Asphalt pavement structure

Abstract

This invention provides an asphalt pavement structure, comprising, from bottom to top: a subgrade, a subbase, a semi-rigid base course, a hot-dip asphalt synchronous chip seal, a first asphalt-stabilized chip seal layer, and an asphalt surface layer. The first asphalt-stabilized chip seal layer has a porosity greater than or equal to a first preset threshold, and its maximum nominal particle size falls within a first range. The thickness of the first asphalt-stabilized chip seal layer is greater than or equal to a second preset threshold. The cross slope between the semi-rigid base course and the hot-dip asphalt synchronous chip seal is K times the designed cross slope of the asphalt surface layer, where K is greater than 1. Through this method, the asphalt pavement structure of this invention can suppress reflective cracking and prevent water damage, substantially improving the road performance and service life of the semi-rigid base asphalt pavement.

Description

Technical Field

[0001] This invention relates to the field of highway construction technology, and more particularly to an asphalt pavement structure. Background Technology

[0002] Semi-rigid base asphalt pavement has advantages such as high overall strength, smooth surface, no joints, comfortable driving, short construction period, simple maintenance, recyclability, and high technical and economic efficiency. In order to save investment and avoid rutting, the asphalt layer of highways is generally about 16-18cm, and the asphalt layer of some extra-heavy-load highways is about 26cm (with an additional layer of asphalt-stabilized crushed stone base).

[0003] Reflective cracking and water damage are typical, widespread, and extremely numerous defects in semi-rigid base asphalt pavements. The superposition of various forms of cracks and water seepage accelerates and exacerbates damage to the pavement structure and performance, and is a major cause of damage to semi-rigid base asphalt pavements, especially structural damage. In existing road engineering technologies, semi-rigid base asphalt pavements inevitably suffer from reflective cracking and water damage, severely impacting their road performance and service life.

[0004] To prevent or mitigate reflective cracking in semi-rigid base asphalt pavements, existing technologies generally involve optimizing the gradation of semi-rigid mixtures, thickening the asphalt layer, or adopting inverted pavement structures. After cracks appear, measures such as asphalt grouting, milling and repaving, and excavation and repaving are taken, but these are all temporary solutions and cannot fundamentally prevent reflective cracking.

[0005] For water damage causing loosening, peeling, pitting, and other defects, measures such as patching and excavation and repaving can be taken. However, there is no way to treat water that has seeped into the structural layer. For internal structural damage caused by water damage, the only option is excavation and repaving. The above options are limited to surface repair or costly, complex, and ineffective excavation and repaving. Summary of the Invention

[0006] This invention provides an asphalt pavement structure to address the defects of reflective cracking and water damage in existing semi-rigid base asphalt pavements, and in particular, to eliminate the cumulative effect of these defects accelerating each other.

[0007] This invention provides an asphalt pavement structure, which, from bottom to top, comprises: a subgrade, a subbase, a semi-rigid base course, a hot asphalt synchronous chip seal, a first asphalt-stabilized chip stone crack-resistant and water-removing layer, and an asphalt surface layer; wherein, the porosity of the first asphalt-stabilized chip stone crack-resistant and water-removing layer is greater than or equal to a first preset threshold, and the maximum nominal particle size of the first asphalt-stabilized chip stone crack-resistant and water-removing layer is within a first value range; the thickness of the first asphalt-stabilized chip stone crack-resistant and water-removing layer is greater than or equal to a second preset threshold; wherein, the cross slope between the semi-rigid base course and the hot asphalt synchronous chip seal is K times the designed cross slope of the asphalt surface layer, where K is greater than 1.

[0008] According to an asphalt pavement structure provided by the present invention, a second asphalt-stabilized crushed stone crack-resistant and water-removing layer is further included between the first asphalt-stabilized crushed stone crack-resistant and water-removing layer and the asphalt surface layer.

[0009] According to an asphalt pavement structure provided by the present invention, an asphalt lower layer is further included between the first asphalt stabilized crushed stone crack-resistant and water-removing layer and the asphalt upper layer.

