Pavement structure of old central separation zone position after one-side widening of expressway

Abstract

The application discloses a highway single-side widening old central separation belt position pavement structure and relates to the technical field of road engineering. The pavement structure is flush with the highway road surface. The pavement structure comprises, in sequence from the old roadbed upwards, a water-tight asphalt mortar layer, a drainage and anti-cracking large-void asphalt mixture layer, a reinforced concrete layer, a high-toughness polyester fiber bundle grid, a micro-permeable asphalt mixture lower layer, a high-modulus asphalt mixture middle layer and a high-anti-skid asphalt mixture surface layer. The top surface of the reinforced concrete layer is provided with a longitudinal drainage gravel blind ditch. A vertical PVC drainage pipe penetrating the reinforced concrete layer is arranged in the blind ditch. The bottom surface of the drainage and anti-cracking large-void asphalt mixture layer is provided with a horizontal drainage pipe. The vertical PVC drainage pipe penetrates the drainage and anti-cracking large-void asphalt mixture layer downwards and is connected with the horizontal drainage pipe. The application can effectively improve the anti-rutting performance and the drainage performance of the old central separation belt position pavement structure after the old central separation belt position is paved as a highway heavy-load lane.

Description

Technical Field

[0001] This invention relates to the field of road engineering technology, specifically to a pavement structure at the location of the old central median strip after one side of a highway has been widened. Background Technology

[0002] With the rapid development of my country's economy, society, and highway transportation, the public's demand for convenient travel is constantly increasing, leading to more frequent highway travel. However, the existing highway capacity is gradually failing to meet this demand. Upgrading and expanding existing highway lanes can effectively improve highway capacity, alleviate traffic congestion, and save costs, resulting in significant economic and social benefits. As a crucial ancillary facility of highways, the rational design of the original median strip pavement structure is essential during highway widening and expansion, especially for widening projects on one side of the highway. On the one hand, the median strip is typically located in the heavy-load lanes of the highway, requiring excellent rutting resistance; on the other hand, while ensuring driving safety, it also provides a channel for rainwater infiltration, posing a potential threat to the stability of the roadbed and pavement structure. Therefore, a well-designed drainage system for the median strip can prevent surface water infiltration, protect the roadbed and pavement from damage caused by water seepage, and prevent the formation of a water film on the road surface, reducing road friction and avoiding traffic accidents.

[0003] The existing median strip structure of highways is generally part of the roadbed design and construction phase. Drainage blind pipes are laid longitudinally along the road within the area enclosed by the shoulders, with gravel laid on top. These blind pipes are connected to drain pipes that direct water to local drainage systems, achieving the timely removal of rainwater and groundwater, reducing the impact of water infiltration on the stability of the road structure. However, for highway widening and reconstruction projects on one side, the median strip treatment structure cannot be constructed like a new roadbed drainage structure. Furthermore, the median strip location on the widened section of a highway is usually a heavy-load lane. If the treatment structure is not properly designed, under heavy loads and environmental conditions, the old median strip may suffer severe rutting and deformation, affecting driver safety and comfort, and also seriously impacting the durability of the entire cross-section road structure of the highway reconstruction project, reducing the road's service life. Therefore, for the median strip of the old road in the widened section on one side of the expressway, it is necessary to design a pavement structure that takes into account both excellent anti-rutting performance and good drainage capacity, based on its location characteristics and performance requirements, so as to effectively ensure the durability of the entire cross-section road structure of the expressway reconstruction and expansion project. Summary of the Invention

[0004] This invention addresses the needs and shortcomings of current technological development by providing a pavement structure for the old median strip location after one side of a highway has been widened. This improves the rutting resistance of the old median strip location after it has been converted into a heavy-duty lane for the highway. At the same time, a drainage structure is provided to enhance the drainage function of the pavement structure, prevent water accumulation inside the pavement structure, and ensure the durability of the entire cross-section road structure in the highway reconstruction and expansion project.

