Design method based on rigid-flexible fusion asphalt pavement structure

Abstract

The invention relates to the technical field of highway structure design, in particular to a design method based on a rigid-flexible fused asphalt pavement structure, which comprises the following steps: step 1, paving a semi-rigid subbase layer on a roadbed; 2, a rigid cement concrete base layer is laid on the semi-rigid subbase layer, special cracking equipment is adopted for treating the rigid cement concrete base layer, a flexible cement concrete base layer is obtained, and the rebound modulus of the flexible cement concrete base layer is made to be equal to that of the asphalt concrete surface layer; and 3, an asphalt concrete surface layer is laid on the flexible cement concrete base layer, so that the flexible cement concrete base layer and the asphalt concrete surface layer are effectively fused into a whole, and common bearing and cooperative deformation are achieved. According to the design method based on the rigid-flexible fusion asphalt pavement structure, the problems of short service life, high repair cost, difficulty in adapting to heavy-load traffic and the like of a highway pavement are solved, and the requirements of heavy-load resistance, rut resistance, crack resistance, low cost and long service life of highway construction in China are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of highway structure design, and particularly relates to a design method based on rigid-flexible fusion asphalt pavement structure. BACKGROUND

[0002] At present, the scale of highway construction in China is huge, among which, semi-rigid base asphalt pavement accounts for 98% in expressway and 85% in national and provincial trunk highway. It is widely applied due to good integrity, strong bearing capacity, low cost, adaptation to heavy vehicle, rich cement and gravel resources. However, this kind of pavement is plagued by problems such as reflection crack easy to seep water and paste, heavy traffic easy to impact damage, etc. The design service life is 10-20 years, and the capital investment for structural repair is large.

[0003] Long-life pavement is mostly full-thickness asphalt pavement, and the design service life is 35-50 years. However, it has defects such as large investment and poor resistance to heavy load, which is difficult to adapt to heavy traffic demand and has limited application.

[0004] In view of the above problems, the prior art has proposed the following solutions. For example, the patent document CN105294005A discloses a mix proportion design method for improving the flexural strength of road cement concrete, which changes the conventional theory and method of using compression concrete. According to the construction characteristics of road concrete and the requirements for flexural strength index, the solid internal flow theory and the design method of matching mortar and voids are proposed to greatly reduce the workability of mortar, change the conventional liquid properties of concrete to solid properties, overcome the "buoyancy effect", enhance the strength of the interface transition zone, improve the interlocking force of stone and mortar, and make more stones contribute to the strength, thereby improving the flexural strength. The workability of the construction is met by the flow of mortar in the voids inside the coarse aggregate skeleton. It has the advantages of high strength, saving cement, convenient construction, saving additive, etc. It can significantly improve the durability of cement concrete pavement, and has high economic and social benefits.

[0005] In summary, the existing semi-rigid base asphalt pavement is prone to damage and needs frequent repair, and the full-thickness asphalt pavement is difficult to adapt to heavy traffic demand, and the technology popularization is limited. In order to solve the problems of short service life of highway pavement, high repair cost, and difficulty in adapting to heavy traffic, it is urgent to develop a pavement structure technology with simple construction, controllable quality, reasonable cost and long service life to meet the demand of "resistance to heavy load, resistance to rutting, resistance to crack, low cost and long service life" of highway construction. SUMMARY

[0008] Based on the above problems, the purpose of the present application is to provide a design method based on rigid-flexible integrated asphalt pavement structure in the exploration and research process of long-life highway and high-durability pavement structure, to solve the problems of short highway pavement life, high repair cost, difficulty in adapting to heavy traffic, etc., to meet the demand of China's highway construction "anti-heavy load, anti-rutting, anti-crack, low cost, long life".

[0009] To achieve the above purpose, the present application provides a design method based on rigid-flexible integrated asphalt pavement structure, comprising: Step one: laying a semi-rigid subbase on the roadbed; Step two: laying a rigid cement concrete base on the semi-rigid subbase, and using a special cracking device to crack the rigid cement concrete base to obtain a flexible cement concrete base, so that the resilient modulus of the flexible cement concrete base is equivalent to that of the asphalt concrete surface; Step three: laying an asphalt concrete surface on the flexible cement concrete base, so that the flexible cement concrete base and the asphalt concrete surface are effectively integrated into one, realizing common bearing and cooperative deformation.

