Novel assembly type pavement composite structure for pavement maintenance and construction method of novel assembly type pavement composite structure

Abstract

The invention discloses a novel assembly type pavement composite structure for pavement maintenance and a construction method thereof. The structure is composed of a structural layer obtained after finish milling of an old road, a flexible leveling transition layer, a concrete prefabricated slab structural layer, a stress absorption functional layer and an ultra-thin overlay wearing layer. A flexible leveling transition layer is laid on a structural layer after finish milling of an old road, then concrete prefabricated slabs are installed and spliced, a concrete prefabricated slab structural layer is obtained after connection between the concrete prefabricated slabs and slab joint treatment, an anti-crack patch is laid, and a stress absorption layer and an ultrathin cover wearing layer are sequentially laid. The invention focuses on key technologies such as a flexible leveling transition layer fine leveling method, a concrete precast slab efficient load transfer connection method, a durable anti-seepage joint filling method between concrete precast slabs, an ultrathin cover surface anti-sliding and anti-cracking construction method and the like, and establishes a perfect fabricated pavement novel combined structure and system for pavement maintenance. And the blank of large-scale application of the fabricated pavement technology in the highway field is filled.

Description

Technical Field

[0001] The present invention relates to the technical field of road engineering, and in particular to a new type of assembled pavement composite structure for pavement maintenance and a construction method. Background Art

[0002] Currently, highway maintenance around the world faces many challenges, the most important of which include the growing traffic volume, complex and changing environmental factors, and aging road infrastructure. Traditional highway maintenance methods usually include surface initialization, local repair, renovation and reconstruction, etc. Although these methods can optimize and improve the durability and performance of roads to a certain extent, they often face many disadvantages and shortcomings: conventional periodic maintenance mode often leads to the scattered use of maintenance resources, cannot accurately target the actual damage of roads, and sometimes may form unnecessary financial burdens; although local repair work can temporarily solve the problem, if thorough structural repair is not carried out, it may lead to more serious structural problems and impact on driving safety. Renovation and reconstruction projects usually involve large-scale construction and require long-term traffic control, which will greatly affect traffic flow and have a significant impact on the social economy. The coupling of environmental factors such as temperature changes, precipitation, and freeze-thaw cycles will have an adverse effect on the effectiveness of traditional maintenance methods and reduce the durability and stability of the road surface.

[0003] The increasingly heavy highway maintenance tasks and high-quality maintenance quality require timely, fast, safe, reliable maintenance work, controllable maintenance costs and excellent maintenance quality. The maintenance operation time should be shortened as much as possible, and traffic should not be closed under normal circumstances. The outstanding technical difficulties faced by durability maintenance and rapid maintenance urgently require a new and reliable maintenance technology to meet the current actual needs for high efficiency of maintenance work and high quality control of maintenance. Prefabricated pavement technology adopts factory standardized customization, rapid on-site installation and splicing, and subsequent modular treatment of damage. It not only guarantees the construction quality and has little impact on traffic, but also can reduce maintenance costs and improve the accuracy of maintenance. It is a feasible solution for achieving rapid highway maintenance and high-quality durability maintenance. However, prefabricated pavement technology developed relatively late in my country. Not only does it account for a small proportion of pavement construction and maintenance, and its application is very limited, but also the theoretical and technical system is imperfect, and the key pavement process technology is not matched. It is still in the exploratory stage as a whole. There is an urgent need for a new composite structure and system of prefabricated pavement suitable for pavement maintenance.

[0004] In the current prefabricated pavement technology, there is no overlay on the concrete precast slab, which is directly used as the road surface layer. The precast slab is directly exposed to the natural environment, resulting in large-scale expansion and contraction and water seepage problems, and the driving comfort of concrete as the road surface layer is far less than that of the overlay layer. Other layers, such as the cement mortar transition layer, have poor leveling effect, and the mortar with high modulus and stiffness will crack and deform as a whole under the action of traffic load for a long time, thus affecting the flatness of the upper precast slab and the smoothness of the overall road surface. At the same time, the current mechanical connection and adhesive connection between concrete precast slabs are relatively complicated, not only there is the problem of loose connection, but also requires high-precision construction and detection methods; and the current welding connection parts have low durability and are easily corroded in long-term use, especially in humid environments, and the corrosion resistance of the welding joints is poor. In addition, the current joints between concrete precast slabs use epoxy joint filling materials MRK, or asphalt mixtures or even cement mortar materials, which will cause performance degradation, cracks or shedding due to factors such as aging and temperature changes. Summary of the invention

[0005] In view of the shortcomings of the above-mentioned existing highway maintenance technologies, the purpose of the present invention is to provide a new composite structure and system of prefabricated pavement suitable for road maintenance. This structure and technical system mainly solve the problems of imperfect technical structure and technical system of current prefabricated pavement and incompatible construction technology, so as to realize rapid highway maintenance and high-quality control durability maintenance.

