Bridge deck pavement rapid reinforcing method based on UHPC-steel mesh composite layer

Abstract

The invention discloses a rapid reinforcing method for bridge deck pavement based on a UHPC-steel mesh composite layer, and belongs to the technical field of bridge engineering reinforcement. According to the method, a scientific disease grading evaluation system is combined with key part correlation analysis to optimize the reinforcement range, reinforcement requirements of different disease areas are accurately matched, and combined with base surface treatment, steel mesh positioning and UHPC material modification processes, collaborative stress of a composite layer, an original base layer and a steel mesh and composite application of the UHPC material and modified steel fibers are enhanced, so that the comprehensive performance of the composite layer is improved. The impermeability, corrosion resistance and mechanical property uniformity of the composite layer are improved, the service cycle of the bridge deck is prolonged, and the bearing performance and damage resistance of the bridge deck are remarkably improved; and meanwhile, the layered pouring and adaptive vibrating technology is combined with the steam rapid curing technology, the construction and curing period is greatly shortened, interference to traffic passing is reduced, the later repair rate is reduced through the precise detection and control technology, the maintenance investment is reduced, and balance of the reinforcing effect and economic benefits is achieved.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering reinforcement technology, and in particular to a rapid reinforcement method for bridge deck pavement based on UHPC-steel mesh composite layer. Background Technology

[0002] Existing bridge deck reinforcement methods mostly employ ordinary concrete pouring, asphalt paving, or single fiber reinforced materials for repair, which suffer from problems such as poor bonding performance, limited improvement in load-bearing capacity, long construction periods, and insufficient durability. For example, Chinese patent application CN119434136A discloses a reinforced structure for concrete bridge decks and its construction method. It includes: an original concrete bridge deck and a pavement layer on top of it. The pavement layer is made of lightweight ultra-high performance concrete. Both the original concrete bridge deck and the pavement layer contain reinforcing steel layers. Connecting steel bars are used to connect the reinforcing steel layers within the original concrete bridge deck and the pavement layer. Prestressed grooves are evenly spaced along the longitudinal direction of the bridge and along the transverse direction of the bridge, with sets of prestressed tendons placed within the prestressed grooves. This patent application uses lightweight ultra-high performance concrete as the overlay and arranges connecting steel bars between the original concrete bridge deck and the new pavement layer. Simultaneously, prestress is applied between the pavement layer and the original bridge deck, enhancing the flexural stiffness of the concrete slab structure, allowing the entire bridge structure to share the load, thus improving the structure's durability and traffic safety.

[0003] However, while the aforementioned patents have improved the bending and crack resistance of bridges, the following problems still exist:

[0004] 1. Existing technologies have not established a systematic disease classification and assessment system, and have not accurately divided the reinforcement scope for different degrees and types of bridge deck pavement diseases. This can easily lead to over-reinforcement or incomplete treatment of local diseases, making it difficult to achieve the precision of reinforcement as needed.

[0005] 2. The existing technology has a complex construction process. The opening of prestressed trenches, the layout and tensioning of prestressed tendons require extremely high construction precision. In addition, the installation of connecting steel bars needs to be deep into the original bridge deck, which can easily cause secondary damage to the original structure. At the same time, the overall process is complicated, the construction period is long, and there is a great deal of interference with traffic, making it difficult to achieve rapid reinforcement and traffic restoration.

[0006] 3. Existing technologies are not well adapted to complex areas such as bridge deck corners and expansion joints, making it difficult to guarantee the filling density and structural integrity of special areas. Summary of the Invention

[0007] The purpose of this invention is to provide a rapid reinforcement method for bridge deck pavement based on UHPC-steel mesh composite layer. Through precise defect classification and reinforcement range optimization, it matches the reinforcement needs of different areas. Layered casting and steam curing technology shorten the construction cycle, reduce traffic interference, and is suitable for reinforcement of complex parts. The synergistic effect of UHPC material and modified steel fiber enhances the corrosion resistance and damage resistance of the composite layer and extends its service life, thereby solving the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A rapid reinforcement method for bridge deck pavement based on UHPC-steel mesh composite layer includes the following steps:

[0010] Pavement structure inspection: Conduct a comprehensive inspection of the original bridge deck pavement layer, determine the level of pavement layer defects and the scope of reinforcement work based on the inspection results, and mark the target areas that need to be cleaned and repaired;

[0011] Steel mesh positioning: The base surface is treated for the determined reinforcement work area, and the steel mesh is cut according to the size of the reinforcement work area. Positioning devices are used to fix the steel mesh laid on the base surface.

