Asphalt pavement edge structure layer and construction method and application thereof

Abstract

The application provides an asphalt pavement edge structure layer, a construction method and application thereof, and belongs to the technical field of road construction. The asphalt pavement edge structure layer is arranged at the edge of an asphalt pavement, the top surface of the asphalt pavement edge structure layer is flush with the asphalt pavement, and the asphalt pavement edge structure layer comprises a gap filling gravel layer and a surface dense water layer. The gap filling gravel layer is arranged on a lower bearing layer, and the components of the gap filling gravel layer comprise aggregate and emulsified asphalt. The surface dense water layer is arranged on the gap filling gravel layer, and the components of the surface dense water layer comprise aggregate, filler and asphalt. The asphalt pavement edge structure layer avoids the risk of external water penetrating into the interlayer from the edge, effectively solves the problem of a large water permeation coefficient of a traditional asphalt pavement, reduces early diseases of the asphalt pavement caused by interlayer water without changing the normal pavement structure layer of the driving lane, and thus prolongs the service life of the asphalt pavement.

Description

Technical Field

[0001] This invention relates to the field of road construction technology, specifically to an asphalt pavement edge structure layer, its construction method, and its application. Background Technology

[0002] With the rapid development of expressways in my country, the construction of expressways has entered a peak period. Under this environment, the quality control of expressway asphalt pavement is particularly critical. Currently, potholes are a prominent early form of expressway damage, and the main cause of pothole formation can be attributed to water damage caused by interlayer water. Studies have shown that the main reason for interlayer water is insufficient compaction of the asphalt pavement structural layers, resulting in an excessively high permeability coefficient and the appearance of interlayer water.

[0003] Insufficient compaction of the structural layers is particularly prominent at the edges of the entire asphalt pavement. This is because segregation occurs in the asphalt mixture during construction, such as aggregate segregation and temperature segregation. Due to the paver itself, the edges are significantly affected by segregation, leading to insufficient compaction of the edge structural layers and a high permeability coefficient. Conversely, the middle section of the pavement, located in the center of the paver, is less affected by segregation and naturally has a lower permeability coefficient. Because the permeability coefficient of the edge structural layers is too high, external water easily seeps from the road surface into the edge structural layers, forming interlayer water. This interlayer water then flows into the middle section of the pavement, increasing the overall interlayer water content and triggering a series of pavement defects. Therefore, most of the interlayer water seeps in from the edges. To address this issue, we typically implement measures during construction, such as adjusting paver parameters to reduce segregation and strengthening edge compaction. These measures improve edge water seepage to some extent, but still fall short of design requirements.

[0004] In current road construction, we often pay great attention to surface drainage, such as using water-blocking troughs and rapid flow channels to collect surface water and drain it through side ditches. However, we often overlook the water that seeps into the structural layers due to asphalt seepage, i.e., interlayer water. Chinese utility model patent publication number "CN205012192U" (application number: CN201520759045.7) discloses an internal drainage system for the bottom of a concave curve in a highway. From top to bottom, it includes a surface layer, a base layer, and a subbase layer. The base layer comprises a permeable base layer on top and an impermeable base layer below, with a permeable sealing layer between them. A collection well and a transverse drainage pipe are installed on the outside of the base layer. Rainwater seeps through the surface layer and permeable base layer to the permeable sealing layer, flows into the collection well, and is then discharged outside the road structure through the transverse drainage pipe. This patented technology utilizes a permeable base course of large-particle-size permeable asphalt concrete, combined with sump pits and transverse drainage pipes. This reduces reflective cracking in the rigid base course and effectively removes water accumulated within the pavement structure, thus minimizing internal water accumulation and interlayer water damage. This significantly improves pavement performance and extends road lifespan. However, in my country, road construction often employs a semi-rigid base course overlaid with an asphalt surface layer. This prevents the effective and complete drainage of water that has penetrated the structural layers. The resulting interlayer water weakens the bond between the asphalt surface layer and the semi-rigid base course, causing water to seep into the aggregate and reducing the adhesion between the asphalt and the aggregate, ultimately leading to pavement defects such as potholes.

