Full-structural regeneration structure and construction technology of middle-low grade highway asphalt pavement

Abstract

The invention discloses a full-structural regeneration structure and a construction process for a middle-low-grade highway asphalt pavement. The full-structural recycled pavement structure comprises a 100% milling material mixing amount cold recycled water-stable base layer, a 100% milling material mixing amount foamed asphalt cold recycled surface layer, a modified emulsified asphalt bonding layer, a 60%-80% milling material mixing amount high-viscosity modified / modified asphalt AC-10 ultrathin wearing layer or a 40%-60% milling material mixing amount high-viscosity modified / modified asphalt AC-13 surface layer from bottom to top. Original pavement old water-stable materials are recycled by 100%, the utilization rate of surface layer milling materials is greatly increased, the road structural performance is improved, meanwhile, the construction cost and energy consumption are reduced, carbon emission is remarkably reduced, the maintenance period is shortened, and remarkable social and environmental benefits are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of road engineering, and particularly relates to a full-structural regeneration structure and construction process of a medium-low grade highway asphalt pavement. BACKGROUND

[0002] By the end of 2024, the total mileage of highways in China will reach about 5.49 million kilometers, most of which are asphalt pavements. However, the actual service life of the asphalt pavement in China is far from the designed service life, and generally needs to be repaired after being in use for 3-5 years, with a maintenance ratio of 99.9%. In traditional road repair and maintenance, especially in structural repair, the existing damaged pavement needs to be removed, which will pollute the environment, and the consumption of new stone materials for repaving new pavement will destroy the ecology and increase the cost.

[0003] (1) The conventional asphalt milling material is mainly used for hot regeneration of the asphalt surface layer, but due to the limited mixing ratio of the milling material, the mixing ratio of the conventional plant-mixed hot regeneration milling material is less than 30%. Due to the influence of the performance of the high-mixing-amount plant-mixed hot regeneration mixture, it is rarely applied to the structural layer.

[0004] (2) The traditional semi-rigid base is prone to problems such as reflection cracking, short service life of the structural layer, and difficult maintenance of structural damage, and the traditional semi-rigid base needs a long maintenance period, which greatly affects the road sections with high traffic requirements.

[0005] The adoption of the cold regeneration of old material recycling technology opens up a new way for highway repair and maintenance work, can fully utilize the existing highway structure and pavement material, improves the performance of the highway structure, reduces the construction cost and energy consumption, shortens the maintenance period, reduces the influence of construction on road traffic and the production and living environment of residents along the road, and has significant social and environmental benefits. SUMMARY

[0006] The present application provides a full-structural regeneration structure and construction process of a medium-low grade highway asphalt pavement, and aims to solve the technical problems of many internal diseases of the old road structure, poor structural durability, and performance attenuation.

[0007] The technical scheme is a full-structural regeneration structure of a medium-low grade highway asphalt pavement, wherein the full-structural regeneration pavement structure comprises, from bottom to top, a 100% milling material mixing amount cold regeneration water-stable base, a 100% milling material mixing amount foamed asphalt cold regeneration surface layer, a modified emulsified asphalt adhesive layer, a 60%-80% milling material mixing amount high-stickiness modified / modification asphalt AC-10 ultra-thin wearing layer, or a 40%-60% milling material mixing amount high-stickiness modified / modification asphalt AC-13 surface layer.

[0008] Preferably, the 100% milling material content cold recycled water-stabilized base course has a thickness of 18~25cm and is made of the following materials in parts by weight: milling material: 100 parts; cement: 3~6 parts; water: 5~8 parts; the milling material is obtained by milling the original road base course.

[0009] Preferably, the 100% milling aggregate foamed asphalt cold recycled surface layer has a thickness of 8-12 cm and is composed of the following parts by weight: milling aggregate: 100 parts; foamed asphalt: 1.5-3.1 parts; cement: 1.3-1.5 parts; water: 1.5-3.5 parts; the milling aggregate is obtained by milling the lower layer of the original road surface; the foamed asphalt is prepared by adding water to 90# asphalt, the asphalt foaming temperature is 155℃-170℃, the expansion rate is ≥16 times, and the half-life is ≥20s.

