Nodular cast iron jacking pipe with composite protective layer

Abstract

The utility model provides a nodular cast iron jacking pipe with a composite protective layer, which belongs to the technical field of anti-corrosion pipelines and comprises a concrete protective layer and an anti-crack protective layer which are sequentially arranged on the outer wall of a nodular cast iron base layer, and the anti-crack protective layer is one of a fiber cement mortar layer or a non-woven fabric layer. According to the cast iron pipe, the concrete protection layer can be further protected through the anti-crack protection layer, so that visible cracks are prevented from appearing on the surface of the concrete protection layer, and the service life of the cast iron pipe is indirectly prolonged.

Description

Technical Field

[0001] This utility model relates to the field of anti-corrosion pipeline technology, specifically to a ductile iron jacking pipe with a composite protective layer. Background Technology

[0002] In the field of pipeline engineering, ductile iron pipes are widely used in water supply and drainage, water conservancy and other projects due to their excellent corrosion resistance, good mechanical properties and reliable joint sealing. With the popularization of trenchless jacking construction technology, the need for pipeline protection under complex geological conditions is becoming increasingly prominent.

[0003] In existing technologies, a composite structure of "reinforced steel cage + concrete" is typically used to protect ductile iron pipes to enhance their resistance to damage during the jacking process. However, this traditional structure has the following technical drawbacks:

[0004] Cracking of Concrete Protective Layer: As a porous material, concrete is prone to micro-cracks due to water loss and shrinkage during long-term outdoor exposure. These cracks not only damage the appearance of the pipeline but also become channels for corrosive media (such as carbon dioxide, oxygenated moisture, and chloride ions in the soil), leading to concrete carbonation and steel corrosion, ultimately endangering the safety of the pipeline structure. The existing patent CN 205938213 U proposes a simple concrete protective layer solution, which does not consider surface protection during long-term service. After exposure to sunlight, surface cracks become significant, accelerating substrate corrosion and failure. Utility Model Content

[0005] In view of this, the present invention provides a ductile iron jacking pipe with a composite protective layer. The present invention can further protect the concrete protective layer through the crack-resistant protective layer, thereby avoiding visible cracks on the surface of the concrete protective layer, and thus indirectly increasing the service life of the cast iron pipe.

[0006] To solve the above-mentioned technical problems, this utility model provides a ductile iron jacking pipe with a composite protective layer, including a concrete protective layer and a crack-resistant protective layer arranged sequentially on the outer wall of the ductile iron base layer. The crack-resistant protective layer is either a fiber cement mortar layer or a non-woven fabric layer, that is, the crack-resistant protective layer prevents the concrete protective layer from cracking.

[0007] An adhesive layer is also provided between the concrete protective layer and the crack-resistant protective layer, which makes the connection between the concrete protective layer and the crack-resistant protective layer more stable.

[0008] The adhesive layer is made of a mixture of silicate cement and styrene-acrylic emulsion.

[0009] The adhesive layer is an epoxy resin layer.

[0010] A steel mesh is also installed between the concrete protective layer and the ductile iron base layer. The steel mesh can prevent the concrete protective layer from developing large cracks due to deformation.

[0011] The ductile iron base layer is also equipped with an anti-corrosion layer, which can prevent materials from corroding the ductile iron base layer from the inside.

[0012] The anti-corrosion layer is formed by combining any one of the following: polyurethane layer, epoxy layer, polyethylene layer, stainless steel layer, or cement mortar layer, with a sealing layer.

[0013] In summary, compared with the prior art, this application includes at least one of the following beneficial technical effects:

[0014] 1. Innovative and enhanced crack-resistant protective layer:

[0015] When fiber-reinforced cement mortar layers are used, the internal three-dimensional fiber network structure can effectively bridge microcracks in concrete. The pull-out action of the fibers dissipates crack propagation energy, blunting the crack tips and significantly inhibiting crack initiation and propagation. Experiments show that this structure can reduce the crack density on the concrete surface by more than 85%.

[0016] When a nonwoven fabric layer is used, its flexible covering effect can shield the inherent cracks in the concrete, forming a physical barrier. The high elongation (≥30%) of the nonwoven fabric can adapt to the dry and wet deformation of the concrete, maintaining complete coverage even after long-term outdoor exposure, ensuring appearance quality.

[0017] 2. Interface bonding strengthening mechanism:

[0018] Silicate cement-styrene-acrylic emulsion composite bonding layer: The polymer particles in the styrene-acrylic emulsion form a flexible film during the cement hydration process, which interpenetrates with the cement hydration products, ensuring both chemical bonding with the concrete matrix and improving the interfacial bonding strength with fiber cement mortar (bonding strength ≥1.5MPa).

[0019] Epoxy resin adhesive layer: Through the chemical reaction between epoxy groups and hydroxyl groups on the concrete surface, chemical bonds are formed (bonding strength ≥2.0MPa). At the same time, the wetting effect of epoxy resin on non-woven fabric can produce a mechanical anchoring effect, ensuring the integrity of the system.

[0020] 3. Advantages of multi-scale collaborative protection:

[0021] The steel mesh (spacing ≤ 100mm) provides macroscopic crack resistance and limits through cracks caused by concrete shrinkage deformation.