[0012] UHPC material preparation: Weigh the corresponding raw materials according to the preset mixing ratio, put the raw materials into the mixing equipment for graded mixing, and mix until the UHPC material meets the preset index requirements to complete the preparation of UHPC material;

[0013] Composite layer casting and forming: The prepared UHPC material is poured in layers on top of and around the fixed steel mesh, and the poured UHPC material is vibrated with a vibrating device. After vibration, the paving surface is leveled and smoothed to form a UHPC-steel mesh composite layer.

[0014] Quality inspection: The UHPC-steel mesh composite layer is inspected for quality, and the interfacial bonding strength between the composite layer and the original pavement base layer is also tested. If all test indicators meet the preset reinforcement technical requirements, the rapid reinforcement of the bridge deck pavement is completed. If there are areas where the test indicators are not up to standard, the areas are repaired and retested until all test indicators meet the requirements.

[0015] Furthermore, the severity level of pavement defects is determined, specifically including:

[0016] Data classification and organization: The test data of the original bridge deck pavement layer are classified and statistically analyzed, invalid test data are removed, and test datasets for each test point of the pavement layer are generated;

[0017] Single-index disease level determination: Based on the detection dataset, a corresponding disease grading standard is formulated for each detection index. The single disease type of the pavement layer corresponding to each detection index is classified into three single-index disease levels: slight, moderate, and severe.

[0018] Comprehensive disease level assessment of pavement layer: Based on the single-index disease level of each detection point, combined with the influence weight of the disease type on the pavement layer, a comprehensive weighted assessment is carried out, and the pavement layer as a whole is divided into three comprehensive disease levels.

[0019] Furthermore, determining the scope of the reinforcement work also includes:

[0020] Obtain the correlation between the defined reinforcement work area and the key parts of the original pavement layer of the bridge, determine the construction operation margin of the reinforcement work area in combination with the construction process requirements of the key parts, and at the same time, make local corrections and boundary optimizations to the reinforcement work area to determine the optimized reinforcement work area.

[0021] Based on the optimized reinforcement work area, the bridge deck is outlined and marked, while key damaged areas within the reinforcement work area are marked separately.

[0022] Furthermore, the surface treatment includes roughening the surface by mechanical shot blasting, with the shot blasting depth controlled at 2-3 mm, resulting in a surface roughness of 4-6 μm. The steel mesh is made of welded steel bars with a diameter of 6-8 mm and a mesh size of 100 mm × 100 mm to 150 mm × 150 mm. The overlap length of the cut steel mesh is not less than two mesh side lengths, and the overlap is fixed by spot welding. The positioning components are high-strength expansion bolts with a spacing of 500-800 mm, and the reserved gap between the steel mesh and the surface is set within the range of 20-30 mm.

[0023] Furthermore, the preparation of the UHPC material also includes:

[0024] The preset mix proportions by weight are: 400-450 parts cement, 80-100 parts silica fume, 600-650 parts ultrafine quartz sand, 120-150 parts steel fiber, 8-12 parts high-efficiency water-reducing agent, and 160-180 parts water.

[0025] The steel fibers used are copper-plated microfiber steel fibers with a diameter of 0.2-0.3 mm, a length of 12-15 mm, and an aspect ratio of 50-60.

[0026] In the preparation of UHPC materials, cement, silica fume, and ultrafine quartz sand are dry-mixed, then high-efficiency water-reducing agent and water are added for wet mixing, and steel fibers are added for low-speed mixing after wet mixing.

[0027] The dry mixing time is 2-3 minutes, the wet mixing time is 4-5 minutes, the material temperature is controlled at 15-25℃ during the mixing process, the low-speed mixing time is 5-8 minutes, and the expansion of UHPC material is tested after mixing is completed.

[0028] Furthermore, the preparation of the UHPC material also includes modifying the steel fibers by immersing the steel fibers in a 3%-5% silane coupling agent solution for 20-30 minutes, and then drying them in an oven at 80-100℃ until constant weight, thereby forming a silane coating layer on the surface of the modified steel fibers.