[0010] As a preferred, the process of treating the rigid cement concrete base in step two to obtain a flexible cement concrete base includes: The flexible cement concrete base is constructed to include a surface layer and a cracking layer, the surface layer being above the cracking layer and being used to contact the asphalt concrete surface; A contact area for transmitting the impact energy of the special cracking device is provided on the surface layer, and the impact energy generated by the free fall of the special cracking device is transmitted to the cracking layer through the contact area, so that the cracking layer produces diagonal cracking from bottom to top under the action of the impact energy, completing the flexible treatment of the rigid cement concrete base.

[0011] As a preferred, step two further includes a step of treating the top of the surface layer: forming a transition layer for enhancing the integration with the asphalt concrete surface on the top of the surface layer by milling and roughening, and the transition layer is constructed to have an embedded groove.

[0012] Wherein, the top of the surface layer of the flexible cement concrete base is milled by 1cm-3cm to form a rough and uneven surface of gravel and cement stone, hot asphalt is spread on it to make it have the characteristics of asphalt mixture, and then the asphalt concrete surface is added to form a rigid-flexible integrated transition layer, so that the upper and lower layers are integrated into one, bearing together and deforming cooperatively.

[0013] As preferred, when the transition layer is treated, 1kg-2kg of hot ordinary asphalt, modified asphalt or high viscosity and high elasticity asphalt is sprinkled on each square meter of the transition layer, and the gravel with a particle size of 1cm-2cm and pre-wrapped 3‰-5‰ asphalt is sprinkled.

[0014] As preferred, when the cracking layer is treated, the cracking rate of the cracking layer is controlled to be above 80%, so that the resilient modulus of the flexible cement concrete base layer is 1000MPa-2000Mpa.

[0015] As preferred, when the contact area is arranged on the surface layer in step two, the contact area is distributed in a quincunx structure on the surface layer, and 3-6 contact areas are arranged on each square meter of the surface layer.

[0016] As preferred, when the rigid cement concrete base layer is laid in step two, ordinary cement concrete or rolled cement concrete above C30 is used, and the thickness of the flexible cement concrete base layer is designed to be 15cm-26cm.

[0017] As preferred, when the semi-rigid subbase layer is laid in step one, the semi-rigid subbase layer is composed of cement stabilized gravel, and the thickness of the semi-rigid subbase layer is designed to be 16cm-46cm.

[0018] As preferred, when the asphalt concrete surface layer is laid in step three, the paving thickness of the asphalt concrete surface layer is controlled to be 3cm-18cm, and the cement concrete belt for ensuring the lateral stability of the pavement is arranged on both sides of the flexible cement concrete base layer, the width of the cement concrete belt is designed to be 50cm-80cm, and the thickness is equal to that of the flexible cement concrete base layer.

[0019] As preferred, the design method based on the rigid-flexible integrated asphalt pavement structure is also applicable to the reconstruction of old cement roads or the reconstruction of old semi-rigid asphalt roads.

[0020] Through the above technical solution, the following technical effects are achieved: The design method based on the rigid-flexible integrated asphalt pavement structure achieves the following technical effects:

[0021] The targeted design of the flexible cement concrete base layer and the asphalt concrete surface layer and the coordinated adjustment of the performance parameters of both make the flexible cement concrete base layer and the asphalt concrete surface layer effectively integrated. Under the action of the vehicle load, the two layers jointly bear and cooperatively deform, changing the condition that the traditional pavement layers are prone to slip and separation, improving the integrity of the pavement structure and enhancing the ability of the pavement structure to resist external load and environmental action, thereby prolonging the service life of the pavement.

[0022] The design parameters of each structural layer can be flexibly adjusted according to actual engineering requirements, such as the thickness of the semi-rigid bottom base layer, the material and processing parameters of the flexible cement concrete base layer and the type of the asphalt concrete surface layer, and can be adapted to highway engineering of different traffic flow, vehicle axle load and regional environment. Whether it is a newly built road or an old road repair, the design method can meet the engineering requirements through reasonable design, thereby expanding the application range of the design method.

