Semi-rigid cement stabilized macadam base structure of asphalt pavement and construction method

Abstract

The application discloses a semi-rigid cement stabilized macadam base structure of asphalt pavement and a construction method thereof, which comprises a cement stabilized macadam lower base, a composite function interlayer and a cement stabilized macadam upper base, the cement stabilized macadam lower base is laid on the top of a roadbed, the composite function interlayer comprises emulsified asphalt, basalt fiber, high-viscosity modified asphalt and macadam, the emulsified asphalt is sprayed on the upside of the cement stabilized macadam lower base, the basalt fiber is scattered on the upper surface of the emulsified asphalt layer, the high-viscosity modified asphalt is sprayed on the upside of the basalt fiber, the macadam is scattered on the upper surface of the high-viscosity modified asphalt layer and is embedded and adhered with the high-viscosity modified asphalt layer, and the cement stabilized macadam upper base is laid on the upside of the composite function interlayer. The application can improve the interlayer bonding strength, the shearing resistance, the tensile strength and the durability, effectively delays or prevents the reflection of the semi-rigid cement stabilized base cracks to the asphalt surface layer, improves the construction quality and efficiency, and prolongs the service life of the asphalt pavement.

Description

Technical Field

[0001] This invention belongs to the field of road engineering technology, and in particular relates to a semi-rigid cement-stabilized crushed stone base structure and construction method for asphalt pavement. Background Technology

[0002] Semi-rigid cement-stabilized crushed stone base courses have become the most commonly used base course structure for high-grade asphalt pavements in my country due to their advantages such as high load-bearing capacity, high stiffness, good integrity, and wide availability of materials. Traditional semi-rigid cement-stabilized crushed stone base course structures typically employ two layers of cement-stabilized crushed stone directly superimposed, relying on the chemical bonding and mechanical interlocking of cement slurry to achieve interlayer bonding. However, with the continuous increase in traffic load and the rising proportion of heavy-duty and overloaded vehicles, the traditional semi-rigid cement-stabilized crushed stone base course structure has revealed the following prominent problems during use: First, the interlayer shear resistance is insufficient. When the upper and lower base layers are in direct contact, the interface is only bonded by cement grout, lacking an effective stress absorption and diffusion structure. Under the action of vehicle horizontal loads, interlayer shear slip is prone to occur, especially when the road surface is under heavy traffic or on long longitudinal slopes, the interface shear resistance is more significantly reduced.

[0003] Secondly, after the shear resistance of the upper and lower base interfaces decreases, the bottom of the upper base is prone to fatigue cracking. The bottom of the upper base bears a large bending tensile stress. Traditional cement-stabilized crushed stone materials have low tensile strength and are prone to fatigue cracking under repeated loading, which gradually reflects to the asphalt surface layer.

[0004] Furthermore, there is a lack of effective reinforcing connection structures between the upper and lower base layers. Conventional gravel seals or stress-absorbing layers typically only serve a single function of waterproofing and stress absorption. The gravel is fixed solely by the adhesive force of the bonding material, making it difficult to form a spatial network-like interlocking structure. Consequently, both shear and crack resistance need to be improved.

[0005] Some improvement solutions have been proposed in publicly available literature. For example, some technologies involve laying geosynthetic materials such as fiberglass geogrids or polyester fiberglass cloth between the lower and upper base layers. However, these solutions still have shortcomings: geosynthetic materials are susceptible to mechanical damage during construction, and the bonding interface with the base layer is poor, resulting in limited improvement in shear resistance and a tendency for voids and cracks to occur at the interface. Summary of the Invention

[0006] The purpose of this invention is to provide a semi-rigid cement-stabilized crushed stone base course structure and construction method for asphalt pavement, which can improve the interlayer bonding strength, shear resistance, tensile strength and durability, effectively delay or prevent cracks in the semi-rigid cement-stabilized base course from reflecting onto the asphalt surface layer, improve construction quality and efficiency, and extend the service life of asphalt pavement.

[0007] To achieve the above-mentioned technical objectives and related technical objectives, the present invention provides a semi-rigid cement-stabilized crushed stone base course structure for asphalt pavement, comprising: Cement-stabilized crushed stone subbase, wherein the cement-stabilized crushed stone subbase is laid on top of the roadbed; A composite functional interlayer comprises emulsified asphalt, basalt fiber, high-viscosity modified asphalt, and crushed stone. The emulsified asphalt is sprayed onto the upper side of the cement-stabilized crushed stone subbase to form an emulsified asphalt layer, and the emulsified asphalt penetrates into the cement-stabilized crushed stone subbase to a depth of 2-5 mm. The basalt fiber is spread on the upper surface of the emulsified asphalt layer, and the high-viscosity modified asphalt is sprayed onto the upper side of the basalt fiber to form a high-viscosity modified asphalt layer. The emulsified asphalt layer and the high-viscosity modified asphalt layer form a chemical bond. The basalt fiber forms a physical interlocking bond with the emulsified asphalt layer and the high-viscosity modified asphalt layer, respectively. The crushed stone is spread on the upper surface of the high-viscosity modified asphalt layer and is embedded and bonded to the high-viscosity modified asphalt layer. The particle size of the crushed stone is 9.5-19.0 mm, and the length of the basalt fiber is 3-6 cm. A cement-stabilized crushed stone upper base layer is laid on the upper side of the composite functional interlayer and bonded to the composite functional interlayer through an organic modified cement slurry layer.

[0008] In one example of the semi-rigid cement-stabilized crushed stone base course structure for asphalt pavement of the present invention, the thickness of the cement-stabilized crushed stone lower base course is 15-18cm, and its 7-day unconfined compressive strength is 2.5-3.5MPa; the thickness of the cement-stabilized crushed stone upper base course is 15-36cm, and its 7-day unconfined compressive strength is 3.5-4.5MPa.