[0010] As a preferred option, after the simultaneous curing of the double-layer cold recycling of the 100% milling aggregate content foamed asphalt cold recycled surface layer and the 100% milling aggregate content cold recycled water-stabilized base layer, a modified emulsified asphalt tack coat is applied. This tack coat is a fast-breaking type, made by mixing high-viscosity modified emulsified asphalt and water in a 1:1 ratio, with a spraying rate of 0.3 kg / m2~0.6 kg / m2 and a thickness of 2~3 mm.

[0011] Preferably, the 60%~80% milling aggregate content high-viscosity modified asphalt / modified asphalt AC-10 ultra-thin wearing layer has a thickness of 2~2.5cm and is composed of 60~80 parts milling aggregate, 20~40 parts aggregate, and 2~3 parts asphalt. The asphalt is high-viscosity modified asphalt or modified asphalt, and the aggregate is basalt or limestone. The 40%~60% milling aggregate content high-viscosity modified / modified asphalt AC-13 surface layer has a thickness of 4cm and is composed of 40~60 parts milling aggregate, 40~60 parts aggregate, and 2~2.5 parts asphalt. The asphalt is high-viscosity modified asphalt or modified asphalt, and the aggregate is basalt or limestone.

[0012] This invention also provides a construction process for a fully regenerated asphalt pavement structure for medium and low-grade highways, comprising the following steps: (a) The original asphalt surface layer is finely milled to 2~2.5cm / 4cm using a Wirtgen W380CR / 240CR cold recycling unit. The milling machine adopts a down-cutting mode, which can make the milled material uniform in gradation and have low variability. The milled material is transported to the nearest mobile special process mixing plant for mixing and is later used for high viscosity modified asphalt / modified asphalt AC-10 ultra-thin wearing course or AC-13 surface course. (b) The remaining asphalt surface layer is cold recycled in situ with 8-12cm foamed asphalt using the Wirtgen W380CR / 240CR cold recycling unit. The finished material is temporarily stored on the adjacent material truck for later use. (c) Immediately afterwards, the water-stabilized base course is cold recycled in situ with cement. After the cold recycled layer of the water-stabilized base course is compacted, foamed asphalt cold recycled mixture is laid before initial setting, so that the foamed asphalt surface layer and the water-stabilized base course are cold recycled simultaneously and integrally formed, which enhances the overall structural strength and effectively reduces reflective cracks. (d) After the water-stabilized base course and asphalt surface course have been cured, an emulsified asphalt tack coat is spread. After the emulsified asphalt is demulsified, a high-viscosity modified asphalt / modified asphalt AC-10 ultra-thin wearing course or AC-13 surface course is laid, which has excellent impermeability, anti-skid and noise reduction performance.

[0013] Beneficial effects: 1) The foamed asphalt surface layer and the water-stabilized base layer are laid in a double layer and completed simultaneously, forming an integral structure, which enhances structural stability. Compared with new water-stabilized materials with high cement dosage, it can reduce the generation of reflective cracks and extend the service life of the pavement.

[0014] 2) The surface layer is covered with a high-viscosity modified / modified asphalt AC-10 ultra-thin wearing course or AC-13 surface layer, which has excellent high and low temperature stability, impermeability, anti-skid and noise reduction performance.

[0015] 3) This technology allows for 100% recycling of the original pavement's old water-stabilized materials, significantly improving the utilization rate of milled surface materials. While improving the structural performance of highways, it also reduces construction costs and energy consumption, significantly reduces carbon emissions, and shortens the maintenance period, resulting in significant social and environmental benefits. Attached Figure Description

[0016] Figure 1 This is a cross-sectional schematic diagram of the fully structural recycled pavement structure in an embodiment of the present invention.