[0005] The present invention provides a pavement structure at the location of the old central median strip after one-sided widening of a highway, and the technical solution adopted to solve the above-mentioned technical problems is as follows:

[0006] A pavement structure for the old central median strip after widening one side of a highway, flush with the highway surface, comprises, from the old roadbed upwards, a water-tight asphalt mortar layer, a drainage and crack-resistant large-void asphalt mixture layer, a reinforced concrete layer, a high-toughness polyester fiber bundle grid, a micro-permeable asphalt mixture lower layer, a high-modulus asphalt mixture middle layer, and a high-skid-resistant asphalt mixture surface layer; wherein, a longitudinal drainage gravel blind ditch is provided on the top surface of the reinforced concrete layer, and a vertical PVC drainage pipe is installed in the blind ditch, penetrating the reinforced concrete layer; a transverse drainage pipe is provided on the bottom surface of the drainage and crack-resistant large-void asphalt mixture layer, and the vertical PVC drainage pipe penetrates downwards through the drainage and crack-resistant large-void asphalt mixture layer and connects to the transverse drainage pipe.

[0007] Optionally, the high-skid-resistance asphalt mixture involved adopts high-skid-resistance SSMA-13 ​​asphalt mixture, including asphalt binder, coarse aggregate, fine aggregate, filler and fiber. Among them, the asphalt binder is high viscoelastic modified asphalt, the coarse aggregate is steel slag, the fine aggregate is a mixture of basalt and limestone with a weight ratio of 1:1, the filler is a mixture of mineral powder and steel slag powder with a weight ratio of 2:1, and the fiber is polyester fiber, mineral fiber or lignin fiber.

[0008] The gradation range of the high skid-resistant SSMA-13 ​​asphalt mixture involved is as follows: 100% passing rate for a standard sieve with a 16mm aperture, 88-98% passing rate for a standard sieve with a 13.2mm aperture, 50-70% passing rate for a standard sieve with a 9.5mm aperture, 25-39% passing rate for a standard sieve with a 4.75mm aperture, 16-26% passing rate for a standard sieve with a 2.36mm aperture, 14-24% passing rate for a standard sieve with a 1.18mm aperture, 12-20% passing rate for a standard sieve with a 0.6mm aperture, 10-16% passing rate for a standard sieve with a 0.3mm aperture, 9-15% passing rate for a standard sieve with a 0.15mm aperture, and 8-12% passing rate for a standard sieve with a 0.075mm aperture.

[0009] The high skid-resistant SSMA-13 ​​asphalt mixture involved has a design void ratio of 3% to 5%, a dynamic friction coefficient greater than 0.55, a residual strength ratio greater than 90% in the freeze-thaw splitting test, a dynamic stability value greater than 6000 cycles / mm at 60℃, a low-temperature bending failure strain greater than 3200με at -10℃, and a maximum deformation of less than 5.0mm in the Hamburg wheel rutting test at 50℃ and 20000 cycles.

[0010] Optionally, the high-modulus asphalt mixture involved is a high-modulus GCA-20 asphalt mixture, including asphalt binder, coarse aggregate, fine aggregate and filler; wherein, the asphalt binder is high-modulus modified asphalt, the coarse aggregate is steel slag, basalt or limestone, the fine aggregate is basalt or limestone, and the filler is a mixture of mineral powder and steel slag powder, with a weight ratio of mineral powder to steel slag powder of 2:1;

[0011] The gradation ranges of the high-modulus GCA-20 asphalt mixtures involved are as follows: 100% passing rate for a standard sieve with a 26.5mm aperture; 92-100% passing rate for a standard sieve with a 19mm aperture; 85-96% passing rate for a standard sieve with a 16mm aperture; 76-88% passing rate for a standard sieve with a 13.2mm aperture; 60-75% passing rate for a standard sieve with a 9.5mm aperture; 38-50% passing rate for a standard sieve with a 4.75mm aperture; 25-35% passing rate for a standard sieve with a 2.36mm aperture; 18-28% passing rate for a standard sieve with a 1.18mm aperture; 12-19% passing rate for a standard sieve with a 0.6mm aperture; 9-15% passing rate for a standard sieve with a 0.3mm aperture; 7-12% passing rate for a standard sieve with a 0.15mm aperture; and 5-8% passing rate for a standard sieve with a 0.075mm aperture.