[0009] In one example of the semi-rigid cement-stabilized crushed stone base course structure for asphalt pavement of the present invention, the application rate of the emulsified asphalt is 0.8–1.2 kg / m³. 2 The emulsified asphalt is sprayed within 20 to 120 minutes after the cement-stabilized crushed stone subbase is compacted.

[0010] In one example of the semi-rigid cement-stabilized crushed stone base structure for asphalt pavement of the present invention, in the basalt fibers, fibers with a length of 3-4 cm account for 40-50% of the total fiber mass, and fibers with a length of 5-6 cm account for 50-60% of the total fiber mass. When spreading the basalt fibers, the surface temperature of the emulsified asphalt layer is controlled at 60-80℃, and the spreading amount is 80-150 g / m³. 2 The coefficient of variation of fiber mass per unit area is ≤15%, and the fibers exhibit a two-dimensional random distribution.

[0011] In an example of the semi-rigid cement-stabilized crushed stone base course structure for asphalt pavement according to the present invention, when the particle size of the crushed stone is 9.5–13.2 mm, the application rate of the high-viscosity modified asphalt is 1.2–1.5 kg / m³. 2 When the particle size of the crushed stone is 13.2–19.0 ​​mm, the application rate of the high-viscosity modified asphalt layer is 1.5–1.8 kg / m³. 2 This forms a high-viscosity modified asphalt layer with a thickness of 3–6 mm.

[0012] In an example of the semi-rigid cement-stabilized crushed stone base course structure for asphalt pavement of the present invention, when spreading the crushed stone, the surface temperature of the high-viscosity modified asphalt layer is controlled at 130-140°C, the depth of the crushed stone particles embedded in the high-viscosity modified asphalt layer is 1 / 4 to 1 / 3 of the crushed stone particle size, and the coverage rate of the crushed stone on the high-viscosity modified asphalt layer is 65-75%.

[0013] In one example of the semi-rigid cement-stabilized crushed stone base structure of the asphalt pavement of the present invention, the high viscosity modified asphalt has a dynamic viscosity at 60℃ ≥100000Pa·s, a softening point ≥85℃, and an elastic recovery at 25℃ ≥90%.

[0014] In one example of the semi-rigid cement-stabilized crushed stone base structure for asphalt pavement of the present invention, the organic material added to the organic modified cement slurry layer is polyacrylamide, the amount of polyacrylamide added is 0.05-0.2% of the cement mass, the water-cement ratio of the organic modified cement slurry is 0.8-1.0, and the spraying amount of the organic modified cement slurry is 0.5-1.0 kg / m³. 2 The 7-day tensile strength of the organic modified cement slurry layer is ≥2.0MPa, and the bonding strength between the organic modified cement slurry layer and the cement-stabilized crushed stone base layer is ≥1.5MPa.

[0015] In one example of the semi-rigid cement-stabilized crushed stone base course structure for asphalt pavement of the present invention, the overall modulus of the composite functional interlayer is 1000-1200 MPa, the Poisson's ratio is 0.25-0.30, and its shear strength meets the following requirements: ≥1.0 MPa under heavy traffic load and ≥1.2 MPa under extra-heavy traffic load.

[0016] This invention also provides a construction method for a semi-rigid cement-stabilized crushed stone base structure for asphalt pavement, the steps of which include: S1. Lay the cement-stabilized crushed stone subbase and compact it into shape; S2. Within 20–120 minutes after the cement-stabilized crushed stone subbase is compacted, emulsified asphalt is sprayed onto the upper surface of the cement-stabilized crushed stone subbase to form an emulsified asphalt layer. The spraying rate of emulsified asphalt is 0.8–1.2 kg / m². 2 ; S3. After the emulsified asphalt layer surface has dried and its surface temperature is 60–80℃, spread basalt fiber at a rate of 80–150 g / m². 2 Then, a light roller with a capacity of 1 to 2 tons is used to statically compact the mixture once, so that some of the basalt fibers are bonded to the surface of the emulsified asphalt layer. S4. Spray high-viscosity modified asphalt on the upper side of the basalt fiber so that the high-viscosity modified asphalt completely covers the basalt fiber and forms a high-viscosity modified asphalt layer with a thickness of 3-6 mm. S5. When the surface temperature of the high-viscosity modified asphalt layer is 130-140℃, evenly spread crushed stone with a particle size of 9.5-19.0mm, so that the coverage rate of crushed stone on the high-viscosity modified asphalt layer is 65-75%. Then, use a small road roller with a capacity of 6-10 tons to compact it 1-2 times, so that the depth of the crushed stone embedded in the high-viscosity modified asphalt layer is 1 / 4 to 1 / 3 of the particle size of the crushed stone, and complete the laying of the composite functional interlayer. S6. Curing of composite functional interlayer and cement-stabilized crushed stone subbase for 5-7 days; S7. Prepare organic modified cement slurry. Add mixing water to the mixer, turn on the mixer and slowly add polyacrylamide. Stir until completely dissolved, then add cement and stir until uniform and lump-free. Control the water-cement ratio to be 0.8-1.0. The amount of polyacrylamide added is 0.05-0.2% of the cement mass. The slump of the organic modified cement slurry after mixing is 120-150 mm. S8. Use a cement slurry sprayer to spray the organically modified cement slurry onto the upper surface of the cured composite functional interlayer. Control the speed of the cement slurry sprayer at 3-5 km / h, the spraying pressure at 0.3-0.5 MPa, and use dual nozzles for cross-spraying. Control the spraying rate of the organically modified cement slurry at 0.5-1.0 kg / m³. 2 Every 500m completed 2 The amount of sprayed was checked by weighing after spraying. S9. Within 30 minutes after the organic modified cement slurry is sprayed and while the cement slurry remains moist, the cement-stabilized crushed stone upper base layer is laid, and the cement-stabilized crushed stone upper base layer is firmly bonded to the composite functional interlayer through the organic modified cement slurry.