[0029] Furthermore, the layered casting includes:

[0030] First layer pouring: Pour UHPC material to the bottom of the steel mesh, and use an immersion vibrator to vibrate along the gaps in the steel mesh. The vibration frequency is controlled at 200~300 times / min, and the vibration time is 30-60 seconds per location, until there are no bubbles on the surface of the slurry and the slurry shows a state of overflowing slurry.

[0031] Second layer pouring: After the first layer is vibrated, the second layer is poured, with the pouring thickness reaching the preset total thickness of the composite layer. A flat plate vibrator is used to vibrate at a uniform speed along the longitudinal direction of the bridge deck, with the vibration speed controlled at 1-1.5 m / min.

[0032] Furthermore, the composite layer casting process also includes: real-time monitoring of the steel mesh position during the casting process, real-time collection of steel mesh planar displacement and vertical deformation data, and synchronous monitoring of the steel mesh stress and strain. If the steel mesh displacement or deformation exceeds the preset warning threshold, the casting process is immediately stopped and adjustments and fixation are performed.

[0033] Furthermore, during the layered pouring, each layer is 50-80mm thick, and the interval between two adjacent layers does not exceed 30 minutes. After the second layer is poured, a mechanical trowel is used in conjunction with manual labor to level and smooth the surface. The trowel rotates at 150-200 r / min, and the flatness deviation of the paved surface after smoothing does not exceed 2mm / m, and there are no obvious trowel marks or air bubble marks on the surface.

[0034] Furthermore, the quality inspection also includes: steel fiber distribution detection inside the UHPC, which involves scanning the composite layer surface at a constant speed using an ultrasonic probe to locate and mark the steel mesh position, dividing the steel mesh-free detection area, and based on the detection results, using an inductive detection device to scan the steel mesh-free detection area to detect the steel fiber content and distribution status within the steel mesh-free detection area, and analyzing the steel fiber content deviation and distribution uniformity.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] This invention utilizes a scientific disease grading and assessment system, combined with key component correlation analysis to optimize the reinforcement range, precisely matching the reinforcement needs of different disease areas. This avoids resource waste and insufficient reinforcement. The combined base treatment, steel mesh positioning, and UHPC material modification process strengthen the synergistic stress between the composite layer, the original base layer, and the steel mesh. The composite application of UHPC material and modified steel fibers improves the composite layer's impermeability, corrosion resistance, and uniformity of mechanical properties, effectively blocking environmental erosion, extending the bridge deck's service life, effectively eliminating hidden dangers such as delamination and hollow areas, and significantly improving the bridge deck's load-bearing capacity and damage resistance. Simultaneously, the layered pouring and adapted vibration compaction process, combined with steam rapid curing technology, significantly shortens the construction and maintenance cycle, reducing interference with traffic. Precise detection and control processes reduce the later repair rate, decrease maintenance investment, and achieve a balance between reinforcement effect and economic benefits. Attached Figure Description

[0037] Figure 1 This is a flowchart of the rapid reinforcement method for bridge deck pavement based on UHPC-steel mesh composite layer according to the present invention. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] To address the shortcomings of existing bridge deck pavement reinforcement methods, such as poor adhesion, limited load-bearing capacity improvement, long construction periods, insufficient durability, lack of a systematic disease classification and assessment system, and poor adaptability to complex locations, please refer to [link to relevant documentation]. Figure 1 The present invention provides the following technical solutions:

[0040] A rapid reinforcement method for bridge deck pavement based on UHPC-steel mesh composite layer includes the following steps:

[0041] Pavement structure inspection: Conduct a comprehensive inspection of the original bridge deck pavement layer, including pavement layer thickness, surface damage, distribution of internal voids and cracks, strength of base concrete and interface bonding performance. Based on the inspection results, determine the pavement layer defect level and reinforcement scope, and mark the target areas that need to be cleaned and repaired.

[0042] Steel Mesh Positioning: For the designated reinforcement area, surface preparation is performed. This involves removing laitance, debris, and loose or damaged sections from the existing pavement surface and roughening the surface using mechanical shot blasting. The shot blasting depth is controlled at 2-3 mm, resulting in a surface roughness of 4-6 μm to ensure strong adhesion between the UHPC material and the surface. The steel mesh is then cut to size according to the reinforcement area. This mesh uses HRB400 grade welded steel reinforcement with a diameter of 6-8 mm and a mesh size of 100mm×100mm-150mm×150mm. The overlap length of the steel mesh shall not be less than two mesh side lengths, and the overlap shall be fixed by spot welding with a weld spacing of not more than 150mm. The steel mesh laid on the base surface shall be fixed by positioning components to ensure that a gap of a predetermined thickness is reserved between the steel mesh and the base surface, and that the steel mesh is laid flat and the overlap is firmly connected within the reinforcement range. The positioning components shall be high-strength expansion bolts with a spacing of 500-800mm. The reserved gap between the steel mesh and the base surface shall be set within the range of 20-30mm. The steel mesh position shall be precisely adjusted and locked by the positioning components to ensure that the flatness deviation of the steel mesh laying does not exceed 3mm / m.

