Bridge head apron combined fiber anti-cracking flexible splicing structure and preparation method thereof

Abstract

The present application relates to the technical field of road engineering, and particularly relates to a bridge-head cover plate combined fiber anti-cracking flexible splicing structure and a preparation method thereof, which comprises a base layer with an asphalt pavement part on the top and an abutment; the base layer, the abutment and the asphalt pavement part form a groove, the side wall of the groove is formed by the asphalt pavement part, the bottom wall of the groove is formed by the base layer and the abutment; the inner wall of the groove is coated with a two-component high-viscosity high-elasticity interface adhesive; from bottom to top, the groove is sequentially filled with a high polymer elastic body and a reinforced anti-cracking asphalt mixture; a basalt fiber bar anchoring member is pre-buried in the inner wall of the groove, and the high polymer elastic body and the reinforced anti-cracking asphalt mixture wrap the basalt fiber bar anchoring member; through the stress diffusion of the interface adhesive layer, the deformation buffer of the flexible bottom layer and the anti-cracking cooperation of the rigid surface layer, the road surface longitudinal slope mutation caused by the differential settlement of the abutment and the base layer is effectively relieved, the vehicle jumping impact force is reduced, the road surface longitudinal corner is reduced, and the driving smoothness and the structural durability are significantly improved.

Description

Technical Field

[0001] This invention relates to the technical field of road engineering, and in particular to a composite fiber-reinforced crack-resistant flexible splicing structure for bridge approach slabs and its preparation method. Background Technology

[0002] In practical engineering, due to significant differences in the structural form, material properties, and stress patterns of bridges and roadbeds, uneven vertical settlement is inevitable. This uneven settlement creates noticeable misalignments at the bridge abutments, causing vehicles to experience bumps and bounces when driving through this area—the so-called "bridge approach slab" phenomenon. Prolonged bridge approach slabs accelerate damage to road and bridge structures, shorten their lifespan, and increase maintenance and repair costs. Furthermore, bridge approach slabs can pose traffic safety hazards, especially at high speeds, increasing the risk of vehicle bumps and loss of control, and easily leading to traffic accidents. To alleviate the bridge approach slab problem, the traditional approach is to install bridge approach slabs. As a transition structure, bridge approach slabs can reduce the settlement difference between the bridge and the roadbed to some extent, reducing the bumps experienced by vehicles.

[0003] Traditional bridge approach slabs are mostly rigid structures with poor adaptability to deformation. When there is a significant difference in settlement between the bridge and the roadbed, rigid approach slabs cannot effectively adapt to this deformation, easily leading to stress concentration at the connection between the approach slab and the bridge or roadbed, resulting in damage such as cracks and fractures. This damage not only weakens the load-bearing capacity of the approach slab but also further exacerbates the "bridge approach slab settlement" problem.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the present invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] The first objective of this invention is to provide a composite fiber-reinforced crack-resistant flexible splicing structure for bridge abutment slabs. Through the synergistic effect of stress diffusion in the interfacial bonding layer, deformation buffering of the flexible bottom layer, and crack resistance of the rigid surface layer, it effectively alleviates the abrupt change in road longitudinal slope caused by differential settlement between the abutment and the base layer, reduces the impact force of vehicle bounce, reduces the longitudinal angle of the road surface, and significantly improves driving smoothness and structural durability.

[0006] The present invention discloses a composite fiber-reinforced crack-resistant flexible splicing structure for bridge approach slabs, comprising a base layer with an asphalt pavement section on top and a bridge abutment; the base layer, bridge abutment, and asphalt pavement section form a groove, the asphalt pavement section forms the sidewall of the groove, and the base layer and bridge abutment form the bottom wall of the groove;

[0007] The inner wall of the groove is coated with a two-component high-viscosity and high-elasticity interfacial adhesive;

[0008] From bottom to top, the groove is filled sequentially with polymer elastomeric toughness and reinforced crack-resistant asphalt mixture;

[0009] Basalt fiber reinforcement anchoring components are pre-embedded in the inner wall of the slot, and the basalt fiber reinforcement anchoring components are wrapped with polymer elastic toughness and reinforced crack-resistant asphalt mixture.

[0010] Both the polymer elastomeric toughening agent and the reinforced crack-resistant asphalt mixture contain fiber mesh layers;

[0011] The splicing structure of this invention utilizes the asphalt pavement as the sidewall of the groove and the base layer and abutment as the bottom wall, forming an open connection area. This provides geometric space for the flexible filling of the polymer elastomeric material and the reinforced crack-resistant asphalt mixture. Unlike the fixed connection of traditional rigid slabs, this groove allows the material to absorb uneven settlement of the bridge and subgrade through its own deformation, avoiding stress concentration caused by excessive stiffness. An adhesive is applied to the inner wall of the groove to form a rigid-flexible transition interface, firmly bonding the rigid base layer and abutment with the flexible filling material. When settlement occurs, the high elasticity of the adhesive can buffer the interface stress, preventing interlayer delamination and crack initiation caused by material stiffness differences in traditional rigid slabs. At the same time, both the polymer elastomeric material and the reinforced crack-resistant asphalt mixture filled in the groove have flexible deformation capabilities, which can adapt to settlement through internal micro-deformation of the material. Furthermore, the pre-embedded basalt fiber reinforcement anchoring components, after being wrapped by the filling material, form mechanical anchor points, dispersing local settlement stress to the entire structural layer. The fiber mesh layer further constrains material deformation through tensile strength, preventing crack propagation.

[0012] As a preferred embodiment of the present invention, the polymer elastomeric material comprises polymer-modified asphalt, basalt crushed stone, filler and functional additives, in a mass ratio of 30-50:90-110:1-1.5:0.5-1.3;

[0013] The basalt gravel has a single particle size, ranging from 15 to 20 mm.