[0012] The high-modulus GCA-20 asphalt mixture involved has a design void ratio of 3% to 4%, a freeze-thaw splitting test residual strength ratio (TSR) greater than 90%, a dynamic stability value at 70℃ greater than 6000 cycles / mm, a low-temperature bending failure strain at -10℃ greater than 3500με, and a maximum deformation of less than 4.0mm in the Hamburg wheel rutting test at 50℃ and 20000 cycles.

[0013] Optionally, the micro-permeable asphalt mixture involved includes asphalt binder, aggregate, filler and fiber; wherein, the asphalt binder is composite modified rubber asphalt or SBS modified asphalt, the coarse and fine aggregates are basalt or limestone, the filler is a mixture of mineral powder and lime powder, and the fiber is polyester fiber or mineral fiber.

[0014] The maximum nominal particle size of the micro-permeable asphalt mixture involved is 26.5 mm, and the design porosity range is 7% to 10%.

[0015] The gradation ranges of the micro-permeable asphalt mixtures involved are as follows: 100% passing rate for a standard sieve with a sieve aperture of 31.5mm, 80-98% passing rate for a sieve aperture of 26.5mm, 65-85% passing rate for a standard sieve aperture of 19mm, 52-72% passing rate for a standard sieve aperture of 13.2mm, 38-57% passing rate for a standard sieve aperture of 9.5mm, 25-39% passing rate for a standard sieve aperture of 4.75mm, 16-26% passing rate for a standard sieve aperture of 2.36mm, 10-18% passing rate for a standard sieve aperture of 1.18mm, 7-12% passing rate for a standard sieve aperture of 0.6mm, 5-9% passing rate for a standard sieve aperture of 0.3mm, 3-6% passing rate for a standard sieve aperture of 0.15mm, and 2-4% passing rate for a standard sieve aperture of 0.075mm.

[0016] The permeability coefficient of the micro-permeable asphalt mixture involved is not less than 0.05 cm / s, the residual strength ratio of the freeze-thaw splitting test is greater than 90%, the dynamic stability value at 60℃ is greater than 5000 times / mm, the low-temperature bending failure strain at -10℃ is greater than 3000 με, and the maximum deformation in the Hamburg wheel rutting test at 50℃ and 20000 times is less than 6.0 mm.

[0017] Optionally, a layer of high-toughness polyester fiber bundle geogrid is fully laid between the lower layer of the micro-permeability anti-rutting asphalt mixture and the reinforced concrete layer. The tensile strength of the high-toughness polyester fiber bundle geogrid is not less than 200kN / m. The high-toughness polyester fiber bundle geogrid is fixed to the surface of the reinforced concrete layer using rivets.

[0018] Optionally, the process for laying the reinforced concrete layer is as follows:

[0019] Select steel bars of a set diameter, arrange them at a set spacing, and weld them together to form a steel mesh;

[0020] Fabricate multi-layer steel mesh and weld the multi-layer steel mesh together vertically according to the set spacing;

[0021] The welded multi-layer steel mesh is placed on the surface of the drainage and crack-resistant large-void asphalt mixture layer, and then C20 early-strength cement concrete is poured. During the pouring process, a longitudinal drainage channel with a set width and height is reserved in the middle of the top of the C20 early-strength cement concrete, and the drainage channel is filled with crushed stone of a set specification.

[0022] A vertical PVC drainage pipe is pre-embedded at regular intervals inside the longitudinal drainage channel, penetrating the reinforced concrete layer. The top of the vertical PVC drainage pipe is wrapped with a layer of reverse filter geotextile, and the bottom of the vertical PVC drainage pipe penetrates downward through the drainage crack-resistant large-void asphalt mixture layer and connects to the transverse drainage pipe.

[0023] Preferably, the thickness of the watertight asphalt mortar layer is 3-5cm, the thickness of the drainage and crack-resistant large-void asphalt mixture layer is 10-14cm, the thickness of the reinforced concrete layer is 36-50cm, the thickness of the micro-permeable asphalt mixture lower layer is 6-10cm, the thickness of the high-modulus asphalt mixture middle layer is 8-12cm, and the thickness of the high-skid-resistant asphalt mixture surface layer is 3-5cm.

[0024] The pavement structure of the old central median strip after widening one side of a highway according to the present invention has the following advantages compared with the prior art:

[0025] 1. This invention can effectively improve the rutting resistance of the old central median strip after it has been paved into a heavy-duty lane for highways. At the same time, the drainage structure can improve the drainage function of the pavement structure, prevent water accumulation inside the pavement structure, and ensure the durability of the entire cross-section road structure in the highway reconstruction and expansion project.

