Composite double-layer structure pavement slab based on snail shell-like structure bionics and rapid paving method of composite double-layer structure pavement slab

Abstract

According to the snail shell-like bionic composite double-layer pavement slab and the rapid paving method thereof, a rigid-flexible combined double-layer structure is adopted, an outer layer is made of Portland cement, quartz sand, steel slag, nano silicon dioxide and steel fibers, the fracture resistance, shear resistance and wear resistance are improved, and traffic load and environmental erosion are effectively resisted. And the inner layer adopts a polyurethane polymer adhesive and polyvinyl alcohol fibers, so that the impact resistance, durability and chemical corrosion resistance are improved, interlayer bonding is optimized, and the overall stability is enhanced. The pavement slabs are spliced in a hexagonal interlocking mode, force transmission is uniform, joint dislocation is reduced, and construction efficiency is improved. Before the prefabricated slabs are laid, an emulsified asphalt ultrathin gravel sealing layer is laid on the ground, and the bonding force between the inner layer and the foundation is enhanced. The double-layer structure characteristic of a snail shell is used for reference, the rigid-flexible combined design is adopted, the high bearing capacity of the rigid outer layer and the impact absorption capacity of the flexible inner layer are combined, hexagonal interlocking splicing is adopted for assistance, and the quick pavement paving material is suitable for quick pavement paving.

Description

Technical Field

[0001] The present invention relates to the fields of road engineering and building materials, and particularly relates to a composite double-layer structural road slab bionic based on a snail shell-like structure and a rapid paving method thereof. The road slab adopts a double-layer structural design combining rigidity and flexibility. The outer layer has high strength, wear resistance and impermeability, and the inner layer has high toughness, impact resistance and excellent bonding performance. The overall stability is improved through a hexagonal interlocking splicing method, and it is applicable to road construction and repair in high-load traffic environments. Background Art

[0002] With the continuous development of modern urban transportation, the requirements for road surface materials in road construction are increasing day by day. Especially in high-load traffic environments such as highways and urban arterial roads, road slabs not only have to bear huge traffic loads, but also need to have good impact resistance, wear resistance, impermeability and durability. However, after long-term use, traditional single-material road slabs (such as cement concrete or asphalt concrete) are prone to problems such as cracks, wear and spalling, affecting the service life and traffic safety of roads. Therefore, how to design a road surface material that can effectively resist external pressure and has good impact absorption performance has become an urgent problem to be solved in the current road engineering field.

[0003] In recent years, bionics has gradually become an effective way to solve this problem. Bionics designs and innovates materials by imitating the characteristics of biological structures in nature and has been widely applied in various fields. As a classic bionic structure in nature, the outer layer of the snail shell is hard and firm, which can effectively resist external pressure and impact; the inner layer is relatively flexible, which can absorb impact force and improve the overall structural stability. Therefore, the double-layer structure of the snail shell has a good combination of rigidity and toughness, providing a new idea for the design of road surface materials.

[0004] Most of the existing road surface material designs focus on improving the performance of single materials, such as enhancing the compressive strength and wear resistance of concrete, but ignore the importance of combining rigidity and flexibility. Especially in high-load and high-impact environments, single materials often cannot meet the long-term use requirements. Therefore, a bionic composite double-layer structural road slab based on the snail shell structure has emerged. This structural design can resist external loads and environmental erosion through the hard outer layer, and at the same time utilize the energy absorption and buffering characteristics of the soft inner layer to enhance the comprehensive performance of the road slab and extend its service life. In addition, the application of rapid paving technology further improves the construction efficiency and reduces on-site pollution and safety risks.

[0005] Therefore, the present invention proposes a composite double-layer structural road slab bionic based on a snail shell-like structure and a rapid paving method thereof. By combining the principles of bionics and polyurethane-based polymer adhesives, it aims to solve the limitations of the existing technology and meet the needs of rapid construction of modern infrastructure. Summary of the Invention

[0006] (1) Technical Problem

[0007] The object of the present invention is to provide a composite double-layer structural pavement slab based on the bionic design of the snail shell structure and its rapid paving method, which realizes ultra-high strength and rapid construction through the synergistic effect of bionic design and polyurethane-based polymer adhesives.

