Photo-thermal response fiber material, preparation method thereof and photo-thermal response type sealing layer

Abstract

The invention belongs to the technical field of road engineering materials, and provides a photo-thermal response fiber material, a preparation method thereof and a photo-thermal response type seal coat. The preparation method comprises the following steps: sequentially carrying out alkali activation treatment, microwave pretreatment, biological enzymolysis treatment and silane coupling agent modification treatment on wheat straws to obtain modified wheat straw fibers; the modified wheat straw fibers are subjected to anoxic pyrolysis treatment, and porous carbon fibers are obtained; and mixing the porous carbon fiber with a phase change material, and carrying out vacuum adsorption to obtain the photo-thermal response fiber material. The photo-thermal response fiber material prepared by the method has excellent photo-thermal response performance, temperature adaptability, environmental protection performance and salt corrosion resistance, a photo-thermal response type seal coat prepared by utilizing the photo-thermal response fiber material also has excellent self-repairing function, salt corrosion resistance and crack resistance, intelligent adjustment of pavement temperature can be realized, and the application range of the photo-thermal response type seal coat is widened. The service life of the pavement is prolonged, and the pavement is suitable for regions with large day and night temperature difference and rich solar energy resources.

Description

Technical Field

[0001] The present invention relates to the technical field of road engineering materials, and in particular to a photothermal responsive fiber material, a preparation method thereof, and a photothermal responsive sealing layer. Background Art

[0002] With the rapid development of my country's transportation industry, the mileage of highways continues to grow. Among various pavement materials, asphalt concrete pavements offer advantages such as high strength, good smoothness, smooth and comfortable driving, low noise, and low maintenance costs. They are the preferred choice for new construction, renovation, expansion, and maintenance projects on all levels of Chinese highways. Currently, over 95% of asphalt pavements utilize a semi-rigid base layer. This base layer not only offers sufficient plate properties, stiffness, and strong diffusion stress, but also possesses certain tensile strength, fatigue resistance, and good water stability. However, the construction of semi-rigid base layers utilizes a large amount of cement. Due to the inherent properties of cement-based materials, they are prone to shrinkage and thermal cracking during use. Once these cracks appear, they gradually expand under the combined influence of vehicle loads, temperature fluctuations, and other factors, forming reflective cracks. If reflective cracks are not promptly repaired and treated, they can lead to serious damage to the pavement structure. In the short term, this can impact traffic flow and driving comfort; in the long term, it can reduce the performance of the asphalt pavement and shorten its service life. When reflective cracks are densely distributed, asphalt pavement will be severely damaged, significantly impacting its normal function and posing a serious threat to driving safety. To effectively address reflective cracking, installing a fiber-based asphalt stress-absorbing layer at the interface between the asphalt surface and the base layer, or between asphalt surface layers, has become one of the more effective methods for addressing reflective cracks.

[0003] However, the fibers in traditional fiber chip seal materials are mostly polyester fibers or pure basalt fibers, and the asphalt is mostly petroleum-based materials, which have the following problems:

[0004] 1. Poor temperature adaptability: When the temperature difference between day and night is large, especially when the temperature difference between day and night often reaches more than 30°C, the traditional sealing material will cause the crack rate to increase by 15% to 20% annually due to temperature stress.

[0005] 2. Single function: Lack of effective use of solar energy and inability to achieve intelligent regulation of road surface temperature.

[0006] 3. Insufficient environmental protection: Petroleum-based materials are difficult to degrade and do not meet the requirements of sustainable development.

[0007] In addition, wheat straw, as an agricultural waste, is abundant in resources but has a low utilization rate. In the existing technology, there is insufficient research on the mechanical properties and functional modification of straw fiber, which limits its application in pavement sealing.

[0008] Therefore, there is an urgent need to provide a sealing layer that uses wheat straw as a fiber raw material, has good temperature adaptability, can achieve intelligent regulation of road surface temperature, and has excellent environmental protection performance. Summary of the Invention

[0009] In view of this, the present invention provides a photothermal responsive fiber material, a preparation method thereof, and a photothermal responsive sealant to solve the problems of poor temperature adaptability, single function, and poor environmental protection of existing traditional sealant materials.