[0043] UHPC material preparation: Weigh the corresponding raw materials according to the preset mixing ratio, including cement, silica fume, ultrafine quartz sand, steel fiber, admixture and water. Put the raw materials into the mixing equipment for graded mixing. Dry mix the cementitious materials and aggregates until they are evenly mixed. Then add the admixture and water for wet mixing. Mix until the UHPC material meets the preset index requirements, that is, it has good workability, fluidity and adhesion. The preparation of UHPC material is completed.

[0044] Composite layer casting and molding: The prepared UHPC material is poured in layers above and around the fixed steel mesh, and the poured UHPC material is vibrated with a vibrating device to ensure that the material is densely filled and free of air bubbles, and that the UHPC material completely covers the steel mesh. After vibration, the paving surface is leveled and smoothed, and the cast UHPC-steel mesh composite layer is cured to achieve rapid hardening and molding of the composite layer, thus forming the UHPC-steel mesh composite layer.

[0045] In this embodiment, after the pouring is completed, the material is kept at room temperature and kept moist for 2 hours. Then, saturated steam at a temperature of 40-50°C is introduced for curing. The curing time is 8-10 hours. During the curing process, the relative humidity of the environment is controlled to be no less than 90%. After the curing is completed, the temperature is slowly reduced at a rate of no more than 5°C / h until the temperature difference between the ambient temperature and the surface temperature of the composite layer is less than the preset temperature threshold of 15°C, so as to avoid cracks in the composite layer due to temperature difference.

[0046] Quality Inspection: The UHPC-steel mesh composite layer is inspected for quality, including the composite layer thickness, surface flatness, appearance quality, and concrete strength. At the same time, the interfacial bonding strength between the composite layer and the original pavement base layer is also tested. If all the test indicators meet the preset reinforcement technical requirements, the rapid reinforcement of the bridge deck pavement is completed. If there are areas where the test indicators are not up to standard, the areas are repaired and retested until all test indicators meet the requirements.

[0047] In this embodiment, based on preliminary testing and combined with standardized base surface treatment and steel mesh positioning technology, potential hazards such as delamination and detachment are avoided, optimizing the overall load-bearing capacity and structural stability of the bridge deck pavement. Simultaneously, the composite application of UHPC material and steel mesh creates a composite layer that not only possesses excellent structural strength but also effectively blocks external environmental erosion, slows down structural aging, and improves bridge deck smoothness and vehicle comfort. Furthermore, the steam curing process accelerates the hardening and forming of the composite layer, significantly shortening the reinforcement operation cycle and quickly restoring bridge deck traffic capacity. This minimizes the impact of construction on traffic flow, ensuring reinforcement quality while maintaining construction efficiency, achieving a dual optimization of practicality and economy. It extends the service life of the bridge deck pavement, reduces subsequent maintenance costs, and comprehensively improves reinforcement effect, construction efficiency, and structural durability.

[0048] In this embodiment, determining the pavement layer defect level specifically includes:

[0049] Data classification and organization: The test data of the original bridge deck pavement layer thickness, surface damage, internal hollow and crack distribution, base concrete strength, and interface bonding performance are classified and statistically analyzed. Invalid test data are removed, and test datasets for each test point of the pavement layer are generated. The test datasets include the type of defect, quantitative indicators and spatial location information of each test point.

[0050] Single-index defect level determination: Based on the relevant technical standards for bridge deck paving engineering, and based on the test dataset, corresponding defect grading standards are formulated for each test index. For each test index, the single defect type such as insufficient paving layer thickness, surface pits / peeling / exposed aggregate, internal hollow area / depth, crack width / length / direction, substandard base concrete strength, and insufficient interface bonding strength are classified into three single-index defect levels: minor, moderate, and severe.