[0017] In one example of the construction method for the semi-rigid cement-stabilized crushed stone base structure of the asphalt pavement of the present invention, before spreading the basalt fiber, the basalt fiber is soaked in a silane coupling agent solution with a concentration of 0.5-1.0% and a soaking time of more than 30 minutes.

[0018] In one example of the construction method for the semi-rigid cement-stabilized crushed stone base structure of the asphalt pavement of the present invention, in step S7, the cement is P.O42.5 grade ordinary Portland cement, and the polyacrylamide is anionic polyacrylamide with a molecular weight of 8 million to 12 million.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. Through the penetration bonding between the emulsified asphalt layer and the cement-stabilized crushed stone base course, the chemical bonding between the high-viscosity modified asphalt layer and the emulsified asphalt layer, and the three-dimensional network interlocking reinforcement structure formed by the interweaving of basalt fiber and crushed stone in the composite functional interlayer, a strong shear-resistant interface is formed, which can effectively resist interlayer slippage caused by vehicle horizontal load. 2. The high-viscosity modified asphalt layer in the composite functional interlayer has high elastic recovery capacity and stress absorption function. Combined with the bridging and reinforcing effect of basalt fiber, it can effectively dissipate the tensile stress generated by the cracks in the cement-stabilized crushed stone underbase layer and significantly delay or prevent the reflection cracks from spreading to the cement-stabilized crushed stone upper base layer and surface layer. 3. The emulsified asphalt layer serves as both a curing membrane for the cement-stabilized crushed stone subbase (eliminating the need for geotextile covering and simplifying construction) and a permanent waterproof and adhesive layer. It penetrates 2-5mm into the surface of the cement-stabilized crushed stone subbase, forming a dense waterproof sealing layer to prevent surface water from seeping into the subbase and causing water damage. 4. The thickness of the high-viscosity modified asphalt layer and the aggregate particle size are designed in synergy. The aggregate embedding depth is 1 / 4 to 1 / 3 of the particle size, and multi-faceted aggregate is used to ensure the best interlocking effect and structural stability. The aggregate coverage of 65-75% takes into account both shear strength and bonding area. 5. Organically modified cement grout with added polyacrylamide has good flexibility and bonding strength, which can firmly bond the crushed stone layer to the cement-stabilized crushed stone upper base layer, while improving the tensile strength of the upper base layer and avoiding interface delamination and cracking. 6. By strictly limiting parameters such as spraying time, temperature of each layer, spraying amount, and number of compaction passes of emulsified asphalt, it is ensured that each functional layer forms a firm bond under optimal conditions, resulting in strong controllability of construction quality and suitability for large-scale promotion.

[0020] In summary, the present invention significantly improves interlayer shear resistance, enhances resistance to load fatigue failure, improves the overall structural flexural fatigue life, has strong stress absorption and dispersion capabilities, excellent resistance to reflective cracking, can buffer interlayer relative displacement caused by temperature gradients, reduce the tensile cracking effect of thermal shrinkage stress on the interface, simplifies curing process, reduces costs, and ensures continuous construction and controllable quality. Detailed Implementation

[0021] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features can be combined with each other. It should also be understood that the terminology used in the embodiments of the present invention is for describing specific implementation schemes and not for limiting the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.

[0022] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention, as well as the prior art known to those skilled in the art and the description of the invention, may be implemented using any prior art methods, devices, and materials similar to or equivalent to the methods, devices, and materials in the embodiments of the present invention.

[0023] This invention provides a semi-rigid cement-stabilized crushed stone base course structure for asphalt pavement, comprising: a cement-stabilized crushed stone lower base course, a composite functional interlayer, and a cement-stabilized crushed stone upper base course. The cement-stabilized crushed stone lower base course is laid on top of the roadbed. The composite functional interlayer comprises emulsified asphalt, basalt fiber, high-viscosity modified asphalt, and crushed stone. The emulsified asphalt is sprayed onto the upper side of the cement-stabilized crushed stone lower base course to form an emulsified asphalt layer. The depth of penetration of the emulsified asphalt into the cement-stabilized crushed stone lower base course is 2-5 mm. The basalt fiber is spread on the upper surface of the emulsified asphalt layer. The high-viscosity modified asphalt is sprayed... A high-viscosity modified asphalt layer is formed on the upper side of the basalt fiber. The emulsified asphalt layer and the high-viscosity modified asphalt layer form a chemical bond. The basalt fiber forms a physical interlocking bond with the emulsified asphalt layer and the high-viscosity modified asphalt layer, respectively. Crushed stone is sprinkled on the upper surface of the high-viscosity modified asphalt layer and is embedded and bonded to the high-viscosity modified asphalt layer. The particle size of the crushed stone is 9.5-19.0 mm, and the length of the basalt fiber is 3-6 cm. The cement-stabilized crushed stone upper base layer is laid on the upper side of the composite functional interlayer and is bonded to the composite functional interlayer through an organic modified cement slurry layer.

[0024] In one example of the semi-rigid cement-stabilized crushed stone base course structure for asphalt pavement of the present invention, the thickness of the cement-stabilized crushed stone lower base course is 15-18cm, and its 7-day unconfined compressive strength is 2.5-3.5MPa; the thickness of the cement-stabilized crushed stone upper base course is 15-36cm, and its 7-day unconfined compressive strength is 3.5-4.5MPa.

