Repair structure and repair method for a pothole

Abstract

This invention relates to a repair technique for cohesive pavements, providing a repair structure and method for potholes. The pothole repair structure includes: a repair step carved downwards in the pavement; a first repair groove carved around the repair step, the outer side of the first repair groove forming an angle of 120°~150° with the bottom surface of the repair step; a second repair groove carved downwards at the bottom of the repair step, the outer side of the second repair groove forming an angle of 30°~60° with the bottom surface of the repair step; a plurality of reinforcing holes carved downwards at the bottom of the repair step; a rubber buffer layer disposed within the reinforcing holes; and a modified asphalt surface layer filling the reinforcing holes, the first repair groove, the second repair groove, and the repair step.

Description

Technical Field

[0001] This invention relates to repair technology for cohesive pavements, specifically to repair structures and methods for potholes. Background Technology

[0002] Currently, the main methods for repairing potholes in asphalt mixtures are hot-mix asphalt mixtures or on-site cold patching. These methods are complex, require sophisticated equipment and significant manpower, involve prolonged road closures leading to traffic congestion, and are highly susceptible to environmental influences, easily resulting in weak joints. Furthermore, pothole repair is characterized by long distances, small areas, scattered repairs, and limited material usage per application, leading to slow progress despite significant investment of equipment and personnel. This often results in excess and wasted repair materials, severely hindering road maintenance. Therefore, pothole repair remains a pressing issue that urgently needs to be addressed.

[0003] Existing road repair technologies employ multiple pre-embedded grooves, which, along with connecting grooves, enhance the strength of the repaired modified asphalt, resulting in better overall connection performance, stronger stability, and preventing cracking and separation. However, when dealing with actual road pothole repair, it's impossible to create pre-embedded and connecting grooves of the target size for small, scattered potholes. Grooving techniques have overly stringent dimensional requirements; in actual pothole repair, untrained engineers using conventional cutting equipment often struggle to accurately achieve the target dimensions, leading to cumbersome construction processes and excessively long repair times.

[0004] Another approach involves creating several reinforcing holes in the original roadbed, filling them with asphalt concrete during the reinforcement layer construction. In this method, the asphalt concrete in the reinforcing holes hardens to form connecting columns. However, simple concrete reinforcing holes are unlikely to provide assistance under axial loads. These simple holes also introduce gaps between the repair structure and the original pavement, and fail to consider the impact of vehicle loads at different locations on the repair structure. Reinforcing holes are simply openings in the structure and filling them with strength material to a uniform depth, without considering the requirements of the repair structure under actual vehicle loads or the mechanism of the structure's resistance to secondary damage. This carries the risk of secondary damage due to an insufficiently compacted bottom structure. Summary of the Invention

[0005] Based on this, the present invention provides a repair structure and repair method for potholes, which solves at least one problem in the prior art.

[0006] The present invention provides a pit repair structure, comprising: Repair steps that are carved downwards into the road surface; A first repair groove is excavated around the repair step, and the angle between the outer side of the first repair groove and the bottom surface of the repair step is 120°~150°. A second repair groove is chiseled downward at the bottom of the repair step, and the angle between the outer side of the second repair groove and the bottom surface of the repair step is 30°~60°. Several reinforcing holes are drilled downwards at the bottom of the repair step; A rubber buffer layer disposed within the reinforcing hole; and A modified asphalt surface layer is used to fill the reinforcing holes, the first repair groove, the second repair groove, and the repair step.

[0007] The present invention provides a method for repairing potholes, comprising the following steps: Break up the pavement around the crack and carve out repair steps; A first repair groove is chiseled around the outer edge of the repair step, with the angle between the outer side of the first repair groove and the bottom surface of the repair step being 120°~150°; and a second repair groove is chiseled downward at the bottom of the repair step, with the angle between the outer side of the second repair groove and the bottom surface of the repair step being 30°~60°. Several reinforcing holes are drilled downward at the bottom of the repair step, and a rubber buffer layer is laid into the reinforcing holes. Modified asphalt is filled into the reinforcing holes, the first repair groove, the second repair groove, and the repair step to form a modified asphalt surface layer.