[0005] Chinese invention patent application CN1477267A (application number CN03112472.0) discloses a method for preventing water seepage between pavement layers and its construction method. The method involves installing a seepage barrier wall on the inner or outer side of the curbstone in the central median of the highway, with the bottom of the barrier wall extending into the relatively impermeable layer of the subgrade. The seepage barrier wall and the relatively impermeable layer of the subgrade form a relatively closed seepage prevention system, which can prevent surface water and stagnant water from seeping into the pavement layer and the underlying structural layers from the cracks on both sides of the central median and the curbstone. This ensures that the upper part of the subgrade, the lime-soil layer, and the stabilized crushed stone remain dry for most of the time. This patent mainly prevents surface water from seeping into and stagnating at the joint between the pavement and the edge structures (curbstone or guardrail), but it still cannot fundamentally solve the problem of water seepage within the pavement structural layers themselves. Summary of the Invention

[0006] To address the shortcomings of existing technologies, and considering that the sides of the entire asphalt pavement do not bear traffic loads, this invention provides an asphalt pavement edge structure layer, its construction method, and its application. This effectively solves the problem of high permeability coefficient in the asphalt pavement edge structure layer, thereby reducing asphalt pavement defects caused by interlayer water and extending the service life of the asphalt pavement.

[0007] The specific technical solution adopted in this invention is as follows:

[0008] An edge structure layer for asphalt pavement is provided at the edge of the asphalt pavement, with its top surface flush with the asphalt pavement, and includes a gap-filling crushed stone layer and a surface watertight layer.

[0009] The gap-filling crushed stone layer is disposed on the underlying layer and its components include aggregate and emulsified asphalt; the surface watertight layer is disposed on the gap-filling crushed stone layer and its components include aggregate, filler and asphalt.

[0010] Preferably, the underlying layer is a seal coat or an asphalt subbase.

[0011] Preferably, the width of the asphalt pavement edge structure layer is 50-80cm.

[0012] Preferably, the thickness of the asphalt pavement edge structure layer is the same as the thickness of the asphalt surface layer, or the same as the total thickness of the asphalt surface layer and the asphalt intermediate layer.

[0013] Preferably, the thickness of the gap-filling crushed stone layer is 2 to 10 cm, and its top surface is 2 cm away from the asphalt pavement.

[0014] More preferably, when the thickness of the interstitial crushed stone layer is <3cm, its composition by weight percentage is: 80-90% coarse aggregate of 3-5mm, 10-20% fine aggregate of 0-3mm, and 5.0-5.8% emulsified asphalt.

[0015] More preferably, when the thickness of the interstitial crushed stone layer is 3-6 cm, its composition by weight percentage is: 75-85% 5-10 mm coarse aggregate, 15-25% 0-3 mm fine aggregate, and 5.5-6.5% emulsified asphalt.

[0016] More preferably, when the thickness of the interstitial crushed stone layer is >6cm, its composition by weight percentage is: 70-80% 10-15mm coarse aggregate, 10-20% 3-5mm coarse aggregate, 5-15% 0-3mm fine aggregate, and 6.2-7.5% emulsified asphalt.

[0017] More preferably, the coarse aggregate is alkaline or neutral rock; the fine aggregate is limestone manufactured sand; and the emulsified asphalt is slow-cracking cationic emulsified asphalt, with the following technical indicators: evaporation residue content of 55-62%, and the properties of the evaporation residue being: penetration of 60-80 (0.1 mm) at 25°C, ductility of ≥60 cm at 15°C, and 5-day storage stability ≤5%.

[0018] Preferably, the thickness of the surface watertight layer is 2cm, and its top surface is flush with the asphalt pavement.

[0019] Preferably, the surface watertight layer is a mixture of mineral aggregate and asphalt; wherein the mineral aggregate consists of coarse aggregate, fine aggregate and filler, and the weight percentage of the asphalt is 7.5% to 8.5%.

[0020] More preferably, the coarse aggregate is alkaline or neutral rock with a particle size of 3-5 mm; the fine aggregate is limestone manufactured sand with a particle size of 0-3 mm; the filler is mineral powder ground from limestone; and the asphalt is 70# road petroleum asphalt or SBS modified asphalt.

