Prestressed concrete pipeline as well as preparation method and application thereof

Abstract

The invention provides a prestressed concrete pipeline, and belongs to the technical field of pipeline engineering. An inner-layer pipe core, a steel cylinder, an outer-layer concrete protection layer, a prestressed steel wire layer and a mortar protection layer are sequentially arranged from inside to outside; the inner-layer pipe core is made of asphalt concrete materials, and the prestressed steel wire layer is anchored on the steel cylinder by tensioning prestressed steel wires to form circumferential prestress used for resisting internal water pressure and external load of the pipeline. The inner-layer pipe core is made of the asphalt concrete material, and the crack resistance and durability of the pipeline are improved by means of the characteristics of high toughness and good impermeability of the asphalt concrete material. The steel cylinder serves as a framework of the pipeline and provides necessary strength and rigidity. The prestressed steel wire layer is anchored on the steel cylinder by tensioning prestressed steel wires to form circumferential prestress so as to resist internal water pressure and external load of the pipeline. And the outer concrete protection layer further enhances the overall performance and durability of the pipeline.

Description

Technical Field

[0001] The present invention relates to the field of pipeline engineering technology, and in particular to a prestressed concrete pipe and a preparation method and application thereof. Specifically, it relates to a prestressed concrete pipe (PCCP) using asphalt concrete as the inner layer pipe core and its vertical casting process, as well as its application in water supply, drainage, farmland irrigation or industrial fluid transportation. The purpose is to provide a pipeline product with better performance and stronger durability. Background Art

[0002] Prestressed concrete pipe (PCCP, Prestressed Concrete Cylinder Pipe) as a high-performance pipe, due to its high strength, high impermeability, good corrosion resistance and long service life, has been widely used in water supply, drainage, farmland irrigation and industrial fluid transportation and other engineering fields. In large-scale water conservancy projects, PCCP is often used as a water pipeline, and its excellent performance ensures the stable transmission of water resources; in municipal construction, PCCP is also often used in the construction of drainage pipe networks, effectively improving the drainage capacity of the city.

[0003] In recent years, as the requirements for pipeline performance in engineering projects continue to increase, researchers have begun to focus on how to further improve the stiffness of PCCP in order to maintain its stability and safety under more complex working conditions. However, studies have shown that simply increasing the stiffness of the pipeline does not always bring positive results. In some cases, excessive stiffness may cause excessive stress concentration when the pipeline is subjected to external pressure or temperature changes, thereby increasing the risk of pipe bursting. This phenomenon has prompted people to rethink the design ideas of PCCP and explore more reasonable and effective ways to improve performance.

[0004] Asphalt concrete has been widely used in road paving and other fields due to its strong toughness, good impermeability and durability. Applying it to PCCP pipelines can not only improve the crack resistance and durability of the pipelines by utilizing its excellent physical properties, but also alleviate the stress concentration problem of the pipelines under complex working conditions through its unique material properties, thereby reducing the risk of pipe bursts. In addition, the construction process of asphalt concrete is relatively mature and has good compatibility with the manufacturing process of PCCP, making this solution highly feasible and operable in practical applications. Summary of the invention

[0005] In view of this, in order to solve the limitations of existing prestressed concrete pipes in improving rigidity and the possible increased risk of pipe burst, on the one hand, the present invention provides a prestressed concrete pipe, which uses asphalt concrete material for the inner pipe core and takes advantage of its strong toughness and good impermeability to improve the crack resistance and durability of the pipe. The steel cylinder serves as the skeleton of the pipe, providing the necessary strength and rigidity. The prestressed steel wire layer forms annular prestress by tensioning the prestressed steel wire and anchoring it on the steel cylinder to resist the internal water pressure and external load of the pipe. The outer concrete protective layer further enhances the overall performance and durability of the pipe.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A prestressed concrete pipe is sequentially provided with an inner pipe core, a steel cylinder, an outer concrete protective layer, a prestressed steel wire layer and a mortar protective layer from the inside to the outside;

[0008] The inner pipe core is made of asphalt concrete material, and the prestressed steel wire layer is formed by tensioning the prestressed steel wire and anchoring it on the steel cylinder to form annular prestress for resisting the internal water pressure of the pipeline and external loads.