[0051] Comprehensive Defect Level Assessment of Pavement Layer: Based on the single-index defect level of each testing point, combined with the weight of the defect type's impact on the structural safety and service durability of the pavement layer, a comprehensive weighted assessment is conducted, dividing the pavement layer into three comprehensive defect levels. The criteria for determining the pavement layer areas requiring reinforcement are clearly defined: Level 1: No defects / minor defects, no reinforcement required; Level 2: Moderate defects, local reinforcement required; Level 3: Severe defects, overall reinforcement required.

[0052] In this embodiment, the single-index disease grading standard is as follows: pavement layer thickness deviation ≤5mm is minor, 5-10mm is moderate, and >10mm is severe; crack width <0.2mm is minor, 0.2-0.5mm is moderate, and >0.5mm is severe; hollow area <0.5㎡ is minor, 0.5-2㎡ is moderate, and >2㎡ is severe; base concrete strength ≥85% of design strength is minor, 60%-85% is moderate, and <60% is severe; interface bond strength ≥1.5MPa is minor, 1.0-1.5MPa is moderate, and <1.0MPa is severe.

[0053] In this embodiment, the comprehensive grade assessment is conducted by weighting the base strength (0.3), interface bonding strength (0.25), crack distribution (0.2), hollow area (0.15), and paving thickness (0.1) to obtain the comprehensive disease score for each area. A score ≤3 is grade one, 3-6 is grade two, and >6 is grade three.

[0054] In this embodiment, determining the scope of the reinforcement work also includes:

[0055] Obtain the relationship between the defined reinforcement work area and key components such as structural joints, expansion joints, and drainage facilities of the original pavement layer of the bridge. Combine the construction process requirements of key components to determine the construction operation margin of the reinforcement work area. At the same time, take into account the structural stability of adjacent unaffected areas, make local corrections and boundary optimizations to the reinforcement work area, and determine the optimized reinforcement work area.

[0056] Based on the optimized reinforcement work area, the bridge deck is marked with conspicuous markings. At the same time, key defect areas such as the core area of ​​severe defects, hollow areas, and areas with concentrated cracks within the reinforcement work area are marked separately to clarify the key areas for subsequent cleaning and repair, and to provide accurate on-site basis for subsequent construction steps such as steel mesh positioning and base surface treatment.

[0057] In this embodiment, by generating a detection dataset containing defect types, quantitative indicators, and spatial location information, various single defect types are classified into levels. Simultaneously, a comprehensive weighted assessment is performed, combining the impact weights of different defect types on the structural safety and durability of the pavement layer. This clarifies the severity of defects in different areas and the corresponding reinforcement needs. Furthermore, when determining the scope of reinforcement work, by analyzing its correlation with key bridge components and considering construction process requirements and the stability of adjacent defect-free areas, the scope is corrected and boundaries optimized. This effectively avoids adverse effects of reinforcement work on key bridge functional components, ensuring the compatibility and coordination between the reinforced area and the original structure. By clearly marking the reinforcement outline and key defect locations, the focus of the work is clarified, improving the targeted and orderly nature of construction, further solidifying the preliminary foundation for reinforcement construction, and optimizing the standardization of the overall construction process.

[0058] In this embodiment, the preparation of the UHPC material further includes:

[0059] The preset mix proportions by weight are: 400-450 parts cement, 80-100 parts silica fume, 600-650 parts ultrafine quartz sand, 120-150 parts steel fiber, 8-12 parts high-efficiency water-reducing agent, and 160-180 parts water; wherein, the steel fiber is copper-plated microfiber steel fiber with a diameter of 0.2-0.3mm, a length of 12-15mm, and an aspect ratio of 50-60;

[0060] In the preparation of UHPC materials, cement, silica fume, and ultrafine quartz sand are dry-mixed, then high-efficiency water-reducing agent and water are added for wet mixing, and steel fibers are added for low-speed mixing after wet mixing.

[0061] The dry mixing time is 2-3 minutes, the wet mixing time is 4-5 minutes, the material temperature is controlled at 15-25℃ during the mixing process, the low-speed mixing time is 5-8 minutes to avoid steel fiber clumping, and the expansion of UHPC material is tested after mixing to ensure that the expansion reaches 600-700mm and the expansion loss does not exceed 50mm in 30 minutes.

