A semi-rigid base asphalt pavement structure

Abstract

The application relates to a semi-rigid base asphalt pavement structure and relates to the technical field of road engineering construction, which comprises a semi-rigid base; an asphalt pavement bottom layer which is laid on the upper surface of the semi-rigid base; the asphalt pavement bottom layer is divided into a side limit area, a heavy load driving area and a plastic flow deformation area along the width direction of the road; the heavy load driving area is located on the two sides of the plastic flow deformation area; the side limit area is located on the two sides of the heavy load driving area; the side limit area is used for limiting the heavy load driving area from being deformed under pressure; the plastic flow deformation area is used for bearing the deformation of the heavy load driving area under pressure; an asphalt pavement middle layer which is laid above the asphalt pavement bottom layer; and an asphalt pavement surface layer which is laid above the asphalt pavement middle layer; the application has the effect of reducing the rutting of the asphalt concrete pavement.

Description

Technical Field

[0001] This application relates to the technical field of road engineering construction, and in particular to a semi-rigid base asphalt pavement structure. Background Technology

[0002] Semi-rigid base courses refer to base courses that are paved with inorganic binder stabilized soil, which can form a slab and have a certain flexural strength. In other words, base courses are paved with inorganic binder stabilized aggregates or soil materials. Semi-rigid base courses have high rigidity and strong load diffusion capacity. Semi-rigid base course materials include cement stabilized, cement fly ash stabilized, and lime fly ash stabilized.

[0003] For a long time, my country's design specifications for semi-rigid base asphalt pavements have consistently adopted the "Specifications for Design of Flexible Highway Pavements" and the "Specifications for Design of Asphalt Highway Pavements." According to these specifications, the pavement grade and surface layer type of semi-rigid base asphalt pavements should be determined based on factors such as highway grade and usage requirements, the cumulative equivalent axle loads within the design life, road construction materials, and construction machinery and equipment. Therefore, the design life is a benchmark for calculating the cumulative equivalent axle loads. Currently, there is a significant gap between the actual service life and the design life of many roads; therefore, the following existing technologies can be referenced.

[0004] An existing semi-rigid base asphalt pavement structure includes an asphalt surface layer and a semi-rigid base material. The materials and thicknesses of the asphalt surface layer and the semi-rigid base material are as follows, depending on the highway grade, traffic volume, and design life: Highways: The semi-rigid base course is cement-stabilized crushed stone or lime-stabilized crushed stone, with a thickness (including the subbase) of t×20cm; the asphalt surface course is asphalt concrete, with a thickness of 5-8cm; traffic volume > 3000 vehicles / (d·lane); design life ten years; Note: If the base course thickness is > 20cm, the subbase course is lime-stabilized soil with a plasticity index of 14-18; t is a proportionality coefficient, which is the area of ​​the deflection basin of the lime-stabilized soil base course with a plasticity index of 5-14 / the area of ​​the deflection basin of the cement-stabilized crushed stone or lime-stabilized crushed stone base course. Class I highway: The semi-rigid base course is cement-stabilized crushed stone or lime-stabilized crushed stone, with a thickness (including the subbase) of t×20cm; the asphalt surface course is asphalt concrete, with a thickness of 4-6cm; the traffic volume is 1500-3000 vehicles / (d·lane); the design life is ten years; Note: If the base course thickness is >20cm, the subbase course is lime-stabilized soil with a plasticity index of 14-18; t is a proportionality coefficient, which is the area of ​​the deflection basin of the lime-stabilized soil base course with a plasticity index of 5-14 / the area of ​​the deflection basin of the cement-stabilized crushed stone or lime-stabilized crushed stone base course. Class II highway: The semi-rigid base course is lime-fly ash soil with a plasticity index of 5-14, and the thickness (including the subbase) is t×15cm. The asphalt surface course is asphalt-aggregate mixed with an asphalt layer and a thickness of 3-4cm. The traffic volume is 600-1500 vehicles / (d·lane). The design life is 15 years. Note: If the base course thickness is >20cm, the subbase course is lime-fly ash soil with a plasticity index of 14-18. t is a proportionality coefficient, which is the area of ​​the deflection basin of the lime-fly ash soil base course with a plasticity index of 5-14 / the area of ​​the deflection basin of the lime-fly ash soil base course with a plasticity index of 5-14. For secondary highways: the semi-rigid base course is lime-soil with a plasticity index (PLI) of 14-18, with a thickness (including the subbase) of t × 15 cm; the asphalt surface course is asphalt concrete or hot-mix asphalt macadam, with a thickness of 3-4 cm; traffic volume is 600-1500 vehicles / (d·lane); design life is ten years; t is a proportionality coefficient, which is the area of ​​the deflection basin of the lime-soil base course with a PLAI of 5-14 divided by the area of ​​the deflection basin of the lime-soil base course with a PLAI of 14-18. The above scheme uses a lime-soil semi-rigid base course with a PLAI below 14 as a benchmark. By comparing its deflection basin area with that of other semi-rigid base courses, a proportionality coefficient is determined, establishing a connection between different semi-rigid base course materials. The base course thickness is determined based on different base course materials, reducing asphalt pavement damage caused by differences in base course compressive strength and narrowing the gap between the design life and the service life.