[0010] According to an asphalt pavement structure provided by the present invention, a second asphalt-stabilized crushed stone crack-resistant and water-removing layer is further included between the asphalt lower layer and the asphalt upper layer.

[0011] According to an asphalt pavement structure provided by the present invention, an asphalt intermediate layer is also included, which is adjacent to the asphalt surface layer and disposed below the asphalt surface layer.

[0012] According to an asphalt pavement structure provided by the present invention, a semi-rigid subbase is further included; the semi-rigid subbase is disposed between the semi-rigid subbase and the subbase.

[0013] According to an asphalt pavement structure provided by the present invention, the first asphalt-stabilized crushed stone crack-resistant and water-removing layer includes lignin fibers.

[0014] According to an asphalt pavement structure provided by the present invention, the mass percentage of lignin fiber in the first asphalt stabilized crushed stone anti-crack and water-removing layer is 2% to 5%.

[0015] According to an asphalt pavement structure provided by the present invention, the first preset threshold is 18%.

[0016] According to the present invention, the first value range of an asphalt pavement structure is 10~40mm.

[0017] According to an asphalt pavement structure provided by the present invention, the second preset threshold is 6cm.

[0018] According to an asphalt pavement structure provided by the present invention, the cross slope between the semi-rigid base course and the hot asphalt synchronous chip seal is twice the design cross slope of the asphalt surface course.

[0019] According to an asphalt pavement structure provided by the present invention, the maximum nominal particle size of the second asphalt stabilized crushed stone crack-resistant and water-removing layer is 10-30 mm; the thickness of the second asphalt stabilized crushed stone crack-resistant and water-removing layer is greater than or equal to 4 cm; the porosity of the second asphalt stabilized crushed stone crack-resistant and water-removing layer is 18-30%; the second asphalt stabilized crushed stone crack-resistant and water-removing layer includes lignin fiber, and the mass percentage of lignin fiber is 2%-5%.

[0020] This invention provides an asphalt pavement structure that is constructed from bottom to top as follows: subgrade, subbase, semi-rigid base course, hot asphalt synchronous chip seal, first asphalt stabilized chip seal layer, and asphalt surface course. It fundamentally solves the problems of reflective cracking and water damage from the perspective of material properties and mechanical principles, inhibits reflective cracking and prevents water damage, eliminates the superimposed effect of their mutual acceleration and aggravation of disease, and substantially improves the road performance and service life of semi-rigid base asphalt pavement. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of an embodiment of the asphalt pavement structure of the present invention;

[0023] Figure 2 This is a schematic diagram of another embodiment of the asphalt pavement structure of the present invention;

[0024] Figure 3 This is a schematic diagram of another embodiment of the asphalt pavement structure of the present invention;

[0025] Figure 4 This is a schematic diagram of another embodiment of the asphalt pavement structure of the present invention;

[0026] Figure 5 This is a schematic diagram of another embodiment of the asphalt pavement structure of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0028] Reflective cracking and water damage are typical, widespread, and extremely numerous defects in semi-rigid base asphalt pavements. The superposition of various forms of cracks and water seepage is the main cause of damage to semi-rigid base asphalt pavements, especially structural damage.

[0029] First, the inherent drying and thermal shrinkage characteristics of semi-rigid materials lead to cracking of the semi-rigid base layer. Consequently, the sharp increase in stress at the crack tip causes reflective cracks in the asphalt concrete surface layer, resulting in a reduction in the overall structural strength and fatigue resistance of the asphalt pavement.

[0030] Secondly, the presence of cracks in asphalt pavement (including various other forms of cracks, such as reflective cracking) and the porosity of the asphalt layer material (both inherent design porosity and localized high porosity due to construction reasons) allows rainwater to infiltrate into the pavement structure. If this moisture is not quickly removed, it will erode the pavement structure materials, reducing their mechanical properties. Because the semi-rigid base material is dense and impermeable, some moisture accumulates between the asphalt layer and the semi-rigid base interface. This erosion and soaking damages the interlayer bonding and causes the mixture to loosen, reducing the overall structural strength and fatigue resistance of the asphalt pavement, increasing pavement deformation, and shortening its service life. Furthermore, water damage at surface cracks can lead to loosening, peeling, potholes, and other defects, severely affecting the pavement's performance.