[0009] Preferably, the thickness of the inner tube core is 70-150 mm, the thickness of the steel tube is 1.2-2.5 mm, the thickness of the outer concrete protective layer is 150-400 mm, the diameter of the prestressed steel wire is 5-10 mm, the wire winding spacing is 10-30 mm, and the thickness of the mortar protective layer is at least 25 mm.

[0010] Preferably, the asphalt-to-oil-rock ratio of the asphalt concrete material is 3% to 6%, wherein the oil-to-rock ratio refers to the mass percentage of asphalt to mineral material in the asphalt concrete.

[0011] Preferably, the surface of the steel cylinder is coated with a high-strength interface agent.

[0012] Preferably, the steel cylinder is a stainless steel cylinder.

[0013] Preferably, the stainless steel cylinder is made of 316 stainless steel.

[0014] Preferably, the prestressed steel wire is a high-strength steel wire surface treated with a room temperature steel surface sensitizing blackening agent.

[0015] Preferably, 0.1%-2% silica fume is added to the mortar protective layer, where the ratio of 0.1%-2% refers to the proportion of silica fume to cementitious materials in the mortar protective layer, which is used to improve the waterproof performance.

[0016] In another aspect, the present invention provides a method for preparing the above-mentioned prestressed concrete pipe, comprising the following steps:

[0017] Step (1), mold preparation;

[0018] Step (2), steel cylinder installation;

[0019] Step (3), applying prestress;

[0020] Step (4), asphalt concrete mixing;

[0021] Step (5), inner layer pouring;

[0022] Step (6), initial maintenance;

[0023] Step (7), pouring outer layer concrete;

[0024] Step (8), roller spraying of the mortar protective layer;

[0025] Step (9), curing and demoulding.

[0026] In another aspect, the present invention provides the use of the above-mentioned prestressed concrete pipe in water supply, drainage, farmland irrigation or industrial fluid transportation.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The prestressed concrete pipe provided by the present invention uses asphalt concrete material for the inner pipe core, and utilizes its strong toughness and good impermeability to improve the crack resistance and durability of the pipe. The steel cylinder serves as the skeleton of the pipe and provides the necessary strength and rigidity. The prestressed steel wire layer is formed by tensioning the prestressed steel wire and anchoring it on the steel cylinder to form a circumferential prestress to resist the internal water pressure and external load of the pipe. The outer concrete protective layer further enhances the overall performance and durability of the pipe.

[0029] The present invention achieves a balance between pipeline rigidity and toughness and improves the overall performance of the pipeline through reasonable material selection and optimized pipeline structure design.

[0030] The present invention is applicable to engineering fields such as water supply, drainage, farmland irrigation and industrial fluid transportation under various complex working conditions, broadens its application scope, and has broad market prospects and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The present invention is a prestressed concrete pipe (PCCP) with asphalt concrete material as the inner layer pipe core;

[0032] Figure 2 It is a longitudinal section view of a prestressed concrete pipe with asphalt concrete as the inner pipe core of the present invention;

[0033] In the figure, 1. mortar protective layer; 2. prestressed steel wire; 3. outer concrete protective layer; 4. steel cylinder; 5. inner pipe core. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making creative work are within the scope of protection of the present invention.

[0035] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", "top / bottom" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0036] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "mounted / connected", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] like Figure 1-2 As shown, the present invention provides a prestressed concrete pipe, which is sequentially arranged from the inside to the outside as an inner pipe core, a steel cylinder, an outer concrete protective layer, a prestressed steel wire layer and a mortar protective layer;

[0038] The inner pipe core is made of asphalt concrete material, which takes advantage of its strong toughness and good impermeability to improve the crack resistance and durability of the pipeline. The steel cylinder serves as the skeleton of the pipeline and provides the necessary strength and rigidity. The prestressed steel wire layer is formed by tensioning the prestressed steel wire and anchoring it on the steel cylinder to form a circumferential prestress to resist the internal water pressure and external load of the pipeline.

