A method for transversely slotting the bottom side of an old concrete slab of a highway

Abstract

The application discloses a method for transversely slotting the bottom and side of an old concrete slab of an expressway, which comprises the following steps: (1) construction preparation and foundation treatment of the widened road surface; (2) transversely slotting the lime-soil layer and lime-gravel layer under the old concrete slab on the side of the old concrete slab to be widened by using a transverse hydraulic disc slotter; (3) installing the formwork of the concrete sleeper beam after the slotting is completed; the formwork installation is in the form of two steps; (4) on-site pouring of the concrete sleeper beam; (5) removing the formwork and curing after the concrete sleeper beam reaches the solidification strength; (6) carrying out core sampling detection on the old concrete slab to be widened after the curing is completed; (7) carrying out the construction of the widened road surface structure layer on the widened side of the concrete sleeper beam until the splicing and widening of the new and old road surfaces are completed after the detection meets the design and specification requirements. The application is convenient to construct, saves the construction cost, improves the construction efficiency and can ensure the splicing quality of the new and old roads.

Description

Technical Field

[0001] This invention relates to the field of highway construction technology, and more specifically, to a method for transversely grooving the bottom side of old concrete slabs for highways. Background Technology

[0002] During the reconstruction of highways, the common approach is to widen the highways on both sides, with some sections separated.

[0003] The pavement structure of a highway typically consists of an asphalt layer, a concrete slab, a lime-stabilized aggregate layer, and a base layer, from top to bottom. After several years of operation, the lime-stabilized aggregate layer beneath the concrete slab becomes fragmented and irregular. Under normal traffic conditions, longitudinal cracks and asphalt-filled cracks often appear at the joints between the concrete slab and the lime-stabilized aggregate, with significant crack widths. During reconstruction, the differences in properties and indicators between the old and new pavement materials at the widened sections easily lead to through-cracks. If these are directly joined, especially near the wheel tracks of the second or third lane, longitudinal cracks will appear at the joint between the concrete and the water-stabilized aggregate (rigid and semi-rigid joints). Over time, this will damage the pavement structure at the joint between the old and new pavements, eventually leading to damage to the entire pavement structure and resulting in substantial economic losses. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for transversely grooving the bottom side of old concrete slabs on highways. This invention offers convenient construction, saves construction costs, improves construction efficiency, and ensures the quality of the connection between new and old road sections.

[0005] To achieve the above objectives, the present invention provides a method for transversely slotting the bottom side of an old concrete slab for highways, comprising the following steps:

[0006] (1) Construction preparation and foundation treatment for widening the road surface;

[0007] (2) On the side of the old concrete panel to be widened, a horizontal hydraulic disc grooving machine is used to groove the lime-lime crushed stone layer and lime-lime soil layer under the old concrete panel.

[0008] (3) After the slotting is completed, the formwork for the concrete sleeper beam is installed; the formwork is installed in a two-tiered step manner.

[0009] (4) Concrete sleeper beams are poured on site;

[0010] (5) After the concrete sleeper beams have reached their solidification strength, remove the formwork and allow them to cure.

[0011] (6) After the curing is completed, core samples are taken from the old concrete panel to be widened.

[0012] (7) After the test shows that the design and specification requirements are met, the construction of the widened pavement structure layer is carried out on the widened side of the concrete sleeper beam until the splicing and widening of the old and new pavements is completed.

[0013] Preferably, in step (1), the construction preparation includes site survey, preparation of construction materials and personnel, and site measurement and setting out; the foundation treatment for widening the road surface includes excavation of the foundation pit and construction of the roadbed and subbase; wherein the construction height of the roadbed and subbase is consistent with the bottom elevation of the trench to be laterally slotted under the old concrete panel.

[0014] In any of the above schemes, it is preferred that, in step (2), the transverse hydraulic disc trenching machine is modified from a combination of a hydraulic disc trenching machine and a tire excavator; the transverse depth of the trench is 20cm embedded in the old concrete panel; when the longitudinal elevation of the old road is 10≤h<20cm, the longitudinal depth of the trench is (40-h)cm; when the longitudinal elevation of the old road is 20≤h<40cm, the longitudinal depth of the trench is 30cm.