[0026] 2. In the pavement structure of the present invention, the middle layer uses high modulus GCA-20 asphalt mixture, and the surface layer uses high skid resistance SSMA-13 ​​asphalt mixture. The synergistic application of the two high-performance asphalt mixtures can not only effectively improve the anti-rutting performance of the pavement structure at the old central median, but also give it excellent skid resistance, which can ensure the driving safety of drivers. Attached Figure Description

[0027] Appendix Figure 1 This is a front view sectional view of a portion of the pavement structure at the location of the old central median strip after the highway was widened on one side in Embodiment 1 of the present invention.

[0028] Appendix Figure 2 This is a top view of a partial pavement structure at the location of the old central divider after the highway was widened on one side in Embodiment 1 of the present invention;

[0029] Appendix Figure 3 This is a left view of a partial pavement structure at the location of the old central divider after the widening of one side of the highway in Embodiment 1 of the present invention.

[0030] The information indicated by the labels in the attached diagram is as follows:

[0031] 1. High-skid-resistance asphalt mixture surface layer; 2. High-modulus asphalt mixture intermediate layer.

[0032] 3. Micro-permeable asphalt mixture lower layer; 4. High-toughness polyester fiber bundle grid.

[0033] 5. Reinforced concrete layer; 6. Drainage and crack-resistant large-void asphalt mixture layer.

[0034] 7. Watertight asphalt mortar layer; 8. Longitudinal drainage channel; 9. Vertical PVC drainage pipe.

[0035] 10. Horizontal drainage pipe; 11. Reverse filter geotextile. Detailed Implementation

[0036] To make the technical solution, the technical problem solved, and the technical effect of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments.

[0037] Example 1:

[0038] Combined with appendix Figure 1 , 2 3. This embodiment proposes a pavement structure at the location of the old central divider after widening one side of a highway. It is flush with the highway road surface and includes, from the old roadbed upwards, a water-tight asphalt mortar layer 7, a drainage and crack-resistant large-void asphalt mixture layer 6, a reinforced concrete layer 5, a high-toughness polyester fiber bundle grid 4, a micro-permeable asphalt mixture lower layer 3, a high-modulus asphalt mixture middle layer 2, and a high-skid-resistant asphalt mixture surface layer 1. Among them, a longitudinal drainage gravel blind ditch is set on the top surface of the reinforced concrete layer 5, and a vertical PVC drainage pipe 9 is set in the blind ditch, penetrating the reinforced concrete layer 5. A transverse drainage pipe 10 is set on the bottom surface of the drainage and crack-resistant large-void asphalt mixture layer 6, and the vertical PVC drainage pipe 9 penetrates the drainage and crack-resistant large-void asphalt mixture layer 6 downwards and connects to the transverse drainage pipe 10.

[0039] In this embodiment, the thickness of the watertight asphalt mortar layer 7 is 4cm, the thickness of the drainage and crack-resistant large-void asphalt mixture layer 6 is 12cm, the thickness of the reinforced concrete layer 5 is 40cm, the thickness of the micro-permeable asphalt mixture lower layer 3 is 8cm, the thickness of the high-modulus asphalt mixture middle layer 2 is 10cm, and the thickness of the high-skid-resistant asphalt mixture surface layer 1 is 4cm.

[0040] In this embodiment, the high-skid-resistance asphalt mixture uses high-skid-resistance SSMA-13 ​​asphalt mixture, which is mainly used for the road surface layer. SSMA-13 ​​is an abbreviation for Anti-slip Stone Mastic Asphalt, and the number 13 indicates that the maximum nominal particle size of this mixture is 13 mm.

[0041] The high skid-resistant SSMA-13 ​​asphalt mixture includes asphalt binder, coarse aggregate, fine aggregate, filler, and fiber. The asphalt binder is high viscoelastic modified asphalt, the coarse aggregate is steel slag, the fine aggregate is a mixture of basalt and limestone with a weight ratio of 1:1, the filler is a mixture of mineral powder and steel slag powder with a weight ratio of 2:1, and the fiber is polyester fiber, mineral fiber, or lignin fiber.