[0008] Due to the adoption of the above technical solutions, the embodiments of the present invention have at least the following beneficial effects: (a) Two-layer grooving is used in conjunction with reinforcing openings. The first repair groove is grooved inward and the second repair groove is grooved outward. Compared with the traditional vertical grooving, the two-layer grooving structure can achieve the coordinated stress and deformation of the new and old pavement, thereby increasing the repair joint area. At the same time, it can reduce the shear stress at the joint. The construction process is simple and time-consuming. (b) By using reinforcing holes of different depths and setting a rubber buffer layer at the bottom, the stress concentration and sudden change of tensile and shear stress caused by the vehicle load concentrated at the edge of the repair structure and when the vehicle load begins to move can be addressed, which can lead to secondary damage to the top surface of the repair. The buffer reinforcement layer not only offsets part of the bottom shear force, but also absorbs energy through the deformation of the rubber itself when subjected to axial pressure, thereby improving the overall toughness of the road surface and making it less prone to cracking and separation. (c) The internal three-dimensional network structure of the twin-screw activated rubber powder composite (ACR / SBS) modified asphalt is partially opened, retaining some of the elasticity of the rubber powder and reducing the cross-linking density, making it easy to blend with asphalt. This makes up for the problems of poor storage stability, poor workability and low dosage of rubber asphalt. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of a pit repair structure in one embodiment of the present invention.

[0010] Figure 2 This is a longitudinal cross-sectional schematic diagram of the repair structure for pits in one embodiment of the present invention.

[0011] Figure 3 This is a schematic diagram of a repair structure for a pit in a comparative example.

[0012] Figure 4 This is a schematic diagram of the repair structure for a pit in another comparative example.

[0013] Explanation of reference numerals in the attached drawings: 1. Foundation; 2. Rubber buffer layer; 3. Reinforcing hole; 4. First repair groove; 5. Modified asphalt concrete surface layer; 6. Second repair groove; 7. Repair step; 8. First vertical repair groove; 9. Second vertical repair groove. Detailed Implementation

[0014] The following will provide a clear and complete description of the concept and technical effects of the present invention, so as to fully explain the purpose, solution and effects of the present invention.

[0015] Conventional repair structures have two main stress states for wall joints: one is when the wheel load is about to reach the repair area, the wall joint is only subjected to bending tension; the other is when the wheel load is above the repair area, the wall joint is simultaneously subjected to compression and shear.

[0016] When vehicle loads are concentrated above the pothole repair area, or when the vehicle load begins to move above the pothole repair area, the repair structure mainly bears the axial pressure from the vehicle load and the friction between the wheel and the pothole surface. This friction is transferred to the bottom bonding layer through the filler material in the repair structure, making it risky for the bottom of the repair material to shear away from the original road surface. Therefore, an excellent repair structure must have good compressive strength in the load-bearing layer and good shear strength at the joints. To this end, in order to achieve the repair of potholes of different areas and scattered locations, and to improve the shear strength of the repair structure, this invention provides a pothole repair structure and repair method.

[0017] First, the present invention provides a repair structure for pits, comprising: Repair steps that are carved downwards into the road surface; A first repair groove is excavated around the repair step, and the angle between the outer side of the first repair groove and the bottom surface of the repair step is 120°~150°. A second repair groove is chiseled downward at the bottom of the repair step, and the angle between the outer side of the second repair groove and the bottom surface of the repair step is 30°~60°. Several reinforcing holes are drilled downwards at the bottom of the repair step; A rubber buffer layer disposed within the reinforcing hole; and A modified asphalt surface layer is used to fill the reinforcing holes, the first repair groove, the second repair groove, and the repair step.

[0018] Because it incorporates a first and a second repair groove, both with sloped outer surfaces, this repair structure increases the repair joint area, thereby reducing the stress level at the joint. Furthermore, the slope reduces shear forces on the walls and bottom compared to traditional vertical grooving. Additionally, the inclusion of reinforcing holes with rubber buffer layers not only offsets some of the bottom shear force but also enhances the overall road surface toughness by absorbing energy through rubber deformation under vertical pressure, making it less prone to cracking and separation. Moreover, the construction is simple, achieving the target dimensions through straightforward and conventional procedures, minimizing traffic disruption and reducing the difficulty for construction workers.

