Anti-icing bridge access walkway composite plank

Abstract

This invention relates to the field of bridge ancillary facilities technology, and discloses a composite material pedestrian slab for anti-icing bridge operation passages, comprising a pedestrian slab substrate, an anti-slip quartz sand layer, and an anti-icing nano-coating. The anti-slip quartz sand layer is disposed on the upper surface of the pedestrian slab substrate, and the anti-icing nano-coating is disposed on the outer surface of the anti-slip quartz sand layer. An array of drainage holes is processed on the pedestrian slab substrate. This invention uses polyurethane-modified epoxy adhesive, silane coupling agent, and high-purity quartz sand to cure and form an anti-slip quartz sand layer. Covalent bonds are established between the high-purity quartz sand and the polyurethane-modified epoxy adhesive to prevent the high-purity quartz sand from falling off the surface. By coating the outer surface of the anti-slip quartz sand layer with an anti-icing nano-film-forming liquid containing fluorinated alkyl silane and heating for co-curing, a dehydration condensation reaction occurs to form interlayer chemical bonds, reducing the surface energy of the anti-icing nano-coating and reducing the adhesion strength of the attached ice layer, thus achieving the anti-slip and anti-icing functions of the composite material pedestrian slab.

Description

Technical Field

[0001] This invention relates to the field of bridge ancillary facilities technology, specifically to a composite material pedestrian slab for anti-icing bridge operation passages. Background Technology

[0002] Bridge access roads are crucial ancillary facilities for ensuring the safety of bridge inspection and maintenance personnel. They typically require composite material walkways. Existing conventional composite walkways are mostly made of ordinary epoxy resin or unsaturated polyester and glass fiber composites. Traditional resins, after curing, have high cross-linking density and a rigid network structure of molecular chains, making them prone to cold brittleness, especially in low-temperature winter environments, lacking the buffering deformation space of flexible chain segments. After long-term exposure to cyclic loads from pedestrian traffic and equipment handling, as well as the thermal expansion and contraction of the natural environment, the rigid resin and glass fiber are highly susceptible to interfacial debonding and microcrack propagation, leading to a reduction in the overall load-bearing capacity of the walkway. Furthermore, traditional walkway surfaces lack drainage design, allowing rainwater or snowmelt to accumulate and create safety hazards.

[0003] To improve the surface friction of walking boards, the conventional approach is to coat the surface with ordinary rigid adhesive and then sprinkle anti-slip particles. However, the anti-slip particles and adhesive usually rely only on simple physical adhesion and mechanical embedding, lacking chemical bonding. When subjected to the instantaneous impact of a heavy object falling or the thermal stress at low temperatures, the rigid adhesive layer cannot work with the substrate to produce elastic deformation, and is prone to brittle fracture. This causes the anti-slip particles to peel off or fall off in chunks along with the adhesive layer, causing the walking board to lose its anti-slip performance within a short service life.

[0004] Furthermore, in low winter temperatures, water on the surface of the walking slab easily condenses into ice, covering the rough surface structure constructed by the anti-slip particles and posing a safety hazard. Current technology involves coating the outside of the anti-slip layer with an anti-icing coating. However, the conventional anti-icing coating and the fully cured underlying adhesive rely solely on intermolecular van der Waals forces for bonding, lacking interlayer chemical cross-linking. Under the friction of footsteps and the internal stress generated by the expansion of the ice layer, the coating is prone to large-area peeling. Simultaneously, the conventional coating solvent evaporates too quickly, lacking sufficient leveling and defoaming time, easily forming pores between the anti-slip particles or obscuring the original rough morphology, allowing liquid water to penetrate into the coating. After the coating peels off, the ice layer forms a deep mechanical anchor within the gaps between the sand layers, ultimately causing the composite walking slab to face a technical bottleneck of dual failure in both anti-slip and anti-icing functions. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a composite material pedestrian slab for anti-icing bridge operation passages. It solves the technical problems of existing composite material pedestrian slabs being too brittle in low-temperature environments, prone to cracking, and having poor interfacial bonding strength and film quality between the anti-icing coating and the anti-icing substrate, resulting in the failure of both anti-icing and anti-slip functions of the pedestrian slab under long-term friction, alternating hot and cold temperatures, and ice expansion stress.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a composite material pedestrian slab for bridge operation passages that prevents icing, comprising a pedestrian slab substrate, an anti-slip quartz sand layer, and an anti-icing nano-coating; the anti-slip quartz sand layer is disposed on the upper surface of the pedestrian slab substrate, the anti-icing nano-coating is disposed on the outer surface of the anti-slip quartz sand layer, and the pedestrian slab substrate is provided with an array of drainage holes.

[0008] The walking board matrix comprises the following raw materials in parts by weight: Continuous alkali-free glass fiber: 70.0-75.0 parts; polyurethane resin: 13.2-18.8 parts; silicone defoamer: 0.2-0.5 parts; silane coupling agent KH-550: 0.5-1.0 parts; antioxidant: 0.1-0.3 parts; alkali-free stitched felt: 5.0-7.0 parts.

[0009] The anti-slip quartz sand layer is formed by curing an adhesive mixture with high-purity quartz sand. The adhesive mixture consists of 100.0 parts by weight of polyurethane modified epoxy adhesive and 2.0-4.0 parts by weight of silane coupling agent KH-560.

[0010] The anti-icing nano-coating is formed by curing an anti-icing nano-film-forming liquid. The anti-icing nano-film-forming liquid comprises the following raw materials in parts by weight, and is formed by mixing and hydrolyzing the following raw materials: Fluoroalkylsilane FAS-17: 15.0-25.0 parts; Methyltrimethoxysilane: 10.0-20.0 parts; Nano SiO2 particles: 5.0-10.0 parts; Silane coupling agent KH-550: 2.0-5.0 parts; Deionized water: 5.0-10.0 parts; Mixed solvent of ethanol and isopropanol: 40.0-60.0 parts.

[0011] Based on the above technical solution, continuous alkali-free glass fiber and polyurethane resin are used as the walking board matrix, and an anti-slip quartz sand layer and an anti-icing nano-coating are introduced to achieve the anti-slip and anti-icing functions of the walking board. The array of drainage holes is used to effectively remove water accumulated on the surface of the walking board matrix.

[0012] The amino group of silane coupling agent KH-550 reacts chemically with polyurethane resin. After the alkoxy group of silane coupling agent KH-550 is hydrolyzed, it undergoes dehydration condensation with the hydroxyl group on the surface of glass fiber to form a covalent bond, thereby significantly improving the interfacial bonding strength between polyurethane resin and glass fiber.

[0013] Polyurethane-modified epoxy adhesive provides adhesion, while silane coupling agent KH-560 contains epoxy and methoxy functional groups. After hydrolysis, the methoxy groups undergo a condensation reaction with the hydroxyl groups on the surface of high-purity quartz sand, while the epoxy groups participate in the cross-linking reaction of the polyurethane-modified epoxy adhesive, forming covalent bonds between the high-purity quartz sand and the polyurethane-modified epoxy adhesive, thereby achieving a stable fixation of the high-purity quartz sand.

[0014] Fluoroalkylsilane FAS-17 and methyltrimethoxysilane first undergo hydrolysis to generate an intermediate containing silanol groups. Subsequently, the silanol groups generated by hydrolysis undergo dehydration condensation with the hydroxyl groups on the surface of nano-SiO2 particles, covalently grafting the fluorine-containing long chain and methyl groups onto the surface of nano-SiO2 particles. At the same time, condensation reactions occur between the free silanol groups to construct a three-dimensional cross-linked network framework.

[0015] The anti-icing nano-film-forming liquid is coated onto the surface of the anti-slip quartz sand layer and then heat-treated. The silanol groups in the anti-icing nano-film-forming liquid undergo de-alcoholization and dehydration condensation reactions with the hydroxyl groups contained in the high-purity quartz sand surface and the polyurethane modified epoxy adhesive layer, forming interlayer chemical bonds. The fluorine-containing long chains endow the coating with low surface energy characteristics, which increases the contact angle of water droplets on the surface of the anti-icing nano-coating, making it difficult for liquid water to wet and adhere. When freezing occurs at low temperatures, the interfacial adhesion strength between the ice layer and the anti-icing nano-coating decreases, and the ice layer is easy to fall off, thus achieving the dual functions of anti-icing and anti-slip.

[0016] Preferably, the alkali-free woven felt forms a covering structure on the outer layer of continuous alkali-free glass fiber, the anti-icing nano-coating completely covers the high-purity quartz sand in the anti-slip quartz sand layer and fills the gaps between the sand layers, and the inner wall of the array-type drainage holes is sealed to prevent leakage.

[0017] Preferably, the polyurethane resin is obtained by mixing diphenylmethane diisocyanate with a polyether polyol having a functionality of 3 and a number average molecular weight of 3000-5000 in a molar equivalent ratio of 1.1-1.3:1.

[0018] Preferably, the antioxidant is selected from antioxidant 1010 and antioxidant 168.

[0019] Preferably, the ethanol and isopropanol mixed solvent is obtained by mixing ethanol and isopropanol in a volume ratio of 1:1.

[0020] Preferably, the polyurethane modified epoxy adhesive has a solid content of 95%-98%, a tensile shear strength of 5.0-8.0 MPa and a bond strength of 3.0-5.0 MPa at 20-25℃.