[0042] The gradation range of high skid-resistant SSMA-13 ​​asphalt mixture is as follows: 100% passing rate through a standard sieve with a 16mm aperture; 88-98% passing rate through a standard sieve with a 13.2mm aperture; 50-70% passing rate through a standard sieve with a 9.5mm aperture; 25-39% passing rate through a standard sieve with a 4.75mm aperture; 16-26% passing rate through a standard sieve with a 2.36mm aperture; 14-24% passing rate through a standard sieve with a 1.18mm aperture; 12-20% passing rate through a standard sieve with a 0.6mm aperture; 10-16% passing rate through a standard sieve with a 0.3mm aperture; 9-15% passing rate through a standard sieve with a 0.15mm aperture; and 8-12% passing rate through a standard sieve with a 0.075mm aperture.

[0043] The high skid-resistant SSMA-13 ​​asphalt mixture has a design void ratio of 3% to 5%, a dynamic friction coefficient greater than 0.55, a residual strength ratio greater than 90% in the freeze-thaw splitting test, a dynamic stability value greater than 6000 cycles / mm at 60℃, a low-temperature bending failure strain greater than 3200με at -10℃, and a maximum deformation of less than 5.0mm in the Hamburg wheel rutting test at 50℃ and 20000 cycles.

[0044] In this embodiment, the high-modulus asphalt mixture uses high-modulus GCA-20 asphalt mixture. High-modulus GCA-20 asphalt mixture is a material used in road construction. It has a high modulus and good fatigue resistance, and is typically used to improve the load-bearing capacity of pavements and extend their service life. In asphalt mixtures, GCA-20 refers to an asphalt concrete mixture with a specific particle size, where the number 20 indicates that the maximum nominal particle size of the aggregate used in the mixture is 20 mm. This type of asphalt mixture is commonly used in the surface or intermediate layers of road construction. Its gradation design aims to provide good pavement performance, including abrasion resistance, rutting resistance, and appropriate permeability.

[0045] High modulus GCA-20 asphalt mixture includes asphalt binder, coarse aggregate, fine aggregate and filler; among which, the asphalt binder is high modulus modified asphalt, the coarse aggregate is steel slag, basalt or limestone, the fine aggregate is basalt or limestone, and the filler is a mixture of mineral powder and steel slag powder, with a weight ratio of mineral powder to steel slag powder of 2:1.

[0046] The gradation range of high modulus GCA-20 asphalt mixture is as follows: 100% passing rate for a standard sieve with a 26.5mm aperture; 92-100% passing rate for a standard sieve with a 19mm aperture; 85-96% passing rate for a standard sieve with a 16mm aperture; 76-88% passing rate for a standard sieve with a 13.2mm aperture; 60-75% passing rate for a standard sieve with a 9.5mm aperture; 38-50% passing rate for a standard sieve with a 4.75mm aperture; 25-35% passing rate for a standard sieve with a 2.36mm aperture; 18-28% passing rate for a standard sieve with a 1.18mm aperture; 12-19% passing rate for a standard sieve with a 0.6mm aperture; 9-15% passing rate for a standard sieve with a 0.3mm aperture; 7-12% passing rate for a standard sieve with a 0.15mm aperture; and 5-8% passing rate for a standard sieve with a 0.075mm aperture.

[0047] The high-modulus GCA-20 asphalt mixture has a design void ratio of 3% to 4%, a freeze-thaw splitting strength ratio (TSR) greater than 90%, a dynamic stability value at 70℃ greater than 6000 cycles / mm, a low-temperature flexural failure strain at -10℃ greater than 3500με, and a maximum deformation of less than 4.0mm in the Hamburg wheel rutting test at 50℃ and 20000 cycles.

[0048] In this embodiment, the micro-permeable asphalt mixture is an environmentally friendly and functional road construction material. Through its special design, it provides excellent drainage and noise reduction while maintaining the road's performance and durability. The micro-permeable asphalt mixture includes asphalt binder, aggregates, fillers, and fibers; wherein the asphalt binder is composite modified rubber asphalt or SBS modified asphalt, the coarse and fine aggregates are basalt or limestone, the fillers are a mixture of mineral powder and lime powder, and the fibers are polyester fibers or mineral fibers.