[0031] Based on this, the present invention provides an asphalt pavement structure, which relates to a structural combination for suppressing reflective cracking and preventing water damage in semi-rigid base asphalt pavements in highway engineering and municipal engineering. Specifically, it refers to a structural combination for improving the structural performance of semi-rigid base asphalt pavements and suppressing reflective cracking and preventing water damage.

[0032] Please see Figure 1 , Figure 1 This is a schematic diagram of an embodiment of the asphalt pavement structure of the present invention. In this embodiment, the asphalt pavement structure includes, from bottom to top, the following components: subgrade 10, cushion layer 20, semi-rigid base course 30, hot asphalt synchronous chip seal 40, first asphalt stabilized chip crack-resistant and water-removing layer 51, and asphalt surface layer 61.

[0033] The porosity of the first asphalt-stabilized crushed stone crack-resistant and water-removing layer 51 is greater than or equal to a first preset threshold, and the maximum nominal particle size of the first asphalt-stabilized crushed stone crack-resistant and water-removing layer 51 is within a first range. The thickness of the first asphalt-stabilized crushed stone crack-resistant and water-removing layer 51 should generally be greater than or equal to a second preset threshold. The cross slope between the semi-rigid base course and the hot asphalt synchronous crushed stone seal layer is K times the designed cross slope of the asphalt surface course, where K is greater than 1.

[0034] Optionally, the first preset threshold is 10%.

[0035] Optionally, the first value range is 10~40mm.

[0036] Optionally, the second preset threshold is 6 cm. Preferably, the thickness of the first asphalt-stabilized crushed stone crack-resistant and water-removing layer is 8-10 cm.

[0037] The porosity of the first asphalt-stabilized crushed stone crack-resistant and water-removing layer 51 is greater than or equal to 18%, the maximum nominal particle size of the first asphalt-stabilized crushed stone crack-resistant and water-removing layer 51 is 10~40mm, and the thickness of the first asphalt-stabilized crushed stone crack-resistant and water-removing layer 51 should generally be greater than or equal to 6cm. The cross slope between the semi-rigid base course and the hot asphalt synchronous crushed stone seal layer is K times the designed cross slope of the asphalt surface course, where K is greater than 1. These designs enable the first asphalt-stabilized crushed stone crack-resistant and water-removing layer to have the function of crack resistance and water removal, and enhance the stability of the asphalt pavement structure.

[0038] The raw materials, mixtures, and construction quality of asphalt pavement structures must all meet the requirements of current relevant industry technical specifications and standards.

[0039] In some embodiments, the subbase 20 may be an antifreeze layer. The provision of an antifreeze layer can improve the adaptability of asphalt pavement structures in cold regions.

[0040] In some embodiments, the asphalt pavement structure further includes a semi-rigid subbase 70; the semi-rigid subbase 70 may be disposed between the semi-rigid base course 30 and the hot asphalt synchronous chip seal. The cross slope of the semi-rigid base course 30 and the semi-rigid subbase 70 is twice the design cross slope of the asphalt surface course.

[0041] In some embodiments, the asphalt pavement structure further includes an asphalt intermediate layer 63, which is adjacent to the asphalt surface layer 61 and disposed below the asphalt surface layer 61.

[0042] In this embodiment, a hot asphalt synchronous chip seal is set to strengthen the connection with the first asphalt stabilized chip seal 51, forming a complete waterproof protective film at the bottom of the first asphalt stabilized chip seal 51, which can effectively prevent moisture from entering the surface-base interface.

[0043] Preferably, the hot asphalt is rubber asphalt, which has good water-sealing properties, strong resistance to deformation, and great elasticity and elastic recovery at high temperatures, which can improve the pavement's resistance to deformation and fatigue cracking.