[0010] In order to achieve the above object, the present invention adopts the following technical solutions:

[0011] The present invention provides a method for preparing a photothermal responsive fiber material, comprising the following steps:

[0012] 1) sequentially subjecting wheat straw to alkali activation treatment, microwave pretreatment, bioenzymatic hydrolysis treatment, and silane coupling agent modification treatment to obtain modified wheat straw fiber;

[0013] 2) subjecting the modified wheat straw fibers to anoxic pyrolysis to obtain porous carbon fibers;

[0014] 3) The porous carbon fiber is mixed with the phase change material and vacuum adsorbed to obtain a photothermal responsive fiber material.

[0015] Preferably, the alkali activation treatment in step 1) is carried out in an alkali solution; the temperature of the alkali activation treatment is 50-70° C., and the time is 0.5-2 hours; the mass concentration of the alkali solution is 0.5-3%; and the alkali solution comprises sodium hydroxide and / or potassium hydroxide.

[0016] Preferably, the power of the microwave pretreatment in step 1) is 700-900 W, and the time is 2.5-4 minutes.

[0017] Preferably, the bio-enzymatic hydrolysis treatment in step 1) is carried out in a bio-enzyme solution; the temperature of the bio-enzymatic hydrolysis treatment is 45-55° C., the system pH is 4.5-5.0, and the time is 1.5-3 hours; the bio-enzyme solution includes one or more of cellulase, xylanase and β-glucanase; the mass concentration of the bio-enzyme solution is 0.3-1.5%.

[0018] Preferably, the silane coupling agent modification treatment in step 1) is carried out in a silane coupling agent; the temperature of the silane coupling agent modification treatment is 40-60° C., and the time is 20-40 min; the mass concentration of the silane coupling agent is 3-7%, and the pH is 4-5; the silane coupling agent includes one or more of KH550 silane coupling agent, KH560 silane coupling agent, KH570 silane coupling agent, and KH590 silane coupling agent.

[0019] Preferably, the temperature of the anoxic pyrolysis treatment in step 2) is 320-380° C., and the time is 35-45 minutes.

[0020] Preferably, the phase change material in step 3) is a mixture of paraffin wax and lauric acid; the mass ratio of the paraffin wax to lauric acid is 6:4 to 7:3.

[0021] Preferably, the vacuum adsorption pressure in step 3) is -0.08 to -0.12 MPa, the temperature is 50 to 80°C, and the time is 25 to 35 min; the loading rate of the phase change material in the photothermal responsive fiber material is ≥65%, and the length of the photothermal responsive fiber material is 8 to 12 cm.

[0022] The present invention also provides a photothermal responsive fiber material prepared by the above-mentioned method for preparing the photothermal responsive fiber material.

[0023] The present invention also provides a photothermal responsive seal layer, comprising an asphalt bonding layer, a photothermal responsive fiber material layer and a chip seal layer; the photothermal responsive fiber material layer is obtained by laying the above-mentioned photothermal responsive fiber material.

[0024] Preferably, the chip seal layer includes a first chip seal layer and a second chip seal layer; the first chip seal layer is basalt crushed stone coated with a microcapsule repair agent, with a porosity of 28-32%, and a particle size of 9-12 mm; the second chip seal layer is diabase crushed stone coated with a microcapsule repair agent, with a porosity of ≤25%, and a particle size of 5-8 mm.

[0025] Preferably, the microcapsule repair agent includes one or more of chitosan-encapsulated SBS modifier, polyurethane-encapsulated epoxy resin, and gelatin-encapsulated asphalt regeneration agent.

[0026] Preferably, the asphalt bonding layer is a hot mix asphalt bonding layer or an emulsified asphalt bonding layer.

[0027] The present invention also provides a method for preparing the above-mentioned photothermal responsive sealing layer, comprising the following steps:

[0028] An asphalt bonding layer, a photothermal responsive fiber material layer, a first chip seal layer and a second chip seal layer are laid on the road surface in sequence. After paving, the layers are rolled and cured to obtain a photothermal responsive seal layer.

