Mud jacking and end sealing method for prefabricated bridge

Abstract

The invention relates to a grouting end sealing method for a prefabricated bridge. The grouting end sealing method comprises the following steps of s1, grouting pretreatment; s2, weighing and preparing raw materials, wherein each cubic meter of cement paste contains 1375kg of cement, 152kg of grouting agent and 473kg of water; s3, preparing cement paste; s4, grouting is conducted; s5, end sealing is conducted, specifically, after end sealing concrete curing is completed, sticky slurry on the surface of the anchor bearing plate and mortar on the upper portion of the outer face of the anchor ring are removed thoroughly, and then waterproof treatment is conducted on a joint seam between the anchor ring and the anchor bearing plate, an anchorage device, the surface of the anchor bearing plate and exposed steel strands through polyurethane waterproof paint; the standardized grouting and end sealing method for the prefabricated bridge is provided, the proportion of the cement paste and the end sealing concrete is included, the quality is good, and the quality of the T-beam concrete is strictly controlled.

Description

Technical Field

[0001] The invention relates to the field of prefabricated bridge construction, and in particular to a grouting end sealing method for a prefabricated bridge. Background Art

[0002] The grouting end sealing process is a key process in the prefabrication of bridges. The density and strength of the grouting play a key role in protecting the steel strands from corrosion, which directly affects the service life of the beam. The purpose of end sealing is separation and waterproofing. Grouting end sealing is a controlled process. The controlled state of the entire construction process of T-beam grouting end sealing needs to be further strengthened. Summary of the invention

[0003] The purpose of the present invention is to provide a grouting end sealing method for a prefabricated bridge, aiming to solve the problem of lack of standardization and uneven quality in the grouting end sealing construction of prefabricated bridges.

[0004] The technical solution adopted by the present invention is: a grouting end sealing method for a prefabricated bridge, comprising the following steps: s1, pre-grouting treatment, within 48 hours after the final tensioning of the prestressing force, after the technical personnel confirm that it meets the design and construction requirements, use a grinding wheel cutter to cut off the steel strand outside the anchor to an exposed length of 35±5mm, and at the same time, the end of the prestressed tendon is ≥40mm away from the end face of the beam, and then clean the anchor head and perform sealing treatment, that is, install an iron pipe with a diameter 5mm larger than the anchor outside the working anchor, seal the joint between the iron pipe and the anchor with a rubber ring, and then cover the bolt holes on the cover plate with the anchor pad for bolting; s2 1. Weigh and configure the raw materials. Each cubic meter of cement slurry contains 1375kg of cement, 152kg of grouting agent, and 473kg of water. s3. Preparation of cement slurry. After cleaning the construction equipment and cleaning the residue, wet the construction equipment, then remove the excess water in the equipment so that there is no visible water in the equipment. Check the filter of the mixer. The diameter of the filter space is ≤3mm. According to the proportion of the weighed raw materials, first add 80% to 90% of the water used in the mixer, start the mixer, evenly add all the grouting agent, stir while adding, then evenly add all the cement, and continue stirring. 2 minutes, finally add the remaining 10% to 20% of water, and stir for another 2 minutes to obtain cement slurry, and introduce the cement slurry into the storage tank through the filter screen, and continue to stir the cement slurry in the storage tank; s4, grouting, use a grouting pump to pump the cement slurry for grouting, and use a vacuum pump to extract the air in the pipeline to cooperate with the grouting process. The grouting pressure is maintained at 0.5-0.6Mpa. After the grouting is in place, the pressure in the pipeline is adjusted to 0.5Mpa and maintained for 3min; s5, end sealing, the anchor hole at the beam end should be roughened, and a steel mesh should be set in the anchor hole. The connecting screw with a hook is screwed into the original anchor plate screw hole Nail the steel mesh and the anchor plate together, and then seal the ends with sealing concrete. The proportion of end-sealing concrete is 416kg of cement, 32kg of fly ash, 50kg of expansion agent, 713kg of fine aggregate, 1069kg of coarse aggregate, 4.98kg of water reducer, 2.49kg of air entraining agent and 142kg of water per cubic meter. After the end-sealing concrete is cured, the mortar on the surface of the anchor plate and the mortar on the upper part of the outside of the anchor ring are scraped off, and then the joint between the anchor ring and the anchor plate, as well as the anchor, the surface of the anchor plate and the exposed steel strands are waterproofed with polyurethane waterproof coating.