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

[0007] One of the technical solutions of the present invention is that the structural form of the new composite structure and system of prefabricated pavement for pavement maintenance is composed of a structural layer (old base layer) after fine milling of the old road, a leveling transition layer, a concrete precast slab structural layer, a stress absorption functional layer, and an ultra-thin cover wear layer; its structural combination is to lay a flexible leveling transition layer on the structure after fine milling of the old road, and then install and splice the concrete precast slabs, and after the connection between the concrete precast slabs and the plate seam treatment, lay anti-cracking stickers and lay the stress absorption layer and the ultra-thin cover wear layer in sequence.

[0008] Furthermore, the structural layer (old base layer) after fine milling of the old road is mainly aimed at the road surface with degraded performance, such as the road surface with serious apparent damage (cracks, subsidence, etc.) and surface aging (surface aging, peeling of adhesive layer, etc.), or the road surface that needs structural upgrading. Through detailed investigation and evaluation of the old road surface, according to the old road surface conditions and design requirements, the milling machine is used to accurately control the milling depth, and the milling depth is determined according to the damage of the old road surface and design requirements;

[0009] The flexible leveling transition layer is located between the old road structure after fine milling and the concrete precast slab, and the thickness of the structure is controlled at 10 to 30 mm, and the flatness needs to be accurately controlled within the range of ≤3 mm;

[0010] The concrete precast slab structural layer is located between the flexible leveling layer and the stress absorbing layer, and the structural thickness is controlled at 60-80 mm, which is used for bearing required by the current highway grade and connecting with each structural layer;

[0011] The stress absorption functional layer is located between the concrete precast panel and the ultra-thin cover layer, and the structural thickness is controlled at 10 to 15 mm, and is used for stress absorption and stress dissipation, as well as for resisting lower reflective cracks;

[0012] The stress absorbing functional layer is hot plate asphalt mixture AC-5.

[0013] The ultra-thin overlay wear layer is located on the stress absorbing layer, and the structural thickness is controlled at 20-25 mm, and is used for waterproofing and anti-seepage, especially for anti-slip, anti-cracking and anti-wear functions.

[0014] The ultra-thin overlay wear layer is a T-paveⅠ type densely distributed asphalt concrete mixture.

[0015] The second technical solution of the present invention is a new composite structure and system of prefabricated pavement for pavement maintenance, which realizes the construction of a new composite structure of prefabricated pavement with rapid maintenance through a flexible leveling transition layer precision leveling method, a concrete precast slab efficient load transfer connection method, a durable anti-seepage caulking method between concrete precast slabs, and an ultra-thin cover anti-skid and anti-cracking construction method.

[0016] Furthermore, the flexible leveling transition layer fine leveling method adopts a combination of a lower layer of high-performance mortar and an upper layer of geotextile flexible functional layer, which improves the traditional paving form of gravel, crushed stone and mortar. The combination of high-performance mortar and flexible functional layer not only has high leveling accuracy and quality, but also has better stress dispersion and deformation coordination capabilities, and can more effectively disperse and buffer traffic loads.

[0017] The methods for fine leveling of the flexible leveling transition layer include the following:

[0018] Step A1: Lay high-performance cement mortar on the structure after fine milling of the old road, and strictly control the surface flatness test result of the 3m ruler to be ≤3mm;

[0019] In particular, the elevation of the structure after fine milling of the old road is verified and the construction surface is cleaned. Then, the edge-banding steel plates are laid according to the designed construction surface dimensions. After the installation is completed, the elevation of the edge-banding steel plates is verified to ensure accuracy.

[0020] Specifically, the well - mixed high - performance cement mortar is evenly spread in the leveling area, and scraping mortar is carried out along the top of the edge - sealing steel plate to evenly spread the leveling mortar. Observe the scraping quality of the leveling layer. In case of less mortar, operations such as replenishing mortar are carried out, and re - scraping is carried out. After the edge - sealing steel plate is scraped flat, local trimming is carried out on the scraped surface, and the surface is finished and polished to reduce shrinkage cracks and locally uneven parts.