[0023] Due to the optimized pavement structure performance and good interlayer fusion effect, the rigid-flexible fusion asphalt pavement has reduced diseases and maintenance frequency during use. Compared with the frequent structural repair of the traditional pavement, the design method effectively reduces the maintenance cost of the highway in the whole life cycle, reduces resource waste and has significant economic and social benefits. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a flowchart of a design method based on a rigid-flexible fusion asphalt pavement structure in an embodiment of the present application.

[0025] Figure 2 is a schematic diagram of a rigid-flexible fusion asphalt pavement structure in an embodiment of the present application.

[0026] Figure 3 is a structural schematic diagram of a flexible cement concrete base layer in an embodiment of the present application.

[0027] Figure 4 is a local structural schematic diagram of a surface layer of a flexible cement concrete base layer in an embodiment of the present application.

[0028] The reference signs are as follows: 1, roadbed; 2, semi-rigid bottom base layer; 3, flexible cement concrete base layer; 4, asphalt concrete surface layer; 5, transition layer; 31, surface layer; 32, cracking layer; 33, contact area. DETAILED DESCRIPTION

[0029] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0030] The embodiment of the application provides a design method based on a rigid-flexible fusion asphalt pavement structure, which aims to solve problems of short pavement service life, high repair cost and difficult adaptation to heavy traffic in the exploration and research process of long-service-life highway and high-durability pavement structure, so as to meet the demand of heavy-load resistance, rut resistance, crack resistance, low cost and long service life in highway construction in China.

[0031] As shown in Figure 1 and Figure 2 , a design method based on a rigid-flexible fusion asphalt pavement structure comprises the following steps. Step 1: laying a semi-rigid subbase 2 on a roadbed 1; Step 2: laying a rigid cement concrete base on the semi-rigid subbase 2, and performing cracking treatment on the rigid cement concrete base by using a special cracking device to obtain a flexible cement concrete base 3, so that the resilient modulus of the flexible cement concrete base 3 is equivalent to the resilient modulus of an asphalt concrete surface 4; Step 3: laying the asphalt concrete surface 4 on the flexible cement concrete base 3, so that the flexible cement concrete base 3 and the asphalt concrete surface 4 are effectively fused into one body to realize common bearing and cooperative deformation.

[0032] Therefore, the semi-rigid subbase 2 as the lowermost structure provides a solid foundation platform for the upper structure by virtue of the high strength, high stability and low deformation characteristics of the semi-rigid material, and the core role is to disperse and transfer the upper load to the roadbed 1, resist the vertical deformation caused by the subgrade settlement, avoid the overall structure damage caused by the lower instability, and eliminate the hidden danger of surface cracking caused by foundation settlement from the root.

[0033] The flexible cement concrete base 3 as the transition core layer connecting the subbase and the surface not only retains the bearing capacity of the cement concrete, but also obtains the adaptive deformation capacity through the flexible treatment, and becomes the key to coordinate the stress of the upper and lower layers.

[0034] The asphalt concrete surface 4 is directly contacted with the vehicle load and the natural environment, relies on the flexibility, skid resistance and sealing property of the asphalt material, provides a comfortable driving surface, and blocks the erosion of external factors such as water and temperature on the base.

[0035] The core pain point of the traditional pavement is that the resilient modulus of the rigid base and the flexible surface is greatly different, usually 10-20 times, so that under the action of the vehicle load, severe stress concentration occurs at the interface between the surface and the base, the surface is cracked due to excessive bending, the base is cracked due to rigid constraint, and finally the chain disease is caused.

[0036] The flexible cement concrete base 3 is controlled to be treated by a special cracking device on the rigid cement concrete, so that the modulus of resilience is reduced to a level comparable to that of the asphalt concrete surface layer 4. Under the action of load, the surface layer and the base are no longer in a "hard rigid flexible" antagonistic relationship, but the elastic deformation occurs synchronously, and the stress generated by the load is evenly distributed in the two-layer structure, so that the local stress does not exceed the material limit. In addition, the similar modulus makes the stress of the bonding interface of the two-layer structure more balanced, reduces the interface peeling caused by relative sliding, and makes the surface layer and the base truly become a force-bearing community to jointly bear the load.