[0008] (2) Technical Solution

[0009] The technical solution of the present invention includes the following core contents:

[0010] (1) Outer layer (hard layer): The outer layer mainly undertakes the functions of compression resistance and wear resistance, simulating the hard outer layer structure of the snail shell.

[0011] Cementitious material: Portland cement

[0012] High-strength aggregate: Fine aggregate is selected as quartz sand with a particle size of 0.3 - 1.2 mm, and coarse aggregate is selected as steel slag with a particle size of 5 - 10 mm. As the skeleton material of concrete, high-strength aggregate can significantly improve the overall strength and toughness of concrete.

[0013] Additive: Add 1% - 3% nano-SiO2 and 0.5% - 2% steel fiber. Nano-silica can improve the impermeability, compressive strength and wear resistance of the outer layer, and reduce surface damage caused by traffic loads.

[0014] (2) Inner layer (soft layer): The inner layer mainly undertakes the functions of shock resistance and energy absorption, simulating the soft inner layer structure of the snail shell.

[0015] Polyurethane-based polymer adhesive: A two-component polyurethane adhesive is used, where component A is isocyanate and component B is polyol. Polyurethane-based polymer adhesives can improve the bonding strength, rapid curing performance and durability of concrete, and at the same time improve the chemical corrosion resistance of concrete.

[0016] Additive: Add 0.5% - 1% polyvinyl alcohol fiber, which can significantly improve the impact resistance and toughness, prevent the formation and expansion of cracks, and improve the fatigue resistance of the pavement slab. In addition, polyvinyl alcohol fiber can also optimize the interlayer bonding effect, enhance the bonding force between the inner and outer layers, thereby improving the stability and durability of the overall structure.

[0017] (3) Emulsified asphalt ultra-thin crushed stone seal layer: It can effectively enhance the bonding force between the inner layer material and the bottom surface, improve the durability and long-term stability of the pavement slab, and avoid peeling or damage caused by poor bonding.

[0018] Matrix material: Use 6 - 8% (calculated by the total mixture weight) emulsified asphalt to provide good adhesiveness

[0019] Aggregate: Ultra-thin crushed stones with a particle size of 1.0 - 5 mm. The crushed stones provide excellent surface wear resistance and anti-skid properties. At the same time, they can enhance the physical strength and uniformity of the seal coat, improve the bonding force with the inner layer material, and ensure the stability of the overall structure.

[0020] 2. Preparation method

[0021] Step 1: Preparation of polyurethane-based polymer adhesive

[0022] The preparation of the polyurethane-based polymer adhesive is to improve the bonding performance and overall strength of the concrete. First, the polyurethane prepolymer (Component A) is synthesized by reacting isocyanate with polyol, controlling the reaction temperature at 70 - 90 °C until the isocyanate and polyol completely react to form the prepolymer. Then, the curing agent (Component B), usually an amine compound, is prepared and stirred in the required proportion. Next, the polyurethane prepolymer and the curing agent are mixed in the designed proportion (5:1), and the viscosity is adjusted as needed. If the viscosity is too high, an appropriate amount of solvent can be added to adjust it. Finally, 0.5% - 1% of polyvinyl alcohol fiber is added to enhance the toughness, impact resistance, and structural stability of the inner layer.

[0023] Step 2: Preparation of high-strength concrete

[0024] First, mix the portland cement with an appropriate amount of aggregate to ensure its uniformity, and then add 1% - 3% nano-silica and 0.5% - 2% steel fiber to improve the impermeability and wear resistance of the outer layer. After all components are mixed evenly, the viscosity of the material can be adjusted as needed to ensure the fluidity and applicability during construction. Finally, pour the outer layer mixture into the mold, and after proper compaction and vibration, form the outer layer material and cure it to ensure that it reaches the expected strength and durability after hardening.