[0021] More preferably, the mineral gradation range of the surface water-tight layer is:

[0022] The passing rates for standard sieve apertures are as follows: 9.5mm aperture: 100%; 4.75mm aperture: 90-100%; 2.36mm aperture: 65-80%; 1.18mm aperture: 40-66%; 0.6mm aperture: 28-50%; 0.3mm aperture: 20-36%; 0.15mm aperture: 16-25%; 0.075mm aperture: 10-15%.

[0023] More preferably, the technical specifications of the mixture of the surface water-tight layer are: penetration at 60℃ ≤ 4mm, flow time at 240℃ 10~20s, and water permeability coefficient of the molded surface ≤ 20mL / min.

[0024] The construction method for the edge structural layer of the above-mentioned asphalt pavement includes the following steps:

[0025] (1) Construct the roadbed, semi-rigid base, sealing layer and asphalt surface layer in sequence. When constructing the asphalt intermediate layer or asphalt surface layer, leave a width of 50-80cm on both sides of the road surface.

[0026] (2) Place the curbstone so that the vertical surface of the asphalt intermediate layer and / or asphalt top layer is 50-80cm away from the inside of the curbstone; allow the curbstone to cure for 1-2 days, and then complete the construction of the earth shoulder on the outside of the curbstone;

[0027] (3) Apply emulsified asphalt to the vertical surfaces and inner sides of curbs of the asphalt intermediate layer and / or asphalt top layer;

[0028] (4) After the emulsified asphalt breaks down, the gap-filling crushed stone layer is constructed: the aggregates are filled in order of decreasing particle size. After all the aggregates are filled, they are vibrated and compacted 2 to 3 times; the emulsified asphalt is evenly sprayed and cured for 1 day.

[0029] (5) Construction of surface watertight layer: Mix the coarse aggregate, fine aggregate and filler of surface watertight layer and dry mix; then add asphalt and wet mix to obtain mixture; spread the mixture evenly on the gap-filling crushed stone layer;

[0030] (6) Compact the road surface.

[0031] Preferably, when the thickness of the interstitial crushed stone layer in step (4) is greater than 6 cm, layered filling and layered compaction are carried out.

[0032] Preferably, when the surface watertight layer is made of 70# road petroleum asphalt, the dry mixing conditions in step (5) are: stirring at 160-180℃ for 15-20s; the wet mixing conditions are: stirring at 160-180℃ for 70-85s; and the discharge temperature of the mixture is 160-170℃.

[0033] When the surface watertight layer uses SBS modified asphalt, the dry mixing conditions in step (5) are: stirring at 190-210℃ for 15-20s; the wet mixing conditions are: stirring at 190-210℃ for 70-85s; and the discharge temperature of the mixture is 180-190℃.

[0034] Because the surface watertight layer mixture has a certain fluidity, it needs to be allowed a certain flow time after unloading, generally controlled at 45 to 90 seconds, before laying.

[0035] Preferably, the compaction step (6) includes initial compaction, intermediate compaction and final compaction; wherein, the initial compaction is to use a small steel wheel roller to stabilize the compaction once, the intermediate compaction is to use a small rubber-tired roller to compact 3 to 4 times, and the final compaction is to use a small steel wheel roller to finish 1 to 2 times.

[0036] The above-mentioned asphalt pavement edge structure layer is used in the construction of asphalt pavement.

[0037] The beneficial effects of this invention are:

[0038] (1) This invention provides an edge structure layer for asphalt pavement. The edge of the asphalt pavement adopts a differentiated structure of “gap-filling crushed stone layer + surface water-tight layer”, which avoids the risk of external water seeping into the interlayer from the edge. It effectively solves the problem of large water permeability coefficient at the edge of traditional asphalt pavement. Without changing the normal pavement structure layer of the driving lane, it reduces the early disease of asphalt pavement caused by interlayer water, thereby extending the service life of asphalt pavement.

[0039] (2) The emulsified asphalt in the gap-filling crushed stone layer is applied by spraying, which can effectively prevent water from flowing between layers to the middle part of the road surface and avoid increasing the water content between the layers of the road surface.

