 5 . The difference between it and the embodiment 1 is that the size of the circular cross section gradually changes along the pipe axis.

[0050] Embodiment 5

[0051] A ladder-shaped FRP composite pipe, a structural diagram of which is shown in the accompanying Figure 6 The difference from the example 1 is that the cross section shape is rectangular and the cross section size gradually changes along the pipe axis.

[0052] It should be understood that the application of the present application is not limited to the above examples, and those skilled in the art can make improvements or changes according to the above description, and all these improvements and changes shall belong to the protection scope of the claims of the present application.

Claims

1. An FRP composite pipe, characterized by, The FRP composite pipe comprises an FRP pipe and an adhesive layer adhered to the inner wall of the FRP pipe, and a steel wire is arranged between the FRP pipe and the adhesive layer. The tensile strength of the steel wire is greater than or equal to 1400 MPa.

2. The FRP composite pipe according to claim 1, characterized by The thickness of the FRP pipe is less than or equal to 6 mm.

3. The FRP composite pipe according to claim 1, wherein The steel wire is arranged along the axial direction of the FRP pipe and is distributed in a spiral shape.

4. The FRP composite pipe according to claim 3, characterized by The steel wire is a spiral steel wire, and the cross-sectional diameter of the spiral steel wire is less than or equal to 12 mm.

5. The FRP composite pipe according to claim 3, wherein The starting end of the steel wire is fixedly connected to the inner wall of one end of the FRP pipe, and the terminal end of the steel wire is fixedly connected to the inner wall of the other end of the FRP pipe.

6. The FRP composite pipe according to claim 5, wherein The steel wire extends along the inner wall of the FRP pipe in a spiral track.

7. The FRP composite pipe according to claim 6, wherein Uniform spacing is maintained between adjacent spiral turns of the steel wire.

8. The FRP composite pipe according to claim 1, wherein The thickness of the adhesive layer is greater than or equal to 1 mm and less than or equal to 1 / 2 of the cross-sectional diameter of the steel wire.

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