[0015] In any of the above schemes, it is preferred that, in step (3), the two-layer step is in the form of an upper step adjacent to the side and groove position of the old concrete panel. When the longitudinal elevation of the old road is 10≤h<20cm, the upper step is higher than the bottom of the old concrete panel by (h-2)cm; when the longitudinal elevation of the old road is 20≤h<40cm, the upper step is higher than the bottom of the old concrete panel by (h-20)cm, and the lateral width of the upper step is 25cm. The lower step is located on the side of the widened new road surface and adjacent to the upper step. The lateral width of the lower step is 25cm. When the longitudinal elevation of the old road is 10≤h<20cm, the height of the lower step is 20cm; when the longitudinal elevation of the old road is 20≤h<40cm, the height of the lower step is (h-10)cm.

[0016] In any of the above schemes, it is preferred that, in step (3), wooden templates are used, and the templates for the two steps are installed at one time; before the templates are installed, surface dirt is removed, and a non-chiseling grout-stopping strip is installed on the inside of the templates; the template joints are kept flat, tight, and leak-proof.

[0017] In any of the above schemes, it is preferred that, in step (4), C30 concrete is poured on site, and the pouring range is the slotted space and the two-layer stepped space formed by the template installation; the pouring adopts the method of pouring the two-layer stepped space into one piece.

[0018] In any of the above schemes, it is preferred that, in step (4), the concrete is vibrated using an immersion vibrator, with the vibrator kept 5-10cm away from the formwork, and each point is vibrated until the concrete does not sink, does not bubble, and is flat without slurry.

[0019] In any of the above schemes, it is preferred that in step (5), the curing is carried out by covering with geotextile and sprinkling water for 7 days; the roughening of the side of the pillow beam is carried out by using a non-roughening grout-stopping strip, which is installed and removed together with the formwork and can be reused.

[0020] In any of the above schemes, it is preferred that, in step (6), a core sample is taken from the old concrete panel to be widened. If the bottom of the core sample is filled with a dense material without any voids, it meets the design and specification requirements.

[0021] In any of the above schemes, it is preferred that, in step (7), a water-stabilized base course, a water-stabilized base course, and an asphalt layer are laid sequentially on the concrete sleeper beam, and a fiberglass grid is laid at the joint between the old and new road surfaces to further reinforce and prevent reflective cracking.

[0022] This invention addresses existing technical problems by proposing a cast-in-place bolster beam solution for sections where the road surface elevation is less than or equal to 40cm, ensuring the quality of the connection between old and new roads. This requires transverse grooving on the sides of the lime-stabilized aggregate under the old concrete slab. Traditionally, manual grooving with electric picks is used, but due to the strength of the lime-stabilized aggregate, manual grooving is slow and yields poor results. Therefore, a combination of a hydraulic disc trencher and a tire excavator is used, modified into a transverse hydraulic disc trencher. Compared to traditional manual grooving, using this machine effectively shortens the construction period. While 5 people can trench 100 meters per day manually, the machine can trench 500 meters per day, saving construction costs and improving efficiency. The bolster beam sides are roughened using a non-roughening grout-stopping strip. This strip is installed and removed together with the formwork and is reusable, making it more convenient and faster than traditional roughening methods, further improving construction efficiency.

[0023] The beneficial effects of this invention are:

[0024] 1. This invention is easy to construct, saves construction costs, improves construction efficiency, and can ensure the quality of the connection between new and old roads.

[0025] 2. This invention strengthens the connection by pouring concrete sleeper beams below the pavement structure layer at the longitudinal connection between the new and old roads. Compared with the traditional method of excavating steps, it improves the connectivity between the widened road and the old road, ensures the overall stress of the road after reconstruction and expansion, and reduces uneven settlement of the road.

[0026] 3. By comprehensively applying these measures, this invention can effectively solve the problem of damage at the junction of new and old road surfaces in highway expansion projects, thereby extending the service life of the road structure and reducing maintenance costs after road construction. Detailed Implementation

[0027] The technical solution of this application will be described in detail below with reference to specific embodiments of this application. However, the following embodiments are only used to understand the present invention. The embodiments and features in the embodiments of this application can be combined with each other. This application can be implemented in a variety of different ways as defined and covered by the claims.

[0028] Example 1

[0029] A method for transversely grooving the bottom side of an old concrete slab for highways includes the following steps:

[0030] (1) Construction preparation and foundation treatment for widening the road surface;

[0031] (2) On the side of the old concrete panel to be widened, a horizontal hydraulic disc grooving machine is used to groove the lime-lime crushed stone layer and lime-lime soil layer under the old concrete panel.

[0032] (3) After the slotting is completed, the formwork for the concrete sleeper beam is installed; the formwork is installed in a two-tiered step manner.