[0021] The high - performance cement mortar is mixed from the following raw materials by mass parts: 210 - 305 parts of cement, 260 - 925 parts of fly ash, 45 - 245 parts of silica fume, 245 parts of quartz sand, 20 - 145 parts of water - reducing agent, 10 - 15 parts of thickening agent, 10 - 15 parts of polypropylene fiber, 10 - 15 parts of polyvinyl alcohol fiber, and 115 - 500 parts of water.

[0022] Step A2, control the initial setting time of the high - performance cement mortar within 30 - 60 min. After 24 - hour curing of the high - performance cement mortar, when the strength reaches ≥20 MPa, lay the geotextile with staggered joints, compact the geotextile through a paving and rolling device, and fix it with a nail - type fixer. Strictly control the surface flatness test result of the 3 - m straightedge ≤3 mm.

[0023] Specifically, after the leveling layer mortar is cured and passes the quality acceptance, re - check the elevation of the leveling layer until it meets the design elevation. Set up the geotextile through machinery, with the rough surface facing up, and then fix one end with a nail - type fixer with a nail length of 8 - 10 cm. Tighten it through machinery or manpower, with a tensile elongation rate of about 1.0% - 1.5%, and lay it flat and tightly against the road surface forward;

[0024] Specifically, the transverse lap of the geotextile is about 4 - 5 cm. According to the paving direction, press the rear end under the front end, and bond it well with hot asphalt or emulsified asphalt, and fix it with a fixer; the longitudinal lap is also about 4 - 5 cm, and it can be directly bonded with adhesive oil. The geotextile should be laid as straight as possible. When turning is required, cut the fabric at the bending part, overlap and lay it, and spray tack coat for bonding.

[0025] The efficient load transfer connection method of the concrete precast slab adopts the welded connection form of the full - length steel bars in the precast slab, which improves the problems of the traditional mechanical connection and adhesive connection between precast slabs being not firm and the high - precision construction, and improves the traditional welding connection method. The layout of the full - length steel bars in the precast slab is adjusted according to the welding lap length and construction convenience, and there is a caulking treatment at the welding connection position to avoid the welding part being eroded during long - term use. It includes the following:

[0026] Step A1, multiple interfaces (such as 2 - 4 interfaces) are respectively set longitudinally and transversely on the concrete precast slab, and full - length steel bars are arranged vertically and horizontally in the concrete precast slab, and the ends of the full - length steel bars at the interfaces are connected in a U - shape;

[0027] In particular, the full-length steel bars laid in the concrete precast slabs are designed with structural reinforcement, the steel bars are densely reinforced at the interfaces, and the ends of adjacent full-length bars are connected.

[0028] Step A2, setting the longitudinal and transverse arrangement of the precast concrete panels by precise positioning;

[0029] In particular, precise positioning is achieved through a digital GPS positioning system and a 3D scanner device, and the precast concrete panels are positioned and assembled using a paving device that integrates intelligent paving and precise positioning;

[0030] Step A3, adjacent concrete precast panels are connected by welding through embedded steel bars at the interfaces of the precast panels, forming a bilaterally symmetrical I-shaped connector.

[0031] In particular, the concrete precast panels adopt the method of single-sided lap welding by manual arc welding, strictly controlling the lap length within the range of 100 to 160 mm, strictly controlling the weld length to 70% to 100% of the lap length, and strictly controlling the effective depth of the weld to not be less than 30% of the steel bar diameter.

[0032] Compared with the traditional technology, the durable anti-seepage caulking method between concrete precast panels proposes special treatment of different positions. The precast panel joints are filled with a lower layer of sulphoaluminate mortar and an upper layer of asphalt sand, and the non-connected parts are filled with a lower layer of sulphoaluminate mortar and an upper layer of high-viscosity asphalt sealant. The special treatment of different positions fully considers the difference between the connection and non-connection positions of the precast panels, which not only ensures the anti-seepage and waterproofing of the precast panel caulking, but also the excellent stress dissipation and deformation coordination ability of the elastic caulking material, and will not show performance degradation, cracks or detachment due to factors such as aging and temperature. It includes the following:

[0033] Step A1: For the position of the concrete precast slab connector, the upper 1 / 4 area of ​​the precast slab is filled with asphalt sand, and the lower 3 / 4 area of ​​the precast slab is filled with 42.5-grade fast-strengthening and fast-hardening sulphoaluminate mortar;

[0034] Step A2: For the non-connector positions of the concrete precast slab, high-viscosity asphalt sealant is used in the upper 1 / 4 area of ​​the precast slab, and 42.5-grade fast-strengthening and fast-hardening sulphoaluminate cement is used to fill the lower 3 / 4 area of ​​the precast slab.