[0044] The first asphalt-stabilized crushed stone crack-resistant and water-removing layer 51 can be regarded as the first functional structural layer. As a functional layer with crack-resistant and water-removing functions, its porosity is required to be ≥18%, and it meets the technical requirements of the current highway drainage specifications.

[0045] Under the condition of ensuring the strength of the mixture and its stability under water immersion and freeze-thaw cycles, the higher the porosity, the better. Preferably, the porosity of the first asphalt-stabilized crushed stone crack-resistant and water-removing layer 51 is 18-30%.

[0046] In some embodiments, to enhance the stability and durability of the first asphalt-stabilized crushed stone fracturing and dewatering layer 51, the first asphalt-stabilized crushed stone fracturing and dewatering layer 51 may include lignin fibers. The lignin fibers are added to the first asphalt-stabilized crushed stone fracturing and dewatering layer 51 at a ratio of 2% to 5% by mass of the mixture. Preferably, the mass percentage of lignin fibers is 3%.

[0047] Lignin fiber is an organic fiber obtained from natural wood through chemical treatment. It has a cotton-like appearance and is effective in preventing coating cracking, improving water retention, enhancing production stability and construction suitability, increasing strength, and strengthening adhesion to surfaces.

[0048] The first asphalt-stabilized crushed stone crack-resistant and water-removing layer 51 also includes an asphalt binder. The asphalt binder can be ordinary asphalt according to highway industry standards, or modified or high-viscosity asphalt, which can significantly improve its stability and durability.

[0049] The aggregate gradation of the first asphalt-stabilized crushed stone crack-resistant and water-removing layer 51 is scientifically designed to form a stable large skeleton gradation and to create effective interconnected voids in the mixture that facilitate lateral drainage. Preferably, the maximum nominal particle size of the first asphalt-stabilized crushed stone crack-resistant and water-removing layer 51 is 10-40 mm.

[0050] Other road performance meets the requirements of current relevant technical specifications; its thickness meets the requirements of current highway drainage specifications, pavement structure mechanical calculation requirements, and material mechanics fracture mechanics calculation requirements regarding crack tip stress and crack propagation. Preferably, the thickness of the first asphalt stabilized crushed stone crack-resistant and water-removing layer 51 is about 6-10cm.

[0051] Appropriate internal collection and drainage facilities should be installed at the shoulders of asphalt roads.

[0052] The present invention provides an asphalt pavement structure, which is constructed from bottom to top by a roadbed 10, a subbase 20, a semi-rigid base course 30, a hot asphalt synchronous chip seal 40, a first asphalt stabilized chip seal layer 51, and an asphalt surface layer 61. It fundamentally solves the problems of reflective cracking and water damage from the perspective of material properties and mechanical principles, inhibits reflective cracking and prevents water damage, and substantially improves the road performance and service life of semi-rigid base asphalt pavement.

[0053] According to an asphalt pavement structure provided by the present invention, a second asphalt-stabilized crushed stone crack-resistant and water-removing layer 52 is further provided between the first asphalt-stabilized crushed stone crack-resistant and water-removing layer 51 and the asphalt surface layer 61.

[0054] Please see Figure 2 , Figure 2 This is a schematic diagram of another embodiment of the asphalt pavement structure of the present invention. In this embodiment, the asphalt pavement structure includes, from bottom to top, the following components: subgrade 10, subbase 20, semi-rigid base course 30, hot asphalt synchronous chip seal 40, first asphalt stabilized chip seal crack-resistant and water-removing layer 51, second asphalt stabilized chip seal crack-resistant and water-removing layer 52, and asphalt surface layer 61.

[0055] The maximum nominal particle size of the second asphalt-stabilized crushed stone crack-resistant and water-removing layer is 10-30 mm; the thickness of the second asphalt-stabilized crushed stone crack-resistant and water-removing layer should generally be greater than or equal to 4 cm, preferably 4-8 cm; the porosity of the second asphalt-stabilized crushed stone crack-resistant and water-removing layer is 18-30%; the second asphalt-stabilized crushed stone crack-resistant and water-removing layer includes lignin fiber, and the mass percentage of lignin fiber is 2%-5%.