[0039] In the present invention, the thickness of the inner tube core is 70-150 mm, the thickness of the steel tube is 1.2-2.5 mm, the thickness of the outer concrete protective layer is 150-400 mm, the diameter of the prestressed steel wire is 5-10 mm, the wire winding spacing is 10-30 mm, and the thickness of the mortar protective layer is at least 25 mm.

[0040] In the present invention, the asphalt-to-oil-rock ratio of the asphalt concrete material is 3% to 6%, wherein the oil-to-rock ratio refers to the mass percentage of asphalt to mineral material in the asphalt concrete.

[0041] In the present invention, the surface of the steel cylinder is coated with a high-strength interface agent, and the high-strength interface agent is preferably EL1230S high-strength interface agent.

[0042] In the present invention, the steel cylinder is preferably made of stainless steel with high corrosion resistance, and the steel cylinder is a stainless steel cylinder, preferably made of 316 stainless steel, because it has stronger resistance to chlorides (such as salt in seawater) and various chemicals.

[0043] In the present invention, the prestressed steel wire is a high-strength steel wire subjected to surface treatment using a room temperature steel surface sensitizing blackening agent. The surface treatment process includes the steps of pretreatment, cleaning, sensitization, re-cleaning, blackening, third cleaning, post-treatment (immersion in sealant), drying and storage.

[0044] In the present invention, 0.1%-2% silica fume is added to the mortar protective layer, where the ratio of 0.1%-2% refers to the ratio of silica fume to cementitious materials in the mortar protective layer, which is used to improve the waterproof performance.

[0045] In another aspect, the present invention provides a method for preparing the above-mentioned prestressed concrete pipe, comprising the following steps:

[0046] Step (1), mold preparation, specifically can be:

[0047] Install the vertical inner and outer molds. Before installing the mold, use precision measuring tools such as a level and a laser measuring instrument to check the horizontality of the mold installation surface to ensure that the installation surface is flat and not tilted. Strengthen the connection parts of the mold, such as welding and bolting, to increase the connection strength to prevent mold failure due to loose connections during the production process. After the mold is installed, perform a sealing test to check the sealing effect of the mold by applying a certain pressure or vacuum to ensure that no leakage occurs. For pressure testing, the test pressure range is between 0.1MPa and 1.0MPa. The specific range of vacuum is between -0.05MPa and -0.1MPa (i.e., negative pressure of 50 to 100kPa). Ensure the verticality and stability of the mold, and check the sealing of the mold.

[0048] In general, the gap between the inner and outer molds needs to be small enough to ensure that the concrete can be fully filled and tightly bonded to the steel cylinder during pouring, but also large enough to avoid concrete damage or mold jamming during demoulding.

[0049] Step (2), steel cylinder installation, specifically can be:

[0050] The steel cylinder is made of 316 stainless steel with high corrosion resistance, and has stronger resistance to other chlorides (such as salt in seawater) and various chemicals. The thickness of the steel cylinder is 1.2 to 2.5 mm. The surface of the steel cylinder is coated with EL1230S high-strength interface agent.

[0051] Before placing the steel cylinder, it needs to be precisely positioned to ensure that its axis coincides with the axis of the inner mold to avoid deviation during installation. At the same time, a temporary support structure needs to be set up inside the inner mold to support the steel cylinder and prevent it from moving or deforming during the next operation. After confirming the position and support, use a crane or lifting equipment to slowly place the steel cylinder into the inner mold. During the placement process, you need to be careful to avoid damaging the steel cylinder or the inner mold.

[0052] Step (3), applying prestress, may specifically be:

[0053] Prestressed steel wire is surface treated by using "normal temperature steel surface sensitization blackening agent" to treat high-strength steel wire. This process includes pretreatment, cleaning, sensitization, re-cleaning, blackening, third cleaning, post-treatment (immersion in sealant), drying and storage. The diameter of the prestressed steel wire is 5-10mm, and the wire winding spacing is 10-30mm.