[0040] (3) The surface watertight layer in this invention has the characteristics of high asphalt content, high fine aggregate content and high filler content, and achieves a certain fluidity under high temperature conditions, and has good compactness and waterproofness.

[0041] (4) The asphalt pavement edge structure layer provided by the present invention is constructed using economical and inexpensive raw materials, and the construction method is simple and low cost. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the overall road surface structure in Example 1;

[0043] In the diagram, 1 is the roadbed; 2 is the cement-stabilized crushed stone base course; 3 is the sealing layer; 4 is the asphalt intermediate course; 5 is the asphalt top course; 6 is the curb stone; 7 is the interstitial crushed stone layer; and 8 is the surface watertight layer. Detailed Implementation

[0044] The following description is based on specific embodiments:

[0045] Explanation of the source of experimental materials:

[0046] SBS modified asphalt and emulsified asphalt were both purchased from Shandong Expressway Building Materials Group Co., Ltd.

[0047] Limestone crushed stone: purchased from Shandong Taixing Stone Material Co., Ltd.;

[0048] Limestone powder: purchased from Shandong Jinshun Environmental Protection Technology Co., Ltd.

[0049] Example 1:

[0050] A construction method for an asphalt pavement edge structure layer, wherein the thickness of the asphalt pavement edge structure layer is consistent with the total thickness of the asphalt surface layer and the asphalt intermediate layer. A schematic diagram of the overall pavement structure is shown below. Figure 1 As shown; the specific construction steps are as follows:

[0051] (1) Construct the roadbed 1, cement-stabilized crushed stone base course 2, sealing layer 3, and asphalt surface course in sequence:

[0052] Construct roadbed 1, then lay a cement-stabilized crushed stone base course 2 with a total thickness of 36cm on top of roadbed 1, and then spray emulsified asphalt tack coat, with the spraying rate controlled at 1.2kg / m³. 2 7-day health regimen;

[0053] Construction of Seal Layer 3: A synchronous chip seal truck is used to simultaneously spread limestone chips with a particle size of 5-10mm and SBS modified asphalt at 150-170℃ onto the road surface; the chip chip application rate is 7kg / m³. 2 The application rate of hot asphalt is 1.6 kg / m³. 2 ;

[0054] Construction of asphalt intermediate layer 4 and asphalt surface layer 5: The width of the paver is less than 140cm of the road surface width. Asphalt intermediate layer 4 and asphalt surface layer 5 are constructed separately. During the construction process, the paver is guaranteed to leave a width of 70cm on both sides of the original road surface. The thickness of asphalt intermediate layer 4 is 6cm and the thickness of asphalt surface layer 5 is 4cm.

[0055] (2) Place the curbstone 6 so that the vertical surfaces of the asphalt intermediate layer 4 and the asphalt top layer 5 are 70cm away from the inner side of the curbstone 6; cure the curbstone for 2 days, and then complete the construction of the earth shoulder on the outer side of the curbstone 6.

[0056] (3) Apply emulsified asphalt to the vertical surfaces of the asphalt intermediate layer 4 and the asphalt top layer 5, and the inner side of the curbstone 6, and wait for the emulsified asphalt to break down.

[0057] (4) After the emulsified asphalt breaks down, proceed with the construction of the gap-filling crushed stone layer 7:

[0058] The thickness of the gap-filling crushed stone layer 7 is 8cm, and the proportions of its various aggregate grades and emulsified asphalt are shown in Table 1 below:

[0059] Table 1. Proportions of Aggregates and Emulsified Asphalt in Gap-Filled Crushed Stone Layers

[0060] weight ratio 70％ 14％ 9.3％ 6.7％

[0061] The thickness of the above-mentioned interstitial crushed stone layer 7 is greater than 6cm, so a two-layer construction method is adopted, with each layer having a thickness of 4cm. In each layer, the aggregates are filled in order of decreasing particle size and compacted with a plate rammer. After all the aggregates are filled, they are vibrated and compacted 3 times with a plate rammer. Emulsified asphalt is then evenly poured and cured for 1 day.