[0005] A further technical solution of the present invention is: in step s2, the grouting agent includes a high-efficiency water reducing agent, a micro-expansion agent and a mineral admixture, wherein the water reducing rate of the water reducing agent is ≥20%.

[0006] A further technical solution of the present invention is that the weighing error of cement, grouting agent and water in step s2 is ±1%.

[0007] A further technical solution of the present invention is that the thickness of the end-sealing concrete in step s5 is ≥30 mm.

[0008] A further technical solution of the present invention is that the chiseling process in step s5 is staggered in horizontal and vertical directions, with a depth of 10±1mm and a spacing of ≤10mm; the chiseling area should account for 100% of the area of ​​the chiseling position.

[0009] A further technical solution of the present invention is: the waterproofing treatment in step s5 is performed three times, and the next waterproofing treatment is performed each time after the polyurethane waterproof coating is completely solidified.

[0010] The beneficial effects of the present invention are as follows: by adopting the above technical scheme, a standardized grouting end-sealing method for prefabricated bridges is provided, including a mix ratio of cement slurry and end-sealing concrete, which has good quality and enables strict quality control of T-beam concrete. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 The invention discloses a construction flow chart of a grouting end sealing method for a prefabricated bridge. DETAILED DESCRIPTION

[0012] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0013] like Figure 1 A grouting end sealing method for a prefabricated bridge is shown.

[0014] Work preparation: 1. Conduct technical briefings for operators and pre-job technical training for construction personnel; 2. Within 48 hours after the final prestressing, the technicians shall confirm that it meets the design and construction requirements, and then use a grinding wheel cutter to cut off the anchor steel strand. The exposed length of the steel strand after cutting shall meet the design requirements, and the exposed length shall be 35±5mm. At the same time, the end of the prestressed tendon shall be no less than 40mm from the end face of the beam; 3. Clean the anchor head and seal it. The third generation of air sealing solution is used for the anchor head sealing, that is, Install an iron pipe (about 5mm larger in diameter than the working anchor) outside the anchor, seal the joint with a rubber ring, and then cover the cover plate and bolt it to the bolt holes on the anchor pad. The airtightness of the anchor head closure will directly affect the vacuum pump's vacuuming and grouting effects, so quality must be ensured during construction; 4. After demolding, promptly seal the longitudinal prestressed channel to prevent debris and rainwater from entering the channel; 5. Check whether the grouting machine can work normally and whether the water and electricity supply are normal; 6. Before grouting, remove debris and accumulated water in the channel.

[0015] Technical requirements: The technicians and operators must be trained and qualified before they can take up their posts; before grouting the prestressed post-tensioned beam channel, the fluidity, water seepage rate, setting time, volume expansion, etc. of the slurry should be tested, and the test results should meet the design requirements; the grouting personnel must stand on both sides of the anchor to operate, and it is strictly forbidden to face the anchor or step on the high-pressure oil pipe; when grouting, effective protection measures must be taken for adjacent beams to prevent the slurry from spraying on other beams.