[0014] Basalt crushed stone uses a single particle size of 15-20mm. The uniform particle size forms a stable skeleton structure, ensuring that the internal pores of the polymer elastic toughness are evenly distributed. This facilitates the full encapsulation of crushed stone particles by polymer-modified asphalt and other binding materials, forming a continuous and dense elastic support system. The single particle size reduces the risk of stress concentration between particles of different sizes, improves the overall deformation coordination of the material, and enables the polymer elastic toughness to absorb and disperse deformation energy more evenly when there is uneven settlement between the bridge and the roadbed. This avoids internal structural failure caused by complex aggregate gradation, thereby enhancing the flexibility, fatigue resistance and long-term service performance of the spliced ​​structure, and effectively alleviating the problem of bridge approach slab settlement.

[0015] As a preferred embodiment of the present invention, the polymer-modified asphalt comprises, by weight, 90-110 parts of base asphalt, 6-8 parts of polyurethane elastomer, 4-5 parts of star-shaped SBS, 3-5 parts of 40-mesh waste tire rubber powder, and 0.5-1.0 parts of nano-silica phase change microcapsules; the polyurethane elastomer imparts ultra-high resilience to the material, enabling rapid release of deformation energy and adaptation to short-term impact loads; the star-shaped SBS forms a three-dimensional cross-linked network through its star-shaped topology, enhancing viscoelasticity and absorbing periodic vibration energy; the added waste tire rubber powder introduces the plastic dissipation capacity of the rubber particles, inhibiting crack propagation; the nano-silica phase change microcapsules rupture under stress, releasing nano-SiO2, filling microcracks and triggering local hardening, forming an adaptive repair mechanism;

[0016] More specifically, the base asphalt includes No. 70 road petroleum asphalt and Indonesian natural rock asphalt in a mass ratio of 7-8.5:2. At high temperatures, the high-hardness mineral skeleton of natural rock asphalt and the flexible matrix of petroleum asphalt form a rigid-flexible interlocking structure, which inhibits the thermal motion of asphalt molecules, reduces high-temperature flow and permanent deformation. At low temperatures, the low viscosity components of petroleum asphalt alleviate the brittleness of natural rock asphalt, maintain structural flexibility, and reduce the risk of low-temperature shrinkage cracking. This allows the modified asphalt to maintain good mechanical properties in the temperature range of -20℃ to 60℃, adapting to repeated deformations caused by temperature changes and vehicle loads at the bridge abutment.

[0017] The filler consists of 2-3 parts of carbon nanotube modified silicate whiskers and 1.5-2.5 parts of activated sodium bentonite, which enhances the skeleton structure and interfacial bonding, thereby improving the material density and crack resistance.

[0018] The functional additives include 0.3-0.6 parts of bio-based epoxy resin, 0.5-0.8 parts of composite hindered phenol / phosphite, 0.2-0.4 parts of graphene lignin, and 0.8-1.2 parts of microencapsulated asphalt regenerator. The bio-based epoxy resin reacts with the polyurethane prepolymer to form an interpenetrating network, which improves chemical corrosion resistance. The composite hindered phenol / phosphite provides dual-mechanism antioxidant protection, extending the high-temperature service life. The microencapsulated asphalt regenerator releases regenerator under pressure, replenishing the components lost due to asphalt aging. The graphene lignin can work synergistically with the microencapsulated regenerator. The lightweight components released by the regenerator preferentially wet the lignin pores, restoring the rheological properties of aged asphalt.

[0019] The polymer elastomeric elastomer of this invention forms an elastic support system with multiple synergistic effects: the matrix asphalt composite polyurethane elastomer, star-shaped SBS, and waste tire rubber powder construct a high-toughness elastic network skeleton, endowing the material with excellent deformation absorption capacity, while carbon nanotube-modified silicate whiskers and activated sodium-based bentonite are uniformly dispersed in the elastic matrix as rigid fillers, forming a rigid-flexible interpenetrating structure. This structure not only limits excessive deformation through the rigid skeleton formed by basalt fragments, but also alleviates stress concentration with the help of the elastic matrix, significantly improving crack resistance; nano-silica phase transition The combination of microcapsules and graphene lignin regulates temperature sensitivity while suppressing volume changes caused by local temperature differences through the thermal conductivity uniformity of graphene. Combined with microencapsulated asphalt regenerator, it achieves the dual functions of temperature adaptability and self-repair, and can dynamically repair early micro-damage. Bio-based epoxy resin strengthens the interfacial adhesion between components and avoids the delamination failure of fillers and matrix. The composite hindered phenol / phosphite delays the aging process of the entire system through a synergistic antioxidant mechanism, so that the material maintains stable mechanical properties and interfacial compatibility during long-term service.

[0020] As a preferred embodiment of the present invention, the fiber-reinforced crack-resistant asphalt mixture comprises polymer-modified asphalt, composite crushed stone and reinforcing fibers, with a mass ratio of 10-30:92-105:0.3-0.55;

[0021] By weight, the composite crushed stone comprises 60-75 parts of 9.5-13.2mm angular crushed stone, 20-30 parts of 2.36-4.75mm diabase sand, and 8-15 parts of 0.075-0.6mm activated coal gangue powder. The 9.5-13.2mm angular crushed stone serves as coarse aggregate, forming a high-strength skeleton structure. Its angular characteristics enhance the interlocking effect between particles, providing the upper layer with the main shear strength and load-bearing capacity, resisting compressive stress and shear deformation caused by vehicle loads. The 2.36-4.75mm diabase sand... Green rock sand fills the gaps between coarse aggregates. Its high strength and wear resistance further optimize the gradation density, reduce porosity, and improve the overall structure's compressive strength and resistance to water damage. 0.075-0.6mm activated coal gangue powder is used as a fine filler. After activation treatment, its surface activity is enhanced, forming a stronger physical adsorption and chemical bond with the asphalt binder. It not only fills the micropores and stabilizes the asphalt structure, but also reduces the high-temperature fluidity and low-temperature brittleness of the mixture. At the same time, the pozzolanic activity of coal gangue participates in the cementing reaction for a long time, enhancing durability.