[0062] The emulsified asphalt described above is a slow-cracking cationic emulsified asphalt, and its technical specifications are shown in Table 2 below:

[0063] Table 2. Technical Specifications of Emulsified Asphalt

[0064]

[0065] (5) After curing, proceed with the construction of the surface watertight layer 8:

[0066] The thickness of the surface watertight layer 8 is 2cm, and the proportions of each aggregate and asphalt are shown in Table 3 below:

[0067] Table 3. Proportions of aggregates and asphalt in each grade of the surface watertight layer

[0068] weight ratio 26％ 60％ 6.5％ 7.5％

[0069] The aggregate gradation design of the surface watertight layer is shown in Table 4 below:

[0070] Table 4. Mineral Gradation Design

[0071] Maximum gradation (%) 100 100 80 66 50 36 25 15 Lower limit of gradation (%) 100 90 65 40 28 20 16 10 Determine the gradation (%) 100.0 93.2 70.5 58.1 40.8 29.5 20.9 12.6

[0072] Intermittent asphalt mixing plant was used to mix the surface watertight layer 8. First, the coarse aggregate, fine aggregate and filler of the surface watertight layer were mixed and dry-mixed at 200℃ for 20s. Then, asphalt was added and wet-mixed at 200℃ for 75s to obtain the mixture. The technical indicators of the mixture were: penetration at 60℃ was 2mm and flow time at 240℃ was 15s.

[0073] The above-mentioned mixture is transported by tank trucks with both heating and stirring functions. The discharge temperature of the mixture is controlled at 185℃. After the mixture is transported to the construction site, it is unloaded using a special unloading device. After unloading, the mixture is given 1 minute of flow time, and then it is manually and evenly spread on the gap-filling crushed stone layer 7.

[0074] (6) Compaction: The initial compaction is carried out by a small steel wheel roller for one pass, the secondary compaction is carried out by a small rubber-tired roller for four passes, and the final compaction is carried out by a small steel wheel roller for two passes.

[0075] Example 2:

[0076] A construction method for an asphalt pavement edge structure layer, wherein the thickness of the asphalt pavement edge structure layer is the same as the thickness of the asphalt surface layer. The specific construction steps differ from those in Example 1: In step (1), only during the construction of the asphalt surface layer is a 70cm width reserved on both sides of the original pavement by the paver, and the thickness of the asphalt surface layer is 4cm; In step (4), the thickness of the gap-filling crushed stone layer is adjusted to 2cm, and the proportions of each grade of aggregate and emulsified asphalt are shown in Table 5 below:

[0077] Table 5. Proportions of Aggregates and Emulsified Asphalt in Different Grades of Gap-Filled Crushed Stone Layers

[0078] weight ratio 80.1％ 14.2％ 5.7％

[0079] The above-mentioned gap-filling crushed stone layer is constructed in a single-layer manner. The aggregates are filled in sequence according to the particle size from large to small and compacted three times with a plate tamper. Then, emulsified asphalt is evenly poured and cured for 1 day.

[0080] The remaining steps are the same as in Example 1.

[0081] Example 3:

[0082] Unlike Example 1, in step (5), the proportions of aggregates and asphalt in each section of the surface watertight layer are shown in Table 6 below:

[0083] Table 6. Proportions of Aggregates and Asphalt in Each Grade of the Surface Watertight Layer

[0084] weight ratio 33％ 55％ 5％ 7％

[0085] The aggregate gradation design of the surface watertight layer is shown in Table 7 below:

[0086] Table 7. Mineral Gradation Design

[0087] Maximum gradation (%) 100 100 80 66 50 36 25 15 Lower limit of gradation (%) 100 90 65 40 28 20 16 10 Determine the gradation (%) 100.0 91.2 66.8 51.2 35.1 24.7 18.9 10.5

[0088] The remaining steps are the same as in Example 1.

[0089] Comparative Example 1:

[0090] Unlike Example 1, in step (1), the roadbed, cement-stabilized crushed stone base course, sealing layer, asphalt intermediate layer and asphalt top layer are constructed in sequence according to the traditional asphalt pavement construction method. In the construction of the asphalt intermediate layer and asphalt top layer, the width of the paver is consistent with the original pavement design width, that is, the asphalt pavement edge structure layer is no longer set.