[0037] The flexible cement concrete base 3 in the embodiment of the application is not simply weakened rigid base, but realizes rigid flexible property reorganization through controllable cracking. The special cracking device generates uniformly distributed microcracks in the rigid cement concrete base, breaks the original rigid whole structure, and gives it a certain flexibility. The microcracks do not damage the skeleton structure of the cement concrete, and still retain the compression and shear capacity, so as to ensure that the load bearing capacity of the base to the upper load does not attenuate.

[0038] The semi-rigid bottom base 2 is designed to be cement stabilized macadam material, and the thickness of the cement stabilized macadam is designed to be 18cm-46cm. The cement dosage is determined through test, so that the 7-day unconfined compressive strength of the cement stabilized macadam is not less than 3MPa, so as to ensure to provide a stable support foundation for the upper structure and disperse the stress from the flexible cement concrete base 3 and the vehicle load.

[0039] The flexible cement concrete base 3 is designed to select cement concrete above C30 as the rigid base material, and ordinary concrete or roller compacted concrete can be selected, and the thickness is designed to be 16cm-26cm. Through the concrete mix design, the water-cement ratio is controlled to be between 0.35-0.5, so as to ensure that the concrete strength meets the design requirements, and has good construction and workability.

[0040] The flexible treatment is designed to use a special cracking device to perform flexible treatment on the rigid cement concrete base. The special cracking device generates cracking energy of 30KJ-60KJ, the convex points of the device are made of special steel, and the contact plane area of the convex points and the cement concrete plate is greater than 140cm². Each square meter is distributed with 3-6 energy transmission contact points, the point spacing is 30-60cm, and the distribution is in the form of a plum blossom pile. Each convex point transmits 10-20KJ of energy. The design makes the rigid cement concrete base after treatment to be flexible as a whole, locally rigid, and the surface is basically undamaged, and the appearance remains integrity, and the modulus of resilience reaches 1200-2000, which is matched with the mechanical properties of the asphalt concrete surface layer 4.

[0041] The design of the asphalt concrete surface layer 4: the paving thickness of the designed asphalt concrete surface layer 4 is 4-18 cm; according to traffic parameters such as traffic flow and vehicle axle load, a suitable type of asphalt concrete is selected, such as AC type, SMA type, etc.; SBS modified asphalt or high-viscosity high-elasticity asphalt is selected, the penetration (25℃, 100g, 5s) of the designed asphalt is 40-80 (0.1mm), and the softening point is not less than 60℃, so as to ensure that the asphalt concrete surface layer 4 has good anti-skid, wear-resistant, waterproof performance, and bonding performance with the flexible cement concrete base 3.

[0042] Structural synergistic design: by adjusting the flexibility degree of the flexible cement concrete base 3 and the material performance parameters of the asphalt concrete surface layer 4, the flexible cement concrete base 3 and the asphalt concrete surface layer 4 can effectively integrate into one when stressed, jointly bear the vehicle load, realize synergistic deformation during vehicle driving, reduce interlayer stress concentration, and improve the overall stability and durability of the pavement structure.

[0043] As preferred, the process of treating the rigid cement concrete base in step two to obtain the flexible cement concrete base 3 includes: constructing the flexible cement concrete base 3 to include a surface layer 31 and a cracking layer 32, the surface layer 31 being located above the cracking layer 32 and used to contact the asphalt concrete surface layer 4.

[0044] A contact area 33 for transmitting the impact energy of the special cracking equipment is arranged on the surface layer 31, the impact energy generated by the free fall of the special cracking equipment is transmitted to the cracking layer 32 through the contact area 33, so that the cracking layer 32 produces oblique cracking from bottom to top under the action of the impact energy, and the flexible treatment of the rigid cement concrete base is completed.

[0045] After step two, a step of treating the top of the surface layer 31 is further included: a transition layer 5 for enhancing the fusion with the asphalt concrete surface layer 4 is formed on the top of the surface layer 31 by milling and roughening, and the transition layer 5 is constructed to have an embedded groove.