[0062] In this embodiment, the preparation of the UHPC material further includes modifying the steel fibers by immersing the steel fibers in a 3%-5% silane coupling agent solution for 20-30 minutes and then drying them in an oven at 80-100℃ until constant weight. The modified steel fibers have a silane coating layer on their surface, which improves the interfacial bonding performance between the steel fibers and the cementitious material, reduces the probability of fiber agglomeration, and ensures the uniformity of the mechanical properties of the UHPC material.

[0063] In this embodiment, the silane coupling agent used is KH-550. When preparing the solution, ethanol is used as the solvent, and the volume ratio of silane coupling agent, ethanol and water is 1:40:5. After stirring evenly, it is allowed to stand for 10-15 minutes to allow the silane coupling agent to be fully hydrolyzed and to ensure the modification effect. The dried steel fibers need to be put into the stirring equipment within 2 hours to avoid the surface modification layer from becoming damp and failing.

[0064] In this embodiment, by adjusting the UHPC material mix ratio, combining a staged mixing process, and strictly controlling the material temperature and mixing time, the clumping of steel fibers can be effectively avoided, ensuring that the material has the required expansion and performance stability, and preventing quality problems such as bubbles and voids. At the same time, the steel fibers are modified with a special silane coupling agent solution to form a stable silane coating layer on the surface of the steel fibers, which strengthens the interfacial bonding performance between the steel fibers and the cementitious material, further reducing the probability of fiber agglomeration, ensuring uniform mechanical properties of the UHPC material, guaranteeing the stability of the modification treatment effect, giving full play to the reinforcing role of steel fibers in the composite layer, improving the synergistic working efficiency of the UHPC material and the steel mesh, and consolidating the quality foundation for bridge deck pavement reinforcement.

[0065] In this embodiment, the layered casting includes:

[0066] First layer pouring: Pour UHPC material to the bottom of the steel mesh. The pouring thickness should just cover the bottom of the steel mesh. Use an immersion vibrator to vibrate along the gaps in the steel mesh. Control the vibration frequency to 200~300 times / min and the vibration time to 30-60 seconds per location until there are no bubbles on the surface of the slurry and the slurry shows a state of overflowing slurry. Ensure that the UHPC slurry fills the bottom of the steel mesh and the gaps at the interface of the base layer to avoid hollow areas.

[0067] Second layer pouring: After the first layer is vibrated, the second layer is poured. The pouring thickness is up to the preset total thickness of the composite layer. A flat plate vibrator is used to vibrate at a uniform speed along the longitudinal direction of the bridge deck. The vibration speed is controlled at 1-1.5m / min. During the vibration process, manual leveling is used to ensure that the surface flatness error of the composite layer is no more than 3mm / 2m.

[0068] In this embodiment, the composite layer casting process further includes: real-time monitoring of the steel mesh position during the casting process, using a combination of laser positioning instrument and strain gauges. The laser positioning instrument is set up with a monitoring point every 200-300mm to collect real-time data on the steel mesh's planar displacement and vertical deformation. The strain gauges are attached to the steel mesh overlap and the fixed position of the positioning component to simultaneously monitor the stress and strain of the steel mesh. If the steel mesh displacement or deformation exceeds the preset warning threshold, the casting is immediately stopped and adjustments and fixation are performed.

[0069] In this embodiment, a small vibratory tool is used to assist in the vibration of complex areas such as the corners of the bridge deck and the perimeter of expansion joints, ensuring that the UHPC grout is filled densely, while avoiding excessive vibration that could cause the steel fibers to float or the grout to segregate.

[0070] In this embodiment, during the layered pouring, each layer is 50-80mm thick, and the interval between two adjacent layers does not exceed 30 minutes to avoid cold joints between layers. After the second layer is poured, a mechanical trowel is used in conjunction with manual labor to level and smooth the surface. The trowel rotates at 150-200 r / min, and the flatness deviation of the paved surface after smoothing does not exceed 2mm / m, and there are no obvious trowel marks or air bubbles on the surface.