[0022] When uneven settlement occurs at the bridgehead, the coarse aggregate skeleton adapts to deformation through inter-particle sliding, avoiding rigid fracture, while the bonding effect between the fine filler and asphalt limits excessive displacement and prevents rapid crack propagation, thus possessing both rigidity and flexible deformation capacity when subjected to dynamic loads.

[0023] The reinforcing fibers include 0.15-0.25 parts of copper-plated basalt chopped fibers, 0.10-0.20 parts of sawtooth polyester fibers, and 0.05-0.10 parts of carbon nanotube-grafted basalt fibers. The nanoscale carbon nanotube-grafted basalt fibers adsorb asphalt molecules due to their high specific surface area, improving the toughness of the binder and reducing the initiation of microcracks inside the asphalt matrix at the micro level. The micron-sized copper-plated basalt chopped fibers and millimeter-sized sawtooth polyester fibers strengthen the interfacial bond between aggregate and asphalt and inhibit peeling damage at the micro level through high-strength bridging and sawtooth mechanical interlocking, respectively. At the macro level, they bridge visible cracks and prevent their propagation. Together, the three fibers construct a multi-level crack-resistant mechanism covering the entire process of microcrack initiation, microfacial damage, and macrocrack propagation, significantly improving the crack resistance of the material.

[0024] Fiber-reinforced crack-resistant asphalt mixture, as the upper structure, utilizes the synergistic effect of a dense skeleton formed by composite crushed stone and reinforcing fibers. It can resist rutting deformation caused by vehicle loads with the rigid skeleton of coarse aggregate, and alleviate tensile / shear stress caused by uneven settlement through the toughening mechanism of fibers. During settlement deformation, it absorbs energy through multiple mechanisms of skeleton sliding, fiber bridging and plastic deformation of cementitious material, reducing cracks and potholes. It forms a rigid-flexible transition system with the lower polymer elastic toughness, which is flexible at the bottom and rigid at the top. The lower layer absorbs large settlement displacement of the foundation, while the upper layer rigidly bears the load and restricts excessive deformation, realizing interlayer synergistic stress distribution to avoid stress concentration.

[0025] As a preferred embodiment of the present invention, basalt fiber reinforced anchor components are symmetrically installed on the side walls and bottom walls, as shown in the figure. The basalt fiber reinforced anchor components include a main body and pointed tips at both ends of the main body, and are generally shaped like a door. They are installed on the side walls or bottom walls through the pointed tips. The basalt fiber reinforced anchor components on the bottom walls are respectively fixed to the abutment and the base layer. The same basalt fiber reinforced anchor component is not connected to the abutment and the base layer.

[0026] Among them, the upper and lower anchoring positions of the basalt fiber reinforcement anchoring members on the side wall are close to the top and bottom of the side wall, respectively;

[0027] Basalt fiber reinforced anchor components are symmetrically embedded in the sidewalls and bottomwalls of the groove. Through a bidirectional anchoring layout with the upper and lower ends close to the top and bottom of the sidewalls and an array distribution on the bottom wall, a network of mechanical anchor points is formed. This evenly transfers the uneven settlement stress between the abutment and the road layer to the polymer elastomeric toughening agent and the reinforced crack-resistant asphalt mixture, avoiding stress concentration at the interface. The basalt fiber reinforced anchor components use high-strength basalt fiber bundles as the base material, which are resin-impregnated and pultruded to form regularly shaped reinforcing bars. Their surfaces are roughened by sandblasting or scored to enhance mechanical bonding with the polymer elastomeric toughening agent and the reinforced crack-resistant asphalt mixture. The interlocking force is achieved by symmetrically embedding components on the side and bottom walls of the slot. The upper and lower ends of the side wall components are close to the asphalt pavement at the top of the slot and the interface of the polymer elastomeric tough body at the bottom, respectively. The bottom wall components are distributed in an array at a horizontal spacing of 300mm, forming a two-way anchoring-symmetrical support system. With the high tensile strength and low elastic modulus of basalt fiber, this component, wrapped in the slot filling material, evenly transfers the settlement stress of the bridge and subgrade to the entire splicing structure. At the same time, through synergy with the fiber mesh layer, it inhibits interface peeling and crack propagation, significantly improving the overall mechanical performance and deformation coordination of the bridge approach slab.

[0028] As a preferred embodiment of the present invention, the fiber mesh layer is formed by bidirectional orthogonal weaving of copper-plated basalt long fibers with a diameter of 15-20μm (warp / weft ratio 3:2) to form a base mesh (single hole size 20×20mm), and the mesh body is impregnated with two-component epoxy resin (coating amount 200-300g / m). 2 It is grafted with silicon carbide particles with a particle size of 50-80nm (coverage rate 18-22%), and simultaneously composited with 12-15% by weight of shape memory polyurethane fiber in each meter of grid line;

[0029] The 3:2 bidirectional orthogonal weaving, through directional reinforcement design, makes the warp fiber density higher, matching the main stress direction in structures such as bridges, forming a regular grid rigid support system. The 20×20mm single hole size can effectively limit aggregate displacement in asphalt mixtures and avoid stress concentration caused by excessively small hole diameters. The geometric structure further solidifies the mechanical transmission capacity of the rigid skeleton.

[0030] Copper plating enhances the interfacial adhesion with the asphalt matrix; two-component epoxy resin impregnation wraps the fiber surface, mitigating modulus differences and forming a flexible transition layer; grafting 50-80nm silicon carbide particles enhances surface hardness and thermal conductivity through nano-reinforcement, suppressing interfacial delamination and local temperature rise; simultaneously, 12-15% by mass of shape memory polyurethane fiber is composited, giving the mesh the ability to recover tension after deformation, complementing the rigidity and flexibility of basalt fiber. Under vehicle loads and foundation settlement, stress is dispersed and crack propagation is suppressed through multiple mechanisms of rigid support, flexible energy dissipation, and memory reset. At the same time, the interlayer synergistic deformation ability of the mesh, polymer elastomeric toughness, and fiber-reinforced crack-resistant asphalt mixture is optimized, significantly improving the structural crack resistance and long-term service stability.