[0054] A tensioning device is set outside the steel cylinder to tension the prestressed steel wire. Start the tensioning equipment to gradually tension the prestressed steel wire. During the tensioning process, the tensioning speed is controlled at 3 to 50 mm / min, and the tensioning prestress is controlled at 65% to 80% of the ultimate tensile strength of the steel wire to ensure that the steel wire can be evenly stressed and avoid excessive stress concentration. At the same time, it is also necessary to monitor the elongation and prestress value of the steel wire to ensure that they meet the design requirements. When the prestressed steel wire reaches the predetermined tensioning value, it needs to be anchored. The anchoring method includes using an anchor to fix the steel wire to the steel cylinder or inner mold to ensure that the prestressed steel wire can maintain a stable prestressed state during subsequent construction.

[0055] Step (4), asphalt concrete mixing, may specifically include:

[0056] The asphalt-to-oil-stone ratio of asphalt concrete materials ranges from 3% to 6%, which can take into account the material's strength, toughness, impermeability, and convenience of construction and maintenance.

[0057] According to the designed proportion, raw materials such as asphalt and mineral materials are put into the asphalt concrete mixing equipment for mixing, and the mixing temperature and time are controlled to ensure the quality of the asphalt concrete. The discharge temperature will be determined according to the viscosity grade of the asphalt, the type of mineral materials and the design requirements, and generally ranges from 130°C to 170°C. In the mixing process of asphalt concrete, the shortest mixing time is a key parameter, which varies according to the specific formula, material properties and the required engineering quality standards. According to the characteristics of the materials used in this patent, the shortest mixing time is set to 60s to 120s.

[0058] Step (5), inner layer pouring, may specifically be:

[0059] The thickness of the inner layer of asphalt concrete is 70-150mm. Use special equipment to evenly lay the mixed asphalt concrete on the inner mold surface, and pay attention to controlling the laying thickness and uniformity. During the laying process, use a vibrator to vibrate the asphalt concrete to improve its density and adhesion to the steel cylinder.

[0060] Step (6), preliminary curing, may specifically include:

[0061] After pouring, preliminary curing is carried out according to the initial setting time of the asphalt concrete material. Commonly used moisturizing materials include plastic film, geotextile, wet sacks, etc. These materials should be tightly covered on the surface of the freshly poured asphalt concrete to reduce the evaporation of water and keep the surface of the concrete moist. The length of the curing time depends on the mix ratio, temperature, humidity and additives used of the asphalt concrete, and should last until the asphalt concrete reaches more than half of the design strength. The degree of curing should be such that the concrete surface has no cracks, no loose particles, uniform color, and has a certain strength. After the curing is completed, the curing effect of the concrete is evaluated by coring tests or non-destructive testing.

[0062] Step (7), pouring the outer layer of concrete, may specifically be:

[0063] After the inner layer of asphalt concrete has initially solidified and reached a certain strength (the specific strength needs to be determined according to the design requirements), first check the inner surface to ensure that there are no cracks, no loose particles, and that it is clean and free of impurities. According to the design requirements, accurately install the outer formwork (external formwork) to ensure that the position of the formwork is accurate, stable and without shaking, and check the sealing of the formwork to prevent leakage during pouring. Install the external formwork and pour the outer concrete protective layer. The thickness of the outer core concrete is 150 to 400 mm. Use an appropriate pouring speed to ensure that the concrete can be evenly and continuously filled into the formwork to avoid voids or stratification. At the same time, pay attention to controlling the pouring height, which should not be too high to avoid a large pressure difference inside the concrete. During the pouring process, use a vibrator to vibrate the concrete to remove bubbles and excess water in the concrete and improve the density and strength of the concrete. The vibration should be uniform and sufficient, but avoid over-vibration to cause concrete segregation.

[0064] Step (8) roller spraying of the mortar protective layer may specifically be as follows:

[0065] The mortar protective layer is added with 0.1%-2% silica fume to improve the waterproof performance. The thickness of the mortar protective layer should be at least 25mm. Clean and polish the surface of the outer core concrete to remove the floating slurry, loose particles, etc., so that the surface is flat and rough, which is conducive to the bonding of the mortar. Use a roller sprayer to evenly spray the mortar onto the surface of the outer core concrete to form a dense mortar protective layer. The spraying pressure and spraying speed should be controlled during roller spraying to ensure that the mortar layer is uniform in thickness and there is no leakage. After the construction of the mortar protective layer is completed, it should be maintained in time. Use wet cloth covering or sprinkling water to keep the surface of the mortar layer moist to avoid cracking. The curing time is determined according to the performance of the mortar and climatic conditions, and is not less than 7 days.