[0025] Step 3: Preparation of precast slabs

[0026] Use a hexagonal interlocking splicing mold to ensure that each slab can be accurately spliced into a stable structure. The size of the mold should meet the design requirements. Usually, the side length of the hexagonal slab is 40 cm to 60 cm, and the thickness is 3 cm to 5 cm. Pour the prepared inner layer polyurethane-based polymer adhesive into the mold, and perform proper compaction and vibration to ensure its density and uniformity. Then, pour the outer layer high-strength mixture and cover the inner layer. Ensure good bonding between the inner and outer layers. After the concrete slab is poured, cure it. Ensure that the slab reaches the expected strength and improve its durability. Control the humidity and temperature during the curing process according to the material requirements to ensure that the slab does not crack.

[0027] Step 4: Emulsified asphalt ultra-thin crushed stone seal coat

[0028] Before laying the precast slabs, first clean the construction ground to ensure its surface is clean and flat. Lay the emulsified asphalt ultra-thin crushed stone seal coat on the ground. Use a seal coat material mixed with emulsified asphalt and fine crushed stone, and evenly lay it on the ground through mechanical equipment. The function of this seal coat is to ensure that the inner layer of polyurethane-based polymer adhesive of the precast slab can fully bond with the ground, and enhance its water resistance, crack resistance and durability. After the construction of the emulsified asphalt seal coat, appropriate curing is required to ensure its hardening and the formation of a firm bonding force with the ground.

[0029] Step 5: Rapid paving

[0030] After the seal coat construction is completed and cured in place, transport the prepared precast pavement slabs to the construction site. Lay the precast pavement slabs one by one on the ground that has been treated with the seal coat according to the hexagonal splicing method as required by the design. Ensure that the interfaces between the slabs are precise and the splicing is tight. Fill the splicing gaps with silicone sealant to enhance the interlayer bonding force, prevent water penetration and improve the structural stability. During the paving process, if it is found that individual slabs are uneven or misaligned, appropriate adjustments should be made to ensure the flatness of the pavement. After the paving of the pavement slabs is completed, carry out on-site curing to ensure the strength and durability of the pavement slabs. Control the temperature and humidity during the curing period to avoid cracking or deformation.

[0031] 3. Mechanism of action

[0032] Bionic double-layer structure: Drawing on the double-layer stacked structure of the snail shell and combining the concept of rigid-flexible combination, the distribution of the inner and outer layer materials of the concrete pavement slab is optimized. The outer layer is responsible for providing high-strength wear resistance to cope with external pressure and wear; the inner layer has high toughness, which can effectively support and absorb impact force, enhancing the stability and durability of the overall structure.

[0033] Polyurethane-based polymer adhesive: The addition of this adhesive effectively improves the overall performance of the concrete, enhancing its bonding strength, durability and construction performance. The rapid curing characteristics and excellent weather resistance of the polyurethane-based polymer adhesive make the performance of the concrete more stable during the construction process and improve its durability in long-term use.

[0034] Ultra-high-strength concrete: As the rigid surface layer material of the outer layer, ultra-high-strength concrete provides extremely strong compressive and wear resistance, ensuring that the surface layer can withstand long-term traffic loads and environmental pressures, and extending the service life of the road or structure.

[0035] Fast paving: The road slab adopts a hexagonal interlocking splicing method. This design has excellent mechanical properties, can evenly distribute external loads, reduce misalignment at the splicing joints, and improve shear strength and stability. The hexagonal splicing can effectively enhance the overall cooperation and durability between the plates, further improving the crack resistance of the slab and the stability of the overall structure. In addition, the modular design facilitates later maintenance and repair, ensuring stability and economy during long-term use.