[0031] As a preferred embodiment of the present invention, a fiber mesh layer is provided in the fiber-reinforced crack-resistant asphalt mixture, and the fiber mesh layer is located at 2 / 3 depth of the fiber-reinforced crack-resistant asphalt mixture. More specifically, the fiber mesh layer is combined with the fiber-reinforced crack-resistant asphalt mixture through a hot-pressing process at 160-165℃, and the pretension of the wire is controlled in the range of 10-12kN / m in the longitudinal direction and 6-8kN / m in the transverse direction.

[0032] The fiber mesh layer is positioned at 2 / 3 of the depth of the fiber-reinforced crack-resistant asphalt mixture, precisely located in the area of ​​maximum tensile stress distribution caused by vehicle loads (middle and lower layers). This depth layout achieves precise crack resistance through stress peak matching and interlayer synergistic reinforcement: On the one hand, the fiber mesh layer can directly intercept fatigue cracks (such as shear cracks caused by the deformation of polymer elastomeric toughness) extending upwards from the lower layer, using the high-strength bridging effect of basalt fibers to prevent cracks from penetrating to the surface; on the other hand, the 2 / 3 depth allows the mesh to balance the compressive stress bearing capacity of the upper asphalt surface layer and the deformation coordination of the lower flexible structure. Through longitudinal pretension of 10-12kN / m and transverse pretension of 6-8kN / m and interfacial bonding formed by hot pressing, the load stress is evenly distributed throughout the mixture layer, avoiding internal cracking and surface cracking caused by stress concentration in traditional upper structures. At the same time, it optimizes the interlayer stiffness transition, improving rutting resistance and long-term service reliability.

[0033] In a preferred embodiment of the present invention, a double-layer fiber mesh layer is provided within the polymer elastic toughness body, and the two fiber mesh layers divide the polymer elastic toughness body into three parts. The lower layer of the polymer elastic toughness body directly bears the tensile / bending stress caused by uneven settlement of the foundation and the shear stress transmitted by the upper asphalt surface layer. The double-layer fiber mesh layer achieves precise protection through the functional division of the upper and lower layers: the upper fiber mesh layer mainly resists the interlayer shear force and lateral horizontal stress generated by vehicle loads, and its basalt fiber skeleton with a warp / weft ratio of 3:2 can quickly disperse the lateral thrust brought by wheel loads, combined with 200-300g / m 2An epoxy resin impregnation layer enhances interfacial adhesion, preventing the elastomeric material from peeling off from the upper asphalt layer due to excessive shear deformation. The lower mesh fiber layer focuses on the longitudinal tensile and bending stresses caused by foundation settlement or freeze-thaw deformation. The bidirectional orthogonally woven 20×20mm single-hole structure provides rigid support, limiting excessive stretching of the elastomeric material. At the same time, shape memory polyurethane fibers, accounting for 12-15% by mass, compensate for minor displacements of the foundation through elastic recovery, reducing the risk of cracks extending from the foundation to the upper layers.

[0034] As a preferred embodiment of the present invention, the two-component high-viscosity and high-elasticity interfacial adhesive comprises, by weight, 40-50 parts epoxy resin, 30-40 parts polyurethane prepolymer, 3-5 parts nano-silica, 1.5-2.5 parts carbon nanotubes / graphene oxide, 8-12 parts core-shell elastomer, 1.2-1.8 parts silane coupling agent, 0.3-0.5 parts light stabilizer, 1.5-2.0 parts flame retardant, 0.8-1.2 parts microcapsule corrosion inhibitor, and 10-15 parts microcapsule curing agent. Through the synergistic effect of nanoparticle penetration and chemical bonding, a rigid-flexible gradient transition interface is formed.

[0035] Epoxy resin and polyurethane prepolymer form a rigid-flexible complementary bonding matrix. Core-shell elastomers enhance impact resistance and toughness. Nano-silica and carbon nanotubes / graphene oxide improve density and interfacial adhesion through cross-scale reinforcement. Silane coupling agents achieve chemical bonding between the substrate and the adhesive. Light stabilizers and flame retardants enhance environmental adaptability. Microencapsulated corrosion inhibitors and curing agents provide self-healing and long-term protection functions. Under the synergistic effect of each component, the interfacial layer formed by the two-component high-viscosity and high-elasticity interfacial adhesive can not only effectively disperse the shear stress caused by the differential settlement through the elastic modulus gradient transition, but also improve the bonding strength by 40% and the weather resistance by 50% through nanoparticle penetration, chemical bonding and microencapsulation technology. It also has the ability to self-heal cracks and inhibit substrate corrosion, becoming a seamless transition layer between rigid and flexible materials with stable mechanical properties for long-term service, fundamentally solving the problems of stress concentration, bonding failure and durability of traditional interfaces.

[0036] A second objective of this invention is to provide a method for preparing the aforementioned composite fiber-reinforced crack-resistant flexible splicing structure for bridge abutment slabs, comprising:

[0037] Make the groove and clean and dry the inner wall of the groove;

[0038] More specifically, the process includes the following steps: accurately locate the position on-site according to the predetermined location and design width, draw the cutting line position on the asphalt surface layer, use an integrated cutting-dust collection device to cut and remove the asphalt surface layer to the design width and depth, and the remaining asphalt surface layer forms the asphalt pavement section; the groove edge line should be straight and aesthetically pleasing, clean the groove with a high-pressure cleaning tool, clean the bridge abutment and base layer, dry the groove opening with an instant heating machine to ensure the dryness of the bonding surface, and clean the working surface until it is clean, dry, and the bottom surface is flat;

[0039] A two-component high-viscosity and high-elasticity interface adhesive is applied to the inner wall of the trench. Basalt fiber reinforcement anchor components are pre-embedded in the side walls and bottom wall of the trench. The upper and lower ends of the basalt fiber reinforcement anchor components are 20-30mm away from the top and bottom of the trench, respectively, and are arranged in a 300mm array at horizontal spacing. More specifically, the basalt fiber reinforcement anchor components are fixed with M20 chemical anchors with an implantation depth of ≥250mm and an exposed length that matches the thickness of the polymer elastic toughness and fiber-reinforced crack-resistant asphalt mixture.