[0029] Preferably, the spreading amount of the photothermal responsive fiber material layer is 100-120 g / m 2 The spreading amount of the first chip seal is 3.5~4.5kg / m 2 , coverage rate ≥90%; the spreading amount of the second chip seal is 2.5~3.5kg / m 2, coverage ≥ 85%; when the asphalt bonding layer is a hot mix asphalt bonding layer, the spreading amount of the asphalt bonding layer is ≥ 2.0 kg / m 2 When the asphalt bonding layer is an emulsified asphalt bonding layer, the spreading amount of the asphalt bonding layer is ≥2.4kg / m 2 .

[0030] It can be seen from the above technical solution that compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The present invention uses agricultural waste wheat straw as its core raw material. The wheat straw is subjected to alkaline activation, microwave pretreatment, bio-enzymatic hydrolysis, and silane coupling agent modification to obtain modified wheat straw fibers. The modified wheat straw fibers are then subjected to anoxic pyrolysis to obtain porous carbon fibers. Finally, the porous carbon fibers are vacuum-adsorbed and loaded with a paraffin wax / lauric acid eutectic phase change material to produce a photothermal responsive fiber material. This photothermal responsive fiber material exhibits excellent photothermal response, temperature adaptability, environmental performance, and salt corrosion resistance. The loaded paraffin wax / lauric acid eutectic phase change material can achieve solar energy absorption, storage, and release functions, significantly reducing temperature fluctuations in the pavement and effectively inhibiting the development of temperature cracks. The wheat straw is modified with a silane coupling agent, and its surface is grafted with a silane coupling agent, thereby improving its salt corrosion resistance to 2.3 times that of traditional polyester fibers. Furthermore, the loading rate of the phase change material in the photothermal responsive fiber material of the present invention is ≥65%, and the remaining pores can absorb salt from the soil, improving the self-cleaning and salt resistance of the pavement.

[0032] 2. The photothermal responsive seal prepared by combining the photothermal responsive fiber material of the present invention with double-layer graded crushed stone and self-repairing microcapsule technology has a crack self-repair healing efficiency of ≥85%, a strength retention rate of ≥80% after 500h of salt spray test, a pavement crack reflectivity of ≤5%, and a pavement temperature fluctuation reduced by 40%. That is, the photothermal responsive seal prepared by the present invention has excellent self-repair function, salt corrosion resistance and crack resistance, and can realize intelligent regulation of pavement temperature, has good temperature adaptability, and extends the service life of the pavement. It is suitable for areas with large temperature differences between day and night and rich solar energy resources. In addition, the photothermal responsive seal of the present invention uses agricultural waste wheat straw as the core raw material, which reduces the use of petroleum-based materials, has excellent environmental protection performance, and meets the requirements of sustainable development. Moreover, the photothermal responsive seal has a low life cycle cost and excellent economic performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0034] Figure 1 This is a schematic structural diagram of the photothermal responsive seal layer prepared in Example 1; wherein: 1. Asphalt bonding layer; 2. Photothermal responsive fiber material layer; 3. Chip seal layer. DETAILED DESCRIPTION

[0035] The present invention provides a method for preparing a photothermal responsive fiber material, comprising the following steps:

[0036] 1) sequentially subjecting wheat straw to alkali activation treatment, microwave pretreatment, bioenzymatic hydrolysis treatment, and silane coupling agent modification treatment to obtain modified wheat straw fiber;

[0037] 2) subjecting the modified wheat straw fibers to anoxic pyrolysis to obtain porous carbon fibers;

[0038] 3) The porous carbon fiber is mixed with the phase change material and vacuum adsorbed to obtain a photothermal responsive fiber material.

[0039] In the present invention, the alkaline activation treatment in step 1) preferably includes a pretreatment operation before the alkaline activation treatment; the pretreatment preferably involves cutting the wheat straw and then washing it with water to remove impurities such as surface sand and dust.

[0040] In the present invention, the length of the cut wheat straw is preferably 8 to 12 cm, more preferably 9 to 11 cm, and even more preferably 10 cm.

[0041] In the present invention, the alkali activation treatment in step 1) is carried out in an alkali solution to remove lignin and wax layers and expose cellulose active groups; the temperature of the alkali activation treatment is 50-70°C, preferably 52-68°C, more preferably 55-65°C, and more preferably 60°C; the time of the alkali activation treatment is 0.5-2h, preferably 0.6-1.8h, more preferably 0.8-1.5h, and more preferably 1h.