[0046] The top of the surface layer of the flexible cement concrete base is milled by 1-3 cm to form a concave-convex uneven surface of gravel and cement stone, hot asphalt is sprinkled thereon, so that the top of the surface layer has the characteristics of asphalt mixture, and then the asphalt concrete surface layer is added, so that the top of the surface layer and the added asphalt concrete surface layer are mutually engaged, bonded and fused into one, a transition layer of rigid-flexible fusion is formed, and then the upper and lower layers are fused into one, jointly bear, and synergistically deform.

[0047] When the transition layer 5 is treated, 1-2 kg of hot ordinary asphalt, modified asphalt or high-viscosity high-elasticity asphalt is sprinkled per square meter on the transition layer 5, and gravel with a particle size of 1-2 cm and pre-wrapped with 3‰-5‰ asphalt is sprinkled, wherein the gravel coverage rate of the transition layer 5 is controlled to be 30%-70%.

[0048] When the cracking layer 32 is processed, the cracking rate of the cracking layer 32 is controlled to be above 80%, so that the resilient modulus of the flexible cement concrete base layer 3 is 1000-2000 MPa.

[0049] In addition, when the asphalt concrete surface layer 4 is laid in step three, the laying thickness of the asphalt concrete surface layer 4 is controlled to be 3-18 cm, and a cement concrete strip for ensuring the lateral stability of the pavement is arranged on both sides of the flexible cement concrete base layer 3, the width of the cement concrete strip is designed to be 50-80 cm, and the thickness is equal to that of the flexible cement concrete base layer.

[0050] As shown in Figure 2 , a rigid-flexible integrated asphalt pavement structure sequentially includes a semi-rigid sub-base layer 2, a flexible cement concrete base layer 3 and an asphalt concrete surface layer 4 laid on a roadbed 1 layer by layer from bottom to top.

[0051] Among them, the flexible cement concrete base layer 3 is configured to be obtained by processing a rigid cement concrete base layer by using a special cracking device.

[0052] The resilient modulus of the flexible cement concrete base layer 3 is equivalent to that of the asphalt concrete surface layer 4, so that the flexible cement concrete base layer 3 and the asphalt concrete surface layer 4 are effectively integrated into one, and jointly bear and cooperatively deform.

[0053] As shown in Figure 2 and Figure 3 , the flexible cement concrete base layer 3 includes a surface layer 31 and a cracking layer 32, the surface layer 31 is located above the cracking layer 32 and is used to contact the asphalt concrete surface layer 4. As shown in Figure 4 , the surface layer 31 is provided with a contact area 33 for transmitting the impact energy of the special cracking device.

[0054] The surface layer 31 is configured to transmit the impact energy of the special cracking device to the cracking layer 32 through the contact area 33; the cracking layer 32 is configured to generate a diagonal cracking from bottom to top under the action of the impact energy, and form a flexible processing of the rigid cement concrete base layer.

[0055] Among them, the surface layer 31 acts as an intermediate layer for energy transmission, and the impact energy of the special cracking device is concentrated and uniformly introduced into the cracking layer 32 through the pre-set contact area 33, so as to avoid unnecessary dissipation or local overload of the energy in the surface layer 31.

[0056] The oblique cracking from bottom to top in the cracking layer 32 is a controllable directional micro-cracking. The cracks start from the bottom of the cracking layer 32 and extend upward in an oblique direction, which can ensure the formation of a uniform micro-crack network inside the cracking layer 32 and strictly limit the crack range, so that the cracking layer 32 will not penetrate the surface layer 31, nor will it affect the semi-rigid base layer 2. This ensures that the rigid cement concrete base layer remains structurally intact while being flexible, avoiding strength decay caused by excessive fragmentation.

[0057] The regular crack system formed by the energy guide of the cracking layer 32 has a significant optimization effect on the structure stress. The oblique cracks form an intersection angle with the vertical and horizontal stresses generated by the vehicle load, which can more efficiently disperse the stress. When the load acts, the cracks can absorb energy through small dislocations to avoid stress concentration in a local area.