[0005] Regarding the aforementioned technologies, during rutting investigation and analysis, it was found that highways constructed with lime-soil base courses still exhibit severe rutting problems on asphalt pavements under high temperatures and heavy loads. Summary of the Invention

[0006] To address the rutting issues of semi-rigid base asphalt pavements, this application provides a semi-rigid base asphalt pavement structure.

[0007] This application provides a semi-rigid base asphalt pavement structure, employing the following technical solution: comprising: a semi-rigid base; an asphalt pavement subbase laid on the upper surface of the semi-rigid base; the asphalt pavement subbase is divided along the width of the highway into a lateral confinement zone, a heavy-load traffic zone, and a plastic flow deformation zone; the heavy-load traffic zone is located on both sides of the plastic flow deformation zone; the lateral confinement zone is located on both sides of the heavy-load traffic zone; the lateral confinement zone is used to limit the deformation of the heavy-load traffic zone under pressure; the plastic flow deformation zone is used to support the deformation of the heavy-load traffic zone under pressure; an asphalt pavement intermediate layer laid on top of the asphalt pavement subbase; and an asphalt pavement surface layer laid on top of the asphalt pavement intermediate layer.

[0008] By adopting the above technical solution, when heavy-duty vehicles are driving normally in a single lane, the pressure exerted on the road is transmitted from the surface layer of the asphalt pavement to the middle layer, and then from the middle layer to the bottom layer. When a heavy-duty vehicle is overloaded, the pressure exceeding the road's design bearing capacity is transmitted to the heavy-duty driving zone. This zone deforms under pressure. The side-limiting zone restricts the deformation of the asphalt concrete in the heavy-duty driving zone towards the side closest to it. The plastic flow deformation zone briefly absorbs the deformation of the asphalt concrete in the heavy-duty driving zone caused by the high pressure impact. When the heavy-duty vehicle passes, the pressure disappears, and the concrete in the heavy-duty driving zone returns to its original position, thus achieving pressure transmission. This reduces irreversible plastic deformation of the pavement caused by overloaded vehicles directly crushing the asphalt pavement, and also reduces the possibility of the pavement failing to withstand heavy loads and cracking. Meanwhile, since the wheelbase of passenger vehicles is smaller than that of heavy-duty vehicles, when passenger vehicles are driving normally in a single lane, the vehicle should be located above the plastic flow deformation zone. At this time, the pressure transmitted by the passenger vehicle to the road is transmitted to the plastic flow deformation zone, causing the deformation rebound that may occur in the heavy-duty driving zone, thereby reducing the deformation that occurs in the heavy-duty driving zone; thus reducing the formation of ruts.

[0009] Preferably, side restriction zones are set between adjacent heavy-duty driving areas of multiple lanes.

[0010] By adopting the above technical solutions, when existing paved highways are wide and divided into multiple lanes according to design dimensions, side restriction zones are set between adjacent lanes, which further reduces the damage caused by overloaded heavy vehicles to the entire road and reduces the formation of ruts; at the same time, when overloaded heavy vehicles change lanes during driving, the side restriction zones can withstand greater pressure without deformation.