[0035] In particular, mortar filling first requires flushing and cleaning of the prefabricated slab joints. The filling process is layered, 3 to 5 cm as a layer. Each layer should be vibrated with a stick after filling. When using asphalt sand or high-viscosity asphalt sealant filling, high-viscosity asphalt sealant should be used as the filling adhesive. The filling process is layered with 1 cm until the filling is 1 to 2 cm higher than the road surface. After filling, the center of the pothole should be convex.

[0036] The above-mentioned ultra-thin surface anti-skid and anti-cracking construction method mainly solves the problem that there is no additional layer on the concrete prefabricated slab in the current prefabricated pavement technology, which is directly used as the road surface layer, and the prefabricated slab is directly exposed to the natural environment, resulting in large-scale expansion and contraction and water seepage, and improves the driving stability and comfort. Compared with traditional process technology, the ultra-thin surface anti-skid and anti-cracking construction method uses high-performance materials, introduces uniform spraying technology and rapid curing technology, ensures the quality of the surface layer and improves construction efficiency. It includes the following:

[0037] Step A1, laying a self-adhesive polyester fiberglass cloth anti-cracking sticker at the seam of the precast concrete slab;

[0038] Step A2, spraying SBS high-viscosity asphalt adhesive layer on the concrete precast slab, and then laying dense-graded AC-5 on the stress absorption layer;

[0039] Step A3, spray SBS high-viscosity asphalt adhesive layer on the stress absorption layer, and then lay T-paveⅠ type densely matched high-strength and high-toughness ultra-thin wear layer, strictly control the ultra-thin cover surface flatness ≤3mm, friction coefficient ≥45.

[0040] In particular, the anti-skid and anti-cracking construction of the ultra-thin overlay is carried out in sequence, including the paving of anti-cracking stickers, the paving of stress absorption layers, and the paving of thin overlays, and the synchronous construction process is selected for the tack layer construction, and the spraying amount of tack layer oil is controlled at 0.7-0.8 kg / m2. In addition, the AC-5 stress absorption layer mixture and the high-strength and high-toughness thin overlay asphalt mixture use a non-contact balance beam device to control the paving thickness, and compact and shape them in time at a higher temperature after paving to ensure the compaction and flatness of the paving material.

[0041] Beneficial effects:

[0042] Aiming at the prefabricated pavement technology suitable for rapid road construction and durable maintenance, the present invention proposes a new type of prefabricated pavement structure combination, focusing on key technologies such as the flexible leveling transition layer precision leveling method, the concrete precast slab efficient load transfer connection method, the durable anti-seepage caulking method between concrete precast slabs, and the ultra-thin cover anti-skid and anti-cracking construction method, and establishes a complete new type of prefabricated pavement combination structure and system for pavement maintenance, and proposes a series of industrialized technical solutions such as structural design-material selection-construction adaptation, filling the gap in the large-scale application of prefabricated pavement technology in the highway field. As a new technical solution, a new type of prefabricated pavement combination structure and system for pavement maintenance has changed the traditional construction method, which is conducive to speeding up the project construction progress, improving the pavement quality, extending the service life, facilitating later maintenance, green environmental protection, etc., which is conducive to the rapid and high-quality development of the industry and has high social and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1New structural combination forms of prefabricated pavement for pavement maintenance;

[0044] Figure 2 Schematic diagram of construction of flexible leveling transition layer of prefabricated pavement;

[0045] Figure 3 Schematic diagram of the layout of prefabricated pavement panels and the connection between panels;

[0046] Figure 4 Schematic diagram of durable anti-seepage caulking between prefabricated road panels;

[0047] Figure 5 Schematic diagram of the anti-skid and anti-cracking structure of the ultra-thin overlay of the assembled pavement;

[0048] In the figure: 1-structural layer after fine milling of the old road, 2-flexible leveling transition layer, 3-concrete precast slab structural layer, 4-stress absorption functional layer, 5-ultra-thin overlay wear layer; 6-edge-sealing steel plate, 7-high-performance cement mortar, 8-geotextile, 9-first fixer, 10-second fixer, 101-longitudinal interface of concrete precast slab, 102-transverse reinforcement of precast slab, 103-longitudinal reinforcement of precast slab, 104-transverse interface of precast concrete slab, 105-type connector, 106-position of connector of precast slab, 107-asphalt sand filler, 108-42.5 grade fast-strengthening and fast-hardening sulphoaluminate mortar, 109-non-connector position of concrete precast slab, 110-high-viscosity asphalt sealant, 111-42.5 grade fast-strengthening and fast-hardening sulphoaluminate cement, 112-polyester glass fiber cloth anti-cracking sticker. DETAILED DESCRIPTION

[0049] The present invention provides a new type of assembled pavement combination structure and system for pavement maintenance. In order to make the purpose, technical solution and effect of the present invention clearer and more specific, an exemplary embodiment of the present invention is now described in detail. This detailed description should not be regarded as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and implementation plans of the present invention.