[0019] In some preferred embodiments, the angle between the outer surface of the first repair groove and the bottom surface of the repair step is 135°, and the angle between the outer surface of the second repair groove and the bottom surface of the repair step is 45°. When the slope is 45°, the effect of reducing the tensile stress at the interface of the patch joint is significant, and the reduction in tensile stress is greater as the groove angle increases. This is because the larger the groove angle, the larger the contact friction area between the patch block and the original road surface, and the stronger the adhesion between them. However, considering that increasing the groove angle would inevitably increase the area of ​​road excavation and milling, resulting in material waste, a 45-degree groove is the most effective.

[0020] In some preferred embodiments, the repair step is cylindrical, and the first repair groove is an annular shape obtained by rotating a right triangle around the axis of the repair step. The length of the right-angled triangle's right-angled side is equal to the depth of the cylinder, and the angle between the hypotenuse of the right-angled triangle and the base of the repair step is 135°. The cylindrical repair step and the annular first repair groove facilitate construction. Furthermore, compared to a rectangular groove shape, the circular groove shape has the lowest stress concentration factor.

[0021] In some preferred embodiments, the second repair groove is shaped like a frustum, with both its top and bottom surfaces being circular, and its longitudinal section being an isosceles trapezoid. The angle between the hypotenuse of the isosceles trapezoid and the bottom surface of the repair step is 45°. The frustum-shaped second repair groove ensures that both its upper and lower sections are circular, thus minimizing the interlayer stress concentration factor.

[0022] In some preferred embodiments, the reinforcing holes are all cylindrical, with a diameter of 0.5-1 cm and a depth of 2-6 cm. Each reinforcing hole is spaced 1-2 cm apart, and its depth increases with the distance from the axis of the repair step. Thus, compared to reinforcing holes of equal length, the stress distribution of the composite repair structure changes from a "surface" to a "layer," increasing the contact area between the reinforcing holes and the original base layer, dispersing the stress at the bottom of the reinforcing holes, and fully utilizing the "arch" effect of the entire repair structure. For example, the depth of the reinforcing hole closest to the axis of the repair step can be 2 cm, the depth of the reinforcing hole farthest from the axis of the repair step can be 6 cm, and the depths of other reinforcing holes can be 3 cm, 3.3 cm, 3.5 cm, 4 cm, 4.4 cm, 4.6 cm, or 5 cm, etc.

[0023] In some preferred embodiments, the thickness of the rubber buffer layer is 15-50% of the depth of the reinforcing hole. For example, the thickness of the rubber buffer layer is 1 cm, and the horizontal cross-sectional radius is 0.6 cm.

[0024] In addition, the present invention provides a method for repairing potholes, which includes the following steps: S1. Break up the road surface around the crack and carve out repair steps; S2. A first repair groove is chiseled around the outer perimeter of the repair step, with the angle between the outer side of the first repair groove and the bottom surface of the repair step being 120°~150°; and a second repair groove is chiseled downward at the bottom of the repair step, with the angle between the outer side of the second repair groove and the bottom surface of the repair step being 30°~60°. S3. Drill several reinforcing holes downward at the bottom of the repair step, and lay a rubber buffer layer into the reinforcing holes; S4. Fill the reinforcing hole, the first repair groove, the second repair groove and the repair step with modified asphalt to form a modified asphalt surface layer.

[0025] In some preferred embodiments, the modified asphalt is twin-screw activated rubber powder composite (ACR / SBS) modified asphalt. Before filling the modified asphalt, an epoxy resin coating can be uniformly applied to the entire repair structure, that is, the epoxy resin coating is applied to the surfaces of the reinforcing holes, the first repair groove, the second repair groove, and the repair step.

[0026] The following are some typical examples. In the following examples and comparative examples, in order to conduct mechanical tests on the repaired structures, the old cement concrete pavement was used as an asphalt pavement (simulating the real pavement) surface structure layer specimen with a radius of 30 cm and a thickness of 20 cm, which was formed in a rut slab mold and demolded after being left to stand naturally for 24 hours.