[0025] In one example of the semi-rigid cement-stabilized crushed stone base structure for asphalt pavement according to the present invention, the spraying rate of the emulsified asphalt is 0.8–1.2 kg / m³. 2 The emulsified asphalt is sprayed within 20 to 120 minutes after the cement-stabilized crushed stone subbase is compacted.

[0026] In one example of the semi-rigid cement-stabilized crushed stone base structure for asphalt pavement of the present invention, in the basalt fibers, fibers with a length of 3-4 cm account for 40-50% of the total fiber mass, and fibers with a length of 5-6 cm account for 50-60% of the total fiber mass. When spreading the basalt fibers, the surface temperature of the emulsified asphalt layer is controlled at 60-80℃, and the spreading amount is 80-150 g / m³. 2 The coefficient of variation of fiber mass per unit area is ≤15%, and the fibers exhibit a two-dimensional random distribution.

[0027] In an example of the semi-rigid cement-stabilized crushed stone base course structure for asphalt pavement according to the present invention, when the particle size of the crushed stone is 9.5–13.2 mm, the application rate of the high-viscosity modified asphalt is 1.2–1.5 kg / m³. 2 When the particle size of the crushed stone is 13.2–19.0 ​​mm, the application rate of the high-viscosity modified asphalt layer is 1.5–1.8 kg / m³. 2 This forms a high-viscosity modified asphalt layer with a thickness of 3–6 mm.

[0028] In an example of the semi-rigid cement-stabilized crushed stone base course structure for asphalt pavement of the present invention, when spreading the crushed stone, the surface temperature of the high-viscosity modified asphalt layer is controlled at 130-140°C, the depth of the crushed stone particles embedded in the high-viscosity modified asphalt layer is 1 / 4 to 1 / 3 of the crushed stone particle size, and the coverage rate of the crushed stone on the high-viscosity modified asphalt layer is 65-75%.

[0029] In one example of the semi-rigid cement-stabilized crushed stone base structure of the asphalt pavement of the present invention, the high viscosity modified asphalt has a dynamic viscosity at 60℃ ≥100000Pa·s, a softening point ≥85℃, and an elastic recovery at 25℃ ≥90%.

[0030] In one example of the semi-rigid cement-stabilized crushed stone base structure for asphalt pavement of the present invention, the organic material added to the organic modified cement slurry layer is polyacrylamide, the amount of polyacrylamide added is 0.05-0.2% of the cement mass, the water-cement ratio of the organic modified cement slurry is 0.8-1.0, and the spraying amount of the organic modified cement slurry is 0.5-1.0 kg / m³. 2 The 7-day tensile strength of the organic modified cement slurry layer is ≥2.0MPa, and the bonding strength between the organic modified cement slurry layer and the cement-stabilized crushed stone base layer is ≥1.5MPa.

[0031] In one example of the semi-rigid cement-stabilized crushed stone base course structure for asphalt pavement of the present invention, the overall modulus of the composite functional interlayer is 1000-1200 MPa, the Poisson's ratio is 0.25-0.30, and its shear strength meets the following requirements: ≥1.0 MPa under heavy traffic load and ≥1.2 MPa under extra-heavy traffic load.

[0032] This invention also provides a construction method for a semi-rigid cement-stabilized crushed stone base structure for asphalt pavement, the steps of which include: S1. Lay the cement-stabilized crushed stone subbase and compact it into shape; S2. Within 20–120 minutes after the cement-stabilized crushed stone subbase is compacted, emulsified asphalt is sprayed onto the upper surface of the cement-stabilized crushed stone subbase to form an emulsified asphalt layer. The spraying rate of emulsified asphalt is 0.8–1.2 kg / m². 2 ; S3. After the emulsified asphalt layer surface has dried and its surface temperature is 60–80℃, spread basalt fiber at a rate of 80–150 g / m². 2 Then, a light roller with a capacity of 1 to 2 tons is used to statically compact the mixture once, so that some of the basalt fibers are bonded to the surface of the emulsified asphalt layer. S4. Spray high-viscosity modified asphalt on the upper side of the basalt fiber so that the high-viscosity modified asphalt completely covers the basalt fiber and forms a high-viscosity modified asphalt layer with a thickness of 3-6 mm. S5. When the surface temperature of the high-viscosity modified asphalt layer is 130-140℃, evenly spread crushed stone with a particle size of 9.5-19.0mm, so that the coverage rate of crushed stone on the high-viscosity modified asphalt layer is 65-75%. Then, use a small road roller with a capacity of 6-10 tons to compact it 1-2 times, so that the depth of the crushed stone embedded in the high-viscosity modified asphalt layer is 1 / 4 to 1 / 3 of the particle size of the crushed stone, and complete the laying of the composite functional interlayer. S6. Curing of composite functional interlayer and cement-stabilized crushed stone subbase for 5-7 days; S7. Prepare organic modified cement slurry. Add mixing water to the mixer, turn on the mixer and slowly add polyacrylamide. Stir until completely dissolved, then add cement and stir until uniform and lump-free. Control the water-cement ratio to be 0.8-1.0. The amount of polyacrylamide added is 0.05-0.2% of the cement mass. The slump of the organic modified cement slurry after mixing is 120-150 mm. S8. Use a cement slurry sprayer to spray the organically modified cement slurry onto the upper surface of the cured composite functional interlayer. Control the speed of the cement slurry sprayer at 3-5 km / h, the spraying pressure at 0.3-0.5 MPa, and use dual nozzles for cross-spraying. Control the spraying rate of the organically modified cement slurry at 0.5-1.0 kg / m³. 2 Every 500m completed2 The amount of sprayed was checked by weighing after spraying. S9. Within 30 minutes after the organic modified cement slurry is sprayed and while the cement slurry remains moist, the cement-stabilized crushed stone upper base layer is laid, and the cement-stabilized crushed stone upper base layer is firmly bonded to the composite functional interlayer through the organic modified cement slurry.