[0017] Figure 2 This is a flowchart illustrating the construction process of the fully structured recycled pavement structure in an embodiment of the present invention. Detailed Implementation

[0018] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention. Example

[0019] as follows Figure 1 The diagram shows a fully regenerated structure for medium- and low-grade asphalt pavement, consisting of the following components from bottom to top: 20cm recycled water-stabilized base course 01; 10cm foamed asphalt cold recycled surface course 02; 2mm emulsified asphalt tack coat 03; and 2cm ultra-thin asphalt wearing course 04.

[0020] The construction of the recycled water-stabilized base course 01 involves milling the base course and then spreading cement and water in a ratio of 100 parts recycled asphalt pavement material (RAP): 5 parts cement: 6 parts water. The resulting new cement-stabilized crushed stone mixture is then mixed using cold recycling equipment, spread on the roadbed, and shaped and compacted to form a water-stabilized structural layer. This process can achieve 100% recycling of asphalt pavement material (RAP).

[0021] The foamed asphalt cold recycled surface layer 02 is a new mixture made by mixing recycled asphalt pavement material (RAP) with foamed asphalt, cement, and water in a ratio of 100:1.5:1.3:1.5 using cold recycling equipment. The foamed asphalt is prepared using 90# asphalt and water, with an asphalt foaming temperature of 170℃, an expansion rate of 20 times, and a half-life of 60s.

[0022] The spraying amount of the emulsified asphalt tack coat 03 is 0.4 kg / m2. The emulsified asphalt tack coat mixture is made by mixing high-viscosity modified emulsified asphalt and water in a 1:1 ratio.

[0023] The ultra-thin asphalt wearing course 04 adopts AC-10 gradation, and the binder is high-viscosity modified asphalt, which is composed of 80 parts milling material, 20 parts aggregate, and 2.5 parts asphalt. The aggregate is basalt with a pendulum friction coefficient of 65BPN, MTD of 0.9mm, and a water permeability coefficient of 1mL / min.

[0024] This embodiment conducted experimental testing on the fully regenerated structure of asphalt pavement for medium and low-grade highways. The technical indicators of each layer are shown in Tables 1 to 5.

[0025] Table 1 Technical Specifications of Cement-Stabilized Crushed Stone Base Course

[0026] Table 2 Technical Specifications of Foamed Asphalt Cold Recycled Surface Layer

[0027] Table 3 Technical Specifications of Emulsified Asphalt Tack Coating

[0028] Table 4 Technical Indicators of High Viscosity Modified Asphalt

[0029] Table 5 Technical Specifications of Ultra-thin Asphalt Wearing Layer

[0030] as follows Figure 2 As shown in this embodiment, the construction process of a fully regenerated asphalt pavement structure for medium and low-grade highways includes the following steps: S1. The original asphalt surface layer is finely milled to 2cm using a Wirtgen W380CR milling machine. The milling machine adopts a down-cutting mode, which can make the milled material uniform in gradation and have low variability. The milled material is transported to the nearest mobile special process mixing plant for mixing and later used in ultra-thin asphalt wearing course. S2. The Wirtgen W380CR cold recycling unit is used to perform 10cm foamed asphalt cold recycling on the asphalt surface layer. The finished material is temporarily stored on the adjacent material truck for later use. S3. The Wirtgen W380CR cold recycling unit is used to carry out in-situ cold recycling of the water-stabilized base course. After the cold recycling layer of the water-stabilized base course is compacted (before initial setting), foamed asphalt cold recycling mixture is laid to achieve simultaneous completion of the foamed asphalt surface layer and the water-stabilized base course double-layer cold recycling, forming an integral shape and enhancing the overall structural strength. S4. After the water-stabilized base course and asphalt surface course have been cured, spread the emulsified asphalt tack coat. After the emulsified asphalt breaks down, lay an ultra-thin asphalt wearing course. Traffic can be opened after the paving is completed. Example

[0031] See Figure 1 A fully regenerated structure for medium and low grade asphalt pavement, comprising, from bottom to top: 25cm recycled water-stabilized base course 01; 12cm foamed asphalt cold recycled surface layer 02; 2mm emulsified asphalt tack coat 03; and 4cm high-viscosity modified asphalt AC-13 surface layer 04.