[0056] Other road performance characteristics meet the requirements of current relevant technical specifications; its thickness meets the requirements of current highway drainage specifications, pavement structure mechanical calculations, and material mechanics fracture mechanics calculations regarding crack tip stress and crack propagation.

[0057] Preferably, the thickness of the second asphalt-stabilized crushed stone crack-resistant and water-removing layer 52 is about 4-8 cm.

[0058] Optionally, a semi-rigid subbase 70 may also be provided between the semi-rigid subbase 30 and the hot asphalt synchronous chip seal 40.

[0059] Optionally, an asphalt intermediate layer 63 may be included between the second asphalt-stabilized crushed stone crack-resistant and water-removing layer 52 and the asphalt surface layer 61.

[0060] According to an asphalt pavement structure provided by the present invention, an asphalt lower layer 62 is further included between the first asphalt stabilized crushed stone crack-resistant and water-removing layer 51 and the asphalt upper layer 61.

[0061] Please see Figure 3 , Figure 3 This is a schematic diagram of another embodiment of the asphalt pavement structure of the present invention. In this embodiment, the asphalt pavement structure includes, from bottom to top, the following components: subgrade 10, cushion layer 20, semi-rigid base course 30, hot asphalt synchronous chip seal layer 40, first asphalt stabilized chip seal layer 51, asphalt lower layer 62, and asphalt upper layer 61.

[0062] Optionally, a semi-rigid subbase 70 may be provided between the semi-rigid base layer 30 and the subbase layer 20.

[0063] Optionally, an asphalt intermediate layer 63 may be included between the asphalt lower layer 62 and the asphalt upper layer 61.

[0064] According to an asphalt pavement structure provided by the present invention, a second asphalt-stabilized crushed stone crack-resistant and water-removing layer 52 is further provided between the asphalt lower layer 62 and the asphalt upper layer 61.

[0065] Please see Figure 4 , Figure 4 This is a schematic diagram of another embodiment of the asphalt pavement structure of the present invention. In this embodiment, the asphalt pavement structure includes, from bottom to top, the following components: subgrade 10, subbase 20, semi-rigid base course 30, hot asphalt synchronous chip seal 40, first asphalt stabilized chip seal layer 51, asphalt lower layer 62, second asphalt stabilized chip seal layer 52, and asphalt upper layer 61.

[0066] Optionally, a semi-rigid subbase may also be provided between the semi-rigid base layer 30 and the subbase layer 20.

[0067] Optionally, an asphalt intermediate layer may also be included between the second asphalt-stabilized crushed stone crack-resistant and water-removing layer 52 and the asphalt surface layer 61.

[0068] Please see Figure 5 , Figure 5 This is a schematic diagram of another embodiment of the asphalt pavement structure of the present invention. In this embodiment, the asphalt pavement structure includes, from bottom to top, the following components: subgrade 10, cushion layer 20, semi-rigid base course 30, semi-rigid subbase course 70, hot asphalt synchronous chip seal 40, first asphalt stabilized chip seal layer 51, asphalt lower layer 62, second asphalt stabilized chip seal layer 52, asphalt intermediate layer 63, and asphalt upper layer 61.

[0069] It should be noted that the structural combination of the first asphalt stabilized crushed stone crack-resistant and water-removing layer, the asphalt lower layer, and the second asphalt stabilized crushed stone crack-resistant and water-removing layer is more suitable for areas with high rainfall; while the structural combination of the first asphalt stabilized crushed stone crack-resistant and water-removing layer and the second asphalt stabilized crushed stone crack-resistant and water-removing layer is more suitable for drier areas with less rainfall.

[0070] In practice, the asphalt pavement structure can be determined based on the traffic volume of a specific highway project, the requirements of pavement structure mechanical calculations, the rainfall in the project area, and the existing road crack situation. This can include structures such as semi-rigid subbase, asphalt base course, second asphalt stabilized crushed stone crack-resistant and water-removing course, and asphalt base course. The specific thickness of the first and second asphalt stabilized crushed stone crack-resistant and water-removing courses must also meet the current highway drainage design specifications and the material mechanics and fracture mechanics requirements regarding crack tip stress and crack propagation.