[0050] The terms used in the present invention are mainly used to describe specific implementations and should not limit the scope of the present invention. In addition, unless otherwise specified, the technical and scientific terms used herein should be considered to have the same meanings as understood by a person skilled in the art with conventional knowledge in the art.

[0051] Example 1

[0052] Combined with Figure 1A new type of assembled pavement composite structure and system for pavement maintenance, the structure of which is composed of a structural layer (1) (old base layer) after fine milling of an old road, a flexible leveling transition layer (2), a concrete precast slab structural layer (3), a stress absorption functional layer (4), and an ultra-thin overlay wear layer (5); the structural combination is to lay a flexible leveling transition layer on the structural layer after fine milling of the old road, then install and splice the concrete precast slabs, and after the connection between the concrete precast slabs and the plate seam treatment, lay an anti-cracking tape and then lay a stress absorption layer and an ultra-thin overlay wear layer in sequence.

[0053] Furthermore, the old road surface is investigated and evaluated in detail. According to the condition of the old road surface and design requirements, the milling depth is precisely controlled using a milling machine. The milling depth is determined according to the damage of the old road surface and design requirements. The flatness of the base surface after milling of the old road is strictly controlled to be ≤3mm.

[0054] The flexible leveling transition layer is located between the old road structure after fine milling and the concrete precast slab, and the structure thickness is 30mm, and the flatness needs to be precisely controlled to ≤3mm;

[0055] The concrete precast slab structural layer is located between the flexible leveling layer and the stress absorbing layer, and the structural thickness is 70 mm, which is used for bearing required by the current highway grade and connecting with each structural layer;

[0056] The stress absorption functional layer is located between the concrete precast panel and the ultra-thin cover layer, with a structural thickness of 15 mm, and is used for stress absorption and stress dissipation, as well as for resisting lower reflective cracks;

[0057] The ultra-thin overlay wear layer is located above the stress absorbing layer, and has a structural thickness of 20 mm. It is used for waterproofing and anti-seepage, and especially for anti-slip, anti-cracking and anti-wear functions.

[0058] The new composite structure and system of prefabricated pavement used for pavement maintenance realizes the construction of a new composite structure of prefabricated pavement with rapid maintenance through the precise leveling method of the flexible leveling transition layer, the efficient load transfer connection method of the prefabricated concrete panels, the durable anti-seepage filling method between the prefabricated concrete panels, and the anti-skid and anti-cracking construction method of the ultra-thin cover.

[0059] Combined with Figure 2 The flexible leveling transition layer fine leveling method includes the following:

[0060] Step A1: Lay high-performance cement mortar on the structure after fine milling of the old road, and strictly control the surface flatness test result of the 3m ruler to be ≤3mm;

[0061] In particular, after the elevation of the structure after fine milling of the old road is checked, the construction surface is cleaned, and the edge sealing steel plate (6) with a thickness of 120 mm is laid according to the designed construction surface size. After the installation is completed, the elevation of the edge sealing steel plate is checked to ensure accuracy.

[0062] In particular, based on the requirements of rapid setting and crack resistance, high-performance cement mortar is prepared by mixing 250 parts of cement, 625 parts of fly ash, 145 parts of silica fume, 245 parts of quartz sand, 75 parts of water reducer, 12 parts of thickener, 15 parts of polypropylene fiber, 10 parts of polyvinyl alcohol fiber and 400 parts of water. The mixed high-performance cement mortar (7) is evenly spread in the leveling area, and the mortar is evenly spread by scraping the mortar with the scraper on the built-in guide rail of the edge-sealed steel plate. The scraping quality of the leveling layer is observed. If there is a lack of slurry, the slurry is supplemented and re-scraped. After the edge-sealed steel plate is scraped, the scraped surface is partially trimmed and smoothed to reduce shrinkage cracks and local uneven parts.

[0063] Step A2, controlling the initial setting time of the high-performance cement mortar to be between 30 and 60 minutes, and laying the geotextile (8) with staggered joints when the strength of the high-performance cement mortar reaches ≥20 MPa after curing for 24 hours, compacting the geotextile by means of a paving and rolling device, and fixing it with a fastener using nails, and strictly controlling the surface flatness test result of a 3m ruler to be ≤3 mm.