[0040] Mix the polymer elastomeric material, lay it into the trench, arrange two layers of fiber mesh at equal intervals, and compact it.

[0041] Mix the fiber-reinforced crack-resistant asphalt mixture, pave it onto the polymer elastic toughness, lay a layer of fiber mesh, and compact it.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows: 1) The present invention breaks through the deformation limitations of traditional rigid slabs by using an open slot structure and a rigid-flexible combined filling system: the slot space formed by the asphalt pavement, base course and abutment provides flexible deformation space for polymer elastic toughness and reinforced crack-resistant asphalt mixture, allowing the material to absorb uneven settlement of bridge and subgrade through its own elasticity and plastic deformation; the two-component high-viscosity and high-elasticity interface adhesive on the inner wall of the slot forms a rigid-flexible gradient transition layer, which firmly bonds the base course and abutment with the flexible filling material. Its high elasticity can buffer the interface shear stress and avoid interlayer delamination caused by sudden change in stiffness in traditional rigid connection; the pre-embedded basalt fiber reinforcement anchoring component and the filling material wrapping form a mechanical anchor point network, which evenly disperses the local settlement stress to the entire structural layer. Combined with the double-layer fiber mesh layer and the upper single-layer mesh layer in the polymer elastic toughness, the rigid skeleton constraint + flexible energy dissipation synergistic mechanism prevents cracks from extending from the foundation to the road surface, and eliminates the core cause of bridge approach slab settlement - stress concentration and interface failure caused by differential settlement from the structural design level;

[0043] 2) The polymer elastomeric matrix forms a stable skeleton through single-size basalt crushed stone, combined with polymer-modified asphalt to construct a high-toughness elastic network. It can limit excessive deformation through the crushed stone skeleton and absorb settlement energy through the elastic matrix, maintaining stable mechanical properties in the temperature range of -20℃ to 60℃. The reinforced crack-resistant asphalt mixture forms a dense skeleton with multi-graded composite crushed stone, combined with a multi-scale reinforcement system composed of copper-plated basalt chopped fibers, sawtooth polyester fibers, and carbon nanotube grafted fibers. It achieves three-level crack resistance: micro-cementitious toughening, micro-interface strengthening, and macro-crack bridging, effectively resisting rutting and fatigue cracking caused by vehicle loads. The combination of the two forms a layered synergy of soft bottom and rigid top: the lower layer is flexible to absorb large displacements of the foundation, while the upper layer is rigid to bear and limit excessive surface deformation, improving the deformation coordination capacity by more than 3 times compared with traditional rigid slabs. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the composite fiber crack-resistant flexible splicing structure for bridge approach slabs of the present invention;

[0045] Figure 2 This is a top view of the fiber mesh layer;

[0046] The following are labeled in the attached diagram: 1. Base course; 2. Abutment; 3. Fiber mesh layer; 4. Polymer elastic toughening agent; 5. Two-component high-viscosity and high-elasticity interfacial adhesive; 6. Fiber-reinforced crack-resistant asphalt mixture; 7. Basalt fiber reinforced anchoring component; 8. Asphalt pavement section. Detailed Implementation

[0047] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0048] Example 1:

[0049] Materials preparation:

[0050] Two-component high-viscosity and high-elasticity interfacial adhesive 5: By weight, prepare 45 parts epoxy resin, 35 parts polyurethane prepolymer, 4 parts nano silica, 2 parts carbon nanotube / graphene oxide, 10 parts core-shell elastomer, 1.5 parts silane coupling agent, 0.4 parts light stabilizer, 1.8 parts flame retardant, 1 part microcapsule corrosion inhibitor and 12 parts microcapsule curing agent.

[0051] Polymer elastomeric 4:

[0052] Polymer-modified asphalt: 100 parts of base asphalt (70-grade road petroleum asphalt and Indonesian natural rock asphalt, with a mass ratio of 8:2), 7 parts of polyurethane elastomer, 4.5 parts of star-shaped SBS, 4 parts of 40-mesh waste tire rubber powder, and 0.8 parts of nano-silica phase change microcapsules.

[0053] Basalt crushed stone: 100 parts of basalt crushed stone with a single particle size of 15-20mm;

[0054] Filler: 2.5 parts carbon nanotube modified silicate whiskers and 2 parts activated sodium bentonite;

[0055] Functional additives: 0.5 parts of bio-based epoxy resin, 0.7 parts of composite hindered phenol / phosphite, 0.3 parts of graphene lignin, and 1 part of microencapsulated asphalt regenerator.

[0056] Fiber-reinforced crack-resistant asphalt mixture 6:

[0057] Polymer-modified bitumen: Same as the polymer-modified bitumen formulation in polymer elastomer 4;

[0058] Composite crushed stone: 70 parts of 9.5-13.2mm angular crushed stone, 25 parts of 2.36-4.75mm diabase sand, and 12 parts of 0.075-0.6mm activated coal gangue powder;

[0059] Reinforcing fibers: 0.2 parts copper-plated basalt chopped fiber, 0.15 parts sawtooth polyester fiber and 0.08 parts carbon nanotube-grafted basalt fiber.

[0060] Basalt fiber reinforced anchoring component 7: A gate-shaped component made of high-strength basalt fiber bundles as the base material, through resin impregnation and pultrusion molding process, and the surface is sandblasted to roughen it.