[0036] Compared with the existing effects, the beneficial effects of the present invention are:

[0037] 1. Combining rigidity and flexibility to improve structural performance: The present invention is based on the bionic double-layer structure design of a snail shell. The outer layer uses high-strength wear-resistant materials to provide excellent flexural strength, shear strength, wear resistance and impermeability to resist long-term traffic loads and environmental erosion; the inner layer uses high-toughness materials that can effectively absorb and disperse impact energy, reduce crack propagation, and improve the impact resistance and durability of the overall structure. The rigid-flexible combined structure design ensures the stability and service life of the road slab in a high-load environment. This structure achieves a compressive strength greater than 120 MPa and a flexural strength of 15 MPa.

[0038] 2. Hexagonal interlocking to improve overall stability: The road slab adopts a hexagonal interlocking splicing method, which can evenly transfer loads, reduce joint misalignment, improve shear resistance, and enhance the crack resistance and durability of the overall road surface. At the same time, the hexagonal structure reduces material loss, improves construction efficiency and economy.

[0039] 3. Polyurethane adhesive enhances bonding strength: Polyurethane-based polymer adhesives are used, which have excellent bonding strength, durability and chemical corrosion resistance, optimize the bonding performance between the inner and outer layers, improve the anti-peeling ability, and enhance the bonding effect between the road slab and the base layer, thereby improving the stability and durability of the overall structure.

[0040] 4. Efficient construction and cost reduction: The precast slab fast paving process is adopted. Compared with the traditional on-site casting process, it can greatly shorten the construction period, improve construction accuracy, and reduce construction pollution and safety hazards. The modular design facilitates later maintenance and replacement, reduces the overall maintenance cost, and enhances the economy and sustainability of road repair.

[0041] 5. Adapt to harsh environments and extend service life: The road slab of the present invention has both high wear resistance and impact resistance, and can be applied to high-load traffic environments and extreme climate conditions, such as highways, heavy-traffic roads and roads in cold regions. Its excellent crack resistance and durability result in a longer service life of the road surface and reduced long-term maintenance costs. Description of the Drawings

[0042] Figure 1 It is a schematic diagram of the bionic double-layer structure.

[0043] Figure 2 It is a schematic diagram of a hexagonal road panel. Specific implementation manners

[0044] The present invention illustrates a composite double-layer structure road panel and its rapid paving method based on biomimetic snail shell structure through specific embodiments, including the design of the double-layer structure, the preparation of polyurethane-based polymer adhesives, the preparation of concrete, and the construction process of precast slabs. By adjusting parameters and setting comparative examples, the effects of the present invention are verified, but the present invention is not limited to the following embodiments.

[0045] In each embodiment of the present invention, the experimental methods are conventional methods unless otherwise specified. The raw materials, reagents, etc. used can be obtained from commercial channels unless otherwise specified.

[0046] Example 1

[0047] (1) Biomimetic double-layer structure design

[0048] In this embodiment, the road panel adopts a biomimetic double-layer structure design. The outer layer mainly undertakes the functions of compression resistance and wear resistance, simulating the hard outer layer structure of the snail shell; the inner layer mainly undertakes the functions of impact resistance and energy absorption, simulating the soft inner layer structure of the snail shell. The outer layer is composed of ultra-high-strength concrete, and the inner layer is composed of polyurethane-based polymer adhesives, enhancing the bonding strength and durability of the concrete.

[0049] (2) Preparation of polyurethane-based polymer adhesives

[0050] The preparation of polyurethane-based polymer adhesives is to improve the bonding performance and overall strength of concrete. First, 50 g of polyurethane prepolymer (Component A) is added to 200 mL of anhydrous ethanol and stirred evenly. Then, 10 g of diisocyanate (MDI) is slowly added and reacted at 70 - 90 °C for 2 hours to increase the molecular crosslinking degree. Then, 5 g of amine-terminated polyether is added and the reaction continues for 1 hour to improve the bonding performance. After the reaction is completed, the obtained adhesive is cooled to room temperature for standby. Finally, 0.5% - 1% of polyvinyl alcohol fiber (PVA) is incorporated into the adhesive. Utilizing its excellent toughening characteristics, the crack resistance and toughness of the material are improved, ensuring that the inner layer can effectively absorb impact energy and reduce crack propagation when stressed.