[0033] (4) Concrete sleeper beams are poured on site;

[0034] (5) After the concrete sleeper beams have reached their solidification strength, remove the formwork and allow them to cure.

[0035] (6) After the curing is completed, core samples are taken from the old concrete panel to be widened.

[0036] (7) After the test shows that the design and specification requirements are met, the construction of the widened pavement structure layer is carried out on the widened side of the concrete sleeper beam until the splicing and widening of the old and new pavements is completed.

[0037] In step (1), the construction preparation includes site survey, preparation of construction materials and personnel, and site measurement and setting out; the foundation treatment for widening the road surface includes excavation of the foundation pit and construction of the roadbed and subbase; wherein the construction height of the roadbed and subbase is consistent with the bottom elevation of the trench to be laterally slotted under the old concrete panel.

[0038] In step (2), the transverse hydraulic disc trenching machine is a combination of a hydraulic disc trenching machine and a tire excavator; the transverse depth of the trench is 20cm embedded in the old concrete panel, the longitudinal elevation height of the old road is h=15cm, and the longitudinal depth of the trench is 25cm.

[0039] In step (3), the two-step form is that the upper step is adjacent to the side and groove of the old concrete panel, the longitudinal elevation height of the old road is h = 15cm, the upper step is 13cm higher than the bottom of the old concrete panel; the lateral width of the upper step is 25cm; the lower step is located on the side of the widened new road and adjacent to the upper step, the lateral width of the lower step is 25cm, and the height of the lower step is 20cm.

[0040] In step (3), wooden templates are used, and the templates for the two steps are installed at one time. Before installation, surface dirt is removed, and a non-chiseling grout-stopping strip is installed on the inside of the template. The template joints are kept flat, tight, and leak-proof.

[0041] In step (4), C30 concrete is poured on site, and the pouring area is the slotted space and the two-layer stepped space formed by the template installation; the pouring adopts the method of pouring the two-layer stepped space into one piece.

[0042] In step (4), the concrete is vibrated using an immersion vibrator. The vibrator is kept 5cm away from the formwork. Each point is vibrated until the concrete does not sink, does not produce air bubbles, and is flat without slurry.

[0043] In step (5), the curing process involves covering the surface with geotextile and sprinkling water for 7 days; the roughening of the sides of the bolster beam is carried out using a non-roughening grout-stopping strip, which is installed and removed together with the formwork and can be reused.

[0044] In step (6), a core sample is taken from the old concrete panel to be widened. If the bottom of the core sample is densely filled and without voids, it meets the design and specification requirements.

[0045] In step (7), a water-stabilized base course, a water-stabilized base course, and an asphalt layer are laid sequentially on the concrete sleeper beam, and a fiberglass grid is laid at the joint between the old and new road surfaces to further reinforce and prevent reflective cracking.

[0046] Example 2

[0047] A method for transversely grooving the bottom side of an old concrete slab for highways includes the following steps:

[0048] (1) Construction preparation and foundation treatment for widening the road surface;

[0049] (2) On the side of the old concrete panel to be widened, a horizontal hydraulic disc grooving machine is used to groove the lime-lime crushed stone layer and lime-lime soil layer under the old concrete panel.

[0050] (3) After the slotting is completed, the formwork for the concrete sleeper beam is installed; the formwork is installed in a two-tiered step manner.

[0051] (4) Concrete sleeper beams are poured on site;

[0052] (5) After the concrete sleeper beams have reached their solidification strength, remove the formwork and allow them to cure.

[0053] (6) After the curing is completed, core samples are taken from the old concrete panel to be widened.

[0054] (7) After the test shows that the design and specification requirements are met, the construction of the widened pavement structure layer is carried out on the widened side of the concrete sleeper beam until the splicing and widening of the old and new pavements is completed.

[0055] In step (1), the construction preparation includes site survey, preparation of construction materials and personnel, and site measurement and setting out; the foundation treatment for widening the road surface includes excavation of the foundation pit and construction of the roadbed and subbase; wherein the construction height of the roadbed and subbase is consistent with the bottom elevation of the trench to be laterally slotted under the old concrete panel.

[0056] In step (2), the transverse hydraulic disc trenching machine is a combination of a hydraulic disc trenching machine and a tire excavator; the transverse depth of the trench is 20cm embedded in the old concrete panel, the longitudinal elevation height of the old road is h=25cm, and the longitudinal depth of the trench is 30cm.