[0061] Fiber mesh layer 3: The base mesh (single hole size 20×20mm) is formed by bidirectional orthogonal weaving of 18μm diameter copper-plated basalt fibers (warp / weft ratio 3:2). The mesh body is impregnated with two-component epoxy resin (coating amount 250g / m²). 2 It is grafted with 60nm silicon carbide particles (20% coverage) and simultaneously composited with 13% by weight of shape memory polyurethane fiber in each meter of grid line.

[0062] A method for preparing a composite fiber-reinforced crack-resistant flexible splicing structure for bridge abutment slabs includes:

[0063] S1 is precisely positioned on-site according to the predetermined location and design width. The cutting line is drawn on the asphalt surface. The asphalt surface is cut and removed to the design width and depth using an integrated cutting and dust collection device. The remaining asphalt surface forms the asphalt pavement section 8, ensuring that the groove edge line is straight and aesthetically pleasing. The groove depth is 10cm and the width is 30cm.

[0064] S2 uses a high-pressure cleaning tool to clean the groove, remove the bridge abutment 2 and base layer 1, and then uses an instant heating machine to dry the groove opening to ensure the bonding surface is dry. Clean the working surface until it is clean, dry and the bottom surface is flat.

[0065] S3 applies a high-viscosity, high-elasticity interface adhesive to the inner wall of the groove. According to the previously prepared formula, the components are thoroughly mixed and stirred evenly, and then evenly applied to the side walls and bottom wall of the groove using special equipment. The coating amount is 3-4 kg / m2.

[0066] S4 pre-embeds basalt fiber reinforced anchor components 7 on both sides and bottom wall of the trench. The upper and lower ends of the basalt fiber reinforced anchor components 7 are 25mm away from the top and bottom of the trench, respectively. The horizontal spacing is arranged in an array of 300mm. M20 chemical anchors are used for fixing. The implantation depth is ≥250mm. The exposed length is adapted to the thickness of the polymer elastic toughness 4 and the fiber-reinforced crack-resistant asphalt mixture 6. The basalt fiber reinforced anchor components 7 on the bottom wall are fixed on the abutment 2 and the base layer 1 respectively. The same basalt fiber reinforced anchor component 7 is not connected to the abutment 2 and the base layer 1.

[0067] S5 adds polymer-modified asphalt, basalt crushed stone, filler and functional additives into the asphalt mixing equipment at a mass ratio of 40:100:1.2:0.8. First, the base asphalt is heated to an appropriate temperature, and then polyurethane elastomer, star-shaped SBS, 40-mesh waste tire rubber powder and nano silica phase change microcapsules are added for modification to produce polymer-modified asphalt. Then, basalt crushed stone, filler and functional additives are added in sequence and stirred thoroughly.

[0068] S6. The mixed polymer elastic toughness 4 is laid into the groove, and two layers of fiber mesh 3 are arranged at equal intervals. The two layers of fiber mesh 3 divide the polymer elastic toughness 4 into three parts. After the laying is completed, it is compacted with a tamping device.

[0069] S7 adds polymer-modified asphalt, composite crushed stone, and reinforcing fibers to an asphalt mixing plant at a mass ratio of 20:98:0.4, and then mixes them thoroughly. The mixed fiber-reinforced crack-resistant asphalt mixture 6 is then laid on the polymer elastic toughness body 4. A fiber mesh layer 3 is arranged at 2 / 3 depth of the fiber-reinforced crack-resistant asphalt mixture 6. The fiber mesh layer 3 is bonded to the fiber-reinforced crack-resistant asphalt mixture 6 through a 162℃ hot-pressing process. The pretension of the wire is controlled within the range of 11kN / m in the longitudinal direction and 7kN / m in the transverse direction. After paving, the mixture is compacted using a tamping device.

[0070] Example 2:

[0071] Materials preparation:

[0072] Two-component high-viscosity and high-elasticity interfacial adhesive 5: By weight, prepare 42 parts of epoxy resin, 38 parts of polyurethane prepolymer, 3.5 parts of nano-silica, 2.2 parts of carbon nanotube / graphene oxide, 11 parts of core-shell elastomer, 1.6 parts of silane coupling agent, 0.35 parts of light stabilizer, 1.7 parts of flame retardant, 0.9 parts of microcapsule corrosion inhibitor and 13 parts of microcapsule curing agent.

[0073] Polymer elastomeric 4:

[0074] Polymer-modified asphalt: 95 parts of base asphalt (70# road petroleum asphalt and Indonesian natural rock asphalt, mass ratio 7.5:2), 6.5 parts of polyurethane elastomer, 4.2 parts of star-shaped SBS, 3.8 parts of 40-mesh waste tire rubber powder, and 0.7 parts of nano-silica phase change microcapsules; Basalt crushed stone: 105 parts of basalt crushed stone with a single particle size of 15-20mm;

[0075] Filler: 2.2 parts of carbon nanotube modified silicate whiskers and 2.3 parts of activated sodium bentonite;

[0076] Functional additives: 0.4 parts of bio-based epoxy resin, 0.6 parts of composite hindered phenol / phosphite, 0.25 parts of graphene lignin, and 0.9 parts of microencapsulated asphalt regenerator.

[0077] Fiber-reinforced crack-resistant asphalt mixture 6:

[0078] Polymer-modified bitumen: Same as the polymer-modified bitumen formulation in polymer elastomer 4;

[0079] Composite crushed stone: 68 parts of 9.5-13.2mm angular crushed stone, 28 parts of 2.36-4.75mm diabase sand, and 10 parts of 0.075-0.6mm activated coal gangue powder;

[0080] Reinforcing fibers: 0.18 parts of copper-plated basalt chopped fiber, 0.16 parts of sawtooth polyester fiber, and 0.07 parts of carbon nanotube-grafted basalt fiber.

[0081] Basalt fiber reinforced anchoring component 7: A gate-shaped component made of high-strength basalt fiber bundles as the base material, through resin impregnation and pultrusion molding process, and the surface is sandblasted to roughen it.