[0011] Preferably, a skeleton assembly is provided between the side limiting zones. The skeleton assembly includes a side limiting plate and a connecting rod. The side limiting plate is laid along the length of the road and is perpendicular to the semi-rigid base layer. The connecting rod is fixedly connected to adjacent side limiting plates.

[0012] By adopting the above technical solution, the side limiting plate is cast in the side limiting area, which improves the compressive strength of the side limiting area, enabling it to withstand greater pressure without deformation and without plastic flow. At the same time, it improves the strength of the side limiting area, thereby reducing the occurrence of plastic flow under pressure. Furthermore, it transmits the pressure on the heavy-duty driving area to the plastic flow deformation area, which is conducive to the recovery of deformation in the heavy-duty driving area.

[0013] Preferably, the connecting rods are evenly distributed along the length direction of the side limiting plate.

[0014] By adopting the above technical solution, the connecting rods are evenly distributed along the length of the side limit plate, making the side limit plate more uniformly stressed. At the same time, the connecting rods connect adjacent side limit plates, improving the overall integrity of the highway and reducing the possibility of settlement caused by a single side limit plate being subjected to excessive design pressure.

[0015] Preferably, the intermediate layer of the asphalt pavement is divided into a pressure transmission zone and a return zone along the width of the road. The pressure transmission zone is located above the lateral confinement zone and the heavy-duty traffic zone; the return zone is located above the plastic flow deformation zone.

[0016] By adopting the above technical solution, when a passenger vehicle is driving above the recoil zone, the pressure generated in the recoil zone is better transmitted to the plastic deformation zone, thereby promoting the rebound of the deformation in the heavy-duty driving zone.

[0017] Preferably, a steel mesh is laid along the length of the road at the connection between the pressure transmission zone and the acceleration zone.

[0018] By adopting the above technical solutions, the installation of steel mesh improves the overall integrity of the highway and enhances the bending resistance at the connection between the pressure transmission zone and the acceleration zone.

[0019] Preferably, the surface layer of the asphalt pavement is paved with high-viscosity asphalt concrete.

[0020] By adopting the above technical solutions, the integrity and plastic resilience of the asphalt pavement surface layer are improved, thereby reducing the occurrence of ruts.

[0021] Preferably, the accelerator zone is made of high flexural strength asphalt concrete.

[0022] By adopting the above technical solutions, asphalt concrete with high flexural strength can better transfer the pressure to the plastic deformation zone.

[0023] In summary, this application includes at least one of the following beneficial technical effects: 1. When a heavy-duty vehicle is overloaded, the heavy-duty driving zone deforms under pressure. At this time, the side-limiting zone restricts the deformation of the asphalt concrete in the heavy-duty driving zone towards the side closest to it. The plastic flow deformation zone temporarily absorbs the deformation of the asphalt concrete caused by the high pressure impact on the heavy-duty driving zone. When the heavy-duty vehicle passes, the pressure disappears, and the concrete in the heavy-duty driving zone returns to its original position, thus achieving pressure transmission. This reduces irreversible plastic deformation of the pavement caused by overloaded vehicles directly rolling over it, and also reduces the possibility of the pavement failing to withstand heavy loads and cracking. Furthermore, since the wheelbase of passenger vehicles is smaller than that of heavy-duty vehicles, when passenger vehicles are driving normally in a single lane, the vehicle should be positioned above the plastic flow deformation zone. In this case, the pressure transmitted from the passenger vehicle to the road is transferred to the plastic flow deformation zone, causing the heavy-duty driving zone to rebound from potential deformation, thereby reducing the deformation in the heavy-duty driving zone and consequently reducing rutting. 2. The side limiting plate is cast in the side limiting zone, which improves the compressive strength of the side limiting zone, allowing it to withstand greater pressure without deformation and plastic flow. At the same time, it improves the strength of the side limiting zone, thereby reducing the occurrence of plastic flow under pressure. Furthermore, it transfers the pressure on the heavy-duty vehicle area to the plastic flow deformation zone, which is conducive to the recovery of deformation in the heavy-duty vehicle area. 3. The installation of steel mesh improves the overall integrity of the highway and enhances the bending resistance at the connection between the pressure transmission zone and the acceleration zone. Attached Figure Description