[0064] In particular, after the leveling layer mortar is cured and passes the quality inspection, the leveling layer elevation is checked again to meet the design elevation. The geotextile is mechanically erected with the rough surface facing upwards, and then one end is fixed with a nail fixture with a nail length of 8cm. It is tightened mechanically or manually, with a tensioning elongation of about 1.0% to 1.5%, and laid straight and close to the road surface;

[0065] In particular, the geotextile is overlapped by about 4 cm in the horizontal direction, and the rear end is pressed under the front end according to the paving direction, and is bonded with hot asphalt or emulsified asphalt, and fixed with the first fixture (9); the longitudinal overlap is also about 4 cm, and is fixed with the second fixture (10). The geotextile should be laid in a straight line as much as possible. When a turn is required, the curved part of the fabric is cut open, and the overlapping layers are laid and bonded by spraying adhesive layer oil.

[0066] Combined with Figure 3 The concrete precast slab efficient load transfer connection method includes the following:

[0067] Step A1: Three interfaces are provided longitudinally and transversely on the precast concrete slab. The transverse interface of the precast slab is 495 mm away from the slab edge, and the distance between interfaces is 1200 mm. The longitudinal interface of the precast slab is 690 mm away from the slab edge, and the distance between interfaces is 630 mm. Also, longitudinally and transversely criss-crossing full-length steel bars are arranged within the precast concrete slab. The transverse steel bar (102) of the precast slab is HRB400, with a diameter of 8 mm and a full-length dimension of 3750 mm. The longitudinal steel bar (103) of the precast slab is HRB 400, with a diameter of 16 mm and a full-length dimension of 3000 mm. The ends of the full-length steel bars at the transverse and longitudinal interfaces of the precast concrete slab are connected in a U-shape.

[0068] Specifically, the full-length steel bars laid in the precast concrete slab are designed through structural reinforcement. Six HRB 400 bars are arranged transversely and longitudinally, and the steel bars are densified at the interfaces, and the ends of adjacent full-length steel bars are connected.

[0069] Step A2: Set the longitudinal and transverse arrangement forms of the precast concrete slabs through precise positioning.

[0070] Specifically, precise positioning is achieved through a digital GPS positioning system and a three-dimensional scanner device. The ZPS120H intelligent slab laying machine is used to achieve precise positioning and intelligent paving of the precast concrete slab.

[0071] Step A3: Adjacent precast concrete slabs are welded and connected through the embedded steel bars at the slab interfaces, forming a left-right symmetric I-shaped connector (105).

[0072] Specifically, the precast concrete slab adopts the method of manual arc welding with single-sided lap welding. The lap length is strictly controlled at 120 mm, the weld length is strictly controlled at 80% of the lap length, and the effective depth of the weld is strictly controlled not to be less than 30% of the steel bar diameter.

[0073] Combined with the attached Figure 4 , the durable anti-seepage joint filling method between the precast concrete slabs is as follows:

[0074] Step A1: At the position of the precast concrete slab connector (106), the upper 2 cm area of the precast slab is filled with asphalt sand filler (107), and the lower 6 cm area of the precast slab is filled with 42.5-grade rapid-hardening sulphoaluminate mortar (108).

[0075] Step A2: At the position of the precast concrete slab non-connector (109), the upper 2 cm area of the precast slab is filled with high-viscosity asphalt sealant (110), and the lower 6 cm area of the precast slab is filled with 42.5-grade rapid-hardening sulphoaluminate cement (111).

[0076] In particular, mortar filling first requires flushing and cleaning of the prefabricated slab joints. The filling process is layered, 3 cm as a layer. Each layer should be vibrated with a stick after filling. When using asphalt sand or high-viscosity asphalt sealant filling, high-viscosity asphalt sealant should be used as the filling adhesive. The filling process is layered with 1 cm until the filling is 1 cm higher than the road surface. After filling, the center of the pothole should be convex.