[0021] Preferably, the high-purity quartz sand has a silica content of 98.0%-99.0%, a high-purity quartz sand mesh of 20-40 mesh, and a particle size of 10.0-50.0 nm for the nano-SiO2 particles.

[0022] Preferably, the diameter of the array of drainage holes is 8.0-12.0 mm.

[0023] Preferably, the thickness of the walking board substrate is 40.0-70.0 mm, and the dry film thickness of the anti-icing nano-coating is 5.0-10.0 μm.

[0024] Based on the above technical solutions, the covering structure formed by alkali-free woven felt can improve the anti-aging performance of the walking board; the anti-icing nano-coating forms a low surface energy protective interface by coating high-purity quartz sand and filling the gaps; after the inner wall of the array-type drainage holes is sealed to prevent leakage, it effectively prevents water from penetrating into the interior of the walking board and avoids interface damage; in addition, the polyurethane resin mixing ratio and material parameters ensure the reactivity of the chemical system and the mechanical strength of the product.

[0025] Preferably, the preparation of anti-icing bridge work passage composite material pedestrian slabs includes the following steps:

[0026] Continuous alkali-free glass fiber is preheated and degassed, and polyurethane resin, silicone defoamer, silane coupling agent KH-550 and antioxidant are mixed evenly. The preheated and degassed continuous alkali-free glass fiber and alkali-free stitch-woven felt are introduced into a curing mold. The mixed polyurethane resin is injected into the curing mold for impregnation. The impregnated continuous alkali-free glass fiber and alkali-free stitch-woven felt are pulled through a segmented heating curing mold for curing to obtain a cured board. The cured board is cut and an array of drainage holes is processed on the surface of the board to obtain the walking board substrate.

[0027] The upper surface of the walking board substrate is roughened, and an adhesive mixture is coated on the upper surface of the walking board substrate. High-purity quartz sand is then laid on the surface of the adhesive mixture. The walking board substrate with high-purity quartz sand is pre-bonded and baked to allow the adhesive mixture to reach a semi-cured gel state. The semi-cured gel state is when the degree of curing of the adhesive mixture reaches 40%-60% as tested by differential scanning calorimetry, and the surface viscosity of the adhesive mixture is 5000-8000 mPa·s. After cooling and removing the loose sand, a semi-finished product with an anti-slip quartz sand layer is obtained.

[0028] A mixture system was prepared by mixing fluoroalkylsilane FAS-17, methyltrimethoxysilane, nano-SiO2 particles, silane coupling agent KH-550, deionized water, and a mixed solvent of ethanol and isopropanol. The pH value of the mixture system was adjusted and the mixture was stirred and hydrolyzed to obtain an anti-icing nano-film-forming liquid. The anti-icing nano-film-forming liquid was coated on the outer surface of a semi-finished product with an anti-slip quartz sand layer. After leveling, the product was placed in an oven for co-curing to form an anti-icing nano-coating, resulting in an anti-icing bridge operation passage composite material pedestrian slab.

[0029] By adopting the above technical solution, the walking board substrate is continuously produced using a molding process, and resin impregnates continuous alkali-free glass fiber; the semi-cured gel state ensures that the high-purity quartz sand is anchored in the adhesive mixture and maintains the surface roughness; the leveling and co-curing process allows the anti-icing nano-film-forming liquid to penetrate into the gaps of the high-purity quartz sand and undergo a chemical cross-linking reaction at the interface.

[0030] Preferably, the specific steps for preheating and degassing continuous alkali-free glass fiber are as follows: the continuous alkali-free glass fiber is spread out on a yarn rack, and the preheating and degassing temperature is 40-50℃ for 20-40 min.

[0031] By adopting the above technical solution, the yarn unfolding and preheating degassing treatment remove moisture and air from the surface of continuous alkali-free glass fiber, reducing the porosity of the material during the curing process.

[0032] Preferably, the mixed polyurethane resin is injected into the curing mold for impregnation, and the injection pressure is 3.5-5.5 MPa.

[0033] By adopting the above technical solution, the injection pressure overcomes the flow resistance of the fiber bundle, ensuring that the mixed polyurethane resin fully penetrates into the interior of the continuous alkali-free glass fiber.

[0034] Preferably, the continuous alkali-free glass fiber and alkali-free stitch-woven felt after traction and impregnation are cured by a segmented heating curing mold. The traction speed is 30-50 cm / min, the inlet temperature of the segmented heating curing mold is 60-80℃, the middle temperature is 120-160℃, and the outlet temperature is 180-220℃.

[0035] By adopting the above technical solution, the lower inlet temperature reduces the viscosity of polyurethane resin, the middle temperature initiates the cross-linking reaction, and the high outlet temperature ensures the complete curing of polyurethane resin. The traction speed is matched with the curing reaction rate, ensuring the processing stability of the continuous molding process.

[0036] Preferably, the upper surface of the walking board substrate is roughened by sandblasting to achieve a surface roughness Ra of 3.2-6.3 μm, and the surface dust is removed by high-pressure blowing. Then, an adhesive mixture is applied to the upper surface of the walking board substrate at a coating weight of 200-300 g / m².2 High-purity quartz sand is spread on the surface of the adhesive mixture using a spreading method. The surface density of the high-purity quartz sand is 300-500 g / m³. 2 .

[0037] By adopting the above technical solution, the sandblasting roughening treatment increases the contact area between the adhesive mixture and the walking board substrate by forming a mechanical interlocking structure, and the coating amount and the laying density are precisely matched to achieve an optimized balance between anti-slip performance and bonding strength.

[0038] Preferably, the specific steps for pre-bonding and baking the walking board substrate with high-purity quartz sand to achieve a semi-cured gel state of the adhesive mixture are as follows: pre-bonding the walking board substrate with high-purity quartz sand at a temperature of 20-25℃ for 25-35 min, and then sending the pre-bonded walking board substrate into an oven and baking it at a temperature of 35-50℃ for 1-2 h.

[0039] By adopting the above technical solution, the high-purity quartz sand settles and is wetted by the adhesive mixture during the pre-adhesion stage. The semi-cured gel state initially fixes the high-purity quartz sand, while retaining active reactive groups on the surface of the adhesive layer for interfacial chemical bonding in the subsequent co-curing stage.

[0040] Preferably, when adjusting the pH value of the mixture, one of glacial acetic acid and dilute hydrochloric acid is added to adjust the pH value of the mixture to 3.0-4.0. The stirring hydrolysis process is carried out at a speed of 300-500 r / min for 30-60 min.

[0041] By adopting the above technical solution, the weakly acidic environment catalyzes the hydrolysis reaction of alkoxy groups in the silane precursor, inhibits the self-condensation reaction, ensures that the concentration of active silanol groups in the system is maintained, and guarantees the reactivity of the anti-icing nanofilm-forming liquid.

[0042] Preferably, the anti-icing nano film-forming liquid is applied using a high-pressure airless spraying method to obtain a semi-finished product of the anti-icing nano film-forming liquid. The spray gun pressure of the high-pressure airless spraying method is 0.3-0.5 MPa, the spraying distance is 20-30 cm, and the semi-finished product coated with the anti-icing nano film-forming liquid is leveled at a temperature of 20-25℃ for 15-20 min. The leveled semi-finished product is then placed in an oven and co-cured at a temperature of 35-50℃ for 2-3 h.

[0043] By adopting the above technical solution, the atomized droplets generated by the high-pressure airless spraying process can penetrate into the crevices of high-purity quartz sand, the leveling process allows the mixed solvent to evaporate and expel the air bubbles inside the liquid layer, and the co-curing process provides heat energy to promote polycondensation and cross-linking reactions between the interfaces.

[0044] This invention provides a composite material pedestrian slab for anti-icing bridge work passages, which has the following beneficial effects:

[0045] 1. This invention uses continuous alkali-free glass fiber, polyurethane resin, and silane coupling agent KH-550 to form a walking board matrix. After the alkoxy groups of the silane coupling agent KH-550 are hydrolyzed, they undergo a dehydration condensation reaction with the hydroxyl groups on the surface of the continuous alkali-free glass fiber to form covalent bonds, thereby improving the interfacial bonding strength between the polyurethane resin and the continuous alkali-free glass fiber. An array of drainage holes is processed on the walking board matrix to drain the water accumulated on the surface of the walking board matrix, thereby improving the load-bearing capacity and drainage performance of the composite material walking board.

[0046] 2. This invention forms an anti-slip quartz sand layer by curing polyurethane-modified epoxy adhesive, silane coupling agent KH-560, and high-purity quartz sand. The methoxy groups of silane coupling agent KH-560 hydrolyze and undergo a condensation reaction with the hydroxyl groups on the surface of high-purity quartz sand. The epoxy groups of silane coupling agent KH-560 participate in the crosslinking reaction of polyurethane-modified epoxy adhesive, establishing covalent bonds between high-purity quartz sand and polyurethane-modified epoxy adhesive, preventing high-purity quartz sand from falling off the surface of the walking board substrate, and maintaining the anti-slip performance of the composite material walking board.