[0071] In this embodiment, favorable conditions are created for the full flow and filling of UHPC slurry, ensuring that the slurry can evenly penetrate to the bottom of the steel mesh and the gaps at the interface of the base layer. At the same time, the layered vibration process can more accurately remove air bubbles in the slurry, eliminating quality problems such as voids and gaps, and ensuring a tight bond between the composite layer and the steel mesh and the original base layer. Controlling the pouring interval between adjacent layers can effectively avoid the formation of cold joints between layers, strengthen the overall bonding of the upper and lower UHPC materials, improve the overall structural strength and load-bearing capacity of the composite layer, and avoid the risk of structural damage caused by layered stress. In addition, layered pouring facilitates precise control of the pouring process, allowing for individual control of the pouring quality of each layer. At the same time, the auxiliary vibration operation adapted to complex parts can take into account the filling density of special areas such as corners and around expansion joints, avoiding problems such as steel fiber floating and slurry segregation caused by over-vibration, ensuring uniform performance of materials, and laying a solid foundation for the overall molding quality and subsequent durability of the composite layer.

[0072] In this embodiment, the quality inspection further includes: detecting the distribution of steel fibers inside the UHPC. This is achieved by using an ultrasonic probe to scan the surface of the composite layer at a uniform speed, locating and marking the position of the steel mesh, dividing the area without steel mesh into inspection zones, eliminating the interference of the steel mesh on the inspection results, and using an inductive testing device to scan the area without steel mesh to detect the content and distribution of steel fibers in the area without steel mesh. The deviation of steel fiber content and the uniformity of distribution are analyzed to ensure that the mechanical properties of the UHPC meet the standards and improve the accuracy of the inspection.

[0073] In the above embodiments, the steel mesh is located by ultrasonic probe and the detection area without steel mesh is divided, which effectively eliminates the interference of steel mesh on the detection results. Combined with the scanning and analysis of steel fiber content and distribution by inductive detection equipment, the uniformity of steel fiber distribution and content deviation can be accurately controlled, further ensuring that the mechanical properties of UHPC meet the standards, improving the accuracy of overall quality detection, and providing dual protection for the molding quality of composite layer and subsequent durability.

[0074] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A rapid reinforcement method for bridge deck pavement based on UHPC-steel mesh composite layer, characterized in that, Includes the following steps: Pavement structure inspection: Conduct a comprehensive inspection of the original bridge deck pavement layer, determine the level of pavement layer defects and the scope of reinforcement work based on the inspection results, and mark the target areas that need to be cleaned and repaired; Steel mesh positioning: The base surface is treated for the determined reinforcement work area, and the steel mesh is cut according to the size of the reinforcement work area. Positioning devices are used to fix the steel mesh laid on the base surface. UHPC material preparation: Weigh the corresponding raw materials according to the preset mixing ratio, put the raw materials into the mixing equipment for graded mixing, and mix until the UHPC material meets the preset index requirements to complete the preparation of UHPC material; Composite layer casting and forming: The prepared UHPC material is poured in layers on top of and around the fixed steel mesh, and the poured UHPC material is vibrated with a vibrating device. After vibration, the paving surface is leveled and smoothed to form a UHPC-steel mesh composite layer. Quality inspection: The UHPC-steel mesh composite layer is inspected for quality, and the interfacial bonding strength between the composite layer and the original pavement base layer is also tested. If all test indicators meet the preset reinforcement technical requirements, the rapid reinforcement of the bridge deck pavement is completed. If there are areas where the test indicators are not up to standard, the areas are repaired and retested until all test indicators meet the requirements.

2. The rapid reinforcement method for bridge deck pavement based on UHPC-steel mesh composite layer as described in claim 1, characterized in that, Determining the severity of pavement defects includes: Data classification and organization: The test data of the original bridge deck pavement layer are classified and statistically analyzed, invalid test data are removed, and test datasets for each test point of the pavement layer are generated; Single-index disease level determination: Based on the detection dataset, a corresponding disease grading standard is formulated for each detection index. The single disease type of the pavement layer corresponding to each detection index is classified into three single-index disease levels: slight, moderate, and severe. Comprehensive disease level assessment of pavement layer: Based on the single-index disease level of each detection point, combined with the influence weight of the disease type on the pavement layer, a comprehensive weighted assessment is carried out, and the pavement layer as a whole is divided into three comprehensive disease levels.

3. The rapid reinforcement method for bridge deck pavement based on UHPC-steel mesh composite layer as described in claim 2, characterized in that, Determining the scope of reinforcement work also includes: Obtain the correlation between the defined reinforcement work area and the key parts of the original pavement layer of the bridge, determine the construction operation margin of the reinforcement work area in combination with the construction process requirements of the key parts, and at the same time, make local corrections and boundary optimizations to the reinforcement work area to determine the optimized reinforcement work area. Based on the optimized reinforcement work area, the bridge deck is outlined and marked, while key damaged areas within the reinforcement work area are marked separately.