[0024] Figure 1 This is a cross-sectional view of an embodiment of this application; Figure 2 This is a schematic diagram of the road surface condition when a heavy-load driving zone is subjected to pressure exceeding the design limit; Figure 3 This is a schematic diagram showing the positional relationship between the skeleton components and the asphalt pavement substrate; Figure 4 This is a top view showing the skeleton components; Figure 5 This is a top view showing the reinforcing mesh.

[0025] In the diagram, 1. Semi-rigid base course; 2. Asphalt pavement base course; 21. Lateral confinement zone; 22. Heavy-duty traffic zone; 23. Plastic flow deformation zone; 3. Asphalt pavement intermediate course; 31. Pressure transmission zone; 32. Rebound zone; 4. Asphalt pavement surface course; 5. Skeleton components; 51. Lateral confinement plate; 52. Connecting rod; 6. Reinforcing mesh. Detailed Implementation

[0026] The following is in conjunction with the appendix Figure 1-5 This application will be described in further detail.

[0027] This application discloses a semi-rigid base asphalt pavement structure.

[0028] Rutting investigation and analysis of asphalt pavement has always been a research focus at home and abroad. In recent years, among the rutting that has been constantly emerging, it has been found that rutting mainly occurs in the middle and bottom layers of asphalt pavement. Experiments show that the contribution rate of rutting in the bottom layer of semi-rigid base asphalt pavement is greater than that in the middle and surface layers.

[0029] refer to Figure 1 and Figure 2A semi-rigid base asphalt pavement structure includes a semi-rigid base layer 1, an asphalt pavement subbase layer 2, an asphalt pavement intermediate layer 3, and an asphalt pavement surface layer 4. The semi-rigid base layer 1, asphalt pavement subbase layer 2, asphalt pavement intermediate layer 3, and asphalt pavement surface layer 4 are laid sequentially from bottom to top; that is, the asphalt pavement subbase layer 2 is laid on the upper surface of the semi-rigid base layer 1, the asphalt pavement intermediate layer 3 is laid on top of the asphalt pavement subbase layer 2, and the asphalt pavement surface layer 4 is laid on top of the asphalt pavement intermediate layer 3. The semi-rigid base layer 1 can be paved with any one of cement-stabilized, cement-fly ash-stabilized, and lime-fly ash-stabilized materials. In this application, lime-soil is used as the main raw material for the semi-rigid base layer 1. The asphalt pavement surface layer 4 is paved with high-viscosity asphalt concrete.

[0030] refer to Figure 1 and Figure 2 The asphalt pavement base layer 2 is divided into a side-confined zone 21, a heavy-load traffic zone 22, and a plastic flow deformation zone 23 along the width of the highway. The heavy-load traffic zone 22 is located on both sides of the plastic flow deformation zone 23, and the side-confined zone 21 is located on both sides of the heavy-load traffic zone 22. When the highway is wide and divided into multiple lanes, a side-confined zone 21 is set between adjacent heavy-load traffic zones 22 of the multiple lanes. The side-confined zone 21 is used to limit the deformation of the heavy-load traffic zone 22 under pressure, and the plastic flow deformation zone 23 is used to support the deformation of the heavy-load traffic zone 22 under pressure. That is, the asphalt strength of the heavy-load traffic zone 22 is higher than that of the plastic flow deformation zone 23.

[0031] Specifically, during highway construction, the total width of the highway is divided into different numbers of lanes. For single-lane highways, the side restriction zone 21 corresponds to the area below the traffic markings along the length of the highway. The distance between the adjacent edge lines of the heavy-duty driving zones 22 is greater than the wheelbase of a passenger car (1.6 meters) and less than the wheelbase of a light truck (2.2 meters). In this embodiment, 2 meters is selected as the spacing between the adjacent edge lines of the heavy-duty driving zones 22. For multi-lane highways, adjacent lanes share the same side restriction zone 21.