[0027] Example 1 Reference Figure 1 and Figure 2 Follow these steps to repair the road surface: S1: Pit and Groove Treatment The old cement concrete pavement is crushed into small pieces by using an impact device to break the entire cement concrete pavement slab into small pieces in one go. At the same time, a pneumatic hammer is used to chisel out a dense network of roughening grooves on the inner wall of the repair step, so that the pavement is transformed from a whole working state to a granular aggregate working state, exposing the hard concrete surface and forming a cylindrical repair step with a radius of 6.8cm and a depth of 4cm (that is, the treatment area is about 4 times the area of ​​the crack). S2: Set the first repair slot and the second repair slot A cutting machine is used to cut a first repair groove along the edge of the cylindrical repair step, creating a sloping shape. The sloping groove is a ring formed by rotating a right-angled triangle around the axis of the repair step, with a depth of 4cm and a width of 4cm. The angle between the sloping groove's longitudinal section and the bottom surface of the repair step is 135 degrees. A second repair groove (e.g., a frustum-shaped groove) is then cut downwards from the center of the repair step, with a top radius of 1cm and a depth of 2cm. The angle between the sloping groove's longitudinal section and the bottom surface of the repair step is 45 degrees. Figure 2 (as shown) S3: Install reinforcing holes and rubber buffer layer Using an electric drill, holes were drilled sequentially around the second repair groove. Three vertical reinforcement holes were set in each of the four directions centered on the second repair groove. The diameter of each vertical reinforcement hole was 0.6 cm, and the distance between adjacent reinforcement holes was 1 cm. The depth of the reinforcement holes in the direction away from the second repair groove was 2 cm, 4 cm, and 6 cm respectively. Then, the dust in the reinforcement holes was sucked out using a dust extraction device. Rubber granules were placed at the bottom of the reinforcement holes to form a rubber buffer layer with a thickness of 1 cm. Finally, epoxy resin coating was evenly applied to the entire repair structure at a rate of 1.1 kg per square meter. S4: Filler modified asphalt The dust in the pit is sucked out by a dust extraction device. The modified asphalt (ACR / SBS) is filled into the first repair groove, the second repair groove, the repair step and the reinforcement hole by twin-screw activated rubber powder composite. Then the modified asphalt is rolled by an asphalt roller. When the rolled asphalt drops, asphalt is added again and rolled again until the modified asphalt is 3mm higher than the asphalt layer of the road surface to complete the repair.

[0028] Example 2 This embodiment is basically the same as Embodiment 1, except that: another damaged road surface is repaired, the radius of the repair step is 6.8cm and the depth is 4cm; the depth of the first repair groove is 4cm and the width is about 5.65cm, and the longitudinal section of the slope forms a 150-degree angle with the bottom surface of the repair step; the radius of the top surface of the second repair groove is 1cm and the depth is 2cm, and the angle between the longitudinal section of the groove and the bottom surface of the repair step is 60 degrees.

[0029] Comparative Example 1 Reference Figure 3 Follow these steps to repair the road surface: S1: Pit and Groove Treatment The old cement concrete pavement is crushed into small pieces by using an impact device to break the entire cement concrete pavement slab into small pieces in one go. At the same time, a pneumatic hammer is used to chisel out a dense network of roughening grooves on the inner wall of the repair step, so that the pavement is transformed from a whole working state to a granular aggregate working state, exposing the hard concrete surface and forming a cylindrical repair step with a radius of 6.8cm and a depth of 4cm (that is, the treatment area is about 4 times the area of ​​the crack). S2: Set the first repair slot and the second repair slot A cutting machine is used to cut the first repair groove on the edge of the cylindrical repair step, forming a ramp shape. The ramp is a ring obtained by rotating a right triangle around the axis of the repair step, with a depth of 4cm and a width of 4cm. The longitudinal section of the ramp forms a 135-degree angle with the bottom surface of the repair step. A frustum-shaped groove is cut downward from the center of the repair step using the cutting machine. The top surface radius is 1cm and the depth is 2cm. The longitudinal section of the groove forms a 45-degree angle with the bottom surface of the repair step, forming the second repair groove. S3: Set reinforcement holes Using an electric drill, holes are drilled sequentially around the second repair groove. Three vertical reinforcement holes are set in each of the four directions centered on the second repair groove. The diameter of each vertical reinforcement hole is 0.6 cm, and the distance between adjacent reinforcement holes is 1 cm. The depth of the reinforcement holes in the direction away from the second repair groove is 2 cm, 4 cm, and 6 cm respectively. Then, epoxy resin coating is evenly applied to the entire repair structure at a rate of 1.1 kg per square meter. S4: Filler modified asphalt The dust in the pit is sucked out by a dust extraction device. The modified asphalt (ACR / SBS) is filled into the first repair groove, the second repair groove, the repair step and the reinforcement hole by twin-screw activated rubber powder composite. Then the modified asphalt is rolled by an asphalt roller. When the rolled asphalt drops, asphalt is added again and rolled again until the modified asphalt is 3mm higher than the asphalt layer of the road surface to complete the repair.