[0049] The gradation range of micro-permeable asphalt mixtures is as follows: 100% passing rate for a standard sieve with a 31.5mm aperture; 80-98% passing rate for a 26.5mm aperture; 65-85% passing rate for a 19mm aperture; 52-72% passing rate for a 13.2mm aperture; 38-57% passing rate for a 9.5mm aperture; 25-39% passing rate for a 4.75mm aperture; 16-26% passing rate for a 2.36mm aperture; 10-18% passing rate for a 1.18mm aperture; 7-12% passing rate for a 0.6mm aperture; 5-9% passing rate for a 0.3mm aperture; 3-6% passing rate for a 0.15mm aperture; and 2-4% passing rate for a 0.075mm aperture.

[0050] The maximum nominal particle size of the micro-permeable asphalt mixture is 26.5 mm, the design porosity range is 7% to 10%, the permeability coefficient is not less than 0.05 cm / s, the residual strength ratio in the freeze-thaw splitting test is greater than 90%, the dynamic stability value at 60℃ is greater than 5000 cycles / mm, the low-temperature bending failure strain at -10℃ is greater than 3000 με, and the maximum deformation in the Hamburg wheel rutting test at 50℃ and 20000 cycles is less than 6.0 mm.

[0051] High-toughness polyester fiber bundle grid 4 is a material used for geotechnical reinforcement. It is commonly used in roadbed reinforcement, retaining walls, and slope protection projects to improve structural stability and load-bearing capacity. It is typically made of high-toughness polyester fibers and can sometimes be combined with other materials (such as steel-plastic composites or fiberglass) to provide additional strength and durability. In this embodiment, the tensile strength of the high-toughness polyester fiber bundle grid 4 is not less than 200 kN / m, and it is fixed to the surface of the reinforced concrete layer 5 using rivets.

[0052] In this embodiment, the paving process of the reinforced concrete layer 5 is as follows:

[0053] Select steel bars of a set diameter, arrange them at a set spacing, and weld them together to form a steel mesh;

[0054] Fabricate multi-layer steel mesh and weld the multi-layer steel mesh together vertically according to the set spacing;

[0055] The welded multi-layer steel mesh is placed on the surface of the drainage and crack-resistant large-void asphalt mixture layer 6, and then C20 early-strength cement concrete is poured. During the pouring process, a longitudinal drainage channel 8 with a set width and height is reserved in the middle of the top of the C20 early-strength cement concrete, and the drainage channel is filled with crushed stone of a set specification.

[0056] A vertical PVC drainage pipe 9 is pre-embedded at intervals inside the longitudinal drainage channel 8, penetrating the reinforced concrete layer 5. The top of the vertical PVC drainage pipe 9 is wrapped with a layer of reverse filter geotextile 11, and the bottom of the vertical PVC drainage pipe 9 penetrates downward through the drainage crack-resistant large-void asphalt mixture layer 6 and connects to the transverse drainage pipe 10.

[0057] In this embodiment, the drainage and crack-resistant large-void asphalt mixture is an asphalt concrete surface material with a high porosity. It can provide good drainage performance and certain crack resistance. The drainage performance is specifically reflected in the fact that the porosity of the drainage and crack-resistant large-void asphalt mixture after compaction is usually around 20%, which can form drainage channels inside the mixture, effectively draining water from the road surface and reducing hydroplaning and water accumulation.

[0058] In this embodiment, watertight asphalt mortar is a waterproof asphalt concrete material commonly used in road construction for waterproofing layers or sealing surfaces. It is primarily composed of asphalt, sand, clay, water, and a small amount of minerals, and features waterproofing, wear resistance, and stability. During construction, watertight asphalt mortar requires mixing, spreading, and compaction using specialized equipment to ensure optimal performance. Furthermore, this material undergoes rigorous quality control before construction to ensure its performance in practical applications meets design requirements.

[0059] In summary, the pavement structure of the old median strip after widening one side of a highway according to the present invention can effectively improve the rutting resistance of the old median strip after it is paved into a heavy-duty lane of the highway. At the same time, the drainage structure can improve the drainage function of the pavement structure, prevent water accumulation inside the pavement structure, and ensure the durability of the entire cross-section road structure of the highway reconstruction and expansion project.