[0051] (3) Preparation of high-strength wear-resistant concrete for the outer layer

[0052] The outer layer of concrete is prepared using portland cement as the cementitious material, fine aggregate as quartz sand with a particle size of 0.3 - 1.2 mm, and coarse aggregate as steel slag with a particle size of 5 - 10 mm. To improve impermeability, compressive strength, and wear resistance, 1% - 3% nano-silica and 0.5% - 2% steel fibers are added. After all materials are stirred evenly, the viscosity is adjusted as needed, and the fluidity of the concrete is ensured to be suitable for construction. Finally, the mixture is poured into a mold, compacted, and vibrated to form the outer layer, and cured to ensure it reaches the expected strength and durability.

[0053] (4) Preparation of precast slabs

[0054] A hexagonal interlocking splicing mold is used for the production of precast slabs. The mold size is designed such that the side length of the hexagonal slab is 40 cm to 60 cm, and the thickness is 3 cm to 5 cm. First, the inner layer of polyurethane-based polymer adhesive is poured into the mold, and appropriately compacted and vibrated to ensure its density and uniformity. Then, the outer layer of high-strength concrete mixture is covered on the inner layer of adhesive to ensure good bonding between the two layers. After the concrete slab is poured, it is cured to ensure that the slab reaches the expected strength after hardening and improves durability.

[0055] (5) Laying of emulsified asphalt ultra-thin chip seal

[0056] Before laying the precast slabs, first clean the construction ground to ensure the ground is flat and clean. Then, lay the emulsified asphalt ultra-thin chip seal on the ground, using a sealant material mixed with 6 - 8% emulsified asphalt and ultra-thin chips (particle size 1.0 - 5 mm), and evenly lay it through mechanical equipment. The seal effectively enhances the bonding force between the inner layer of polyurethane-based polymer adhesive and the bottom surface, enhancing the durability and long-term stability of the pavement slab. After the seal is laid, it is cured to ensure it hardens and forms a firm bonding force with the ground.

[0057] (6) Rapid paving

[0058] After the emulsified asphalt seal construction is completed and cured in place, start laying the precast pavement slabs. Lay the precast slabs one by one on the processed ground according to the hexagonal splicing method as required by the design. Ensure the interfaces between the slabs are precise and the splicing is tight. Fill the splicing gaps with silicone sealant to enhance the interlayer bonding force, prevent water penetration, and improve structural stability. During the laying process, if it is found that individual slabs are uneven or misaligned, appropriate adjustments should be made to ensure the pavement is flat. After the pavement slabs are laid, on-site curing is carried out to ensure the strength and durability of the pavement slabs. Control the temperature and humidity during the curing period to avoid cracking or deformation.

[0059] Comparative Example 1

[0060] To verify the performance advantages of the bionic double-layer structured pavement slab of the present invention, a traditional single-layer high-strength concrete pavement slab was selected as the control group, and a comparative analysis was carried out on the mechanical properties, durability, construction convenience, etc. of the two.

[0061] (1) Preparation of the concrete for the comparative example

[0062] Under the same mix ratio, no polyurethane-based polymer binder was added, and the remaining construction processes were the same as those in Example 1.

[0063] (2) Comparison of the performance of the pavement slabs

[0064] Test item Example 1 Comparative example 1 Compressive strength (MPa) 125 95 Flexural strength (MPa) 16 9 Impact resistance (drop hammer impact failure height, cm) 120 55 <![CDATA[Wear resistance (volume wear rate cm 3 / 50cm 2 )]]> 0.35 0.75

[0065] Performance comparison

[0066] (1) Compressive strength: The compressive strength of the example of the present invention is 125 MPa, which is significantly higher than 95 MPa of the comparative example, an increase of about 31.6%. This result shows that through the rigid-flexible combination design of the bionic double-layer structure, the load-bearing capacity of the pavement slab is enhanced, enabling it to withstand higher pressures and external loads and meet the heavy-load requirements in the long-term use environment.