[0047] 3. This invention involves coating an anti-icing nanofilm-forming liquid containing fluorinated alkylsilane FAS-17 and nano-SiO2 particles onto the outer surface of an anti-slip quartz sand layer and then heating and co-curing it. The silanol groups in the anti-icing nanofilm-forming liquid undergo de-alcoholization and dehydration condensation reactions with the hydroxyl groups on the surface of the high-purity quartz sand and the polyurethane-modified epoxy adhesive layer to form interlayer chemical bonds. The fluorinated long chains provided by fluorinated alkylsilane FAS-17 reduce the surface energy of the anti-icing nanocoating surface, reduce the adhesion strength between the ice layer and the anti-icing nanocoating, and cause the attached ice layer to detach from the surface of the anti-icing nanocoating, thereby achieving the anti-icing function of the composite material walking board. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the cross-sectional structure of the composite material pedestrian slab for the anti-icing bridge operation passage of the present invention;

[0049] Figure 2 This is a top view of the composite material pedestrian slab for the anti-icing bridge operation passage of the present invention.

[0050] Figure 3 This is a biaxial graph showing the mechanical properties and surface friction coefficient of the composite material pedestrian slab for the anti-icing bridge operation passage of the present invention.

[0051] Figure 4 This is a biaxial graph showing the icing delay time and ice shear adhesion of the composite material pedestrian slab for the anti-icing bridge operation passage of the present invention.

[0052] Figure 5 This is a biaxial composite diagram showing the critical tensile force and the percentage of detachment area of ​​the composite material pedestrian slab for the anti-icing bridge operation passage of the present invention.

[0053] Figure 6 This is a biaxial graph showing the dry film thickness range and the proportion of macroscopic defect area in the present invention.

[0054] Figure 7 This is a biaxial graph showing the pull-out force retention rate and the percentage of peeling and detachment area of ​​the composite material pedestrian slab for the anti-icing bridge operation passage of the present invention.

[0055] Figure 8 This is a biaxial graph showing the decrease in contact angle after wear and the increase in ice shear force after freeze-thaw cycles for the anti-icing bridge operation passage composite material walking slab of the present invention.

[0056] In the diagram: 1 - Walking board substrate; 2 - Anti-slip quartz sand layer; 3 - Anti-icing nano-coating; 4 - Drainage hole. Detailed Implementation

[0057] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to test examples. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0058] Example 1:

[0059] This embodiment provides a method for preparing a composite material pedestrian slab for anti-icing bridge operation passages, including the following steps:

[0060] S1. 73 parts by weight of continuous alkali-free glass fiber are spread on a yarn frame and preheated and degassed at 45°C for 20 min. 16 parts by weight of polyurethane resin (obtained by mixing diphenylmethane diisocyanate with a polyether polyol of functionality 3 and number average molecular weight 4000 at a molar equivalent ratio of 1.25:1), 0.3 parts by weight of silicone defoamer, 0.7 parts by weight of silane coupling agent KH-550, and 0.2 parts by weight of antioxidant 1010 are mixed evenly. The preheated and degassed continuous alkali-free glass fiber and 6 parts by weight of alkali-free stitch-woven felt are introduced into a curing mold equipped with a glue injection box. The alkali-free stitch-woven felt forms a covering structure on the outer layer of the continuous alkali-free glass fiber. After laying, the upper and lower molds are installed, ensuring no gaps at the mold parting line. The mixed polyurethane resin is injected into the curing mold at a glue injection pressure of 4.5 MPa, allowing the polyurethane resin to fully impregnate the alkali-free stitch-woven felt and continuous alkali-free glass fiber. The mixture is then traction-driven at a 40°C... At a speed of cm / min, alkali-free woven felt and continuous alkali-free glass fiber impregnated with polyurethane resin are pulled through a segmented heating curing mold. The inlet temperature of the curing mold is set to 70℃, the middle temperature is set to 140℃, and the outlet temperature is set to 200℃. The curing board is cut to a fixed length using a traction machine. An array of drainage holes 4 with a diameter of 10 mm is machined on the surface of the cut board, and the inner wall of the drainage holes 4 is sealed to prevent leakage, resulting in a walking board substrate 1 with a thickness of 55 mm.

[0061] S2. The upper surface of the walking board substrate 1 is roughened by sandblasting until the surface roughness Ra reaches 4.5 μm. High-pressure air is used to remove the floating dust from the upper surface of the walking board substrate 1. The adhesive mixture (composed of 100 parts by weight of polyurethane modified epoxy adhesive and 3 parts by weight of silane coupling agent KH-560) is applied at a ratio of 250 g / m². 2 The coating is evenly applied to the upper surface of the walking board substrate 1. The polyurethane-modified epoxy adhesive has a solid content of 96%, a tensile shear strength of 6 MPa at 22℃, and a bond strength of 4 MPa. It is applied to the surface of the adhesive mixture using a spreading method, resulting in a surface density of 400 g / m². 2 The 30-mesh high-purity quartz sand has a silica content of 98.5%. The walking board substrate 1, which is covered with high-purity quartz sand, is pre-bonded at 22°C for 30 minutes and then placed in an oven to bake at 42°C for 1.5 hours. After baking, the walking board substrate 1 is cooled to 22°C, and the loose sand that is not firmly bonded on the surface of the adhesive mixture is removed with a brush to obtain a semi-finished product with an anti-slip quartz sand layer 2.

[0062] S3. Mix 20 parts by mass of fluoroalkylsilane FAS-17, 15 parts by mass of methyltrimethoxysilane, 8 parts by mass of nano-SiO2 particles with a particle size of 30 nm, 3 parts by mass of silane coupling agent KH-550, 8 parts by mass of deionized water and 53 parts by mass of a mixed solvent of ethanol and isopropanol (obtained by mixing ethanol and isopropanol in a volume ratio of 1:1). Add glacial acetic acid to the mixture to adjust the pH value of the system to 3.5. Stir the mixture at 400 r / min for 45 min to hydrolyze and obtain an anti-icing nanofilm-forming solution.

[0063] S4. Using a high-pressure airless spraying method, the anti-icing nano film-forming liquid is uniformly applied in two coats to the outer surface of the semi-finished anti-slip quartz sand layer 2 at a spray gun pressure of 0.4 MPa, a spraying distance of 25 cm, and a spraying speed of 0.6 m / s. This ensures that the anti-icing nano film-forming liquid completely coats the high-purity quartz sand in the anti-slip quartz sand layer 2 and fills the gaps between the sand layers. After the semi-finished product coated with the anti-icing nano film-forming liquid is leveled at 22℃ for 18 min, it is then placed in an oven and cured at 42℃ for 2.5 h to complete the interfacial de-alcoholization condensation chemical cross-linking between the anti-icing nano film-forming liquid and the anti-slip quartz sand layer 2. This cures the anti-icing nano coating 3 with a dry film thickness of 8 μm on the outer surface of the anti-slip quartz sand layer 2, finally obtaining the anti-icing bridge operation passage composite material pedestrian board.

[0064] Example 2:

[0065] This embodiment provides a method for preparing a composite material pedestrian slab for anti-icing bridge operation passages, including the following steps:

[0066] S1. 75 parts by weight of continuous alkali-free glass fiber are spread on a yarn rack and preheated and degassed at 50°C for 40 min. 18.8 parts by weight of polyurethane resin (obtained by mixing diphenylmethane diisocyanate with a polyether polyol of functionality 3 and number average molecular weight 5000 at a molar equivalent ratio of 1.3:1), 0.5 parts by weight of silicone defoamer, 1.0 parts by weight of silane coupling agent KH-550, and 0.3 parts by weight of antioxidant 1010 are mixed evenly. The preheated and degassed continuous alkali-free glass fiber and 7 parts by weight of alkali-free stitch-woven felt are introduced into a curing mold equipped with a glue injection box. The alkali-free stitch-woven felt forms a covering structure on the outer layer of the continuous alkali-free glass fiber. After laying, the upper and lower molds are installed, ensuring no gaps at the mold parting line. The mixed polyurethane resin is injected into the curing mold at a glue injection pressure of 5.5 MPa, allowing the polyurethane resin to fully impregnate the alkali-free stitch-woven felt and continuous alkali-free glass fiber. The mixture is then traction-driven at a 50°C... At a speed of cm / min, alkali-free woven felt and continuous alkali-free glass fiber impregnated with polyurethane resin are pulled through a segmented heating curing mold. The inlet temperature of the curing mold is set to 80℃, the middle temperature is set to 160℃, and the outlet temperature is set to 220℃. The curing board is cut to a fixed length using a traction machine. An array of drainage holes 4 with a diameter of 12 mm is processed on the surface of the cut board, and the inner wall of the drainage holes 4 is sealed to prevent leakage, resulting in a walking board substrate 1 with a thickness of 70 mm.

[0067] S2. The upper surface of the walking board substrate 1 is roughened by sandblasting until the surface roughness Ra reaches 6.3 μm. High-pressure air is used to remove floating dust from the upper surface of the walking board substrate 1. The adhesive mixture (composed of 100 parts by mass of polyurethane modified epoxy adhesive and 4 parts by mass of silane coupling agent KH-560) is applied at a concentration of 300 g / m². 2 The coating is evenly applied to the upper surface of the walking board substrate 1. The polyurethane-modified epoxy adhesive has a solid content of 98%, a tensile shear strength of 8 MPa at 25℃, and a bond strength of 5 MPa. It is applied to the surface of the adhesive mixture using a spreading method, resulting in a surface density of 500 g / m². 2 The 40-mesh high-purity quartz sand has a silica content of 99%. The walking board substrate 1, which is covered with high-purity quartz sand, is pre-bonded at 25°C for 35 minutes and then baked in an oven at 50°C for 2 hours. After baking, the walking board substrate 1 is cooled to 25°C, and the loose sand that is not firmly bonded on the surface of the adhesive mixture is removed with a brush to obtain a semi-finished product with an anti-slip quartz sand layer 2.