4. The rapid reinforcement method for bridge deck pavement based on UHPC-steel mesh composite layer as described in claim 1, characterized in that, The surface treatment includes roughening the surface by mechanical shot blasting, with the shot blasting depth controlled at 2-3mm to achieve a surface roughness of 4-6μm. The steel mesh is made of welded steel bars with a diameter of 6-8mm and a mesh size of 100mm×100mm-150mm×150mm. The overlap length of the cut steel mesh is not less than two mesh side lengths, and the overlap is fixed by spot welding. The positioning components are high-strength expansion bolts with a spacing of 500-800mm. The reserved gap between the steel mesh and the surface is set within the range of 20-30mm.

5. The rapid reinforcement method for bridge deck pavement based on UHPC-steel mesh composite layer as described in claim 1, characterized in that, The preparation of the UHPC material also includes: The preset mix proportions by weight are: 400-450 parts cement, 80-100 parts silica fume, 600-650 parts ultrafine quartz sand, 120-150 parts steel fiber, 8-12 parts high-efficiency water-reducing agent, and 160-180 parts water. In the preparation of UHPC materials, cement, silica fume, and ultrafine quartz sand are dry-mixed, then high-efficiency water-reducing agent and water are added for wet mixing, and steel fibers are added for low-speed mixing after wet mixing. The dry mixing time is 2-3 minutes, the wet mixing time is 4-5 minutes, the material temperature is controlled at 15-25℃ during the mixing process, the low-speed mixing time is 5-8 minutes, and the expansion of UHPC material is tested after mixing is completed.

6. The rapid reinforcement method for bridge deck pavement based on UHPC-steel mesh composite layer as described in claim 5, characterized in that, The preparation of the UHPC material also includes modifying the steel fibers by immersing the steel fibers in a 3%-5% silane coupling agent solution for 20-30 minutes, and then drying them in an oven at 80-100℃ until constant weight. A silane coating layer is formed on the surface of the modified steel fibers.

7. The rapid reinforcement method for bridge deck pavement based on UHPC-steel mesh composite layer as described in claim 1, characterized in that, The layered casting includes: First layer pouring: Pour UHPC material to the bottom of the steel mesh, and use an immersion vibrator to vibrate along the gaps in the steel mesh. The vibration frequency is controlled at 200~300 times / min, and the vibration time is 30-60 seconds per location, until there are no bubbles on the surface of the slurry and the slurry shows a state of overflowing slurry. Second layer pouring: After the first layer is vibrated, the second layer is poured, with the pouring thickness reaching the preset total thickness of the composite layer. A flat plate vibrator is used to vibrate at a uniform speed along the longitudinal direction of the bridge deck, with the vibration speed controlled at 1-1.5 m / min.

8. The rapid reinforcement method for bridge deck pavement based on UHPC-steel mesh composite layer as described in claim 7, characterized in that, The composite layer casting process also includes: real-time monitoring of the steel mesh position during the casting process, real-time collection of steel mesh planar displacement and vertical deformation data, and synchronous monitoring of the steel mesh stress and strain. If the steel mesh displacement or deformation exceeds the preset warning threshold, the casting process is immediately stopped and adjustments and fixation are performed.

9. A rapid reinforcement method for bridge deck pavement based on UHPC-steel mesh composite layer as described in claim 8, characterized in that, During the layered pouring, each layer is 50-80mm thick, and the interval between two adjacent layers does not exceed 30 minutes. After the second layer is poured, a mechanical trowel is used in conjunction with manual labor to level and smooth the surface. The trowel rotates at 150-200 r / min. After smoothing, the flatness deviation of the paved surface does not exceed 2mm / m, and there are no obvious trowel marks or air bubbles on the surface.

10. The rapid reinforcement method for bridge deck pavement based on UHPC-steel mesh composite layer as described in claim 1, characterized in that, The quality inspection also includes: steel fiber distribution detection inside UHPC, which involves scanning the surface of the composite layer at a constant speed using an ultrasonic probe to locate and mark the steel mesh position, dividing the steel mesh-free detection area, and based on the detection results, using an inductive detection device to scan the steel mesh-free detection area to detect the steel fiber content and distribution status within the steel mesh-free detection area, and analyzing the steel fiber content deviation and distribution uniformity.

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