[0091] According to the test methods recorded in the "Specifications for Field Testing of Highway Subgrade and Pavement" (JTG 3450—2019), the permeability coefficient of the asphalt pavement shaped surfaces laid in Examples 1 to 3 and Comparative Example 1 was tested, and the test results were taken as the average value of both sides.

[0092] The test results are shown in Table 8 below:

[0093] Table 8. Permeability Coefficient Test Results

[0094]

[0095]

[0096] As shown in Table 8, after setting the asphalt pavement edge structure layer, the permeability coefficient of the asphalt pavement edges (0-65cm from the inner side of the curb) in Examples 1-3 is 0 mL / min, effectively avoiding the risk of external water seeping from the asphalt pavement edges. In contrast, the asphalt pavement in Example 1, constructed using traditional methods, has a much higher permeability coefficient at its edges than in Examples 1-3 due to limitations in its mixture composition and the influence of segregation during construction, failing to meet the requirements for pavement permeability coefficient. Table 8 also shows that there is some water seepage near the middle of the pavement (100cm and 200cm from the inner side of the curb), but this permeability coefficient meets the basic requirements of the pavement. The permeability coefficient decreases closer to the middle, which is because the middle section of the pavement is paved more uniformly.

[0097] It is evident that the asphalt pavement edge structure layer in this invention can effectively avoid the risk of water seepage at the edges of the asphalt pavement, thereby preventing the occurrence of interlayer water at the edges of the pavement and the risk of interlayer water seeping into the middle part of the pavement, and greatly reducing the occurrence and accumulation of interlayer water in the entire pavement.

[0098] The pavement strength of the asphalt pavement edges (35cm from the inside of the curb) of Examples 1-3 and Comparative Example 1 was tested using a portable falling weight deflectometer (PFWD). The results are shown in Table 9 below:

[0099] Table 9. Road surface strength test results

[0100]

[0101]

[0102] As shown in Table 9, the surface deflection values ​​of the asphalt pavement edges in Examples 1 to 3 are 7 μm, 5 μm, and 9 μm, respectively, while the surface deflection value of the asphalt pavement edges in Comparative Example 1 is 6 μm. This indicates that although the present invention adopts a differentiated design for the pavement edges, it can still meet the basic requirements of traffic load at the pavement edges.

Claims

1. A side structural layer for asphalt pavement, characterized in that, It is set at the edge of the asphalt pavement, with its top surface flush with the asphalt pavement, and includes a gap-filling crushed stone layer and a surface watertight layer. The gap-filling crushed stone layer is placed on the underlying layer and its components include aggregate and emulsified asphalt. The underlying layer is a sealing layer. The surface watertight layer is placed on the gap-filling crushed stone layer and its components include aggregate, filler and asphalt. The interstitial crushed stone layer comprises coarse aggregate, fine aggregate, and emulsified asphalt: the coarse aggregate is alkaline or neutral rock; the fine aggregate is limestone manufactured sand; and the emulsified asphalt is slow-cracking cationic emulsified asphalt with the following technical specifications: evaporation residue content of 55-62%, and the properties of the evaporation residue are: penetration of 60-80 (0.1 mm) at 25℃, ductility of ≥60 cm at 15℃, and 5-day storage stability ≤5%. The surface watertight layer comprises coarse aggregate, fine aggregate, filler, and asphalt: the coarse aggregate is alkaline or neutral rock; the fine aggregate is limestone manufactured sand; the filler is mineral powder ground from limestone; and the asphalt is 70# road petroleum asphalt or SBS modified asphalt. The technical specifications of the mixture of the surface watertight layer are: penetration at 60℃ ≤ 4mm, flow time at 240℃ 10~20s, and water permeability coefficient of the formed surface ≤ 20mL / min. The thickness of the gap-filling crushed stone layer is 2-10cm, and its top surface is 2cm away from the asphalt pavement. When the thickness of the interstitial crushed stone layer is <3cm, its composition by weight percentage is: 80~90% 3~5mm coarse aggregate, 10~20% 0~3mm fine aggregate, and 5.0~5.8% emulsified asphalt; When the thickness of the interstitial crushed stone layer is 3-6cm, its composition by weight percentage is: 75-85% 5-10mm coarse aggregate, 15-25% 0-3mm fine aggregate, and 5.5-6.5% emulsified asphalt. When the thickness of the interstitial crushed stone layer is greater than 6cm, its composition by weight percentage is: 70-80% 10-15mm coarse aggregate, 10-20% 3-5mm coarse aggregate, 5-15% 0-3mm fine aggregate, and 6.2-7.5% emulsified asphalt.