[0068] S3. Mix 25 parts by mass of fluoroalkylsilane FAS-17, 20 parts by mass of methyltrimethoxysilane, 10 parts by mass of 50 nm nano-SiO2 particles, 5 parts by mass of silane coupling agent KH-550, 10 parts by mass of deionized water and 60 parts by mass of a mixed solvent of ethanol and isopropanol (obtained by mixing ethanol and isopropanol in a 1:1 volume ratio). Add glacial acetic acid to the mixture to adjust the pH value to 4.0. Stir the mixture at 500 r / min for 60 min to hydrolyze it and obtain an anti-icing nanofilm-forming solution.

[0069] S4. Using a high-pressure airless spraying method, the anti-icing nano-film-forming liquid is uniformly applied to the outer surface of the semi-finished anti-slip quartz sand layer 2 in three applications at a spray gun pressure of 0.5 MPa, a spraying distance of 30 cm, and a spraying speed of 0.8 m / s. This ensures that the anti-icing nano-film-forming liquid completely coats the high-purity quartz sand in the anti-slip quartz sand layer 2 and fills the gaps between the sand layers. After the semi-finished product coated with the anti-icing nano-film-forming liquid is leveled at 25℃ for 20 min, it is placed in an oven and cured at 50℃ for 3 h to complete the interfacial de-alcoholization condensation chemical cross-linking between the anti-icing nano-film-forming liquid and the anti-slip quartz sand layer 2. This cures to form an anti-icing nano-coating 3 with a dry film thickness of 10 μm on the outer surface of the anti-slip quartz sand layer 2, finally yielding an anti-icing bridge operation passage composite material pedestrian slab.

[0070] Example 3:

[0071] This embodiment provides a method for preparing a composite material pedestrian slab for anti-icing bridge operation passages, including the following steps:

[0072] S1. 70 parts by weight of continuous alkali-free glass fiber are spread out on a yarn rack and preheated and degassed at 40°C for 30 min. 13.2 parts by weight of polyurethane resin (obtained by mixing diphenylmethane diisocyanate with a polyether polyol with a functionality of 3 and a number average molecular weight of 3000 at a molar equivalent ratio of 1.1:1), 0.2 parts by weight of silicone defoamer, 0.5 parts by weight of silane coupling agent KH-550, and 0.1 parts by weight of antioxidant 1010 are mixed evenly. The preheated and degassed continuous alkali-free glass fiber and 5 parts by weight of alkali-free stitch-woven felt are introduced into a curing mold equipped with a glue injection box. The alkali-free stitch-woven felt forms a covering structure on the outer layer of the continuous alkali-free glass fiber. After laying, the upper and lower molds are installed, ensuring no gaps at the mold parting line. The mixed polyurethane resin is injected into the curing mold at a glue injection pressure of 3.5 MPa, allowing the polyurethane resin to fully impregnate the alkali-free stitch-woven felt and continuous alkali-free glass fiber. The mixture is then traction-driven at 30... At a speed of cm / min, alkali-free woven felt and continuous alkali-free glass fiber impregnated with polyurethane resin are pulled through a segmented heating curing mold. The inlet temperature of the curing mold is set to 60℃, the middle temperature is set to 120℃, and the outlet temperature is set to 180℃. The cured board is cut to a fixed length using a traction machine. An array of drainage holes 4 with a diameter of 8 mm is machined on the surface of the cut board, and the inner wall of the drainage holes 4 is sealed to prevent leakage, resulting in a walking board substrate 1 with a thickness of 40 mm.

[0073] S2. The upper surface of the walking board substrate 1 is roughened by sandblasting until the surface roughness Ra reaches 3.2 μm. High-pressure air is used to remove floating dust from the upper surface of the walking board substrate 1. The adhesive mixture (composed of 100 parts by mass of polyurethane modified epoxy adhesive and 2 parts by mass of silane coupling agent KH-560) is applied at a ratio of 200 g / m². 2 The coating is evenly applied to the upper surface of the walking board substrate 1. The polyurethane-modified epoxy adhesive has a solid content of 95%, a tensile shear strength of 5 MPa at 20℃, and a bond strength of 3 MPa. It is applied to the surface of the adhesive mixture using a spreading method, with a surface density of 300 g / m². 2 The 20-mesh high-purity quartz sand has a silica content of 98%. The walking board substrate 1, which is covered with high-purity quartz sand, is pre-bonded at 20°C for 25 min and then baked in an oven at 35°C for 1 h. After baking, the walking board substrate 1 is cooled to 20°C, and the loose sand that is not firmly bonded on the surface of the adhesive mixture is removed with a brush to obtain a semi-finished product with an anti-slip quartz sand layer 2.

[0074] S3. Mix 15 parts by mass of fluoroalkylsilane FAS-17, 10 parts by mass of methyltrimethoxysilane, 5 parts by mass of 10 nm nano-SiO2 particles, 2 parts by mass of silane coupling agent KH-550, 5 parts by mass of deionized water and 40 parts by mass of a mixed solvent of ethanol and isopropanol (obtained by mixing ethanol and isopropanol in a 1:1 volume ratio). Add glacial acetic acid to the mixture to adjust the pH value to 3.0. Stir the mixture at 300 r / min for 30 min to hydrolyze and obtain an anti-icing nanofilm-forming solution.

[0075] S4. Using a high-pressure airless spraying method, the anti-icing nano film-forming liquid is uniformly applied in two coats to the outer surface of the semi-finished anti-slip quartz sand layer 2 at a spray gun pressure of 0.3 MPa, a spraying distance of 20 cm, and a spraying speed of 0.5 m / s. This ensures that the anti-icing nano film-forming liquid completely coats the high-purity quartz sand in the anti-slip quartz sand layer 2 and fills the gaps between the sand layers. After the semi-finished product coated with the anti-icing nano film-forming liquid is leveled at 20℃ for 15 min, it is then placed in an oven and cured at 35℃ for 2 h. This completes the interfacial de-alcoholization condensation chemical cross-linking between the anti-icing nano film-forming liquid and the anti-slip quartz sand layer 2, forming an anti-icing nano coating 3 with a dry film thickness of 5 μm on the outer surface of the anti-slip quartz sand layer 2. Finally, an anti-icing bridge operation passage composite material pedestrian slab is obtained.

[0076] Comparative Example 1:

[0077] Compared with Example 1, the difference is that in step S3, 53 parts by mass of the mixed solvent of ethanol and isopropanol are replaced with 53 parts by mass of anhydrous ethanol, and the rest are the same.

[0078] Comparative Example 2:

[0079] Compared with Example 1, the difference is that in step S2, the baking time at 42°C for 1.5 hours is changed to baking at 42°C for 5 hours to allow the polyurethane modified epoxy adhesive to reach a fully cured state. All other steps are the same.

[0080] Comparative Example 3:

[0081] Compared with Example 1, the difference is that methyltrimethoxysilane is not added in step S3, and the amount of fluoroalkylsilane FAS-17 added is increased from 20 parts by mass to 35 parts by mass, while the rest are the same.

[0082] Comparative Example 4:

[0083] Compared with Example 1, the difference is that in step S2, the polyurethane modified epoxy adhesive is replaced with an equal amount of bisphenol A type epoxy resin, and the rest are the same.

[0084] Comparative Example 5:

[0085] Compared with Example 1, the difference is that nano-SiO2 particles with a particle size of 30 nm were not added in step S3, while the rest are the same.

[0086] Test Example 1:

[0087] Density ρ of composite material pedestrian slabs for anti-icing bridge operation passages was tested according to the method in GB / T 1463.

[0088] The compressive strength of the composite material pedestrian slab for anti-icing bridge access was tested according to the method in GB / T 1448.

[0089] The bending strength of composite material pedestrian slabs for anti-icing bridge operation passages was tested according to the method in GB / T 1449.

[0090] Deionized water was evenly sprayed onto the surface of the anti-icing nano-coating 3 of the composite material pedestrian slab of the anti-icing bridge operation passage to keep the surface of the anti-icing nano-coating 3 moist. A standard rubber slider was placed on the moist surface of the anti-icing nano-coating 3, and a portable static friction coefficient tester was started to pull the standard rubber slider at a constant speed. The pulling force value of the standard rubber slider at the moment of transition from stationary to relative sliding was recorded. The friction coefficient value of the slab surface was obtained based on the ratio of the pulling force value to the weight value of the standard rubber slider.