[0058] The contact area 33 serves as an energy input point, reducing the loss of impact energy during transmission, so that each micro-crack in the cracking layer 32 is driven by controllable energy, avoiding local over-cracking or under-cracking caused by traditional blind impact, and greatly improving the quality uniformity of the flexible treatment.

[0059] By pre-setting the position and density of the contact area 33, the cracking degree can be adjusted according to the design requirements of the pavement, and customized as needed. At the same time, directional cracking reduces the vibration impact on the surrounding structure and reduces the disturbance of construction on the surrounding environment.

[0060] As shown in Figure 4 The contact area 33 is distributed in a quincunx pile structure on the surface layer 31. The area of the contact area 33 is greater than 140 cm². There are 3-6 contact areas 33 per square meter on the surface layer 31.

[0061] Therefore, compared with the row-column distribution, the quincunx pile layout can form a more dense energy transmission node network on the surface layer 31, ensuring that each area of the cracking layer 32 can be effectively covered by impact energy. Even in road sections with a large width, local uncracking or over-cracking caused by uneven energy distribution can be avoided, and the resilience modulus of the cracking layer 32 can be kept highly consistent throughout the road section.

[0062] The impact energy transmitted by adjacent contact areas 33 forms a cross-over stress field inside the cracking layer 32. The oblique cracks will tend to be more regular due to the energy intersection, avoiding disordered diffusion of cracks due to energy disorder, and further improving the structural stability of the cracking layer 32.

[0063] According to some preferred embodiments of the present application, the cracking rate of the cracking layer 32 reaches more than 80%, so that the resilience modulus of the flexible cement concrete base layer 3 is 1000-2000 MPa.

[0064] Traditional pavement interlayer bonding relies on single primer or tack coat, which is easy to cause interface peeling due to excessive load shear force. Figure 2 As shown in FIG. 1, the top of the surface layer 31 is formed with a transition layer 5 for enhancing fusion with the asphalt concrete surface layer 4 by milling and roughening, which is configured to form implantation grooves on the top of the surface layer 31 by milling and roughening.

[0065] 1kg-2kg of hot ordinary asphalt, modified asphalt or high-viscosity high-elasticity asphalt is sprinkled on each square meter of the transition layer 5, and the gravel with a particle size of 1cm-2cm and pre-wrapped with 3‰-5‰ asphalt. The gravel coverage of the transition layer 5 is 30%-70%.

[0066] According to some preferred embodiments of the present application, the flexible cement concrete base layer 3 uses ordinary cement concrete or rolled cement concrete with a C30 or above. The thickness of the flexible cement concrete base layer 3 is 15cm-26cm. The semi-rigid bottom base layer 2 is composed of cement stabilized gravel. The thickness of the semi-rigid bottom base layer 2 is 18cm-46cm.

[0067] As preferred, the asphalt concrete surface layer 4 is paved with a thickness of 4cm-18cm. Cement concrete bands for ensuring lateral stability of the pavement are arranged on both sides of the flexible cement concrete base layer 3. The width of the cement concrete band is 50cm-80cm, and the thickness is equal to that of the flexible cement concrete base layer 3.

[0068] The rigid cement concrete base layer in the rigid-flexible integrated asphalt pavement structure proposed in the embodiments of the present application can also be obtained by structural repair of the old semi-rigid asphalt pavement.

[0069] If the old semi-rigid asphalt pavement is a thin-layer asphalt pavement with a thickness of 10cm or below, a milling machine is used for rough milling with a milling depth of 0.5cm-2cm to obtain the surface layer 31 of the flexible cement concrete base layer 3; if the old semi-rigid asphalt pavement is a thin-layer asphalt pavement with a thickness of 10cm or above, a milling machine is used for rough milling with a milling depth of 0.5cm-2cm to obtain the surface layer 31 of the flexible cement concrete base layer 3.