[0032] When a heavy-duty vehicle is traveling normally in a single lane, the pressure exerted on the road is transmitted from the asphalt pavement surface layer 4 to the asphalt pavement middle layer 3, and then from the asphalt pavement middle layer 3 to the asphalt pavement bottom layer 2. At this time, when the heavy-duty vehicle is overloaded, the pressure exceeding the road's design bearing capacity is transmitted to the heavy-duty driving zone 22. The heavy-duty driving zone 22 undergoes reversible deformation under pressure. At this time, the side-limiting zone restricts the deformation of the asphalt concrete in the heavy-duty driving zone 22 towards the side closest to it. The plastic flow deformation zone 23 briefly absorbs the deformation of the asphalt concrete in the heavy-duty driving zone 22 caused by the impact of high pressure. When the heavy-duty vehicle passes, the pressure disappears, and the concrete in the heavy-duty driving zone 22 returns to its original position, thus realizing pressure transmission. This reduces the irreversible plastic deformation of the road surface caused by overloaded heavy-duty vehicles directly rolling over the asphalt pavement, and at the same time reduces the possibility that the road surface cannot withstand heavy loads and will break. Meanwhile, since the wheelbase of passenger vehicles is smaller than that of heavy-duty vehicles, when passenger vehicles are driving normally in a single lane, the vehicle should be located above the plastic flow deformation zone 23. At this time, the pressure transmitted by the passenger vehicle to the road is transmitted to the plastic flow deformation zone 23, causing the deformation rebound that may occur in the heavy-duty driving zone 22, thereby reducing the deformation that occurs in the heavy-duty driving zone 22; thus reducing the generation of ruts.

[0033] refer to Figure 3 and Figure 4 A skeleton assembly 5 is provided between the side limiting zones 21. The skeleton assembly 5 includes a side limiting plate 51 and a connecting rod 52. The side limiting plate 51 is laid along the length of the road and is perpendicular to the semi-rigid base layer 1. The connecting rod 52 is vertically fixed to the adjacent side limiting plates 51. There are multiple connecting rods 52, and the multiple connecting rods 52 are equidistantly distributed along the length of the side limiting plate 51.

[0034] The side limiting plate 51 is cast within the side limiting zone 21, which improves the compressive strength of the side limiting zone 21, enabling it to withstand greater pressure without deformation and preventing plastic flow. Simultaneously, it increases the strength of the side limiting zone 21, further reducing the likelihood of plastic flow under pressure. Furthermore, it transmits the pressure on the heavy-duty driving zone 22 to the plastic flow deformation zone 23, facilitating the recovery of deformation in the heavy-duty driving zone 22. The connecting rods 52 are evenly distributed along the length of the side limiting plate 51, making the force on the side limiting plate 51 more uniform. At the same time, the connecting rods 52 connect adjacent side limiting plates 51, improving the overall integrity of the highway and reducing the possibility of settlement due to excessive pressure on a single side limiting plate 51.

[0035] refer to Figure 3 and Figure 5The asphalt pavement intermediate layer 3 is divided into a pressure transmission zone 31 and a return zone 32 along the width of the highway. The pressure transmission zone 31 is located above the lateral confinement zone 21 and the heavy-duty traffic zone 22. The return zone 32 is located above the plastic flow deformation zone 23. A steel mesh 6 is laid along the length of the highway at the connection between the pressure transmission zone 31 and the return zone 32. The return zone 32 is made of asphalt concrete with high bending resistance, that is, hot-mixed and hot-laid dense-graded crushed stone asphalt concrete can be used.

[0036] When a passenger vehicle travels over the recovery zone 32, the higher strength and better integrity of the asphalt concrete in the recovery zone 32 allow for better transmission of pressure to the plastic deformation zone 23, thereby promoting the rebound of deformation in the heavy-duty driving zone 22. The reinforcement mesh 6 improves the overall integrity of the road and enhances the bending resistance at the connection between the pressure transmission zone 31 and the recovery zone 32. When the connection between the pressure transmission zone 31 and the recovery zone 32 is subjected to shear force, it ensures good integrity and stability.