[0016] Raw materials for grouting: 1. The cement uses low-alkali ordinary Portland cement with stable performance and strength grade of P.O42.5 (the admixture powder is only fly ash or slag), and the C3A content in the cement clinker is not more than 8%; its various technical indicators are the same as those of the cement used for beam concrete and comply with the provisions of GB175-2007. This beam yard uses low-alkali ordinary Portland cement with strength grade PO 42.5 produced by Guizhou Fuquan Southwest Cement Co., Ltd.; 2. In order to reduce the water seepage rate and shrinkage rate of cement slurry and improve the early strength of cement slurry and concrete, our cement slurry admixture uses a grouting agent composed of high-efficiency water reducing agent, micro-expansion agent, mineral admixture, etc., and the dosage is determined by the test report. The performance of high-efficiency water-reducing agent has good adaptability with the selected cement, the water-reducing rate of water-reducing agent is not less than 20%, and other indicators meet the requirements of the current national standard "Concrete Admixture" GB / T 8076-2008. The homogeneity of admixture is tested according to the "Test Method for Homogeneity of Concrete Admixture" GB / T 8077-2012. The pipe grouting agent used in this beam yard is the product of Shanxi Jindunyuan Building Materials Co., Ltd.; 3. The grouting material shall not contain high-alkali (total alkali content shall not exceed 0.75%) expansive agent or expansive agent with aluminum powder as the expansion source. It is strictly forbidden to add chloride-containing salts, nitrites or other admixtures that are corrosive to prestressed tendons; 4) The total chloride ion content in the grouting material shall not exceed 0.06% of the total amount of cementitious materials.

[0017] Grouting steps and methods: 1. After the prestressing of the prestressed steel strands is completed, grouting must be carried out within 2 days. In order to ensure the durability of the beam body, a certain proportion of pipe grouting agent is added to the cement slurry; 2. Mixing of cement slurry: Before grouting the pipeline, the grouting material used should be trial-mixed. The amount of each material and the water-cement ratio shall be determined by the test report issued by the laboratory. The weighing of cement, pipe grouting agent, water, etc. shall be accurate to ±1% (all by mass). The measuring instruments shall be qualified by the statutory metrology inspection and used within the validity period. The water-cement ratio shall not exceed 0.33, and no water shall be exuded. The fluidity out of the machine is 18±4s, and it should not be greater than 30s after 30 minutes. After trial mixing, the measured fluidity, apparent density, water exudation rate, and 7-day and 28-day compressive and flexural strength of the cement slurry mixture shall meet the requirements of the specifications; Mixing process: Before mixing, the construction equipment must be cleaned and no residue shall be allowed. After cleaning, the construction equipment shall be moistened, and then the excess water in the equipment shall be removed. Make sure there is no visible water in the equipment, and check the filter of the mixer. When the grouting material enters the storage tank from the mixer, it must pass through the filter. The space of the filter shall not be larger than 3mm×3mm. The cement slurry is mixed with P.O42.5 low-alkali ordinary Portland cement and an appropriate amount of grouting agent. The dosage is determined by the laboratory through experiments. The laboratory issues a grouting ingredient notice. The amount of cement per cubic meter is 1375kg, grouting agent 152kg, and water 473kg. The slurry mixing operation sequence is: first add 80% to 90% of the actual mixing water into the mixer, start the mixer, evenly add all the grouting agent, stirring while adding, and then evenly add all the cement. After all the powder is added, stir for 2 minutes; then add the remaining 10% to 20% of the mixing water and continue stirring for 2 minutes. After stirring evenly, check the fluidity of the slurry in the mixing barrel (check once every 10 plates). If the fluidity is within the specified range (18±4s, should not be greater than 30s after 30 minutes), it can pass through the filter screen into the storage tank.The slurry continues to be stirred in the storage tank to ensure the fluidity of the slurry. The stirring of the slurry is strictly carried out according to the mix ratio. The cement and pipe grouting agent are accurately weighed with a calibrated scale, and the water is measured with a calibrated special container. It is prohibited to add extra water due to insufficient fluidity during construction; 3) The slurry temperature of the beam body, slurry and ambient temperature during grouting should be between 5℃ and 30℃. The beam body and ambient temperature should not be lower than 5℃ within 3 days after grouting, otherwise preheating and insulation measures should be taken to meet the requirements - when the ambient temperature is higher than 35℃, choose a time with lower temperature for construction, such as at night; when the ambient temperature is lower than 5℃, it should be handled as winter construction. , air-entraining agent can be appropriately increased, and the air content is determined by experiments. Antifreeze should not be used in grouting agent. The following insulation measures should be taken for grouting in winter - mix with warm water, cover and heat the beam, keep the temperature above 5°C, and maintain it for more than 3 days. The slurry should be weighed and proportioned strictly according to the mix ratio. At the same time, before mixing the slurry for pouring, the mixer should be added with water and stirred in the air for several minutes to drain the accumulated water and make the inner wall fully moist. Raw materials should be added before all the slurry is used up. The method of discharging and feeding at the same time cannot be adopted. The mixed slurry must be used up at one time. The grouting pump should have a fine-tuning device, and only fine-tuning can be made when replenishing the pressure in the channel. The maximum replenishing pressure cannot exceed 0.6MPa.