[0057] In step (3), the two-step form is that the upper step is adjacent to the side and groove of the old concrete panel, the longitudinal elevation height of the old road is h = 25cm, the upper step is 5cm higher than the bottom of the old concrete panel, and the lateral width of the upper step is 25cm; the lower step is located on the side of the widened new road and is adjacent to the upper step, the lateral width of the lower step is 25cm, and the height of the lower step is 15cm.

[0058] In step (3), wooden templates are used, and the templates for the two steps are installed at one time. Before installation, surface dirt is removed, and a non-chiseling grout-stopping strip is installed on the inside of the template. The template joints are kept flat, tight, and leak-proof.

[0059] In step (4), C30 concrete is poured on site, and the pouring area is the slotted space and the two-layer stepped space formed by the template installation; the pouring adopts the method of pouring the two-layer stepped space into one piece.

[0060] In step (4), the concrete is vibrated using an immersion vibrator. The vibrator is kept 10cm away from the formwork. Each point is vibrated until the concrete does not sink, does not bubble, and is flat without slurry.

[0061] In step (5), the curing process involves covering the surface with geotextile and sprinkling water for 7 days; the roughening of the sides of the bolster beam is carried out using a non-roughening grout-stopping strip, which is installed and removed together with the formwork and can be reused.

[0062] In step (6), a core sample is taken from the old concrete panel to be widened. If the bottom of the core sample is densely filled and without voids, it meets the design and specification requirements.

[0063] In step (7), a water-stabilized base course, a water-stabilized base course, and an asphalt layer are laid sequentially on the concrete sleeper beam, and a fiberglass grid is laid at the joint between the old and new road surfaces to further reinforce and prevent reflective cracking.

[0064] Furthermore, to further improve the technical effect of the present invention, in this embodiment, the transverse hydraulic disc grooving machine includes:

[0065] The core control unit is located inside the transverse hydraulic disc grooving machine;

[0066] The data monitoring unit includes a transverse grooving depth detection module, a side pressure sensor, a grooving machine angle sensor, and a data collection and analysis module. The data collection and analysis module is connected to the core control unit, and the transverse grooving depth detection module, the side pressure sensor, and the grooving machine angle sensor are respectively connected to the data collection and analysis module.

[0067] A transverse grooving depth detection module is installed on the hydraulic disc trencher to detect the transverse grooving depth of the hydraulic disc trencher; a side pressure sensor is installed on the hydraulic disc trencher to detect the side pressure exerted by the trencher on the old concrete panel during grooving; a trencher angle sensor is installed on the hydraulic disc trencher to detect the angle of the hydraulic disc trencher relative to the side of the old concrete panel; a data collection and analysis module collects the data detected by the transverse grooving depth detection module, the side pressure sensor, and the trencher angle sensor and sends them to the core control unit.

[0068] The adjustment mechanism includes a cylinder control module, a hydraulic valve group, a side extrusion cylinder, and an angle adjustment cylinder. The core control unit is connected to the cylinder control module, which is connected to the hydraulic valve group. The hydraulic valve group is connected to the side extrusion cylinder and the angle adjustment cylinder. The side extrusion cylinder is mounted on the frame of the transverse hydraulic disc grooving machine and connected to the hydraulic disc trencher. The angle adjustment cylinder is mounted on the frame of the transverse hydraulic disc grooving machine and connected to the hydraulic disc trencher. The core control unit controls the movement of the side extrusion cylinder and the angle adjustment cylinder through the cylinder control module and the hydraulic valve group. The side extrusion cylinder and the angle adjustment cylinder change the side extrusion force of the depth limiting wheel and the angle of the hydraulic disc trencher relative to the side of the old concrete panel through their own movements.

[0069] This embodiment achieves precise control of the transverse grooving depth of the transverse hydraulic disc grooving machine, improving construction quality. Compared with existing technologies, this invention employs a method based on combined control of lateral pressure and angle, enabling the transverse grooving depth to reach the ideal value.

[0070] Example 3

[0071] A method for transversely grooving the bottom side of an old concrete slab for highways includes the following steps:

[0072] (1) Construction preparation and foundation treatment for widening the road surface;

[0073] (2) On the side of the old concrete panel to be widened, a horizontal hydraulic disc grooving machine is used to groove the lime-lime crushed stone layer and lime-lime soil layer under the old concrete panel.