[0060] The above specific examples illustrate the principles and implementation methods of the present invention in detail. These embodiments are merely for the purpose of helping to understand the core technical content of the present invention. Based on the above specific embodiments of the present invention, any improvements and modifications made to the present invention by those skilled in the art without departing from the principles of the present invention should fall within the patent protection scope of the present invention.

Claims

1. A pavement structure at the location of the old central median strip after a highway has been widened on one side, flush with the highway surface, characterized in that, From the old roadbed upwards, it consists of, in sequence: a water-tight asphalt mortar layer, a drainage-resistant and crack-resistant large-void asphalt mixture layer, a reinforced concrete layer, a high-toughness polyester fiber bundle grid, a micro-permeable asphalt mixture lower layer, a high-modulus asphalt mixture intermediate layer, and a high-skid-resistance asphalt mixture surface layer; among which: A longitudinal drainage gravel blind ditch is set on the top surface of the reinforced concrete layer. A vertical PVC drainage pipe is set in the blind ditch, penetrating the reinforced concrete layer. A horizontal drainage pipe is set on the bottom surface of the drainage crack-resistant large-void asphalt mixture layer. The vertical PVC drainage pipe penetrates downward through the drainage crack-resistant large-void asphalt mixture layer and connects to the horizontal drainage pipe. The high skid-resistant asphalt mixture adopts high skid-resistant SSMA-13 ​​asphalt mixture, including asphalt binder, coarse aggregate, fine aggregate, filler and fiber. The asphalt binder is high viscoelastic modified asphalt, the coarse aggregate is steel slag, the fine aggregate is a mixture of basalt and limestone with a weight ratio of 1:1, the filler is a mixture of mineral powder and steel slag powder with a weight ratio of 2:1, and the fiber is polyester fiber, mineral fiber or lignin fiber. The high-modulus asphalt mixture adopts high-modulus GCA-20 asphalt mixture, including asphalt binder, coarse aggregate, fine aggregate and filler; wherein, the asphalt binder is high-modulus modified asphalt, the coarse aggregate is steel slag, basalt or limestone, the fine aggregate is basalt or limestone, and the filler is a mixture of mineral powder and steel slag powder, with a weight ratio of mineral powder to steel slag powder of 2:1; The micro-permeable asphalt mixture includes asphalt binder, aggregate, filler and fiber; wherein, the asphalt binder is composite modified rubber asphalt or SBS modified asphalt, the aggregate is basalt or limestone, the filler is a mixture of mineral powder and lime powder, and the fiber is polyester fiber or mineral fiber. A layer of high-toughness polyester fiber bundle grid is fully laid between the lower layer of the micro-permeable anti-rutting asphalt mixture and the reinforced concrete layer. The tensile strength of the high-toughness polyester fiber bundle grid is not less than 200kN / m. The high-toughness polyester fiber bundle grid is fixed to the surface of the reinforced concrete layer using rivets. The paving process of the reinforced concrete layer is as follows: Select steel bars of a set diameter, arrange the steel bars at a set spacing and weld them to form a steel mesh; make multiple layers of steel mesh, and weld the multiple layers of steel mesh together vertically at a set spacing; place the welded multi-layer steel mesh on the surface of the drainage and crack-resistant large-void asphalt mixture layer, and then pour C20 early-strength cement concrete. During the pouring process, a longitudinal drainage channel of a set width and height is reserved in the middle of the top of the C20 early-strength cement concrete, and the drainage channel is filled with crushed stone of a set specification; a vertical PVC drainage pipe penetrating the reinforced concrete layer is embedded in the longitudinal drainage channel at a set interval, and a layer of reverse filter geotextile is wrapped on the top of the vertical PVC drainage pipe.