[0018] Precautions for vacuum pump operation: 1. The most important point of vacuum pump grouting is the sealing of the channel, so the sealing installation and pipeline connection of the channel should be carried out strictly in accordance with the requirements; 2. The water inlet must be opened before the vacuum pump is turned on, and the exhaust port can be overflowed with water. Dry operation without water is strictly prohibited; 3. The steering of the vacuum pump should be correct, and reverse operation is not allowed; 4. The air inlet should be unobstructed when the vacuum pump is started, and the opening condition of each valve should be checked before turning it on; 5. If the channel has been flushed with water in advance, the water must be flushed out with compressed air before vacuuming, otherwise a large amount of water will block the air inlet pipe of the pump body, making it impossible to vacuumize; 6. Be careful not to squeeze the air inlet hose during the operation of the vacuum pump, otherwise the pressure gauge will not accurately reflect the pressure. 7. The length of the air inlet transparent hose shall not be less than 6 meters. The status of the air inlet transparent hose should be closely observed during work. Once cement slurry enters the hose, the machine should be shut down immediately and the slurry discharge valve should be opened to prevent cement slurry from entering the negative pressure container or even the pump body, which will cause serious consequences; 8. The water in the negative pressure container should be discharged in time, and the negative pressure container should be cleaned in time depending on the situation of the hole. Generally, it is cleaned when the starting pressure increases significantly within one shift and the reason cannot be found; 9. When the vacuum pump is working (including testing), the air inlet will generate a large suction force. Be careful not to aim at the ground to prevent foreign matter such as gravel and dust from entering the pump body; 10. Clean the inside of the steel wire pipe with clean water to prevent cement from solidifying in the pipe.

[0019] Maintenance matters of vacuum pump: 1. If the pump stops running for a long time, the vacuum pump should be emptied. When operating, the valve should be opened, the drain port should be opened, and clean water should be injected from the water inlet for flushing. Then, the motor fan should be turned by hand until no liquid flows out. The machine can also be tilted 45 degrees for emptying; 2. After the pump body is emptied, protective oil can be poured from the cavitation holes, drain holes, air inlet holes or exhaust holes of the pump body for protection; 3. If the impeller is stuck after the pump is stopped for a long time due to the use of hard water, 10% oxalic acid can be filled in the pump cavity for about 30 minutes; 4. The motor should be maintained and used according to the motor instructions; 5. In order to avoid the wear of the impeller or even the jamming of the impeller, the dust particles that enter the pump body with the gas and working fluid can be flushed through the drain port; 6. The exposed working surface should be wiped frequently to keep it clean. When it is idle, it should be covered with dustproof and placed indoors. When it is temporarily placed outdoors, it should be dustproof, rainproof and sun-proof.