[0066] Step (9) curing and demoulding, specifically, can be:

[0067] According to the maintenance requirements of asphalt concrete and concrete, the pipeline is properly maintained. After the concrete is completely hardened, the inner and outer molds are removed, and the pipeline is trimmed and quality tested.

[0068] The technical solution of the present invention is clearly described in detail below in conjunction with specific embodiments.

[0069] Example 1

[0070] According to the above-mentioned prestressed concrete pipe (PCCP) with asphalt concrete as the inner layer core and its vertical casting process, the process parameters are selected as follows:

[0071] The steel cylinder is made of 316 stainless steel with a thickness of 1.2mm and is coated with EL1230S high-strength interface agent.

[0072] The inner layer pipe core made of asphalt concrete material has an asphalt-stone ratio of 3%, a thickness of 70 mm, a coarse aggregate ratio of 50%, and a filler ratio of 35%.

[0073] The thickness of the outer concrete protective layer is 150mm.

[0074] The diameter of the prestressed steel wire is 7mm and the wire winding spacing is 12.1mm.

[0075] The silica fume content in the mortar protective layer is 0.1%, and the thickness of the mortar protective layer is 28mm.

[0076] Example 2

[0077] According to the above-mentioned prestressed concrete pipe (PCCP) with asphalt concrete as the inner layer core and its vertical casting process, the process parameters are selected as follows:

[0078] The steel cylinder is made of 316 stainless steel, 2.0mm thick, and the surface is coated with EL1230S high-strength interface agent.

[0079] The inner layer pipe core made of asphalt concrete material has an asphalt-stone ratio of 5%, a thickness of 120 mm, a coarse aggregate ratio of 50%, and a filler ratio of 35%.

[0080] The thickness of the outer concrete cover is 230mm.

[0081] The diameter of the prestressed steel wire is 10mm and the wire winding spacing is 10mm.

[0082] The silica fume content in the mortar protective layer is 2%, and the thickness of the mortar protective layer is 32mm.

[0083] Example 3

[0084] Same as Example 1, except that the steel cylinder is made of 316 stainless steel with a thickness of 2.2 mm and is coated with EL1230S high-strength interface agent.

[0085] The inner layer pipe core made of asphalt concrete material has an asphalt-stone ratio of 6%, a thickness of 135 mm, a coarse aggregate ratio of 50%, and a filler ratio of 35%.

[0086] The thickness of the outer concrete cover is 310mm.

[0087] The diameter of the prestressed steel wire is 5mm and the wire winding spacing is 30mm.

[0088] The silica fume content in the mortar protective layer is 1%, and the thickness of the mortar protective layer is 40mm.

[0089] Example 4

[0090] Same as Example 1, except that the steel cylinder is made of 316 stainless steel with a thickness of 2.5 mm and is coated with EL1230S high-strength interface agent.

[0091] The inner layer pipe core made of asphalt concrete material has an asphalt-stone ratio of 5%, a thickness of 150 mm, a coarse aggregate ratio of 50%, and a filler ratio of 35%.

[0092] The thickness of the outer concrete protective layer is 400mm.

[0093] The diameter of the prestressed steel wire is 9.6mm and the wire winding spacing is 20mm.

[0094] The silica fume content in the mortar protective layer is 0.1%, and the thickness of the mortar protective layer is 50mm.

[0095] Comparative Example 1

[0096] The steel cylinder is made of Q235 carbon steel with a thickness of 1.2mm.

[0097] The mix ratio of the inner pipe core is the same as that of the outer concrete protective layer, which is C25 concrete, consisting of water, cement, water reducer, river sand, coarse aggregate and fine aggregate. The water-cement ratio is 0.4, the water reducer content is 1.5% of the cement mass, and the thickness is 70mm.

[0098] The thickness of the outer concrete protective layer is 150mm.

[0099] The diameter of the prestressed steel wire is 7mm and the wire winding spacing is 12.1mm.

[0100] The silica fume content in the mortar protective layer is 0.1%, and the thickness of the mortar protective layer is 28mm.