[0082] Fiber mesh layer 3: The base mesh (single hole size 20×20mm) is formed by bidirectional orthogonal weaving of 17μm diameter copper-plated basalt long fibers (warp / weft ratio 3:2). The mesh body is impregnated with two-component epoxy resin (coating amount 230g / m). 2 It is grafted with 70nm silicon carbide particles (19% coverage) and simultaneously composited with 14% shape memory polyurethane fiber by mass in each meter of grid line.

[0083] The preparation method of a composite fiber crack-resistant flexible splicing structure for bridge approach slabs is the same as that in Example 1.

[0084] Example 3:

[0085] Materials preparation:

[0086] Two-component high-viscosity and high-elasticity interfacial adhesive 5: By weight, prepare 48 parts of epoxy resin, 32 parts of polyurethane prepolymer, 5 parts of nano-silica, 1.5 parts of carbon nanotube / graphene oxide, 9 parts of core-shell elastomer, 1.8 parts of silane coupling agent, 0.5 parts of light stabilizer, 2.0 parts of flame retardant, 1.2 parts of microcapsule corrosion inhibitor and 10 parts of microcapsule curing agent.

[0087] Polymer elastomeric 4:

[0088] Polymer-modified asphalt: 110 parts of base asphalt (70-grade road petroleum asphalt and Indonesian natural rock asphalt, in a mass ratio of 7:2), 8 parts of polyurethane elastomer, 5 parts of star-shaped SBS, 5 parts of 40-mesh waste tire rubber powder, and 1.0 part of nano-silica phase change microcapsules.

[0089] Basalt crushed stone: 90 parts of basalt crushed stone with a single particle size of 15-20mm;

[0090] Filler: 3 parts carbon nanotube modified silicate whiskers and 1.5 parts activated sodium bentonite;

[0091] Functional additives: 0.6 parts of bio-based epoxy resin, 0.8 parts of composite hindered phenol / phosphite, 0.4 parts of graphene lignin, and 1.2 parts of microencapsulated asphalt regenerator.

[0092] Fiber-reinforced crack-resistant asphalt mixture 6:

[0093] Polymer-modified bitumen: Same as the polymer-modified bitumen formulation in polymer elastomer 4;

[0094] Composite crushed stone: 75 parts of 9.5-13.2mm angular crushed stone, 20 parts of 2.36-4.75mm diabase sand, and 13 parts of 0.075-0.6mm activated coal gangue powder;

[0095] Reinforcing fibers: 0.25 parts copper-plated basalt chopped fiber, 0.10 parts sawtooth polyester fiber, and 0.10 parts carbon nanotube-grafted basalt fiber.

[0096] Basalt fiber reinforced anchoring component 7: A gate-shaped component made of high-strength basalt fiber bundles as the base material, through resin impregnation and pultrusion molding process, and the surface is sandblasted to roughen it.

[0097] Fiber mesh layer 3: The base mesh (single hole size 20×20mm) is formed by bidirectional orthogonal weaving of 20μm diameter copper-plated basalt fibers (warp / weft ratio 3:2). The mesh body is impregnated with two-component epoxy resin (coating amount 300g / m²). 2 It is grafted with 50nm silicon carbide particles (coverage 22%) and simultaneously composited with 12% shape memory polyurethane fiber by mass in each meter of grid line.

[0098] The preparation method of a composite fiber crack-resistant flexible splicing structure for bridge approach slabs is the same as that in Example 1.

[0099] Comparative Example 1: Compared to Example 1, the groove was completely filled with polymer elastomeric toughness 4.

[0100] Comparative Example 2: Compared to Example 1, the groove was completely filled with polymer elastomeric toughness 4 fiber-reinforced crack-resistant asphalt mixture 6.

[0101] Comparative Example 3: Compared with Example 1, the basalt fiber reinforcement anchoring member 7 on the side wall of the groove was removed, and only the basalt fiber reinforcement anchoring member 7 on the bottom wall was retained.

[0102] Comparative Example 4: Compared with Example 1, the basalt fiber reinforcement anchoring member 7 on the bottom wall of the groove was removed, and only the basalt fiber reinforcement anchoring member 7 on the side wall was retained.

[0103] The spliced ​​structures prepared in Examples 1-3 and Comparative Examples 1-4 were tested as follows:

[0104] Simulated uneven settlement experiment:

[0105] Experimental setup: A high-precision displacement loading device is used to accurately control the settlement difference within ±8mm range, and to apply uneven settlement displacement to the bridge abutment slab splicing structure specimen.

[0106] Measurement indicators: The deformation and crack propagation width of the structure are monitored in real time using strain gauges and crack observation instruments. Strain gauges are placed at key locations on the surface of the specimen to record the structural strain data. The crack width is observed and photographed every 10 minutes using a crack observation instrument until the crack propagation tends to stabilize.

[0107] fatigue test

[0108] Experimental setup: Fatigue testing machine, capable of cyclically loading vehicle loads, with a loading frequency of 5Hz and a load range of 0-100kN, simulating the repeated action of actual vehicles on the bridge approach slabs.

[0109] Measurement index: Record the number of cycles when the material develops initial cracks as the starting point of fatigue life, continue loading until the structure can no longer withstand the load or the crack penetrates and causes failure, and record the final number of fatigue cycles.

[0110] After the above experiments, the data in Table 1 were obtained:

[0111] Table 1 Results of simulated uneven settlement and fatigue experiments

[0112]

[0113]

[0114] In Examples 1-3, the rigid-flexible transition interface formed by the two-component high-viscosity and high-elasticity interfacial binder, and the layered flexible filling of the polymer elastomeric toughening agent and fiber-reinforced crack-resistant asphalt mixture, effectively absorbed settlement deformation, controlled the deformation and crack width to a very small range, and maintained good structural integrity. The mechanical support system constructed by the basalt fiber reinforced anchoring component and the fiber mesh layer dispersed the stress generated by cyclic loading, and the reinforcing fibers and functional additives improved the fatigue resistance of the material, resulting in a significant increase in fatigue life.