[0020] Use and maintenance of grouting pump: 1. Preparation work before starting the machine, (1) Check whether the electrical wires are intact, check the oil level in the reducer, and install the pressure gauge (fill the gauge seat with glycerin), (2) Check whether the rotation direction of the reducer motor is in line with the direction indicated by the arrow on the casing (for grouting, the motor rotates in the direction of the arrow; if used for suction, the rotation direction is opposite), (3) Turn on the power, start the motor, fill the machine and pipeline with clean water, run for a while, fully lubricate the screw and sleeve (rotor, stator), avoid burning the rubber sleeve, and check whether the machine and pipeline are blocked or leaking, (4) Filter the conveying medium, and do not allow large particles and hard objects to enter the machine body to avoid clogging and damage to the rotor and stator, (5) The cement slurry must be stirred evenly; 2. Normal operation, (1) Start the equipment and convey the medium; (2) When the conveying distance and conveying height cannot be reached, the screw The nails are used to clamp the outer shell to deform the stator rubber sleeve until it meets the working requirements. However, it should not be clamped too tightly to avoid aggravating the wear of the rubber sleeve during operation and reducing its service life. The pressure in the cavity can refer to the indication on the pressure gauge. If it does not work, it means that the stator rubber sleeve or rotor screw has been excessively worn and needs to be replaced with a new one. (3) During operation, pay attention to whether the operation is normal. When any fault is found, the machine should be shut down immediately. When the fault is found, the shutdown time should not be too long to avoid the cement slurry solidifying and blocking the entire slurry delivery system. 3. Shutdown and maintenance. (1) After the work is completed, it is recommended to loosen the clamping sleeve. When using it next time, readjust the tightness of the clamping sleeve according to the workload. In this way, unreasonable wear and power consumption of the rotor and stator can be avoided. (2) After each use, inject clean water, start the machine, and rinse the equipment and pipelines. (3) The equipment should be placed in a dry environment without wind and snow.

[0021] A grouting trolley can be used to complete concrete mixing and grouting work. The use and maintenance of the grouting trolley are as follows: (1) Fully automatic operation. When using it, you only need to set the ratio of powder to water and the amount to be mixed. The trolley will automatically control the amount of water and material added and the mixing time, and automatically open the discharge valve after mixing. The cement slurry after high-speed mixing is placed in the low-speed storage barrel for standby. Fully automatic operation can completely avoid the influence of manual operation on the mixing process and ensure the mixing quality; (2) High-speed mixing. High-speed mixing can fully mix the powder and water. The mixing speed of the high-speed mixing drum of this trolley is as high as 1000rpm, which is 10 to 20 times the speed of other mixers currently available; (3) Low-speed storage to prevent solidification. This trolley is equipped with a large-capacity (about 0.5m3) low-speed mixing drum, which can collect cement slurry after 2 to 3 high-speed mixing to meet the needs of large-capacity use; (4) It has its own walking system. All the equipment of this trolley is installed on a single-axle frame, which can be easily towed to the place of use by other vehicles. The whole machine can be moved Convenient; (5) Automatic pressure stabilization during pumping and grouting. The trolley can be equipped with optional or self-equipped grouting equipment to form a complete set of equipment from the base material to the final grouting. The pressure gauge with electric contacts randomly distributed can automatically control the start and stop of the grouting equipment according to the grouting pressure during grouting to ensure that the pressure is within the specified range during the pressure maintenance period; (6) The mixing data is traceable. The data recording system of the controller can record the mixing data of the trolley for more than 7,200 times, including the date and time of each mixing, mixing weight, weight of water and powder and other key data. When necessary, it can be connected to a common computer to read the relevant data for reference; (7) Real-time display of feeding error (controller). During the mixing process, the three-row display of the controller can respectively display the target weight, current weight and relative error of the material being fed, so that the feeding accuracy is clear at a glance; (8) Maintenance of the machine. Check the oil level of the reducer every month, add or replace the engine oil if necessary, regularly check whether the mixing blades are worn, regularly check whether the wheels of the mobile frame are intact, and overhaul and maintain once a year.

[0022] Notes: (1) Do not over-stir in the high-speed mixing barrel, and the total mass of the slurry should be less than 500kg; (2) Ensure reliable grounding or protective grounding of electrical equipment; (3) After each shift, the systems of the trolley must be emptied and the mixing barrel must be cleaned; (4) There are three fixing bolts at the bottom edge of the high-speed mixing barrel. When transporting over long distances, use these bolts to push the high-speed mixing barrel 3-5mm away from the weighing sensor and fasten it to the column bracket to avoid damaging the weighing sensor. Before moving to the destination and re-activating it, the three fixing bolts should be completely loosened (the three fixing bolts have been locked in the transportation state by the manufacturer before the first use. When using it, they should be completely loosened and ensure that the bolts do not touch the fixing points of the nuts); (5) When connecting to an external power supply, ensure that the rotation direction of each rotating system is correct; (6) Read the instructions carefully before using the trolley to avoid damage to the equipment caused by improper operation; (7) The stirring tube should be completely emptied, and cement and additives are not allowed, but water cleaning is not allowed.