[0033] In one example of the construction method for the semi-rigid cement-stabilized crushed stone base structure of the asphalt pavement of the present invention, before spreading the basalt fiber, the basalt fiber is soaked in a silane coupling agent solution with a concentration of 0.5-1.0% and a soaking time of more than 30 minutes.

[0034] In one example of the construction method for the semi-rigid cement-stabilized crushed stone base structure of the asphalt pavement of the present invention, in step S7, the cement is P.O42.5 grade ordinary Portland cement, and the polyacrylamide is anionic polyacrylamide with a molecular weight of 8 million to 12 million.

[0035] The present invention will be further described below through several embodiments. It should be noted that, unless otherwise specified, the materials, reagents and equipment used in the embodiments can all be purchased through commercial means.

[0036] Example 1: A construction method for a semi-rigid cement-stabilized crushed stone base structure for asphalt pavement, comprising the following steps: S1. Lay a cement-stabilized crushed stone subbase and compact it. The thickness of the cement-stabilized crushed stone subbase is 16cm, and the 7-day unconfined compressive strength is 3.0MPa. S2. Within 60 minutes of compacting the cement-stabilized crushed stone subbase, spray emulsified asphalt onto the upper surface of the subbase to form an emulsified asphalt layer. The spraying rate of emulsified asphalt is 1 kg / m². 2 The depth to which emulsified asphalt penetrates into the cement-stabilized crushed stone subbase is 3.5 mm; S3. After the emulsified asphalt layer surface has dried and its surface temperature is 60-80℃, spread basalt fiber at a rate of 120g / m². 2 Then, a 2-ton light roller is used to statically compact the asphalt once, so that some of the basalt fibers are bonded to the surface of the emulsified asphalt layer. Before spreading the basalt fibers, the basalt fibers are soaked in a 1.0% silane coupling agent solution for 30 minutes. Among them, the fibers with a length of 3-4 cm account for 50% of the total fiber mass, and the fibers with a length of 5-6 cm account for 50% of the total fiber mass. S4. Apply high-viscosity modified asphalt to the upper side of the basalt fibers, ensuring complete coverage and forming a 5mm thick layer. The application rate of the high-viscosity modified asphalt is 1.5 kg / m³. 2; S5. When the surface temperature of the high-viscosity modified asphalt layer is 130-140℃, evenly spread crushed stone with a particle size of 13.2mm, so that the coverage rate of crushed stone on the high-viscosity modified asphalt layer is 70%. Then, use an 8-ton small road roller to compact it once, so that the depth of the crushed stone embedded in the high-viscosity modified asphalt layer is 1 / 3 of the crushed stone particle size, and complete the laying of the composite functional interlayer. S6. Curing of composite functional interlayer and cement-stabilized crushed stone subbase for 7 days; S7. To prepare organic modified cement slurry, add water for mixing to the mixer, turn on the mixer and slowly add polyacrylamide, stir until completely dissolved, then add cement and stir until uniform and lump-free. Control the water-cement ratio to 1.0, the amount of polyacrylamide added is 0.2% of the cement mass, and the slump of the organic modified cement slurry after mixing is 150mm. S8. Use a cement slurry sprayer to spray the organically modified cement slurry onto the upper surface of the cured composite functional interlayer. Control the speed of the cement slurry sprayer at 5 km / h, the spraying pressure at 0.5 MPa, and use a dual-nozzle cross-spraying method to control the spraying rate of the organically modified cement slurry at 0.8 kg / m³. 2 Every 500m completed 2 The amount of sprayed was checked by weighing after spraying. S9. Within 30 minutes after the organic modified cement slurry is sprayed and while the cement slurry remains moist, the cement-stabilized crushed stone upper base layer is laid. The cement-stabilized crushed stone upper base layer is firmly bonded to the composite functional interlayer through the organic modified cement slurry. The thickness of the cement-stabilized crushed stone upper base layer is 18cm, and the 7-day unconfined compressive strength is 4.5MPa.

[0037] Example 2: A construction method for a semi-rigid cement-stabilized crushed stone base structure for asphalt pavement, comprising the following steps: S1. Lay a cement-stabilized crushed stone subbase and compact it. The thickness of the cement-stabilized crushed stone subbase is 15cm, and the 7-day unconfined compressive strength is 2.5MPa. S2. Within 20 minutes of compacting the cement-stabilized crushed stone subbase, spray emulsified asphalt onto the upper surface of the subbase to form an emulsified asphalt layer. The spraying rate of emulsified asphalt is 0.8 kg / m². 2 The depth to which emulsified asphalt penetrates into the cement-stabilized crushed stone subbase is 2mm; S3. After the emulsified asphalt layer surface has dried and its surface temperature is 60-80℃, spread basalt fiber at a rate of 80g / m². 2Then, a 1-ton light roller is used to statically compact the asphalt once, so that some of the basalt fibers are bonded to the surface of the emulsified asphalt layer. Before spreading the basalt fibers, the basalt fibers are soaked in a 0.5% silane coupling agent solution for 30 minutes. Among them, the fibers with a length of 3-4 cm account for 40% of the total fiber mass, and the fibers with a length of 5-6 cm account for 60% of the total fiber mass. S4. Apply high-viscosity modified asphalt to the upper side of the basalt fibers, ensuring complete coverage and forming a 3mm thick layer. The application rate of the high-viscosity modified asphalt is 1.2 kg / m³. 2 ; S5. When the surface temperature of the high-viscosity modified asphalt layer is 130-140℃, evenly spread crushed stone with a particle size of 9.5mm, so that the coverage rate of crushed stone on the high-viscosity modified asphalt layer is 65%. Then, use a 6-ton small road roller to compact it twice, so that the depth of the crushed stone embedded in the high-viscosity modified asphalt layer is 1 / 4 of the crushed stone particle size, and complete the laying of the composite functional interlayer. S6. Curing of the composite functional interlayer and cement-stabilized crushed stone subbase for 5 days; S7. To prepare organic modified cement slurry, add mixing water to the mixer, turn on the mixer and slowly add polyacrylamide, stir until completely dissolved, then add cement and stir until uniform and lump-free. Control the water-cement ratio to be 0.8, the amount of polyacrylamide added is 0.05% of the cement mass, and the slump of the organic modified cement slurry after mixing is 120mm. S8. Use a cement slurry sprayer to spray the organically modified cement slurry onto the upper surface of the cured composite functional interlayer. Control the speed of the cement slurry sprayer at 3 km / h, the spraying pressure at 0.3 MPa, and use a dual-nozzle cross-spraying method. Control the spraying rate of the organically modified cement slurry at 0.5 kg / m³. 2 Every 500m completed 2 The amount of sprayed was checked by weighing after spraying. S9. Within 30 minutes after the organic modified cement slurry is sprayed and while the cement slurry remains moist, the cement-stabilized crushed stone upper base layer is laid. The organic modified cement slurry is used to firmly bond the cement-stabilized crushed stone upper base layer to the composite functional interlayer. The thickness of the cement-stabilized crushed stone upper base layer is 15cm, and the 7-day unconfined compressive strength is 3.5MPa.