[0030] Comparative Example 2 Reference Figure 4Follow these steps to repair the road surface: S1: Pit and Groove Treatment The old cement concrete pavement is crushed into small pieces by using an impact device to break the entire cement concrete pavement slab into small pieces in one go. At the same time, a pneumatic hammer is used to chisel out a dense network of roughening grooves on the inner wall of the repair step, so that the pavement is transformed from a whole working state to a granular aggregate working state, exposing the hard concrete surface and forming a cylindrical repair step with a radius of 6.8cm and a depth of 4cm (that is, the treatment area is about 4 times the area of ​​the crack). S2: Set the first vertical repair groove and the second vertical repair groove. A cutting machine is used to cut a first vertical repair groove on the edge of the cylindrical repair step. The first vertical repair groove is a cube with a side length of 4cm (i.e., the length and width of the top surface are both 4cm, and the depth is 4cm). A cutting machine is used to cut a cylindrical groove downward from the center of the repair step to form a second repair groove with a radius of 1cm (i.e., the radius of the circle on the top surface is 1cm, and the depth is 2cm). S3: Install reinforcing holes and rubber buffer layer Drill holes around the cube-shaped repair groove using an electric drill. Three vertical reinforcement holes are made in each of the four directions centered on the cube-shaped repair groove. Each vertical reinforcement hole has a diameter of 0.6 cm, and the distance between adjacent reinforcement holes is 1 cm. The depths of the reinforcement holes, moving away from the second repair groove, are 2 cm, 4 cm, and 6 cm respectively. Dust is then removed from the reinforcement holes using a vacuum cleaner. Rubber granules are placed at the bottom of the reinforcement holes to form a rubber buffer layer with a thickness of 1 cm. Finally, epoxy resin coating is evenly applied to the entire repair structure at a rate of 1.1 kg per square meter. S4: Filler modified asphalt The dust in the pit is sucked out by a vacuuming device. The modified asphalt (ACR / SBS) is filled into the cubic repair groove, repair step and reinforcement hole by twin screw activated rubber powder composite. Then the modified asphalt is rolled by an asphalt roller. When the rolled asphalt drops, more asphalt is added and rolled again until the modified asphalt is 3mm higher than the asphalt layer of the road surface to complete the repair.

[0031] Comparative Example 3 This comparative example is basically the same as Example 1, except that another damaged road surface was repaired, and the depth of all reinforcement holes was 4 cm.

[0032] For the pothole repair structures mentioned in the above embodiments and comparative examples, the interlayer shear strength of their pavement structure was determined by the following method.

[0033] To better simulate actual traffic vehicle loads, tests were conducted according to the requirements for specimen arrangement, preparation, and processing dimensions specified in the "Code for Geotechnical Investigation" (GB50021-2001), using the oblique push method for loading. The normal load can be applied in 4-5 levels. When the normal deformation reaches a stable state, the shear load can be applied; here, a vertical pressure of 75 kPa is uniformly taken. The test can be terminated when the shear deformation increases rapidly or reaches 1 / 10 of the specimen size.

[0034] The ultimate shear strength and shear modulus of the repaired structures in each embodiment and comparative example were obtained through testing, as shown in the table below.

[0035] Table 1 Ultimate shear strength and shear modulus of the repaired structures in each embodiment and comparative example. Therefore, compared with Comparative Example 1, Example 1, which uses reinforcing holes of different depths and a rubber buffer layer at the bottom, can not only fill the gaps between the asphalt surface layer and the grooves and increase the contact area when subjected to shear stress generated by the inclined pushing method, but also improve the shear strength and shear modulus through the deformation energy absorption of the rubber itself. Data measured in the laboratory shows that the rubber buffer layer increases the ultimate shear strength by 14.5% and the shear modulus by 10.2% compared to simply using reinforcing holes.