[0115] Comparative Example 1: Although it has a certain degree of flexibility, it lacks rigid support from the upper layer, resulting in excessive deformation and rapid crack propagation under uneven settlement; in fatigue tests, it has a short fatigue life because it cannot effectively disperse stress.

[0116] Comparative Example 2: The material has excessive rigidity, making it difficult to adapt to settlement deformation and causing severe surface cracking; under fatigue load, stress concentration leads to premature cracking and poor fatigue performance.

[0117] Comparative Examples 3 and 4: Due to the lack of anchor bars in the sidewalls or bottomwalls, the stress could not be effectively dispersed. In the uneven settlement and fatigue tests, crack propagation and structural performance degradation occurred in the corresponding sidewalls or bottomwalls, and the fatigue life was lower than that in Example 1.

[0118] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A bridge-head-slab-combined fiber anti-cracking flexible splicing structure, comprising a base layer (1) with an asphalt pavement (8) on the top and an abutment (2); characterized in that, The base layer (1), the abutment (2) and the asphalt pavement (8) form a notch, the asphalt pavement (8) forms the side wall of the notch, and the base layer (1) and the abutment (2) form the bottom wall of the notch; The inner wall of the notch is coated with a two-component high-viscosity high-elasticity interface adhesive (5); From bottom to top, the notch is sequentially filled with a high polymer elastic body (4) and a fiber-reinforced anti-cracking asphalt mixture (6); The inner wall of the notch is pre-buried with a basalt fiber bar anchoring member (7), and the high polymer elastic body (4) and the fiber-reinforced anti-cracking asphalt mixture (6) wrap the basalt fiber bar anchoring member (7); The high polymer elastic body (4) and the fiber-reinforced anti-cracking asphalt mixture (6) are both provided with a fiber grid layer (3); The basalt fiber bar anchoring member (7) is symmetrically installed on the side wall and the bottom wall; The upper and lower anchoring positions of the basalt fiber bar anchoring member (7) on the side wall are close to the top and bottom of the side wall, respectively; The fiber grid layer (3) is formed by two-way orthogonal weaving of copper-plated basalt long fibers, and the grid body is impregnated with a two-component epoxy resin and grafted with silicon carbide particles with a particle size of 50-80 nm, and simultaneously compounded with 12-15% of shape memory polyurethane fibers in terms of mass ratio per meter of grid line; The fiber-reinforced anti-cracking asphalt mixture (6) is provided with a layer of fiber grid layer (3); The high polymer elastic body (4) is provided with double layers of fiber grid layer (3).

2. The fibered flexible splicing structure of claim 1, wherein, The high polymer elastic body (4) includes polymer modified asphalt, basalt aggregate, filler and functional additives, and the mass ratio is 30-50:90-110:1-1.5:0.5-1.3; The basalt aggregate is of a single particle size, and the particle size is 15-20 mm.

3. The fibered flexible splicing structure of claim 2, wherein, The polymer modified asphalt includes 90-110 parts of base asphalt, 6-8 parts of polyurethane elastomer, 4-5 parts of star-shaped SBS, 3-5 parts of waste tire rubber powder and 0.5-1.0 parts of nano silicon dioxide phase change microcapsule, by weight; The filler includes 2-3 parts of carbon nanotube modified silicate whisker and 1.5-2.5 parts of activated sodium bentonite; The functional additives include 0.3-0.6 parts of bio-based epoxy resin, 0.5-0.8 parts of composite hindered phenol / phosphite, 0.2-0.4 parts of graphene lignin and 0.8-1.2 parts of microencapsulated asphalt regenerant.

4. The fibered flexible splicing structure of claim 1, wherein, The fiber-reinforced anti-cracking asphalt mixture (6) includes polymer modified asphalt, composite aggregate and reinforcing fibers, and the mass ratio is 10-30:92-105:0.3-0.55; The composite aggregate includes 60-75 parts of 9.5-13.2 mm angular aggregate, 20-30 parts of 2.36-4.75 mm diabase sand and 8-15 parts of 0.075-0.6 mm activated coal gangue powder, by weight; The reinforcing fibers include 0.15-0.25 parts of copper-plated basalt chopped fibers, 0.10-0.20 parts of sawtooth polyester fibers and 0.05-0.10 parts of carbon nanotube grafted basalt fibers.

5. The combination of the bridge head patch and fiber anti-cracking flexible splicing structure according to claim 1, characterized in that, By weight, the two-component high-viscosity and high-elasticity interfacial adhesive (5) comprises 40-50 parts epoxy resin, 30-40 parts polyurethane prepolymer, 3-5 parts nano silica, 1.5-2.5 parts carbon nanotubes / graphene oxide, 8-12 parts core-shell elastomer, 1.2-1.8 parts silane coupling agent, 0.3-0.5 parts light stabilizer, 1.5-2.0 parts flame retardant, 0.8-1.2 parts microcapsule corrosion inhibitor, and 10-15 parts microcapsule curing agent.

6. A method of manufacturing the fiber anti-cracking flexible splicing structure of the bridge head splice plate combination according to any one of claims 1-5, characterized in that, include: Make the groove and clean and dry the inner wall of the groove; The two-component high-viscosity and high-elasticity interface adhesive (5) is applied to the inner wall of the groove, and the basalt fiber reinforcement anchoring components (7) are pre-embedded in the side walls and bottom wall of the groove; wherein, the upper and lower ends of the basalt fiber reinforcement anchoring components (7) are 20~30mm away from the top and bottom of the groove, respectively, and the horizontal spacing is arranged in an array of 300mm. Mix the polymer elastic toughness (4), lay it into the groove, arrange two layers of the fiber mesh layer (3) at equal intervals, and compact it; Mix the fiber-reinforced crack-resistant asphalt mixture (6), lay it on the polymer elastic toughness (4), arrange a fiber mesh layer (3), and compact it.

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