[0038] Example 3: A construction method for a semi-rigid cement-stabilized crushed stone base structure for durable asphalt pavement, comprising the following steps: S1. Lay a cement-stabilized crushed stone subbase and compact it. The thickness of the cement-stabilized crushed stone subbase is 17cm, and the 7-day unconfined compressive strength is 3.2MPa. S2. Within 100 minutes of compacting the cement-stabilized crushed stone subbase, spray emulsified asphalt onto the upper surface of the subbase to form an emulsified asphalt layer. The spraying rate of emulsified asphalt is 1.1 kg / m². 2 The depth to which emulsified asphalt penetrates into the cement-stabilized crushed stone subbase is 4mm; S3. After the emulsified asphalt layer surface has dried and its surface temperature is 60-80℃, spread basalt fiber at a rate of 100g / m². 2 Then, a 2-ton light roller is used to statically compact the asphalt once, so that some of the basalt fibers are bonded to the surface of the emulsified asphalt layer. Before spreading the basalt fibers, the basalt fibers are soaked in a 1.0% silane coupling agent solution for 30 minutes. Among them, the fibers with a length of 3-4 cm account for 50% of the total fiber mass, and the fibers with a length of 5-6 cm account for 50% of the total fiber mass. S4. Apply high-viscosity modified asphalt to the upper side of the basalt fibers, ensuring complete coverage and forming a 4.5mm thick layer. The application rate of the high-viscosity modified asphalt is 1.4 kg / m³. 2 ; S5. When the surface temperature of the high-viscosity modified asphalt layer is 130-140℃, evenly spread crushed stone with a particle size of 12mm so that the coverage rate of crushed stone on the high-viscosity modified asphalt layer is 70%. Then, use an 8-ton small road roller to compact it once so that the depth of the crushed stone embedded in the high-viscosity modified asphalt layer is 1 / 4 of the particle size of the crushed stone, thus completing the laying of the composite functional interlayer. S6. Curing of composite functional interlayer and cement-stabilized crushed stone subbase for 6 days; S7. To prepare organic modified cement slurry, add mixing water to the mixer, turn on the mixer and slowly add polyacrylamide, stir until completely dissolved, then add cement and stir until uniform and lump-free. Control the water-cement ratio to be 0.9, the amount of polyacrylamide added is 0.1% of the cement mass, and the slump of the organic modified cement slurry after mixing is 140mm. S8. Use a cement slurry sprayer to spray the organically modified cement slurry onto the upper surface of the cured composite functional interlayer. Control the speed of the cement slurry sprayer at 4 km / h, the spraying pressure at 0.4 MPa, and use a dual-nozzle cross-spraying method to control the spraying rate of the organically modified cement slurry at 0.8 kg / m³. 2 Every 500m completed 2 The amount of sprayed was checked by weighing after spraying. S9. Within 30 minutes after the organic modified cement slurry is sprayed and while the cement slurry remains moist, the cement-stabilized crushed stone upper base layer is laid. The cement-stabilized crushed stone upper base layer is firmly bonded to the composite functional interlayer through the organic modified cement slurry. The thickness of the cement-stabilized crushed stone upper base layer is 25cm, and the 7-day unconfined compressive strength is 4.5MPa.