[0074] (3) After the slotting is completed, the formwork for the concrete sleeper beam is installed; the formwork is installed in a two-tiered step manner.

[0075] (4) Concrete sleeper beams are poured on site;

[0076] (5) After the concrete sleeper beams have reached their solidification strength, remove the formwork and allow them to cure.

[0077] (6) After the curing is completed, core samples are taken from the old concrete panel to be widened.

[0078] (7) After the test shows that the design and specification requirements are met, the construction of the widened pavement structure layer is carried out on the widened side of the concrete sleeper beam until the splicing and widening of the old and new pavements is completed.

[0079] In step (1), the construction preparation includes site survey, preparation of construction materials and personnel, and site measurement and setting out; the foundation treatment for widening the road surface includes excavation of the foundation pit and construction of the roadbed and subbase; wherein the construction height of the roadbed and subbase is consistent with the bottom elevation of the trench to be laterally slotted under the old concrete panel.

[0080] In step (2), the transverse hydraulic disc trenching machine is a combination of a hydraulic disc trenching machine and a tire excavator; the transverse depth of the trench is 20cm embedded in the old concrete panel, the longitudinal elevation height of the old road is h=35cm, and the longitudinal depth of the trench is 30cm.

[0081] In step (3), the two-step form is that the upper step is adjacent to the side and groove of the old concrete panel, the longitudinal elevation height of the old road is h = 35cm, the upper step is 15cm higher than the bottom of the old concrete panel, and the lateral width of the upper step is 25cm; the lower step is located on the side of the widened new road and adjacent to the upper step, the lateral width of the lower step is 25cm, and the height of the lower step is 25cm.

[0082] In step (3), wooden templates are used, and the templates for the two steps are installed at one time. Before installation, surface dirt is removed, and a non-chiseling grout-stopping strip is installed on the inside of the template. The template joints are kept flat, tight, and leak-proof.

[0083] In step (4), C30 concrete is poured on site, and the pouring area is the slotted space and the two-layer stepped space formed by the template installation; the pouring adopts the method of pouring the two-layer stepped space into one piece.

[0084] In step (4), the concrete is vibrated using an immersion vibrator. The vibrator is kept 8cm away from the formwork. Each point is vibrated until the concrete does not sink, does not produce air bubbles, and is flat without slurry.

[0085] In step (5), the curing process involves covering the surface with geotextile and sprinkling water for 7 days; the roughening of the sides of the bolster beam is carried out using a non-roughening grout-stopping strip, which is installed and removed together with the formwork and can be reused.

[0086] In step (6), a core sample is taken from the old concrete panel to be widened. If the bottom of the core sample is densely filled and without voids, it meets the design and specification requirements.

[0087] In step (7), a water-stabilized base course, a water-stabilized base course, and an asphalt layer are laid sequentially on the concrete sleeper beam, and a fiberglass grid is laid at the joint between the old and new road surfaces to further reinforce and prevent reflective cracking.

[0088] Furthermore, to further improve the technical effect of the present invention, in this embodiment, the transverse hydraulic disc grooving machine is equipped with a dust collection device, including multiple dust collection pipes, each dust collection pipe having multiple dust collection nozzles at one end, the dust collection nozzles being fixed and facing the outer periphery of the hydraulic disc grooving machine. The dust collection device is also equipped with a dust collection pump, which is connected to the other ends of the multiple dust collection pipes; the dust collection pump is connected to the dust collection box via a flexible hose.

[0089] During grooving, a dust collection device is installed. When the horizontal hydraulic disc grooving machine is working, a large amount of construction dust is generated. The dust collection pump works in conjunction with the dust collection pipe and nozzle to collect the generated construction dust, preventing the dust from being inhaled into the workers' bodies and affecting their health. At the same time, it also prevents the dust from floating into the air and causing environmental pollution, thus playing a role in protecting the environment and making it more practical.

[0090] As can be seen from the above embodiments, the present invention is convenient to construct, saves construction costs, improves construction efficiency, and can ensure the quality of the connection between new and old roads.

[0091] This invention strengthens the connection by pouring concrete sleeper beams below the pavement structure layer at the longitudinal connection between the old and new roads. Compared with the traditional method of excavating steps, it improves the connectivity between the widened road and the old road, ensures the overall stress of the road after reconstruction and expansion, and reduces uneven settlement of the road.

[0092] This invention, through the comprehensive application of these measures, can effectively solve the problem of damage at the junction of new and old road surfaces in highway expansion projects, thereby extending the service life of the road structure and reducing maintenance costs after road construction.