[0032] The construction of the recycled water-stabilized base course 01 involves milling the base course and then spreading cement and water in a ratio of 100 parts recycled asphalt pavement material (RAP): 4 parts cement: 5 parts water. The resulting new cement-stabilized crushed stone mixture is then mixed using cold recycling equipment, spread on the roadbed, and shaped and compacted to form a water-stabilized structural layer. This process can achieve 100% recycling of asphalt pavement material (RAP).

[0033] The foamed asphalt cold recycled surface layer 02 is a new mixture made by mixing recycled asphalt pavement material (RAP) with foamed asphalt, cement, and water in a ratio of 100:3:1.4:2.5 using cold recycling equipment. The foamed asphalt is prepared using 90# asphalt and water, with an asphalt foaming temperature of 170℃, an expansion rate of 20 times, and a half-life of 60s.

[0034] The spraying amount of the emulsified asphalt tack coat 03 is 0.5 kg / m2. The emulsified asphalt tack coat mixture is made by mixing high-viscosity modified emulsified asphalt and water in a 1:1 ratio.

[0035] The high-viscosity modified asphalt AC-13 surface layer 04 is composed of 60 parts milled material, 40 parts aggregate, and 2.3 parts asphalt, with basalt as the aggregate. The mixture has a dynamic stability of 6400 cycles / mm at 60℃ and a failure flexural strain of 2500με at -10℃.

[0036] Table 6 Technical Specifications of High-Viscosity Modified Asphalt AC-13

[0037] as follows Figure 2 As shown in this embodiment, the construction process of a fully regenerated asphalt pavement structure for medium and low-grade highways includes the following steps: S1. The original asphalt surface layer is finely milled to 4cm using a Wirtgen W380CR milling machine. The milling machine adopts a down-cutting mode, which can make the milled material uniform in gradation and have low variability. The milled material is transported to the nearest mobile special process mixing plant for mixing and later used for the paving of high viscosity modified asphalt AC-13 surface layer. S2. The Wirtgen W380CR cold recycling unit is used to perform 12cm foamed asphalt cold recycling on the asphalt surface layer. The finished material is temporarily stored on the adjacent material truck for later use. S3. The Wirtgen W380CR cold recycling unit is used to carry out in-situ cold recycling of the water-stabilized base course. After the cold recycling layer of the water-stabilized base course is compacted (before initial setting), foamed asphalt cold recycling mixture is laid to achieve simultaneous completion of the foamed asphalt surface layer and the water-stabilized base course double-layer cold recycling, forming an integral shape and enhancing the overall structural strength. S4. After the water-stabilized base course and asphalt surface course have been cured, spread the emulsified asphalt tack coat. After the emulsified asphalt has broken down, lay the high-viscosity modified asphalt AC-13 surface course. Traffic can be opened after the paving is completed.

[0038] Compared with traditional technical solutions, the present invention has the following advantages, as shown in Table 7: Table 7. Comparison of Advantages between Overhaul Full-Structural Regeneration Technology and Traditional Milling Solution

[0039] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the protection scope of the present invention.

Claims

1. A fully regenerative asphalt pavement structure for medium and low-grade highways, characterized in that, The fully structured recycled pavement structure, from bottom to top, consists of a 100% milled aggregate cold recycled water-stabilized base course, a 100% milled aggregate foamed asphalt cold recycled surface course, a modified emulsified asphalt tack coat, and a 60%~80% milled aggregate high-viscosity modified / modified asphalt AC-10 ultra-thin wearing course or a 40%~60% milled aggregate high-viscosity modified / modified asphalt AC-13 surface course.