[0023] End sealing: 1. The purpose of end sealing is to ensure the outline size of the beam body and prevent the anchor from rusting; 2. In order to strengthen the connection between the end sealing concrete and the beam body, the anchor hole at the beam end should be roughened, and a steel mesh should be set in the anchor hole. The connecting screws with hooks are screwed into the original anchor plate screw holes to connect the steel mesh and the anchor pad together. Before pouring the end sealing concrete of the beam body, the mortar on the surface of the anchor pad and the mortar on the upper part of the anchor ring should be scraped clean, and the joint between the anchor ring and the anchor pad, as well as the anchor, the surface of the anchor pad and the exposed steel strands should be waterproofed with polyurethane waterproof coating directly acting on the waterproof layer. After inspection and confirmation by quality inspection personnel, concrete can be poured. The thickness of the protective layer of the end sealing concrete is not more than 100%. It should be less than 30mm; 3. The proportion of end-sealing concrete is 416kg cement, 32kg fly ash, 50kg expansion agent, 713kg fine aggregate, 1069kg coarse aggregate, 4.98kg water reducer, 2.49kg air entraining agent and 142kg water per cubic meter; 4. For end-sealing concrete, take 2 groups of concrete specimens for each work shift (1 group is cured with standard conditions, and 1 group is cured with the same conditions as the beam); 5. A steel mesh is set in the anchor hole, and the purchased connecting screws are screwed into the original anchor plate screw holes to connect the steel mesh with the anchor pad. Before sealing the anchor, remove the anchor head sealing slurry block, and roughen the surrounding of the anchor hole. The roughening process is staggered horizontally and vertically, with a depth of about 10mm, and the spacing shall not exceed If the thickness exceeds 10mm, the roughening area should account for 100% of the roughening position area, and the depth should be exposed to the coarse aggregate of the concrete; 6. Anchor sealing construction process, anchor sealing construction process - anchor hole concrete roughening → cleaning and moistening → installing steel bars → pouring non-shrinkage concrete → curing → applying the first layer of waterproof coating → applying the second layer of waterproof coating → applying the third layer of waterproof coating → quality inspection engineer acceptance → storage; 7. Concrete filling should be divided into two steps. First, fill with relatively dry and hard concrete to about 5cm from the top of the anchor hole, and tamp it tightly. Then fill and smooth it with normal hardness concrete. After the filled concrete hardens, apply it on all the sealed surfaces and the joints between the new and old concrete at the sealed ends (coating (If the material is applied beyond 8cm from the joint line), polyurethane waterproof coating shall be used for waterproofing, and the coating thickness shall not be less than 2mm; 8. The sealed concrete shall be naturally cured and covered with plastic film. The number of watering shall be to keep the concrete surface fully moist, and the curing time shall be no less than 14d; 9. After sealing, polyurethane waterproof coating shall be used for waterproofing. Before painting, the scum on the surface of the sealed concrete shall be cleaned, and then the first layer of waterproof coating shall be applied to the joints of the new concrete. The coating width is 8cm at each joint. After the first layer is completely solidified (it is best when the paint surface is not sticky when pressed with fingers), the second layer of waterproof coating shall be applied, and finally the third layer of waterproof coating shall be applied.

[0024] Grouting quality inspection: 1. When grouting each pipe hole, thick slurry flows out of the slurry outlet, then close the slurry valve and the grouting machine continues to increase the pressure to a maximum of 0.6Mpa. During the stable period, the pressure is maintained at 0.5Mpa for 3 minutes. The oil pressure value on the pressure gauge remains unchanged, which means that the pipe is fully grouted; 2. After grouting, check for pressure leakage. If there is any pressure leakage, grouting should be carried out on the leaking pipe to ensure that the grouting is full; 3. During the grouting process, cement slurry specimens should be randomly made for curing under the same conditions. Three groups of standard curing specimens (40mm×40mm×160mm) should be made for each beam hole. The compressive strength of the cement slurry should not be less than 50MPa, and the flexural strength should not be less than 10MPa. After grouting, check the density of the grouting from the anchor plate pressure / slurry outlet hole. If it is not solid, it should be replenished in time to ensure that the hole is completely dense.