[0093] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for transversely slotting the bottom side of an old concrete slab on a highway, characterized in that, Includes the following steps: (1) Construction preparation and foundation treatment for widening the road surface; (2) On the side of the old concrete panel to be widened, a horizontal hydraulic disc grooving machine is used to groove the lime-lime crushed stone layer and lime-lime soil layer under the old concrete panel. (3) After the grooving is completed, the formwork for the concrete sleeper beam is installed. The formwork is installed in a two-tiered step configuration. The upper step is adjacent to the side of the old concrete panel and the grooving position. When the longitudinal elevation of the old road is 10≤h<20cm, the upper step is higher than the bottom of the old concrete panel by (h-2)cm. When the longitudinal elevation of the old road is 20≤h<40cm, the upper step is higher than the bottom of the old concrete panel by (h-20)cm. The lateral width of the upper step is 25cm. The lower step is located on the side of the widened new road surface and is adjacent to the upper step. The lateral width of the lower step is 25cm. When the longitudinal elevation of the old road is 10≤h<20cm, the height of the lower step is 20cm. When the longitudinal elevation of the old road is 20≤h<40cm, the height of the lower step is (h-10)cm. (4) Concrete sleeper beams are poured on site; (5) After the concrete sleeper beams have reached their solidification strength, remove the formwork and allow them to cure. (6) After the curing is completed, core samples are taken from the old concrete panel to be widened. (7) After the test shows that the design and specification requirements are met, the construction of the widened pavement structure layer is carried out on the widened side of the concrete sleeper beam until the splicing and widening of the old and new pavements is completed.

2. The method for transverse grooving the bottom side of old concrete slabs for highways according to claim 1, characterized in that, In step (1), the construction preparation includes site survey, preparation of construction materials and personnel, and site measurement and setting out; the foundation treatment for widening the road surface includes excavation of the foundation pit and construction of the roadbed and subbase; wherein the construction height of the roadbed and subbase is consistent with the bottom elevation of the trench to be laterally slotted under the old concrete panel.

3. The method for transversely grooving the bottom side of old concrete slabs for highways according to claim 1 or 2, characterized in that, In step (2), the transverse hydraulic disc trenching machine is a combination of a hydraulic disc trenching machine and a tire excavator; the transverse depth of the trench is 20cm embedded in the old concrete panel; when the longitudinal elevation of the old road is 10≤h<20cm, the longitudinal depth of the trench is (40-h)cm; when the longitudinal elevation of the old road is 20≤h<40cm, the longitudinal depth of the trench is 30cm.

4. The method for transversely grooving the bottom side of old concrete slabs for highways according to claim 3, characterized in that, In step (3), wooden templates are used, and the templates for the two steps are installed at one time. Before installation, surface dirt is removed, and a non-chiseling grout-stopping strip is installed on the inside of the template. The template joints are kept flat, tight, and leak-proof.

5. The method for transverse grooving the bottom side of old concrete slabs for highways according to claim 4, characterized in that, In step (4), C30 concrete is poured on site, and the pouring area is the slotted space and the two-layer stepped space formed by the template installation; the pouring adopts the method of pouring the two-layer stepped space into one piece.

6. The method for transversely grooving the bottom side of old concrete slabs for highways according to claim 4 or 5, characterized in that, In step (4), the concrete is vibrated using an immersion vibrator. The vibrator is kept 5-10cm away from the formwork. Each point is vibrated until the concrete does not sink, does not produce air bubbles, and is flat without slurry.

7. The method for transverse grooving the bottom side of old concrete slabs for highways according to claim 6, characterized in that, In step (5), the curing process involves covering the surface with geotextile and sprinkling water for 7 days; the roughening of the sides of the bolster beam is carried out using a non-roughening grout-stopping strip, which is installed and removed together with the formwork and can be reused.

8. The method for transverse grooving the bottom side of old concrete slabs for highways according to claim 7, characterized in that, In step (6), a core sample is taken from the old concrete panel to be widened. If the bottom of the core sample is densely filled and without voids, it meets the design and specification requirements.

9. The method for transverse grooving the bottom side of old concrete slabs for highways according to claim 8, characterized in that, In step (7), a water-stabilized base course, a water-stabilized base course, and an asphalt layer are laid sequentially on the concrete sleeper beam, and a fiberglass grid is laid at the joint between the old and new road surfaces to further reinforce and prevent reflective cracking.