[0039] Example 4: A construction method for a semi-rigid cement-stabilized crushed stone base structure for asphalt pavement, comprising the following steps: S1. Lay a cement-stabilized crushed stone subbase and compact it. The thickness of the cement-stabilized crushed stone subbase is 18cm, and the 7-day unconfined compressive strength is 3.5MPa. S2. Within 120 minutes after the cement-stabilized crushed stone subbase is compacted, emulsified asphalt is sprayed onto the upper surface of the cement-stabilized crushed stone subbase to form an emulsified asphalt layer. The spraying rate of emulsified asphalt is 1.2 kg / m². 2 The depth to which emulsified asphalt penetrates into the cement-stabilized crushed stone subbase is 5mm; S3. After the emulsified asphalt layer surface has dried and its surface temperature is 60-80℃, spread basalt fiber at a rate of 150g / m². 2 Then, a 2-ton light roller is used to statically compact the asphalt once, so that some of the basalt fibers are bonded to the surface of the emulsified asphalt layer. Before spreading the basalt fibers, the basalt fibers are soaked in a 1.0% silane coupling agent solution for 30 minutes. Among them, the fibers with a length of 3-4 cm account for 50% of the total fiber mass, and the fibers with a length of 5-6 cm account for 50% of the total fiber mass. S4. Apply high-viscosity modified asphalt to the upper side of the basalt fibers, ensuring complete coverage and forming a 6mm thick layer. The application rate of the high-viscosity modified asphalt is 1.8 kg / m³. 2 ; S5. When the surface temperature of the high-viscosity modified asphalt layer is 130-140℃, evenly spread crushed stone with a particle size of 19.0mm, so that the coverage rate of crushed stone on the high-viscosity modified asphalt layer is 75%. Then, use a 10-ton small road roller to compact it twice, so that the depth of the crushed stone embedded in the high-viscosity modified asphalt layer is 1 / 4 of the crushed stone particle size, and complete the laying of the composite functional interlayer. S6. Curing of composite functional interlayer and cement-stabilized crushed stone subbase for 7 days; S7. To prepare organic modified cement slurry, add water for mixing to the mixer, turn on the mixer and slowly add polyacrylamide, stir until completely dissolved, then add cement and stir until uniform and lump-free. Control the water-cement ratio to 1.0, the amount of polyacrylamide added is 0.2% of the cement mass, and the slump of the organic modified cement slurry after mixing is 150mm. S8. Use a cement slurry sprayer to spray the organically modified cement slurry onto the upper surface of the cured composite functional interlayer. Control the speed of the cement slurry sprayer at 5 km / h, the spraying pressure at 0.5 MPa, and use a dual-nozzle cross-spraying method. Control the spraying rate of the organically modified cement slurry at 1.0 kg / m³. 2 Every 500m completed 2 The amount of sprayed was checked by weighing after spraying. S9. Within 30 minutes after the organic modified cement slurry is sprayed and while the cement slurry remains moist, the cement-stabilized crushed stone upper base layer is laid. The organic modified cement slurry is used to firmly bond the cement-stabilized crushed stone upper base layer to the composite functional interlayer. The thickness of the cement-stabilized crushed stone upper base layer is 36cm, and the 7-day unconfined compressive strength is 4.5MPa.

[0040] The composite functional sandwich layers prepared in Examples 1 to 4 have an overall modulus of 1000–1200 MPa and a Poisson's ratio of 0.25–0.30. Their shear strength meets the following requirements: ≥1.0 MPa under heavy traffic load and ≥1.2 MPa under extra-heavy traffic load. The mechanical property test results of the composite functional sandwich layers are as follows: shear strength at a shear angle of 25° ≥1.2 MPa, shear strength at a shear angle of 60° ≥0.8 MPa, pull-out strength ≥1.0 MPa, flexural tensile strength ≥2.5 MPa, and fatigue life (10,000 cycles) ≥500.

[0041] The long-term durability test results of the semi-rigid cement-stabilized crushed stone base structure of the asphalt pavement prepared in Examples 1 to 4 are as follows: after 20 freeze-thaw cycles, the shear strength retention rate is ≥90%; after 168 hours of high-temperature aging, the shear strength retention rate is ≥85%; after 7 days of water immersion, the shear strength retention rate is ≥88%; and after 2 years of actual engineering service, the cracking rate is ≤3%.

[0042] In summary, the present invention significantly improves interlayer shear resistance, enhances resistance to load fatigue failure, improves the overall structural flexural fatigue life, has strong stress absorption and dispersion capabilities, excellent resistance to reflective cracking, can buffer interlayer relative displacement caused by temperature gradients, reduce the tensile cracking effect of thermal shrinkage stress on the interface, simplifies curing process, reduces costs, ensures continuous construction and controllable quality, and is suitable for widespread promotion.

[0043] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A semi-rigid cement-stabilized crushed stone base structure for asphalt pavement, characterized in that, include: Cement-stabilized crushed stone subbase, wherein the cement-stabilized crushed stone subbase is laid on top of the roadbed; A composite functional interlayer comprises emulsified asphalt, basalt fiber, high-viscosity modified asphalt, and crushed stone. The emulsified asphalt is sprayed onto the upper side of the cement-stabilized crushed stone subbase to form an emulsified asphalt layer, and the emulsified asphalt penetrates into the cement-stabilized crushed stone subbase to a depth of 2-5 mm. The basalt fiber is spread on the upper surface of the emulsified asphalt layer, and the high-viscosity modified asphalt is sprayed onto the upper side of the basalt fiber to form a high-viscosity modified asphalt layer. The emulsified asphalt layer and the high-viscosity modified asphalt layer form a chemical bond. The basalt fiber forms a physical interlocking bond with the emulsified asphalt layer and the high-viscosity modified asphalt layer, respectively. The crushed stone is spread on the upper surface of the high-viscosity modified asphalt layer and is embedded and bonded to the high-viscosity modified asphalt layer. The particle size of the crushed stone is 9.5-19.0 mm, and the length of the basalt fiber is 3-6 cm. A cement-stabilized crushed stone upper base layer is laid on the upper side of the composite functional interlayer and bonded to the composite functional interlayer through an organic modified cement slurry layer.

2. The semi-rigid cement-stabilized crushed stone base course structure for asphalt pavement as described in claim 1, characterized in that, The thickness of the cement-stabilized crushed stone lower base course is 15-18cm, and its 7-day unconfined compressive strength is 2.5-3.5MPa. The thickness of the cement-stabilized crushed stone upper base course is 15-36cm, and its 7-day unconfined compressive strength is 3.5-4.5MPa.

3. The semi-rigid cement-stabilized crushed stone base course structure for asphalt pavement as described in claim 1, characterized in that, The application rate of the emulsified asphalt is 0.8–1.2 kg / m³. 2 The emulsified asphalt is sprayed within 20 to 120 minutes after the cement-stabilized crushed stone subbase is compacted.