[0077] Combined with Figure 5 The anti-slip and anti-cracking construction method of the ultra-thin cover comprises the following:

[0078] Step A1, laying a self-adhesive polyester glass fiber cloth anti-cracking sticker (112) at the seam of the precast concrete slab;

[0079] Step A2, spraying SBS high-viscosity asphalt tack layer on the concrete precast board, and then laying the dense graded AC-5 mixed with basalt coarse aggregate, limestone fine aggregate with apparent relative density ≥2.5g / cm3, limestone fine ground powder with apparent density ≥2.5g / cm3, and PG88 high-viscosity and high-elastic asphalt on the stress absorption layer (4); Step A3, spraying SBS high-viscosity asphalt tack layer on the stress absorption layer, and then laying the T-paveⅠ type dense high-strength and high-toughness ultra-thin wear layer (5) mixed with basalt coarse aggregate, limestone fine aggregate with apparent relative density ≥2.5g / cm3, limestone fine ground powder with apparent density ≥2.5g / cm3, and PG100 high-viscosity and high-elastic asphalt, and strictly controlling the ultra-thin cover surface flatness ≤3mm, and the friction coefficient ≥45.

[0080] In particular, the anti-slip and anti-cracking construction of the ultra-thin overlay is carried out in sequence by laying the anti-cracking sticker, paving the stress absorption layer and paving the thin overlay, and the synchronous construction process is selected for the tack layer construction, and the tack layer oil spraying amount is controlled at 0.7-0.8kg / m 2 In addition, the AC-5 stress absorption layer mixture and the high-strength and high-toughness thin-layer overlay asphalt mixture use a non-contact balance beam device to control the paving thickness to 35mm, and compaction and molding are carried out in time at a temperature not lower than 180℃ after paving, and the rolling termination temperature is controlled to be not lower than 135℃.

[0081] The present invention proposes a new type of prefabricated pavement structure combination form, from the key technologies such as the flexible leveling transition layer precision leveling method, the concrete precast slab efficient load transfer connection method, the concrete precast slab durable anti-seepage caulking method, the ultra-thin cover anti-skid and anti-cracking construction method, etc., to establish a complete new type of prefabricated pavement combination structure and system for pavement maintenance, and proposes a series of industrialized technical solutions such as structural design-material selection-construction adaptation, which not only ensures the quality of pavement maintenance and has a low impact on traffic, but also can reduce the pavement maintenance cost and improve the accuracy of maintenance.

[0082] Mechanical analysis is the basis for studying the bearing capacity and deformation characteristics of structural foundations. In the embodiments of the present invention, by analyzing the stress distribution, deformation characteristics and failure modes of the pavement structure under the coupling of effects (such as traffic loads, temperature changes, humidity changes, etc.), the feasibility of a prefabricated pavement composite structure scheme for pavement maintenance is further demonstrated.

[0083] The size of the concrete precast slab is 3750mm×3000mm×70mm. Three interfaces (101, 104) are set in the longitudinal and transverse directions of the concrete precast slab. The transverse interface of the precast slab is 495mm away from the edge of the slab, and the distance between the interfaces is 1200mm; the longitudinal interface of the precast slab is 690mm away from the edge of the slab, and the distance between the interfaces is 630mm. In addition, crisscrossed full-length steel bars are set in the concrete precast slab. The transverse steel bars (102) of the precast slab are HRB 400 with a diameter of 8mm; the longitudinal steel bars (103) of the precast slab are HRB400 with a diameter of 16mm. The results of the hoisting calculation of the concrete precast slab, the load transfer efficiency analysis between the precast slabs, and the structural fatigue life calculation are shown in the following table.

[0084] Table 1 Concrete precast slab hoisting stress

[0085]

[0086] Table 2 Load transfer efficiency between concrete precast panels

[0087]

[0088] Table 3 Maximum mechanical response of concrete precast slabs (traffic load)

[0089]

[0090] Table 4 Maximum mechanical response of ECC prefabricated panels (temperature effect)

[0091]

[0092] The combined structure meets the hoisting calculation requirements of concrete precast panels, and the load transfer efficiency between precast panels is greater than 90%. In addition, fatigue cracking and ultimate fracture do not occur under the combined effects of vehicle load and temperature gradient. The mechanical analysis results show that a prefabricated pavement combined structure scheme for pavement maintenance meets the requirements of hoisting and load transfer, and has excellent fatigue resistance and ultimate fracture resistance. The scheme is proven to be feasible.

[0093] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0094] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0095] Obviously, those skilled in the art can make various changes and modifications to the invention without departing from the spirit and scope of the invention. Thus, if these modifications and variations of the invention fall within the scope of the claims of the invention and their equivalents, the invention is also intended to include these modifications and variations.

Claims

1. An assembled pavement structure for pavement maintenance, characterized in that: It consists of the structural layer after fine milling of the old road, a flexible leveling transition layer, a precast concrete slab structural layer, a stress absorption functional layer, and an ultra-thin wearing course. A flexible leveling transition layer is laid on the structural layer after fine milling of the old road, and then the precast concrete slabs are installed and spliced. After the connection between the precast concrete slabs and the treatment of the slab joints, a precast concrete slab structural layer is obtained. An anti-cracking sticker is laid, and then a stress absorption layer and an ultra-thin wearing course are laid in sequence.