[0071] The raw materials, mixtures, and construction quality of the roadbed, subbase, semi-rigid base course, semi-rigid base course, asphalt lower course, asphalt intermediate course, asphalt upper course, and internal drainage facilities at the shoulder in the above-mentioned structural forms must meet the requirements of the current relevant industry technical specifications and standards.

[0072] This invention scientifically designs the pavement structure and the crack-resistant and water-repellent functional layer based on mechanical principles. It eliminates stress at the crack tip and prevents the reflection of semi-rigid base layer cracks to the asphalt layer based on fracture mechanics theory. Addressing the mechanisms of asphalt layer reflection cracking and water damage, the invention designs a functional layer in the asphalt pavement structure that simultaneously inhibits reflection cracking and promotes water repellency. This inhibits the upward reflection of semi-rigid base layer cracks, eliminates reflection cracking in the asphalt pavement, and rapidly removes water entering the pavement structure in various forms to the outside, thus preventing structural water damage. It significantly reduces the derivative damage to pavement performance caused by pavement cracking and eliminates the cumulative effect of these cracking defects. By fundamentally solving the problems of reflection cracking and water damage from the perspective of material properties and mechanical principles, this invention achieves the technical effect of significantly improving the pavement's performance and extending its service life.

[0073] The above embodiments of the present invention are not intended to limit the scope of protection of the present invention. The implementation of the present invention is not limited thereto. All other modifications, substitutions or alterations made to the above structure of the present invention based on the above content of the present invention, in accordance with ordinary technical knowledge and common practices in the field, without departing from the basic technical idea of ​​the present invention, such as simplifying or complicating the number and position of structural layers, increasing or decreasing the thickness of each structural layer, etc., should fall within the scope of protection of the present invention.

Claims

1. An asphalt pavement structure, characterized in that, From bottom to top, it includes: subgrade, subbase, semi-rigid base course, hot asphalt synchronous chip seal, first asphalt stabilized chip seal layer, crack-resistant and water-removing layer, and asphalt top layer; Wherein, the porosity of the first asphalt-stabilized crushed stone crack-resistant and water-removing layer is greater than or equal to 18%, the maximum nominal particle size of the first asphalt-stabilized crushed stone crack-resistant and water-removing layer is 10~40mm, and the thickness of the first asphalt-stabilized crushed stone crack-resistant and water-removing layer is greater than or equal to 6cm. When the second asphalt-stabilized crushed stone crack-resistant and water-removing layer is above the first asphalt-stabilized crushed stone crack-resistant and water-removing layer, a hot asphalt synchronous crushed stone seal layer is set between the two layers. It also includes a semi-rigid subbase; the semi-rigid subbase is disposed between the semi-rigid subbase and the cushion layer; Between the first asphalt-stabilized crushed stone crack-resistant and water-removing layer and the asphalt upper layer, there is also an asphalt lower layer; Between the lower asphalt layer and the upper asphalt layer, there is also a second asphalt-stabilized crushed stone crack-resistant and water-removing layer; It also includes an asphalt intermediate layer, which is adjacent to the asphalt top layer and disposed below the asphalt top layer; The first asphalt-stabilized crushed stone crack-resistant and water-removing layer includes lignin fibers; In the first asphalt-stabilized crushed stone fracturing and water-removing layer, the mass percentage of lignin fiber is 2% to 5%; The cross slope between the semi-rigid base course and the hot asphalt synchronous chip seal is twice the design cross slope of the asphalt surface course. The maximum nominal particle size of the second asphalt-stabilized crushed stone crack-resistant and water-removing layer is 10-30 mm; the thickness of the second asphalt-stabilized crushed stone crack-resistant and water-removing layer is greater than or equal to 4 cm; the porosity of the second asphalt-stabilized crushed stone crack-resistant and water-removing layer is 18-30%; the second asphalt-stabilized crushed stone crack-resistant and water-removing layer includes lignin fiber, and the mass percentage of the lignin fiber is 2%-5%.

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