[0036] Compared to Comparative Example 2, Example 1 employs two layers of inclined grooves (a first repair groove and a second repair groove), and the repair grooves are located only at the edge of the repair structure. The inclined grooves can effectively bear a portion of the vertical load, and when the first repair groove is subjected to normal force, the angle of the grooves further distributes a portion of the force to the circular vertical reinforcing hole. In Comparative Example 2, the only vertical gap is prone to cracking during actual vehicle load movement, resulting in lower shear strength. Data measured in the laboratory shows that using edge repair grooves increases the ultimate shear strength by 27% and the shear modulus by 6.5% compared to vertical grooves. Compared to Comparative Example 3, the progressively longer and shorter reinforcing holes in Example 1, compared to equal-length reinforcing holes, cause the stress on the composite repair structure to change from a "surface" to a "layer" due to the interval arrangement of the long and short reinforcing holes. This increases the contact area between the reinforcing holes and the original base layer, disperses the stress at the bottom of the reinforcing holes, and fully utilizes the "arch" effect of the entire repair structure. Data measured in the laboratory shows that the interval arrangement of long and short reinforcing holes increases the ultimate shear strength by 11.3% compared to equal-length reinforcing holes.

[0037] The above description is merely a preferred embodiment of the present invention. The present invention is not limited to the above-described embodiments. Any embodiment that achieves the technical effects of the present invention by the same or equivalent means should fall within the protection scope of the present invention. Within the protection scope of the present invention, various modifications and variations can be made to the technical solutions and / or implementation methods.

Claims

1. A repair structure for potholes, comprising: Repair steps that are carved downwards into the road surface; A first repair groove is excavated around the repair step, and the angle between the outer side of the first repair groove and the bottom surface of the repair step is 135°. A second repair groove is chiseled downward at the bottom of the repair step, and the angle between the outer side of the second repair groove and the bottom surface of the repair step is 45°. Several reinforcing holes are drilled downwards at the bottom of the repair step. The reinforcing holes are all cylindrical in shape, with a diameter of 0.5~1cm and a depth of 2~6cm. A reinforcing hole is set every 1~2cm, and its depth increases with the distance from the axis of the repair step. The depth of the reinforcing hole closest to the axis of the repair step is 2cm, the depth of the reinforcing hole farthest from the axis of the repair step is 6cm, and the depths of the other reinforcing holes are 3cm, 3.3cm, 3.5cm, 4cm, 4.4cm, 4.6cm or 5cm. A rubber buffer layer is disposed within the reinforcing hole, the thickness of the rubber buffer layer being 15-50% of the depth of the reinforcing hole; and A modified asphalt surface layer is used to fill the reinforcing holes, the first repair groove, the second repair groove, and the repair step.

2. The repair structure for potholes according to claim 1, characterized in that, The repair step is cylindrical in shape, and the first repair groove is an annular shape obtained by rotating a right triangle around the axis of the repair step. The length of the right-angled side of the right triangle is equal to the depth of the cylinder, and the angle between the hypotenuse of the right triangle and the bottom surface of the repair step is 135°.

3. The repair structure for potholes according to claim 1, characterized in that, The second repair groove is shaped like a frustum, with both its top and bottom surfaces being circular, and its longitudinal section being an isosceles trapezoid. The angle between the hypotenuse of the isosceles trapezoid and the bottom surface of the repair step is 45°.

4. A method for repairing pits based on the pit repair structure of claim 1, comprising the following steps: Break up the road surface around the crack and carve out repair steps; A first repair groove is chiseled around the outer edge of the repair step, with an angle of 135° between the outer side of the first repair groove and the bottom surface of the repair step; and a second repair groove is chiseled downward at the bottom of the repair step, with an angle of 45° between the outer side of the second repair groove and the bottom surface of the repair step. Several reinforcing holes are drilled downward at the bottom of the repair step, and a rubber buffer layer is laid into the reinforcing holes. Modified asphalt is filled into the reinforcing holes, the first repair groove, the second repair groove, and the repair step to form a modified asphalt surface layer.

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