[0070] The present application is not limited to the specific technical solutions described in the above embodiments, and in addition to the above embodiments, the present application can also have other implementation manners. For those skilled in the art, any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A design method for asphalt pavement structures based on rigid-flexible fusion, characterized in that, include: Step 1: Lay a semi-rigid subbase on the roadbed; Step 2: Lay a rigid cement concrete base course on the semi-rigid base course, and use a special cracking equipment to crack the rigid cement concrete base course to obtain a flexible cement concrete base course, so that the resilient modulus of the flexible cement concrete base course is comparable to that of the asphalt concrete surface course. Step 3: Lay an asphalt concrete surface layer on the flexible cement concrete base layer, so that the flexible cement concrete base layer and the asphalt concrete surface layer can be effectively integrated into one, achieving joint load-bearing and coordinated deformation.

2. The design method for rigid-flexible integrated asphalt pavement structure according to claim 1, characterized in that, The process of treating the rigid cement concrete base layer to obtain a flexible cement concrete base layer in step two includes: The flexible cement concrete base layer is constructed to include a surface layer and a cracked layer, with the surface layer located above the cracked layer for contact with the asphalt concrete surface layer. A contact area is set on the surface to transmit the impact energy of the special cracking equipment. The impact energy generated by the special cracking equipment through free fall is transmitted to the cracking layer through the contact area, so that the cracking layer will produce oblique cracks from bottom to top under the action of impact energy, thus completing the flexible treatment of the rigid cement concrete base.

3. The design method for rigid-flexible integrated asphalt pavement structure according to claim 2, characterized in that, Step two is followed by a step of treating the top of the surface layer: forming a transition layer on the top of the surface layer by milling and roughening to enhance the fusion with the asphalt concrete surface layer, the transition layer being configured to have an implantation groove. The flexible cement concrete base layer is milled 1cm-3cm from the top to form an uneven, exposed aggregate of gravel and cement stone. Hot asphalt is then spread on it to give it the characteristics of an asphalt mixture. This aggregate is then interlocked and bonded with the overlaid asphalt concrete surface layer to form a rigid-flexible transition layer. This allows the upper and lower layers to merge into one, share the load, and deform together.

4. The design method for rigid-flexible integrated asphalt pavement structure according to claim 3, characterized in that, When treating the transition layer, spray 1kg-2kg of hot ordinary asphalt, modified asphalt or high-viscosity and high-elasticity asphalt per square meter on the transition layer, and spread crushed stone with a particle size of 1cm-2cm and pre-coated with 3‰-5‰ asphalt. The crushed stone coverage of the transition layer is controlled at 30%-70%.

5. The design method for rigid-flexible integrated asphalt pavement structure according to claim 2, characterized in that, When the cracked layer is treated, the cracking rate of the cracked layer is controlled to reach more than 80%, so that the resilient modulus of the flexible cement concrete base layer is between 1000MPa and 2000MPa.

6. The design method for rigid-flexible integrated asphalt pavement structure according to claim 2, characterized in that, In step two, when setting contact areas on the surface, the contact areas are distributed in a quincunx pattern on the surface, with 3-6 contact areas per square meter on the surface.

7. The design method for rigid-flexible integrated asphalt pavement structure according to claim 1, characterized in that, When laying the rigid cement concrete base in step two, ordinary cement concrete or roller-compacted cement concrete of grade C30 or above is used, and the thickness of the flexible cement concrete base is designed to be 15cm-26cm.

8. The design method for rigid-flexible integrated asphalt pavement structure according to claim 1, characterized in that, When laying the semi-rigid base layer in step one, cement-stabilized crushed stone is used to form the semi-rigid base layer, and the thickness of the semi-rigid base layer is designed to be 16cm-46cm.

9. The design method for rigid-flexible integrated asphalt pavement structure according to claim 1, characterized in that, In step three, when laying the asphalt concrete surface layer, the thickness of the asphalt concrete surface layer is controlled to be 3cm-18cm. Cement concrete strips are set on both sides of the flexible cement concrete base to ensure the lateral stability of the road surface. The width of the cement concrete strips is designed to be 50cm-80cm, and the thickness is the same as that of the flexible cement concrete base.

10. The design method for rigid-flexible integrated asphalt pavement structure according to claim 1, characterized in that, It is also suitable for the renovation of old cement roads or old semi-rigid asphalt pavements.

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