2. The pavement structure at the location of the old central median strip after widening one side of a highway according to claim 1, characterized in that, The gradation range of the high skid-resistant SSMA-13 ​​asphalt mixture is as follows: 100% passing rate for a standard sieve with a 16mm aperture, 88-98% passing rate for a standard sieve with a 13.2mm aperture, 50-70% passing rate for a standard sieve with a 9.5mm aperture, 25-39% passing rate for a standard sieve with a 4.75mm aperture, 16-26% passing rate for a standard sieve with a 2.36mm aperture, 14-24% passing rate for a standard sieve with a 1.18mm aperture, 12-20% passing rate for a standard sieve with a 0.6mm aperture, 10-16% passing rate for a standard sieve with a 0.3mm aperture, 9-15% passing rate for a standard sieve with a 0.15mm aperture, and 8-12% passing rate for a standard sieve with a 0.075mm aperture. The high skid-resistant SSMA-13 ​​asphalt mixture has a design void ratio of 3%~5%, a dynamic friction coefficient greater than 0.55, a residual strength ratio greater than 90% in the freeze-thaw splitting test, a dynamic stability value greater than 6000 cycles / mm at 60℃, a low-temperature bending failure strain greater than 3200με at -10℃, and a maximum deformation of less than 5.0mm in the Hamburg wheel rutting test at 50℃ and 20000 cycles.

3. The pavement structure at the location of the old central median strip after widening one side of a highway according to claim 2, characterized in that, The gradation range of the high-modulus GCA-20 asphalt mixture is as follows: 100% passing rate for a standard sieve with a 26.5mm aperture, 92-100% passing rate for a standard sieve with a 19mm aperture, 85-96% passing rate for a standard sieve with a 16mm aperture, 76-88% passing rate for a standard sieve with a 13.2mm aperture, 60-75% passing rate for a standard sieve with a 9.5mm aperture, 38-50% passing rate for a standard sieve with a 4.75mm aperture, 25-35% passing rate for a standard sieve with a 2.36mm aperture, 18-28% passing rate for a standard sieve with a 1.18mm aperture, 12-19% passing rate for a standard sieve with a 0.6mm aperture, 9-15% passing rate for a standard sieve with a 0.3mm aperture, 7-12% passing rate for a standard sieve with a 0.15mm aperture, and 5-8% passing rate for a standard sieve with a 0.075mm aperture. The high-modulus GCA-20 asphalt mixture has a designed void ratio of 3%~4%, a residual strength ratio greater than 90% in the freeze-thaw splitting test, a dynamic stability value greater than 6000 cycles / mm at 70℃, a low-temperature bending failure strain greater than 3500με at -10℃, and a maximum deformation of less than 4.0mm in the Hamburg wheel rutting test at 50℃ and 20000 cycles.

4. The pavement structure at the location of the old central median strip after widening one side of a highway according to claim 3, characterized in that, The maximum nominal particle size of the micro-permeable asphalt mixture is 26.5 mm, and the designed porosity range is 7% to 10%. The gradation range of the micro-permeable asphalt mixture is as follows: 100% passing rate for a standard sieve with a 31.5mm aperture, 80-98% passing rate for a 26.5mm aperture, 65-85% passing rate for a 19mm aperture, 52-72% passing rate for a 13.2mm aperture, 38-57% passing rate for a 9.5mm aperture, 25-39% passing rate for a 4.75mm aperture, 16-26% passing rate for a 2.36mm aperture, 10-18% passing rate for a 1.18mm aperture, 7-12% passing rate for a 0.6mm aperture, 5-9% passing rate for a 0.3mm aperture, 3-6% passing rate for a 0.15mm aperture, and 2-4% passing rate for a 0.075mm aperture. The micro-permeable asphalt mixture has a permeability coefficient of not less than 0.05 cm / s, a residual strength ratio of more than 90% in the freeze-thaw splitting test, a dynamic stability value of more than 5000 cycles / mm at 60℃, a low-temperature bending failure strain of more than 3000 με at -10℃, and a maximum deformation of less than 6.0 mm in the Hamburg wheel rutting test at 50℃ and 20000 cycles.

5. The pavement structure at the location of the old central median strip after widening one side of a highway according to claim 1, characterized in that, The thickness of the watertight asphalt mortar layer is 3-5cm, the thickness of the drainage and crack-resistant large-void asphalt mixture layer is 10-14cm, the thickness of the reinforced concrete layer is 36-50cm, the thickness of the micro-permeable asphalt mixture lower layer is 6-10cm, the thickness of the high-modulus asphalt mixture middle layer is 8-12cm, and the thickness of the high-skid-resistant asphalt mixture surface layer is 3-5cm.

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