[0091] Table 1 Mechanical properties and coefficient of friction of the plate surface Group <![CDATA[Density (ρ) / (g / cm 3 )]]> Compressive strength (MPa) Bending strength (MPa) Plate surface friction coefficient Example 1 1.98 631.5 865.2 0.66 Example 2 2.04 668.3 821.6 0.61 Example 3 2.01 642.7 846.9 0.68 Comparative Example 1 1.96 628.9 851.4 0.64 Comparative Example 2 2.02 615.4 798.2 0.65 Comparative Example 3 1.99 625.1 841.5 0.58 Comparative Example 4 2.03 541.2 683.7 0.63 Comparative Example 5 1.97 629.8 853.1 0.41

[0092] According to the data in Table 1, the density of the anti-icing bridge work passage composite material pedestrian slabs prepared in Examples 1 to 3 is between 1.98 and 2.04 g / cm³. 3The compressive strength is in the range of 631.5-668.3 MPa, the flexural strength is in the range of 821.6-865.2 MPa, and the coefficient of friction of the board surface is in the range of 0.61-0.68. Continuous alkali-free glass fiber and alkali-free stitch-woven felt serve as the skeleton structure of the composite material, bearing the mechanical stress applied externally. The polyurethane resin contains urethane bonds formed by the condensation of isocyanate and polyether polyol. Under injection pressure, the polyurethane resin fills the internal gaps of the continuous alkali-free glass fiber and alkali-free stitch-woven felt, curing and cross-linking to form a three-dimensional network structure. The polyurethane resin network structure fixes the position of the continuous alkali-free glass fiber, uniformly transferring the load to the continuous alkali-free glass fiber when subjected to external compressive and bending loads. The polyether polyol component provides flexible molecular chain segments, which produce elastic deformation under stress, avoiding internal stress concentration and damage, and maintaining the mechanical integrity of the walking board matrix 1. The high-purity quartz sand on the surface of the anti-slip quartz sand layer 2 combines with the nano-SiO2 particles in the anti-icing nano-coating layer 3 to construct a macroscopic and multi-scale rough structure on the surface, providing frictional resistance to resist relative sliding.

[0093] In Comparative Example 4, the polyurethane-modified epoxy adhesive was replaced with an equal amount of bisphenol A type epoxy resin. The compressive strength decreased to 541.2 MPa and the flexural strength decreased to 683.7 MPa. The bisphenol A type epoxy resin cured to produce a rigid molecular network with a high cross-linking density. Lacking the flexible buffer deformation space provided by the polyurethane grafted segments, the adhesive layer composed of bisphenol A type epoxy resin could not follow the deformation of the underlying composite substrate. The stress exceeding the yield strength caused microcracks to form in the rigid molecular network. During continuous loading, the microcracks extended into the interior of the walking board matrix 1, cutting off the stress transmission path inside the matrix layer, resulting in a decrease in the overall load-bearing capacity of the material.

[0094] In Comparative Example 5, without the addition of 30 nm nano-SiO2 particles, the coefficient of friction on the plate surface decreased to 0.41. The anti-icing nano-coating 3 lacks the rigid node support and nanoscale surface roughness provided by the nano-SiO2 particles; the surface friction resistance relies solely on the high-purity quartz sand within the anti-slip quartz sand layer 2. The lack of dimensional roughness results in a smoothed surface for the anti-icing nano-coating 3. When the standard rubber slider slides on the surface, the water film cannot be pierced and dissipated by the raised structures. The water film exists at the contact interface and acts as a lubricant, leading to a decrease in the measured friction resistance force.

[0095] Test Example 2:

[0096] Using a microsyringe, 5 μL of deionized water was drawn and dropped onto the anti-icing nano-coating surface of the composite material pedestrian slab of the anti-icing bridge operation passage. After the deionized water droplet stabilized, a contact angle meter was used to measure the static contact angle at room temperature and the value was recorded. Then, the sample stage of the meter was tilted at a rate of 1 ° / s, and the tilt angle of the sample stage when the deionized water droplet slid relative to the anti-icing nano-coating surface was recorded as the roll angle. Measurements were taken at five different locations on the surface of the composite material pedestrian slab of the anti-icing bridge operation passage and the data were recorded.

[0097] The prepared anti-icing bridge operation passage composite material pedestrian board was placed in a high and low temperature alternating test chamber set at -15℃ and kept at a constant temperature for 2 hours. 10 μL of deionized water was taken with a pipette and dropped onto the surface of the anti-icing nano-coating in the -15℃ environment. The time taken from the moment the deionized water droplet came into contact with the anti-icing nano-coating surface until the deionized water droplet completely lost its transparency and became a solid opaque ice crystal was recorded as the icing delay time.

[0098] In an environment with a constant temperature of -15℃, a hollow cylindrical bottomless silicone mold with an inner diameter of 20 mm and a height of 25 mm was placed on the surface of the anti-icing nano-coating of the composite material pedestrian slab for the anti-icing bridge operation passage. The hollow cylindrical bottomless silicone mold was filled with deionized water and left to stand at -15℃ for 24 hours, during which the deionized water completely froze to form a cylindrical ice block. The hollow cylindrical bottomless silicone mold was then removed vertically. Using a digital push-pull force gauge, the cylindrical ice block was pushed close to the surface of the anti-icing nano-coating along a direction parallel to the surface of the composite material pedestrian slab for the anti-icing bridge operation passage. The peak value of the push-pull force gauge displayed at the moment the cylindrical ice block detached from the surface of the anti-icing nano-coating was recorded. The peak value of the push-pull force was divided by the actual contact area between the cylindrical ice block and the anti-icing nano-coating to obtain the ice layer shear adhesion value.

[0099] Table 2 Anti-icing capability test data Group Static contact angle (°) Roll angle (°) Ice-forming delay time (s) Ice layer shear adhesion (kPa) Example 1 158.4 4.3 8532 28.7 Example 2 161.7 3.8 9121 24.5 Example 3 156.9 4.9 7965 31.2 Comparative Example 1 141.2 16.5 4218 86.4 Comparative Example 2 157.6 5.1 7845 34.1 Comparative Example 3 159.8 4.5 8214 30.6 Comparative Example 4 155.8 5.6 7632 38.4 Comparative Example 5 119.5 37.2 1642 189.6

[0100] According to the data in Table 2, the anti-icing bridge operation passage composite walking slabs prepared in Examples 1 to 3 all had static contact angles exceeding 156°, rolling angles below 5°, icing delay times ranging from 7965 to 9121 s, and ice layer shear adhesion ranging from 24.5 to 31.2 kPa. The fluorinated alkylsilane FAS-17 in the anti-icing nanofilm-forming liquid underwent hydrolysis and condensation, providing low surface energy fluorinated groups. Together with nano-SiO2 particles, these groups constructed a micro-nano composite geometrically rough morphology on the surface of the anti-slip quartz sand layer 2. The cross-linking of chemical composition and morphology trapped the air layer, reducing the solid-liquid contact area between deionized water droplets and the anti-slip quartz sand layer 2. The heat transfer medium changed from solid-liquid contact to partial solid-gas contact, reducing the heat transfer rate, hindering the phase change process from liquid water to solid ice, and reducing the mechanical engagement depth at the bottom of the solid ice block.

[0101] In Comparative Example 5, without the addition of nano-SiO2 particles, the surface of the anti-icing nano-coating lost its nanoscale surface roughness, the static contact angle decreased to 119.5°, the icing delay time decreased to 1642 s, and the ice layer shear adhesion surged to 189.6 kPa. Due to the lack of rough protrusions constructed by nanoparticles, deionized water droplets completely penetrated into the sand layer gaps of the anti-slip quartz sand layer 2, causing the deep anchoring phenomenon of ice blocks.

[0102] In Comparative Example 1, using 53 parts by mass of anhydrous ethanol instead of the ethanol and isopropanol mixture resulted in a decrease in the static contact angle to 141.2°, a reduction in the freezing delay time to 4218 s, and an increase in the ice layer shear adhesion to 86.4 kPa. The anti-icing nano-coating failed to uniformly coat the high-purity quartz sand and fill the gaps between the sand layers. Residual pores led to capillary action, allowing deionized water to enter the incompletely coated areas, resulting in a deterioration of the anti-icing parameters. The gradient evaporation characteristics generated by the mixture of ethanol and isopropanol ensured sufficient leveling and cross-linking windows for the silane hydrolysis products, forming a dense, impermeable network.

[0103] Test Example 3:

[0104] In a normal temperature environment, the surface of the anti-icing nano-coating of the composite pedestrian slab of the anti-icing bridge access road was wiped with anhydrous ethanol using a cotton swab. Epoxy structural adhesive was then evenly applied to the surface of the anti-icing nano-coating. A cylindrical aluminum test ingot with a diameter of 20 mm was vertically pressed onto the surface of the epoxy structural adhesive-coated anti-icing nano-coating and allowed to stand for 24 hours until the epoxy structural adhesive was completely cured. A digital pull-out tester was then connected to the cylindrical aluminum test ingot, and a tensile load was applied at a loading rate of 1 MPa / s along a direction perpendicular to the surface of the composite pedestrian slab of the anti-icing bridge access road. The load value at the instant the cylindrical aluminum test ingot was removed from the surface of the anti-icing nano-coating was recorded as the critical tensile force value.

[0105] The composite material pedestrian walkway for the anti-icing bridge operation channel was cut into square specimens with a side length of 100 mm. The square specimens were horizontally fixed on the test turntable of a wheel abrasion tester. An H-22 type rubber grinding wheel was installed at the bottom of the support arm of the wheel abrasion tester, and a constant load of 500 g was applied to the top of the support arm. The test turntable was started, and the rotation speed was set to 60 r / min. It was run continuously for 1000 friction cycles. After stopping, the detached abrasion debris on the surface of the square specimen was removed using a soft brush. The difference between the initial mass and the mass after the test was calculated as the mass loss value.