[0025] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A grouting end sealing method for a prefabricated bridge, comprising the following steps: s1. Pre-grouting treatment: within 48 hours after the final prestressing, after the technical staff confirms that it meets the design and construction requirements, use a grinding wheel cutter to cut off the steel strand outside the anchor to an exposed length of 35±5mm, and at the same time, the end of the prestressed tendon is ≥40mm away from the end face of the beam. Then clean the anchor head and perform sealing treatment, that is, install an iron pipe with a diameter 5mm larger than the anchor outside the working anchor, seal the joint between the iron pipe and the anchor with a rubber ring, and then cover the bolt holes on the cover plate and bolt them together; s2. Weigh and configure the raw materials. Each cubic meter of cement slurry contains 1375kg of cement, 152kg of grouting agent, and 473kg of water; s3. Preparation of cement slurry: After cleaning the construction equipment and clearing the residue, wet the construction equipment, then drain the excess water in the equipment so that there is no visible water in the equipment, check the filter screen of the mixer, and the diameter of the filter screen is ≤3mm; according to the weighed raw material ratio, first add 80% to 90% of the water used in the mixer, start the mixer, evenly add all the grouting agent, stir while adding, then evenly add all the cement, continue to stir for 2 minutes, finally add the remaining 10% to 20% of the water used, stir for another 2 minutes to obtain cement slurry, and introduce the cement slurry into the storage tank through the filter screen, and continue to stir the cement slurry in the storage tank; s4. Grouting: Use a grouting pump to pump cement slurry for grouting, and use a vacuum pump to extract the air in the pipeline to cooperate with the grouting process. The grouting pressure is maintained at 0.5-0.6Mpa. After the grouting is in place, adjust the pressure in the pipeline to 0.5Mpa and maintain it for 3 minutes; s5. End sealing. The anchor holes at the ends of the beams should be roughened, and steel mesh should be set in the anchor holes. The steel mesh and the anchor plate should be connected together by screwing in the connecting screws with hooks through the original anchor plate screw holes. The ends are then sealed with end-sealing concrete. The end-sealing concrete mix ratio contains 416kg of cement, 32kg of fly ash, 50kg of expansion agent, 713kg of fine aggregate, 1069kg of coarse aggregate, 4.98kg of water reducer, 2.49kg of air entraining agent and 142kg of water per cubic meter. After the end-sealing concrete is cured, the mortar on the surface of the anchor plate and the mortar on the upper part of the outside of the anchor ring should be scraped off cleanly, and then the joints between the anchor ring and the anchor plate, as well as the anchor, the surface of the anchor plate and the exposed steel strands should be waterproofed with polyurethane waterproof coating.

2. The grouting end sealing method for a prefabricated bridge according to claim 1, characterized in that: In step s2, the grouting agent includes a high-efficiency water reducing agent, a micro-expansion agent and a mineral admixture, wherein the water reducing rate of the water reducing agent is ≥20%.

3. The grouting end sealing method for a prefabricated bridge according to claim 1 is characterized in that: The weighing error of cement, grouting agent and water in step s2 is ±1%.

4. The grouting end sealing method for a prefabricated bridge according to claim 3 is characterized in that: The thickness of the end-sealing concrete in step s5 is ≥30 mm.

5. The grouting end sealing method for a prefabricated bridge according to claim 1 is characterized in that: The chiseling process in step s5 is staggered horizontally and vertically, with a depth of 10±1mm and a spacing of ≤10mm; the chiseling area should account for 100% of the area of ​​the chiseling position.

6. The grouting end sealing method for a prefabricated bridge according to claim 1, characterized in that: The waterproofing treatment in step s5 is performed three times, and the next waterproofing treatment is performed each time after the polyurethane waterproof coating is completely solidified.

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