[0101] The anti-permeability and bearing capacity tests of Examples 1-4 and Comparative Example 1 were conducted by using a step-by-step pressure test method. The test process is as follows:

[0102] Install the pipe section to be tested into a sealed container and ensure that both ends of the pipe are well sealed to prevent water leakage from the joints.

[0103] The water pressure was set at 0.6MPa at the beginning of the test, and then increased by 0.1MPa every 24 hours. During this period, humidity sensors were used to monitor the humidity changes at specific locations inside the pipeline. When the humidity at the steel cylinder changed dramatically, the pipeline was considered to be leaking, and the water pressure at this time was the pipeline's anti-seepage capacity. Strain sensors were used to monitor the strain of the outer concrete protective layer of the pipeline. When the strain reached the limit of macro cracks, the pipeline was considered to be damaged, and the water pressure at this time was the pipeline's bearing capacity.

[0104] The test results are shown in Table 1 below.

[0105] Table 1 Anti-seepage and load-bearing capacity of Examples 1-4 and Comparative Example 1 under gradient load

[0106]

[0107]

[0108] From the contents of Table 1 above, it can be seen that the inner layer of the pipe core in the present invention adopts asphalt concrete material, which greatly improves the crack resistance and durability of the pipeline by taking advantage of its strong toughness and good anti-permeability. At the same time, the toughness advantage of asphalt concrete is fully utilized, combined with the structural advantages of stainless steel tube and PCCP itself, to achieve a balance between pipeline rigidity and toughness, thereby improving the overall performance of the pipeline.

[0109] The above are only preferred specific implementations of the present invention; however, the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and improved concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A prestressed concrete pipe, characterized in that: From inside to outside, it is arranged in sequence as follows: inner tube core, steel cylinder, outer concrete protective layer, prestressed steel wire layer and mortar protective layer; The inner pipe core is made of asphalt concrete material, and the prestressed steel wire layer is formed by tensioning the prestressed steel wire and anchoring it on the steel cylinder to form annular prestress for resisting the internal water pressure of the pipeline and external loads.

2. A prestressed concrete pipe according to claim 1, characterized in that: The thickness of the inner tube core is 70~150mm, the thickness of the steel tube is 1.2~2.5mm, the thickness of the outer concrete protective layer is 150~400mm, the diameter of the prestressed steel wire is 5-10mm, the wire winding spacing is 10~30mm, and the thickness of the mortar protective layer is at least 25mm.

3. The prestressed concrete pipe according to claim 1, characterized in that: The asphalt-to-rock ratio of the asphalt concrete material is 3% to 6%, wherein the asphalt-to-rock ratio refers to the mass percentage of asphalt to mineral material in the asphalt concrete.

4. The prestressed concrete pipe according to claim 1, characterized in that: The surface of the steel cylinder is coated with a high-strength interface agent.

5. The prestressed concrete pipe according to claim 1, characterized in that: The steel cylinder is a stainless steel cylinder.

6. The prestressed concrete pipe according to claim 1, characterized in that: The stainless steel cylinder is made of 316 stainless steel.

7. The prestressed concrete pipe according to claim 1, characterized in that: The prestressed steel wire is obtained by surface treating the high-strength steel wire using a normal temperature steel surface sensitizing blackening agent.

8. A prestressed concrete pipe according to any one of claims 1 to 7, characterized in that: The mortar protective layer is added with 0.1%-2% silica fume, where the ratio of 0.1%-2% refers to the proportion of silica fume to the cementitious material in the mortar protective layer, which is used to improve the waterproof performance.

9. A method for preparing a prestressed concrete pipe according to any one of claims 1 to 8, characterized in that: The steps include: Step (1), mold preparation; Step (2), steel cylinder installation; Step (3), applying prestress; Step (4), asphalt concrete mixing; Step (5), pouring the inner layer; Step (6), initial maintenance; Step (7), pouring outer layer concrete; Step (8), roller spraying of the mortar protective layer; Step (9), curing and demoulding.

10. Use of a prestressed concrete pipe according to any one of claims 1 to 8 in water supply, drainage, farmland irrigation or industrial fluid transportation.

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