[0022] The anti-corrosion layer (such as a 3mm thick epoxy layer) prevents soil corrosive media from penetrating into the substrate, forming a double barrier of "internal resistance and external protection" with the outer protective system.

[0023] This composite protection system extends the overall service life of pipelines by 3-5 times and is particularly suitable for complex geological environments such as coastal saline-alkali land and collapsible loess. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a ductile iron jacking pipe with a composite protective layer according to this utility model.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1. Ductile iron base layer; 2. Concrete protective layer; 3. Crack-resistant protective layer; 4. Adhesive layer; 5. Reinforcing mesh; 6. Anti-corrosion layer. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the following will be described in conjunction with the appendices of the embodiments of this utility model. Figure 1 The technical solutions of the embodiments of this utility model are clearly and completely described herein. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the described embodiments of this utility model are within the protection scope of this utility model.

[0028] Example 1;

[0029] This embodiment provides a ductile iron jacking pipe with a composite protective layer, such as... Figure 1 As shown: including a concrete protective layer 2 and a crack-resistant protective layer 3 sequentially arranged on the outer wall of the ductile iron base 1;

[0030] Specifically, the crack-resistant protective layer 3 can be set as a fiber cement mortar layer with a thickness of 1-5mm.

[0031] Furthermore, an adhesive layer 4 is provided between the concrete protective layer 2 and the fiber cement mortar layer. This adhesive layer 4 is made of a mixture of silicate cement and styrene-acrylic emulsion in a mass ratio of 1:1 to 1:2. The two mixed materials ensure that the material is similar to the concrete layer, which facilitates the material to penetrate to the surface of the concrete layer and achieve its connection with the adhesive layer. At the same time, the material is also similar to the fiber cement mortar layer on its surface, which ensures its effective adhesion. The thickness of the adhesive layer 4 is 10-50 μm.

[0032] The adhesive layer 4 was applied to the outside of the concrete protective layer 2, and then the fiber cement mortar layer was applied to the surface of the adhesive layer 4. After the prepared cast iron jacking pipe was placed outdoors for 3 months, the appearance of the fiber cement mortar layer did not change and no cracking occurred.

[0033] A steel reinforcement mesh 5 is also provided between the concrete protective layer 2 and the ductile iron base layer 1. The steel reinforcement mesh 5 can further resist cracking of the concrete protective layer 2 and ensure that the concrete protective layer 2 will not develop large cracks due to deformation.

[0034] The ductile iron base layer 1 is also provided with an anti-corrosion layer 6. The anti-corrosion layer 6 is formed by combining any one of the following: polyurethane layer, epoxy layer, polyethylene layer, stainless steel layer or cement mortar layer with a sealing layer. The anti-corrosion layer 6 can prevent the corrosive media inside the cast iron pipe from corroding the ductile iron base layer 1, thereby further increasing the service life of the cast iron jacking pipe.

[0035] Example 2;

[0036] The difference from Example 1 is that the crack-resistant protective layer 3 is a non-woven fabric layer with a thickness of 0.08mm to 1.2mm, which means that the non-woven fabric can cover the cracks in the concrete protective layer 2.

[0037] Furthermore, the adhesive layer 4 is an epoxy resin layer with a thickness of 10-500μm. It is bonded to the surface of the concrete protective layer 2 through the penetration of the epoxy resin layer, thereby effectively bonding the concrete protective layer 2 to the non-woven fabric.

[0038] The epoxy resin material was coated on the surface of the concrete protective layer 2 to form an adhesive layer. Then, non-woven fabric was bonded to the surface of the adhesive layer. The successfully prepared jacking pipe was placed outdoors for 3 months. The appearance of the non-woven fabric layer did not change and no cracking occurred.

[0039] The above description is the preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. A ductile iron jacking pipe with a composite protective layer, characterized in that: The concrete protective layer (2) and the crack-resistant protective layer (3) are sequentially arranged on the outer wall of the ductile iron base (1), wherein the crack-resistant protective layer (3) is either a fiber cement mortar layer or a non-woven fabric layer.

2. The ductile iron jacking pipe with a composite protective layer as described in claim 1, characterized in that: An adhesive layer (4) is also provided between the concrete protective layer (2) and the crack-resistant protective layer (3).

3. A ductile iron jacking pipe with a composite protective layer as described in claim 2, characterized in that: The adhesive layer (4) is made of silicate cement and styrene-acrylic emulsion.

4. A ductile iron jacking pipe with a composite protective layer as described in claim 2, characterized in that: The adhesive layer (4) is an epoxy resin layer.

5. A ductile iron jacking pipe with a composite protective layer as described in claim 1, characterized in that: A steel reinforcement mesh (5) is also provided between the concrete protective layer (2) and the ductile iron base layer (1).

6. A ductile iron jacking pipe with a composite protective layer as described in claim 1, characterized in that: The ductile iron base layer is also provided with an anti-corrosion layer (6).

7. A ductile iron jacking pipe with a composite protective layer as described in claim 6, characterized in that: The anti-corrosion layer (6) is formed by combining any one of the following: polyurethane layer, epoxy layer, polyethylene layer, stainless steel layer or cement mortar layer with the sealing layer.

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