4. The semi-rigid cement-stabilized crushed stone base course structure for asphalt pavement as described in claim 1, characterized in that, In the basalt fibers, fibers with a length of 3-4 cm account for 40-50% of the total fiber mass, and fibers with a length of 5-6 cm account for 50-60% of the total fiber mass. When spreading the basalt fibers, the surface temperature of the emulsified asphalt layer is controlled at 60-80℃, and the spreading amount is 80-150 g / m³. 2 The coefficient of variation of fiber mass per unit area is ≤15%, and the fibers exhibit a two-dimensional random distribution.

5. The semi-rigid cement-stabilized crushed stone base course structure for asphalt pavement as described in claim 1, characterized in that, When the particle size of the crushed stone is 9.5–13.2 mm, the application rate of the high-viscosity modified asphalt is 1.2–1.5 kg / m³. 2 When the particle size of the crushed stone is 13.2–19.0 ​​mm, the application rate of the high-viscosity modified asphalt layer is 1.5–1.8 kg / m³. 2 This forms a high-viscosity modified asphalt layer with a thickness of 3–6 mm.

6. The semi-rigid cement-stabilized crushed stone base course structure for asphalt pavement as described in claim 1, characterized in that, When spreading the crushed stone, the surface temperature of the high-viscosity modified asphalt layer is controlled at 130-140°C, the depth of the crushed stone particles embedded in the high-viscosity modified asphalt layer is 1 / 4 to 1 / 3 of the crushed stone particle size, and the coverage rate of the crushed stone on the high-viscosity modified asphalt layer is 65-75%.

7. The semi-rigid cement-stabilized crushed stone base course structure for asphalt pavement as described in claim 1, characterized in that, The organic compound added to the organically modified cement slurry layer is polyacrylamide, with an addition amount of 0.05–0.2% of the cement mass. The water-cement ratio of the organically modified cement slurry is 0.8–1.0, and the spraying rate of the organically modified cement slurry is 0.5–1.0 kg / m³. 2 The 7-day tensile strength of the organic modified cement slurry layer is ≥2.0MPa, and the bonding strength between the organic modified cement slurry layer and the cement-stabilized crushed stone base layer is ≥1.5MPa.

8. The construction method of the semi-rigid cement-stabilized crushed stone base structure for asphalt pavement as described in any one of claims 1 to 7, characterized in that the steps are as follows: include: S1. Lay the cement-stabilized crushed stone subbase and compact it into shape; S2. Within 20–120 minutes after the cement-stabilized crushed stone subbase is compacted, emulsified asphalt is sprayed onto the upper surface of the cement-stabilized crushed stone subbase to form an emulsified asphalt layer. The spraying rate of emulsified asphalt is 0.8–1.2 kg / m². 2 ; S3. After the emulsified asphalt layer surface has dried and its surface temperature is 60–80℃, spread basalt fiber at a rate of 80–150 g / m². 2 Then, a light roller with a capacity of 1 to 2 tons is used to statically compact the mixture once, so that some of the basalt fibers are bonded to the surface of the emulsified asphalt layer. S4. Spray high-viscosity modified asphalt on the upper side of the basalt fiber so that the high-viscosity modified asphalt completely covers the basalt fiber and forms a high-viscosity modified asphalt layer with a thickness of 3-6 mm. S5. When the surface temperature of the high-viscosity modified asphalt layer is 130-140℃, evenly spread crushed stone with a particle size of 9.5-19.0mm, so that the coverage rate of crushed stone on the high-viscosity modified asphalt layer is 65-75%. Then, use a small road roller with a capacity of 6-10 tons to compact it 1-2 times, so that the depth of the crushed stone embedded in the high-viscosity modified asphalt layer is 1 / 4 to 1 / 3 of the particle size of the crushed stone, and complete the laying of the composite functional interlayer. S6. Curing of composite functional interlayer and cement-stabilized crushed stone subbase for 5-7 days; S7. Prepare organic modified cement slurry. Add mixing water to the mixer, turn on the mixer and slowly add polyacrylamide. Stir until completely dissolved, then add cement and stir until uniform and lump-free. Control the water-cement ratio to be 0.8-1.

0. The amount of polyacrylamide added is 0.05-0.2% of the cement mass. The slump of the organic modified cement slurry after mixing is 120-150 mm. S8. Use a cement slurry sprayer to spray the organically modified cement slurry onto the upper surface of the cured composite functional interlayer. Control the speed of the cement slurry sprayer at 3-5 km / h, the spraying pressure at 0.3-0.5 MPa, and use dual nozzles for cross-spraying. Control the spraying rate of the organically modified cement slurry at 0.5-1.0 kg / m³. 2 Every 500m completed 2 The amount of sprayed was checked by weighing after spraying. S9. Within 30 minutes after the organic modified cement slurry is sprayed and while the cement slurry remains moist, the cement-stabilized crushed stone upper base layer is laid, and the cement-stabilized crushed stone upper base layer is firmly bonded to the composite functional interlayer through the organic modified cement slurry.

9. The construction method of the semi-rigid cement-stabilized crushed stone base structure for asphalt pavement as described in claim 8, characterized in that, Before spreading the basalt fibers, the basalt fibers are soaked in a silane coupling agent solution with a concentration of 0.5-1.0% for at least 30 minutes.

10. The construction method of the semi-rigid cement-stabilized crushed stone base structure for asphalt pavement as described in claim 8, characterized in that, In step S7, the cement is P.O42.5 grade ordinary Portland cement, and the polyacrylamide is anionic polyacrylamide with a molecular weight of 8 million to 12 million.