[0106] The composite material pedestrian walkway of the anti-icing bridge access road was placed in a low-temperature test chamber with a constant internal temperature of -15°C for 4 hours, and then transferred to the working base of a drop hammer impact testing machine. A 1 kg steel hemispherical drop hammer was raised to a height of 1 m vertically above the surface of the anti-icing nano-coating. The steel hemispherical drop hammer was released and allowed to fall freely along the guide rail to impact the surface of the anti-icing nano-coating. The drop hammer was removed, and the impact area was observed. A transparent grid plate with a 1 mm spacing was used to cover the impact area, and the actual area of ​​interlayer delamination and block detachment of the anti-slip quartz sand layer was counted. The actual area of ​​interlayer delamination and block detachment was divided by the projected area generated by the impact of the steel hemispherical drop hammer to obtain the percentage of detached area.

[0107] Impact toughness (23℃) was determined according to GB / T 1451, with the notch direction of the specimen perpendicular to the glass fiber.

[0108] The notch direction of the impact toughness (-40℃) specimen is perpendicular to the glass fiber. The specimen is placed in a low temperature test chamber. After the temperature drops to -40℃±2℃, the specimen is placed in the chamber and kept at a constant temperature for 2 hours. The specimen is then removed and tested according to the method of GB / T 1451.

[0109] Table 3 Test Data Group Critical tensile force (MPa) Mass loss (mg) Percentage of area detached (%) <![CDATA[Impact toughness (23 °C) / (kJ / m 2 )]]> <![CDATA[Impact toughness (-40 °C) / (kJ / m 2 )]]> Example 1 8.86 46.2 1.32 320 315 Example 2 9.24 42.8 1.14 344 345 Example 3 8.17 51.5 1.85 312 300 Comparative Example 1 7.95 53.6 2.05 300 256 Comparative Example 2 5.32 112.5 14.62 206 198 Comparative Example 3 8.41 48.9 1.96 296 176 Comparative Example 4 4.65 135.8 28.41 203 156 Comparative Example 5 8.12 55.3 1.78 295 286

[0110] According to the data in Table 3, the tensile critical value of the anti-icing bridge operation passage composite walking slabs prepared in Examples 1 to 3 is in the range of 8.17-9.24 MPa, the mass loss is in the range of 42.8-51.5 mg, and the proportion of detached area is in the range of 1.14%-1.85%. By controlling the polyurethane-modified epoxy adhesive in a semi-cured gel state, unreacted epoxy groups are retained. In the subsequent co-curing step at 42℃ to 50℃, the amino groups contained in the silane coupling agent KH-550 in the anti-icing nanofilm-forming liquid undergo ring-opening addition reactions with the unreacted epoxy groups inside the polyurethane-modified epoxy adhesive in the semi-cured gel state. This establishes a chemical bond network between the anti-icing nano-coating and the polyurethane-modified epoxy adhesive, improving the overall interlayer bonding strength of the coating system and resisting the horizontal frictional cutting stress during grinding wheel operation.

[0111] In Comparative Example 2, the baking time was extended to 5 h, and the polyurethane modified epoxy adhesive reached a fully cured state. The tensile critical value decreased to 5.32 MPa, the mass loss increased to 112.5 mg, and the proportion of detached area increased to 14.62%. The fully cured state consumed all the active epoxy groups inside the adhesive layer. After hydrolysis, the anti-icing nano film-forming liquid could only be adsorbed onto the surface of the anti-slip quartz sand layer 2 and the bottom adhesive through intermolecular van der Waals forces, losing the chemical bonding pathway. When subjected to external pulling and friction, interfacial fracture occurred.

[0112] In Comparative Example 4, an equal mass of bisphenol A type epoxy resin was used to replace the polyurethane modified epoxy adhesive. The tensile critical value decreased to 4.65 MPa, the mass loss increased to 135.8 mg, and the proportion of detached area increased to 28.41%. After curing, the molecular chain of bisphenol A type epoxy resin has a rigid network structure and lacks flexible chain segments. In an environment of -15℃, the rigid molecular chain exhibits low-temperature brittleness. When a steel hemispherical drop hammer applies an instantaneous impact load, the rigid structure cannot absorb and dissipate the impact kinetic energy through the deformation of the molecular chain segments. The high-intensity impact stress is directly concentrated at the bottom interface of the anti-slip quartz sand layer 2, inducing brittle fracture and causing a large area of ​​anti-slip quartz sand layer 2 to peel off.

[0113] Test Example 4:

[0114] In a normal temperature environment, an ultrasonic coating thickness gauge was used to measure the surface of the composite material pedestrian slab for the anti-icing bridge access road. Twenty equal-sized test areas were evenly divided on the surface of the anti-slip quartz sand layer 2 of the composite material pedestrian slab. The dry film thickness of the anti-icing nano-coating was measured at the center of each test area, and the maximum and minimum dry film thickness values ​​were recorded for all 20 test areas. The difference between the maximum and minimum dry film thickness values ​​was calculated to obtain the dry film thickness range. A smaller dry film thickness range indicates a more uniform film thickness for the anti-icing nano-coating.

[0115] The composite material pedestrian walkway for the anti-icing bridge operation passage was placed on the workbench of a light source observation box with an internal D 65 standard light source. A transparent polyester mapping film with a 1 mm square grid was completely and smoothly covered on the surface of the anti-icing nano-coating of the composite material pedestrian walkway. Under the illumination of the D 65 standard light source, the number of grids exhibiting whitening, orange peel, or porosity was manually observed and counted. The total area corresponding to the grids exhibiting whitening, orange peel, or porosity was divided by the total actual tested surface area of ​​the composite material pedestrian walkway for the anti-icing bridge operation passage to obtain the percentage of macroscopic defects.

[0116] Table 4. Dry film thickness variation and percentage of macroscopic defect area Group Dry film thickness range (μm) Percentage of area with macroscopic defects (%) Example 1 1.15 0.85 Example 2 1.42 1.24 Example 3 0.96 0.68 Comparative Example 1 4.87 9.45

[0117] According to the data in Table 4, the dry film thickness of the anti-icing bridge work passage composite walking slabs prepared in Examples 1 to 3 ranged from 0.96 to 1.42 μm, and the proportion of macroscopic defect area ranged from 0.68% to 1.24%. Ethanol and isopropanol were mixed to form an ethanol-isopropanol mixed solvent. Utilizing the different saturated vapor pressures of ethanol and isopropanol, the anti-icing nanofilm-forming liquid was applied to the surface of the anti-slip quartz sand layer 2 using a high-pressure airless spraying method. Ethanol, with its higher vapor pressure, evaporated first. This preferential evaporation of ethanol caused an initial increase in the viscosity of the anti-icing nanofilm-forming liquid, preventing gravity-induced sagging on the vertical or inclined surface of the anti-slip quartz sand layer. Isopropanol, with its lower vapor pressure, evaporated more slowly and temporarily remained inside the anti-icing nanofilm-forming liquid. The retention of isopropanol provides a leveling window for the fluoroalkylsilane FAS-17 and methyltrimethoxysilane on the surface of the anti-slip quartz sand layer 2. During this leveling window, the anti-icing nanofilm-forming liquid penetrates and fills the gaps between the high-purity quartz sand particles through capillary action, while simultaneously expelling tiny air bubbles trapped within the coating liquid. The solvent gradient evaporation mechanism alleviates the shrinkage stress of the coating system during the polycondensation and crosslinking process, resulting in a uniformly thick dry film network.

[0118] In Comparative Example 1, replacing 53 parts by mass of the mixed solvent of ethanol and isopropanol with 53 parts by mass of anhydrous ethanol increased the dry film thickness range to 4.87 μm and the proportion of macroscopic defect area to 9.45%. Anhydrous ethanol, as a single solvent, detached from the coating system at a consistent and rapid rate. The rapid evaporation of the solvent caused a sharp increase in the viscosity of the anti-icing nanofilm-forming liquid. The silane hydrolysis condensate did not fully spread on the surface of the anti-slip quartz sand layer 2 before it lost its fluidity and gelled. The accumulation of coating liquid in local areas increased the dry film thickness range. Due to the lack of leveling time and degassing window, the air bubbles that did not escape were trapped inside the cured coating, forming pores. The incompletely spread areas produced orange peel wrinkles during curing shrinkage. The abnormal surface roughness caused diffuse reflection of external light, which appeared as a whitening defect under macroscopic observation.

[0119] Test Example 5:

[0120] The composite material walkway for the anti-icing bridge operation passage was placed in a high and low temperature alternating test chamber. The high temperature test condition was set to 60℃ and the low temperature test condition to -20℃. After maintaining the high temperature at 60℃ for 2 hours, the internal temperature of the working chamber was steadily reduced to -20℃ within 30 minutes and maintained at that temperature for 2 hours to complete one complete hot and cold alternating cycle. This was repeated 50 times. The composite material walkway for the anti-icing bridge operation passage that had undergone the cycle test was then removed and left to stand in a normal temperature environment for 24 hours. Following the pull-out adhesion test procedure in Test Example 3 above, the critical pull-out force value after the cycle was determined. The critical pull-out force value after the cycle was divided by the initial critical pull-out force value of the same batch of composite material walkway for the anti-icing bridge operation passage that had not undergone the hot and cold alternating cycle, and then multiplied by 100% to obtain the pull-out force retention rate value.