[0037] The implementation principle of a semi-rigid base asphalt pavement structure in this application embodiment is as follows: When a heavy-duty vehicle is driving normally in a single lane, the pressure applied to the road is transmitted from the asphalt pavement surface layer 4 to the asphalt pavement middle layer 3, and then from the asphalt pavement middle layer 3 to the asphalt pavement base layer 2. At this time, when the heavy-duty vehicle is overloaded, the pressure exceeding the road's design bearing capacity is transmitted to the heavy-duty driving zone 22. The heavy-duty driving zone 22 deforms under pressure. At this time, the side-limiting zone restricts the asphalt concrete of the heavy-duty driving zone 22 from deforming towards the side closer to it. The plastic flow deformation zone 23 temporarily absorbs the deformation of the asphalt concrete of the heavy-duty driving zone 22 caused by the pressure impact. When the heavy-duty vehicle passes, the pressure disappears, and the concrete of the heavy-duty driving zone 22 returns to its original position, thus realizing pressure transmission. This reduces the irreversible plastic deformation of the pavement caused by the direct crushing of the asphalt pavement by overloaded heavy-duty vehicles, and at the same time reduces the possibility of the pavement being unable to withstand heavy loads and breaking. Meanwhile, since the wheelbase of passenger vehicles is smaller than that of heavy-duty vehicles, when passenger vehicles are driving normally in a single lane, the vehicle should be located above the plastic flow deformation zone 23. At this time, the pressure transmitted by the passenger vehicle to the road is transmitted to the plastic flow deformation zone 23, causing the deformation rebound that may occur in the heavy-duty driving zone 22, thereby reducing the deformation that occurs in the heavy-duty driving zone 22; thus reducing the generation of ruts.

[0038] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A semi-rigid base asphalt pavement structure, characterized in that: include: Semi-rigid base layer (1); The asphalt pavement base layer (2) is laid on the upper surface of the semi-rigid base layer (1); the asphalt pavement base layer (2) is divided into a lateral confinement zone (21), a heavy-duty traffic zone (22), and a plastic flow deformation zone (23) along the width of the highway; the heavy-duty traffic zone (22) is located on both sides of the plastic flow deformation zone (23); the lateral confinement zone (21) is located on both sides of the heavy-duty traffic zone (22); the lateral confinement zone (21) is used to limit the deformation of the heavy-duty traffic zone (22) under pressure; the plastic flow deformation zone (23) is used to support the deformation of the heavy-duty traffic zone (22) under pressure. The intermediate layer (3) of the asphalt pavement is laid on top of the bottom layer (2) of the asphalt pavement; The asphalt pavement surface layer (4) is laid on top of the asphalt pavement intermediate layer (3); Side-limiting zones (21) are set between adjacent heavy-load driving areas (22) of multiple lanes; A skeleton assembly (5) is provided between the side limiting areas (21). The skeleton assembly (5) includes a side limiting plate (51) and a connecting rod (52). The side limiting plate (51) is laid along the length of the road and is perpendicular to the semi-rigid base layer (1). The connecting rod (52) is fixedly connected to the adjacent side limiting plates (51). The asphalt pavement intermediate layer (3) is divided into a pressure transmission zone (31) and a return zone (32) along the width of the road. The pressure transmission zone (31) is located above the lateral confinement zone (21) and the heavy-duty traffic zone (22); the return zone (32) is located above the plastic flow deformation zone (23).

2. The semi-rigid base asphalt pavement structure according to claim 1, characterized in that: The connecting rods (52) are equidistantly distributed along the length of the side limiting plate (51).

3. The semi-rigid base asphalt pavement structure according to claim 1, characterized in that: A steel mesh (6) is laid along the length of the road at the connection between the pressure transmission zone (31) and the recovery zone (32).

4. The semi-rigid base asphalt pavement structure according to claim 1, characterized in that: The surface layer (4) of the asphalt pavement is paved with high-viscosity asphalt concrete.

5. A semi-rigid base asphalt pavement structure according to claim 1, characterized in that: The recovery zone (32) is made of high flexural strength asphalt concrete.

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