[0067] (2) Flexural strength: The flexural strength of the example reaches 16 MPa, which is significantly higher than 9 MPa of the comparative example, an increase of about 77.8%. This increase indicates that the double-layer structure design significantly improves the flexural capacity of the pavement slab. Especially when facing bending or deformation, the synergistic effect of the outer hard layer and the inner soft layer enables the pavement slab to better resist deformation and extend its service life.

[0068] (3) Abrasion resistance: The volume wear rate of the pavement slab in the example is 0.35 cm 3 / 50 cm 2 , while that of the single-layer structured pavement slab in the comparative example is 0.75 cm 3 / 50 cm 2 , and the wear rate is reduced by about 53.3%. This result shows that the outer ultra-high-strength concrete of the double-layer structure has remarkable wear resistance. Under long-term traffic loads and environmental abrasion, it can effectively maintain the integrity of the pavement slab and reduce maintenance costs.

[0069] (4) Impact resistance: The pavement slab of the present invention can withstand a drop hammer impact height of 120 cm, while the pavement slab of the comparative example can only withstand 55 cm, an increase of about 118.2%. This shows that the double-layer structure has remarkable advantages in impact resistance. The high-toughness material inside effectively absorbs and disperses the impact energy, reduces the occurrence of cracks, and thus enhances the stability and durability of the pavement slab under stress.

Claims

1. A composite double-layer structural pavement slab based on biomimetic snail shell structure and its rapid paving method, characterized in that, It includes an outer layer and an inner layer; the outer layer is composed of portland cement, quartz sand with a particle size of 0.3 - 1.2 mm, steel slag with a particle size of 5 - 10 mm, steel fibers and nano-silica; the inner layer is composed of a two-component polyurethane adhesive and polyvinyl alcohol fibers, and the two-component polyurethane adhesive includes isocyanate (Component A) and polyol (Component B).

2. The composite double-layer structural road slab according to claim 1, wherein, In the outer layer, the dosage of nano-silica is 1% - 3%, and the dosage of steel fibers is 0.5% - 2%.

3. The composite double-layer structural road slab according to claim 1, wherein, In the inner layer, the mass ratio of Component A to Component B of the two-component polyurethane adhesive is 5:1, and the dosage of polyvinyl alcohol fibers is 0.5% - 1%.

4. The composite double-layer structural road slab according to claim 1, characterized in that, The composite double-layer structural pavement slab further includes an emulsified asphalt ultra-thin crushed stone seal coat, and the seal coat is composed of 6 - 8% emulsified asphalt and ultra-thin crushed stone with a particle size of 1.0 - 5 mm.

5. A rapid paving method for a composite double-layer structural pavement slab bionic based on the snail shell structure, characterized in that, It includes the following steps: (1) Prepare the inner layer material, react isocyanate with polyol to form a polyurethane prepolymer, add polyvinyl alcohol fibers to enhance toughness, and after mixing with a curing agent, pour it into a mold, compact and cure it. (2) Prepare the outer layer material, mix portland cement, quartz sand, steel slag, steel fibers and nano-silica evenly, pour it into a mold, compact and cure it. (3) Combine the outer layer and inner layer materials into a precast slab. (4) Lay an emulsified asphalt ultra-thin crushed stone seal coat on the ground: (5) Lay the precast slabs on the ground in a hexagonal splicing manner, fill the splicing gaps with silicone sealant, and ensure that the sealant fully penetrates into the interior of the splicing gaps to improve the sealing performance and durability of the joints.

6. The rapid paving method according to claim 5, characterized in that The side length of the precast slab is 40 cm to 60 cm, and the thickness is 3 cm to 5 cm.

7. The rapid paving method according to claim 5, characterized in that The emulsified asphalt ultra-thin crushed stone seal coat is used to enhance the bonding force between the inner layer and the ground.

Images