[0121] The composite material pedestrian walkway for the anti-icing bridge operation channel was cut into strip-shaped test samples with a length of 300 mm and a width of 50 mm. The strip-shaped test samples were placed horizontally on the three-point bending metal supports of a universal testing machine, with a span of 200 mm between the two supports. The indentation rate of the testing machine head was set to 2 mm / min. A vertical load was applied downwards from the center of the strip-shaped test sample, causing a downward bending deflection of 15 mm at the center. This 15 mm bending deflection was maintained for 10 minutes. The vertical load was then released, and the strip-shaped test sample was removed. The surface of the anti-slip quartz sand layer 2 on the stretched side of the strip-shaped test sample was observed. A transparent measuring film with a 1 mm side square grid was used to cover the bending center area. The actual area of ​​interlayer fracture and detachment of the anti-slip quartz sand was manually counted. The percentage of detached area was obtained by dividing the actual area of ​​fracture and detachment by the total area of ​​the stretched area of ​​the strip-shaped test sample.

[0122] Table 5 Pull-out tension retention rate and percentage of peeling / detachment area Group Pull-out tension retention rate (%) Percentage of peeled / detached area (%) Example 1 88.4 3.2 Example 2 91.7 2.5 Example 3 86.2 4.1 Comparative Example 2 41.5 19.8 Comparative Example 4 33.6 26.7

[0123] According to the data in Table 5, the anti-icing bridge work passage composite pedestrian slabs prepared in Examples 1 to 3 exhibited a pull-out tensile strength retention rate ranging from 86.2% to 91.7%, and a peeling / detachment area percentage ranging from 2.5% to 4.1%. The polyurethane-modified epoxy adhesive was in a semi-cured gel state before coating with the anti-icing nano-film-forming liquid, retaining abundant unreacted active epoxy groups on its surface. These groups underwent a co-curing crosslinking reaction with the amino groups in the anti-icing nano-film-forming liquid, forming a cross-interface chemical covalent bond network. The combination of chemical covalent bonds and the flexible chain segment structure maintained the structural integrity of the overall coating system.

[0124] In Comparative Example 2, the baking time was increased, and the polyurethane-modified epoxy adhesive was fully cured before the anti-icing nano film-forming liquid was applied. The fully cured state consumed all the active functional groups on the surface of the adhesive. The anti-slip quartz sand layer 2 and the polyurethane-modified epoxy adhesive only maintained an adsorption effect. After 50 cycles of hot and cold alternation, there was a difference in the coefficient of thermal expansion between the polyurethane resin matrix, the epoxy adhesive layer and the high-purity quartz sand. The heating and cooling process triggered interfacial shear internal stress with repeated alternation of direction. The pull-out tensile strength retention rate decreased to 41.5%, and the peeling and detachment area percentage increased to 19.8%.

[0125] Comparative Example 4 used an equal mass of bisphenol A type epoxy resin to replace the polyurethane modified epoxy adhesive. After curing, the molecular network of bisphenol A type epoxy resin exhibits a highly dense and rigid state, lacking a flexible molecular structure that can provide buffering deformation space. When a vertical load is applied to produce a 15 mm bending deflection, dense tensile stress is generated on the stretched side of the bottom of the long strip test sample. The rigid bisphenol A type epoxy resin adhesive layer cannot follow the underlying composite substrate to produce synchronous deformation in a coordinated manner. The stress instantly exceeds the yield limit of the material itself and brittle fracture occurs. The fracture cracks rapidly extend to the surface, destroying the connection between the anti-slip quartz sand layer 2 and the underlying substrate, causing large-scale sheet peeling of the anti-slip quartz sand layer 2, with a peeling and detachment area percentage of 26.7% and a pull-out tensile strength retention rate dropping to 33.6%.

[0126] Test Example 6:

[0127] The composite material walkway for the anti-icing bridge operation passage was fixed on the test platform of a reciprocating linear abrasion testing machine. 400-grit silicon carbide sandpaper was installed on the friction head of the abrasion testing machine, and a constant vertical load of 200 g was applied to the friction head. The reciprocating linear abrasion testing machine was started, and the reciprocating speed of the friction head was set to 40 times / min, with a friction stroke of 50 mm. 500 reciprocating friction cycles were performed continuously. The machine was then stopped, and the composite material walkway for the anti-icing bridge operation passage was removed. Compressed air was used to blow away the wear debris from the surface. Following the static contact angle test procedure in Test Example 2 above, the static contact angle of the friction area was measured. The initial static contact angle value before friction was subtracted from the static contact angle value after friction to obtain the decrease in contact angle after abrasion.

[0128] A hollow cylindrical bottomless silicone mold with an inner diameter of 20 mm and a height of 25 mm was placed on the surface of the composite material pedestrian slab for the anti-icing bridge operation passage. The hollow cylindrical bottomless silicone mold was filled with deionized water. The mold with deionized water and the composite material pedestrian slab for the anti-icing bridge operation passage were sent into a high and low temperature alternating test chamber. The temperature inside the test chamber was set to drop to -20℃ and maintained at a constant temperature for 3 hours to cause the deionized water to freeze completely into solid ice. Then the temperature inside the test chamber was raised to 20℃ and maintained at a constant temperature for 3 hours to cause the solid ice to melt completely into liquid water. The above cooling and heating process was completed as a complete freeze-thaw cycle. 30 complete freeze-thaw cycles were executed continuously. After the cooling and freezing stage of the 30th freeze-thaw cycle, the low temperature environment of -20℃ was maintained. Following the ice shear adhesion test procedure in Test Example 1 above, the ice shear adhesion value was measured. The ice shear adhesion value after the 30th freeze-thaw cycle was subtracted from the initial ice shear adhesion value before the cycle to obtain the increase in ice shear force after the freeze-thaw cycle.

[0129] The resistance to damp heat aging was determined according to the method specified in GB / T 2573 for the composite material pedestrian slab of the anti-icing bridge operation passage. The aging was carried out for 720 h, and the longitudinal bending strength retention rate was used for characterization.

[0130] Table 6 Comparison of overall durability in terms of weather resistance and anti-icing properties Group The decrease in contact angle after wear (°) Increase in ice shear stress (kPa) after freeze-thaw cycles Longitudinal bending strength retention rate (%) Example 1 12.4 6.8 86 Example 2 10.9 5.2 87 Example 3 14.1 8.3 85 Comparative Example 3 45.6 28.7 72 Comparative Example 5 58.2 42.1 67

[0131] According to the data in Table 6, the anti-icing bridge operation passage composite walking slabs prepared in Examples 1 to 3 showed a contact angle decrease of 10.9°-14.1° after wear, and an ice shear force increase of 5.2-8.3 kPa after freeze-thaw cycles. The anti-icing nanofilm-forming liquid system simultaneously contains fluoroalkylsilane FAS-17, methyltrimethoxysilane, and particles with a particle size of 30-50 μm. The nano-sized SiO2 particles, with a molecular structure containing three methoxy functional groups in methyltrimethoxysilane, undergo hydrolysis in a mixed solvent of ethanol and isopropanol to generate a large number of highly active silanol groups. These silanol groups then undergo co-condensation with the hydrolysis products of fluoroalkylsilane FAS-17, constructing a three-dimensional cross-linked siloxane network. This high-density cross-linked siloxane network anchors the nano-SiO2 particles and fluorine-containing groups that provide low surface energy to the surface of the anti-slip quartz sand layer 2. The nano-SiO2 particles act as rigid skeleton nodes within the cross-linked network, enhancing the overall mechanical resistance of the coating. Facing the mechanical cutting stress generated by reciprocating linear friction and the volume expansion and compressive stress caused by water freezing, the three-dimensional cross-linked network and the nanoparticle skeleton work synergistically to resist the peeling and structural damage of the coating surface, maintaining the anti-icing micro-nano rough morphology composed of fluorine-containing groups and nano-protrusions.

[0132] Comparative Example 3 did not add methyltrimethoxysilane, but increased the amount of fluoroalkylsilane FAS-17 from 20 parts by mass to 35 parts by mass. After wear, the contact angle decreased by 45.6°, and after freeze-thaw cycles, the ice shear force increased by 28.7 kPa. The fluoroalkylsilane FAS-17 molecule carries long-chain fluoroalkyl groups at its end groups, resulting in significant steric hindrance. Furthermore, the number of active sites participating in hydrolysis and polycondensation is limited. Polycondensation of a single fluoroalkylsilane FAS-17 results in a polymer network with low cross-linking density and loose inter-chain bonding. When subjected to mechanical friction from silicon carbide sandpaper or expansion stress from ice crystal growth, the low cross-linking density siloxane network breaks down, causing the desorption and loss of low surface energy fluorine-containing substances, and a decrease in the contact angle value.