2. The fully regenerative structure for medium- and low-grade highway asphalt pavement according to claim 1, characterized in that, The 100% milling material content cold recycled water-stabilized base course has a thickness of 18~25cm and is made of the following materials by weight: milling material: 100 parts; cement: 3~6 parts; Water: 5-8 parts; the milling material is obtained by milling the original road base layer.

3. The fully regenerative structure for medium- and low-grade asphalt pavement according to claim 1, characterized in that, The 100% milling material content foamed asphalt cold recycled surface layer has a thickness of 8~12cm and is made of the following materials in parts by weight: milling material: 100 parts; Foamed asphalt: 1.5~3.1 parts; Cement: 1.3~1.5 parts; Water: 1.5~3.5 parts; the milled material is obtained by milling the lower layer of the original road surface; the foamed asphalt is prepared by adding water to 90# asphalt, the asphalt foaming temperature is 155℃~170℃, the expansion rate is ≥16 times, and the half-life is ≥20s.

4. The fully regenerative structure for medium- and low-grade highway asphalt pavement according to claim 1, characterized in that, After the 100% milling aggregate content foamed asphalt cold recycled surface layer and the 100% milling aggregate content cold recycled water-stabilized base layer are cured simultaneously by double-layer cold recycling, a modified emulsified asphalt tack coat is spread. The tack coat is a fast-breaking type, made of high-viscosity modified emulsified asphalt and water in a 1:1 ratio, with a spraying rate of 0.3kg / m2~0.6kg / m2 and a thickness of 2~3mm.

5. The fully regenerative structure for medium- and low-grade asphalt pavement according to claim 1, characterized in that, The 60%~80% milling aggregate content high-viscosity modified asphalt / modified asphalt AC-10 ultra-thin wearing layer has a thickness of 2~2.5cm and is composed of 60~80 parts milling aggregate, 20~40 parts aggregate, and 2~3 parts asphalt. The asphalt is high-viscosity modified asphalt or modified asphalt, and the aggregate is basalt or limestone. The 40%~60% milling aggregate content high-viscosity modified / modified asphalt AC-13 surface layer has a thickness of 4cm and is composed of 40~60 parts milling aggregate, 40~60 parts aggregate, and 2~2.5 parts asphalt. The asphalt is high-viscosity modified asphalt or modified asphalt, and the aggregate is basalt or limestone.

6. A construction process for a fully regenerated asphalt pavement structure for medium and low-grade highways, characterized in that, Includes the following steps: (a) The original asphalt surface layer is finely milled to 2~2.5cm / 4cm using a Wirtgen W380CR / 240CR cold recycling unit. The milling machine adopts a down-cutting mode, which can make the milled material uniform in gradation and have low variability. The milled material is transported to the nearest mobile special process mixing plant for mixing and is later used for high viscosity modified asphalt / modified asphalt AC-10 ultra-thin wearing course or AC-13 surface course. (b) The remaining asphalt surface layer is cold recycled in situ with 8-12cm foamed asphalt using the Wirtgen W380CR / 240CR cold recycling unit. The finished material is temporarily stored on the adjacent material truck for later use. (c) Immediately afterwards, the water-stabilized base course is cold recycled in situ with cement. After the cold recycled layer of the water-stabilized base course is compacted, foamed asphalt cold recycled mixture is laid before initial setting, so that the foamed asphalt surface layer and the water-stabilized base course are cold recycled simultaneously and integrally formed, which enhances the overall structural strength and effectively reduces reflective cracks. (d) After the water-stabilized base course and asphalt surface course have been cured, an emulsified asphalt tack coat is spread. After the emulsified asphalt is demulsified, a high-viscosity modified asphalt / modified asphalt AC-10 ultra-thin wearing course or AC-13 surface course is laid, which has excellent impermeability, anti-skid and noise reduction performance.

Images