2. The assembled pavement structure for pavement maintenance according to claim 1, characterized in that: The thickness of the flexible leveling transition layer is controlled within 10 - 30 mm; the thickness of the precast concrete slab structural layer is controlled within 60 - 80 mm; the thickness of the stress absorption functional layer structure is controlled within 10 - 15 mm; the thickness of the ultra-thin wearing course structure is controlled within 20 - 25 mm.

3. The assembled pavement structure for pavement maintenance according to claim 1, characterized in that: The stress absorption functional layer is a hot plate asphalt mixture AC-5.

4. The assembled pavement structure for pavement maintenance according to claim 1, characterized in that: The ultra-thin wearing course is a T-pave type I dense graded asphalt concrete mixture.

5. A construction method of an assembled pavement composite structure for pavement maintenance, characterized in that: It includes the following steps: Step S1, for a pavement with performance degradation or a pavement that needs structural upgrading, use a milling machine to precisely control the milling depth, and the milling depth is determined according to the damage of the old pavement and design requirements; Step S2, lay high-performance cement mortar on the structure after fine milling of the old road. When the mortar begins to set and has a certain strength, lay geotextile in a staggered joint manner and compact and fix it to form a flexible leveling transition layer; Step S3, install and splice the precast concrete slabs, and after the connection between the precast concrete slabs and the treatment of the slab joints, form a precast concrete slab structural layer; Step S4, lay an anti-cracking sticker and then lay a stress absorption layer and an ultra-thin wearing course in sequence to realize the construction of a new combined structure of a fast-curing prefabricated pavement.

6. The construction method of a prefabricated pavement composite structure for pavement maintenance according to claim 5, characterized in that: In Step S2, when laying high-performance cement mortar on the structure after fine milling of the old road, strictly control the surface flatness detection result of a 3 m straightedge ≤ 3 mm.

7. The construction method of a prefabricated pavement composite structure for pavement maintenance according to claim 5, characterized in that: In Step S3, the connection method of the precast concrete slabs includes the following: Step A1, multiple interfaces are respectively set longitudinally and transversely on the precast concrete slabs, and longitudinal and transverse through-length steel bars are arranged in a criss-cross pattern inside the precast concrete slabs. The ends of the through-length steel bars at the interfaces are connected in a C shape; Step A2, set the longitudinal and transverse arrangement forms of the precast concrete slabs through precise positioning; Step A3, adjacent precast concrete slabs are welded and connected through the embedded steel bars at the precast slab interfaces, forming a left-right symmetric I-shaped connector.

8. The construction method of a prefabricated pavement composite structure for pavement maintenance according to claim 5, characterized in that: In Step S3, the treatment of the slab joints between the precast concrete slabs includes the following: Step A1, for the position of the precast concrete slab connector, the upper 1 / 4 area of the precast slab is filled with asphalt sand filler; the lower 3 / 4 area of the precast slab is filled with 42.5 grade fast-hardening and early-strength sulphoaluminate mortar; Step A2, for the position of the precast concrete slab where there is no connector, the upper 1 / 4 area of the precast slab is filled with high-viscosity asphalt sealant, and the lower 3 / 4 area of the precast slab with a thickness of 1 / 4 of the precast slab thickness is filled with 42.5 grade fast-hardening and early-strength sulphoaluminate cement.

9. The construction method of a prefabricated pavement composite structure for pavement maintenance according to claim 5, characterized in that: In Step S4, the construction method of laying an anti-cracking sticker and then laying a stress absorption layer and an ultra-thin wearing course in sequence includes the following: Step A1, lay a self-adhesive polyester fiberglass cloth anti-cracking sticker at the precast concrete slab joints; Step A2, spraying SBS high-viscosity asphalt adhesive layer on the concrete precast slab, and then laying dense-graded AC-5 on the stress absorption layer; Step A3, spray SBS high-viscosity asphalt adhesive layer on the stress absorption layer, and then lay T-pave Ⅰ type densely matched high-strength and high-toughness ultra-thin wear layer, strictly control the flatness of the ultra-thin cover surface ≤3 mm, and the friction coefficient ≥45.

10. The construction method of the assembled pavement composite structure for pavement maintenance according to claim 9, characterized in that: The spraying amount of SBS high viscosity asphalt tack coat oil is controlled at 0.7~0.8kg / m 2 .

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