[0133] In Comparative Example 5, without the addition of nano-SiO2 particles, the contact angle decreased after wear, and the ice shear force increased after freeze-thaw cycles. The system lacked the rigid support provided by nano-SiO2 particles, resulting in a decrease in coating hardness and scratch resistance. The polymer coating was easily worn away during friction. In 30 consecutive freeze-thaw cycles, deionized water repeatedly changed between liquid and solid phases. Liquid water penetrated into the interior of the coating, which lacked a nano-rough structure. The wedge-shaped force generated by freezing expansion caused interlayer delamination of the coating. The coating defects expanded with the increase of the number of cycles. Liquid water directly penetrated into the internal gaps of the anti-slip quartz sand layer 2. The ice block generated deep mechanical anchoring inside the gaps of the sand layer, causing the ice layer shear adhesion to show an upward trend.

[0134] In summary, this invention improves the load-bearing capacity, drainage performance, and anti-slip performance of composite material pedestrian slabs for anti-icing bridge operation passages, thus realizing the anti-icing function of composite material pedestrian slabs for anti-icing bridge operation passages.

Claims

1. A composite material pedestrian slab for anti-icing bridge work passages, characterized in that, It includes a walking board substrate (1), an anti-slip quartz sand layer (2), and an anti-icing nano-coating (3); the anti-slip quartz sand layer (2) is disposed on the upper surface of the walking board substrate (1), and the anti-icing nano-coating (3) is disposed on the outer surface of the anti-slip quartz sand layer (2); The raw materials for preparing the walking board substrate (1) include: continuous alkali-free glass fiber, polyurethane resin, silicone defoamer, silane coupling agent, antioxidant and alkali-free stitch-woven felt; The anti-slip quartz sand layer (2) is formed by curing an adhesive mixture with quartz sand, wherein the adhesive mixture is composed of a polyurethane modified epoxy adhesive and a silane coupling agent; The anti-icing nano-coating (3) is formed by curing an anti-icing nano-film-forming liquid, which is prepared by hydrolyzing the following raw materials: fluoroalkylsilane, methyltrimethoxysilane, nano-SiO2 particles, silane coupling agent, deionized water and mixed solvent.

2. The anti-icing bridge work passage composite material pedestrian slab according to claim 1, characterized in that, The walking board substrate (1) comprises the following raw materials in parts by weight: continuous alkali-free glass fiber: 70.0-75.0 parts; polyurethane resin: 13.2-18.8 parts; silicone defoamer: 0.2-0.5 parts; silane coupling agent KH-550: 0.5-1.0 parts; antioxidant: 0.1-0.3 parts; alkali-free stitched felt: 5.0-7.0 parts; In the anti-slip quartz sand layer (2), the quartz sand is high-purity quartz sand, and the adhesive mixture is composed of 100.0 parts by weight of polyurethane modified epoxy adhesive and 2.0-4.0 parts by weight of silane coupling agent KH-560. The anti-icing nanofilm-forming solution is prepared by hydrolyzing the following raw materials in parts by weight: The fluoroalkylsilane FAS-17: 15.0-25.0 parts; the methyltrimethoxysilane: 10.0-20.0 parts; the nano-SiO2 particles: 5.0-10.0 parts; the silane coupling agent KH-55: 2.0-5.0 parts; the deionized water: 5.0-10.0 parts; the mixed solvent is a mixture of ethanol and isopropanol: 40.0-60.0 parts.

3. The anti-icing bridge work passage composite material pedestrian slab according to claim 2, characterized in that, The thickness of the walking board substrate (1) is 40.0-70.0 mm, and the dry film thickness of the anti-icing nano-coating (3) is 5.0-10.0 μm; The walking board substrate (1) is provided with an array of drainage holes (4), the diameter of which is 8.0-12.0 mm, and the inner wall of which is sealed to prevent leakage. The alkali-free stitch-woven felt forms a covering structure on the outer layer of the continuous alkali-free glass fiber; The anti-icing nano-coating (3) completely coats the high-purity quartz sand in the anti-slip quartz sand layer (2) and fills the gaps between the sand layers in the anti-slip quartz sand layer (2); The polyurethane resin is prepared by mixing diphenylmethane diisocyanate with a polyether polyol with a functionality of 3 and a number average molecular weight of 3000-5000 in a molar equivalent ratio of 1.1-1.3:

1. The antioxidant is selected from antioxidant 1010 and antioxidant 168; The ethanol and isopropanol mixed solvent is prepared by mixing ethanol and isopropanol in a 1:1 volume ratio; The polyurethane-modified epoxy adhesive has a solid content of 95%-98%, a tensile shear strength of 5.0-8.0 MPa at 20-25℃, and an adhesive strength of 3.0-5.0 MPa. The high-purity quartz sand has a silica content of 98.0%-99.0% and a mesh size of 20-40. The particle size of the nano-SiO2 particles is 10.0-50.0 nm.

4. The anti-icing bridge work passage composite material pedestrian slab according to claim 2, characterized in that, The steps for preparing the anti-icing bridge work passage composite material pedestrian slab are as follows: The continuous alkali-free glass fiber is preheated and degassed, and the polyurethane resin, the silicone defoamer, the silane coupling agent KH-550 and the antioxidant are mixed evenly. The preheated and degassed continuous alkali-free glass fiber and the alkali-free stitch-woven felt are introduced into the curing mold. The mixed polyurethane resin is injected into the curing mold for impregnation. The impregnated continuous alkali-free glass fiber and the alkali-free stitch-woven felt are pulled through the segmented heating curing mold for curing to obtain a cured and shaped board. The cured and shaped board is cut, and an array of drainage holes (4) is processed on the surface of the board to obtain the walking board substrate (1). The upper surface of the walking board substrate (1) is roughened, the adhesive mixture is coated on the upper surface of the walking board substrate (1), the high-purity quartz sand is laid on the surface of the adhesive mixture, the walking board substrate (1) with the high-purity quartz sand is pre-bonded and baked so that the adhesive mixture reaches a semi-cured gel state, cooled and the loose sand is removed to obtain a semi-finished product with the anti-slip quartz sand layer (2); The fluoroalkylsilane FAS-17, the methyltrimethoxysilane, the nano-SiO2 particles, the silane coupling agent KH-550, the deionized water, and the mixed solvent of ethanol and isopropanol were mixed to obtain a mixed system. The pH value of the mixed system was adjusted and the mixture was stirred and hydrolyzed to obtain the anti-icing nanofilm-forming liquid. The anti-icing nano film-forming liquid is coated on the outer surface of the semi-finished anti-slip quartz sand layer (2), and after leveling, it is sent into an oven for co-curing to form the anti-icing nano coating (3), thus obtaining the anti-icing bridge operation passage composite material pedestrian board.

5. The anti-icing bridge work passage composite material pedestrian slab according to claim 4, characterized in that, The specific steps for preheating and degassing the continuous alkali-free glass fiber are as follows: the continuous alkali-free glass fiber is spread on a warp frame, the preheating and degassing temperature is set to 40-50℃, and the time is set to 20-40 min.

6. The composite material pedestrian slab for anti-icing bridge work passages according to claim 4, characterized in that, The mixed polyurethane resin is injected into the curing mold for impregnation, and the injection pressure is set to 3.5-5.5 MPa. The continuous alkali-free glass fiber and the alkali-free stitch-woven felt, after being traction-impregnated, are cured by the curing mold heated in sections. The traction speed is set to 30-50 cm / min. The inlet temperature of the curing mold is set to 60-80℃, the middle temperature is set to 120-160℃, and the outlet temperature is set to 180-220℃.

7. The anti-icing bridge work passage composite material pedestrian slab according to claim 4, characterized in that, The upper surface of the walking board substrate (1) is roughened by sandblasting to achieve a surface roughness Ra of 3.2-6.3 μm, and the floating dust on the upper surface of the walking board substrate (1) is removed by high-pressure blowing; the adhesive mixture is then coated onto the upper surface of the walking board substrate (1) at a coating amount of 200-300 g / m². 2 The high-purity quartz sand is spread on the surface of the adhesive mixture using a spreading method, and the surface density of the high-purity quartz sand is 300-500 g / m³. 2 .

8. The anti-icing bridge work passage composite material pedestrian slab according to claim 4, characterized in that, The specific steps for pre-bonding and baking the walking board substrate (1) covered with the high-purity quartz sand to achieve a semi-cured gel state of the adhesive mixture are as follows: the walking board substrate (1) covered with the high-purity quartz sand is pre-bonded at a temperature of 20-25℃ for 25-35 min, and the pre-bonded walking board substrate (1) is sent into an oven and baked at a temperature of 35-50℃ for 1-2 h.

9. The anti-icing bridge work passage composite material pedestrian slab according to claim 4, characterized in that, When adjusting the pH of the mixture, one of glacial acetic acid and dilute hydrochloric acid is added to adjust the pH of the mixture to 3.0-4.

0. The stirring hydrolysis is carried out at a speed of 300-500 r / min and the reaction time is 30-60 min.

10. The anti-icing bridge work passage composite material pedestrian slab according to claim 4, characterized in that, The anti-icing nanofilm-forming liquid coating is applied using a high-pressure airless spraying method to obtain a semi-finished product. The spray gun pressure of the high-pressure airless spraying method is 0.3-0.5 MPa, and the spraying distance is 20-30 cm. The semi-finished product is leveled at a temperature of 20-25℃ for 15-20 min, and then the leveled semi-finished product is placed in an oven and cured at a temperature of 35-50℃ for 2-3 h.

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