2. The asphalt pavement edge structure layer as described in claim 1, characterized in that, The width of the edge structural layer of the asphalt pavement is 50~80cm.

3. The asphalt pavement edge structure layer as described in claim 1, characterized in that, The thickness of the edge structural layer of the asphalt pavement is the same as the thickness of the asphalt surface layer, or the same as the total thickness of the asphalt surface layer and the asphalt intermediate layer.

4. The asphalt pavement edge structure layer as described in claim 1, characterized in that, The thickness of the surface watertight layer is 2cm, and its top surface is flush with the asphalt pavement.

5. The asphalt pavement edge structure layer as described in claim 1, characterized in that, The surface watertight layer is a mixture of mineral aggregate and asphalt; wherein the mineral aggregate consists of coarse aggregate, fine aggregate and filler, and the weight percentage of the asphalt is 7.5~8.5%.

6. The asphalt pavement edge structure layer as described in claim 5, characterized in that, The mineral gradation range of the surface water-tight layer is: The passing rates for standard sieve apertures are as follows: 9.5mm aperture: 100%; 4.75mm aperture: 90-100%; 2.36mm aperture: 65-80%; 1.18mm aperture: 40-66%; 0.6mm aperture: 28-50%; 0.3mm aperture: 20-36%; 0.15mm aperture: 16-25%; 0.075mm aperture: 10-15%.

7. The asphalt pavement edge structure layer as described in claim 1, characterized in that, The coarse aggregate of the surface water-tight layer is alkaline or neutral rock with a particle size of 3-5 mm; the fine aggregate is limestone manufactured sand with a particle size of 0-3 mm.

8. A construction method for an asphalt pavement edge structure layer as described in any one of claims 1 to 7, characterized in that, Includes the following steps: (1) Construct the roadbed, semi-rigid base, sealing layer and asphalt surface layer in sequence. When constructing the asphalt intermediate layer or asphalt surface layer, leave a width of 50-80cm on both sides of the road surface. (2) Place the curbstone so that the vertical surface of the asphalt intermediate layer and / or asphalt top layer is 50-80cm away from the inside of the curbstone; allow the curbstone to cure for 1-2 days, and then complete the construction of the earth shoulder outside the curbstone; (3) Apply emulsified asphalt to the vertical surfaces and inner sides of curbs of the asphalt intermediate layer and / or asphalt top layer; (4) After the emulsified asphalt breaks down, the gap-filling crushed stone layer is constructed: the aggregates are filled in order of decreasing particle size. After all the aggregates are filled, they are vibrated and compacted 2-3 times; the emulsified asphalt is evenly sprayed and cured for 1 day. (5) Construction of surface watertight layer: Mix the coarse aggregate, fine aggregate and filler of surface watertight layer and dry mix; then add asphalt and wet mix to obtain mixture; spread the mixture evenly on the gap-filling crushed stone layer; (6) Compact the road surface.

9. The construction method as described in claim 8, characterized in that, When the surface watertight layer is made of 70# road petroleum asphalt, the dry mixing conditions in step (5) are: stirring at 160~180℃ for 15~20s; the wet mixing conditions are: stirring at 160~180℃ for 70~85s; and the discharge temperature of the mixture is 160~170℃. When the surface watertight layer uses SBS modified asphalt, the dry mixing conditions in step (5) are: stirring at 190~210℃ for 15~20s; the wet mixing conditions are: stirring at 190~210℃ for 70~85s; and the discharge temperature of the mixture is 180~190℃.

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