[0042] In the present invention, the mass concentration of the alkali solution is 0.5-3%, preferably 0.6-2.5%, more preferably 0.7-2.0%, and more preferably 1%; the alkali solution includes sodium hydroxide and / or potassium hydroxide.

[0043] In the present invention, the power of the microwave pretreatment in step 1) is 700-900 W, preferably 720-870 W, more preferably 750-850 W, and more preferably 800 W; the time of the microwave pretreatment is 2.5-4 min, preferably 2.6-3.8 min, more preferably 2.8-3.5 min, and more preferably 3 min; it is used to quickly vaporize the moisture inside the fiber, produce a micro-explosion effect, destroy the dense structure of the fiber, form micropores, increase the specific surface area, and create channels for subsequent enzymatic hydrolysis and thermal decomposition; the pore size of the micropores is preferably 1-10 μm, more preferably 2-8 μm, and more preferably 5-7 μm.

[0044] In the present invention, the bio-enzymatic hydrolysis treatment in step 1) is carried out in a bio-enzymatic solution, wherein the bio-enzymatic solution directionally hydrolyzes the lignin and hemicellulose remaining on the fiber surface, further opens the fiber pore structure, and improves the subsequent pyrolysis efficiency; the temperature of the bio-enzymatic hydrolysis treatment is 45-55°C, preferably 46-53°C, more preferably 48-51°C, and more preferably 50°C; the pH of the system of the bio-enzymatic hydrolysis treatment is 4.5-5.0, preferably 4.6-4.9, and more preferably 4.7-4.8; the time of the bio-enzymatic hydrolysis treatment is 1.5-3h, preferably 1.6-2.8h, more preferably 1.8-2.5h, and more preferably 2h.

[0045] In the present invention, the biological enzyme solution includes one or more of cellulase, xylanase and β-glucanase; the mass concentration of the biological enzyme solution is 0.3-1.5%, preferably 0.35-1.25%, more preferably 0.4-0.9%, and more preferably 0.5%.

[0046] In the present invention, the silane coupling agent modification treatment in step 1) is carried out in a silane coupling agent, wherein the silane coupling agent reacts with the hydroxyl group (-OH) on the fiber surface to form a Si-OC bond, thereby enhancing the hydrophobicity of the modified wheat straw fiber and the interfacial bonding strength with asphalt; the contact angle of the modified wheat straw fiber is preferably ≥90°; and the interfacial bonding strength between the modified wheat straw fiber and asphalt is preferably ≥1.2MPa.

[0047] In the present invention, the temperature of the silane coupling agent modification treatment is 40 to 60° C., preferably 42 to 58° C., more preferably 45 to 55° C., and more preferably 50° C., and the time of the silane coupling agent modification treatment is 20 to 40 min, preferably 22 to 37 min, more preferably 25 to 35 min, and more preferably 30 min.

[0048] In the present invention, the mass concentration of the silane coupling agent is 3-7%, preferably 3.5-6.5%, more preferably 4-6%, and more preferably 5%; the pH of the silane coupling agent is 4-5, preferably 4.2-4.9, more preferably 4.3-4.8, and more preferably 4.5; the silane coupling agent includes one or more of KH550 silane coupling agent, KH560 silane coupling agent, KH570 silane coupling agent, and KH590 silane coupling agent.

[0049] In the present invention, the silane coupling agent modification treatment in step 1) preferably further includes a drying and curing step; the drying and curing temperature is preferably 70 to 100° C., more preferably 80 to 95° C., and more preferably 85 to 90° C.; the drying and curing time is preferably 30 to 90 min, more preferably 40 to 80 min, and more preferably 50 to 60 min; this is used to improve the interfacial properties and weather resistance of the fiber and the adaptability to subsequent processes.

[0050] In the present invention, the tensile strength of the modified wheat straw fiber is ≥18 MPa; and the salt corrosion resistance of the modified wheat straw fiber is 2.3 times that of traditional polyester fiber.

[0051] In the present invention, the temperature of the anaerobic pyrolysis treatment in step 2) is 320-380°C, preferably 330-360°C, more preferably 340-355°C, and more preferably 350°C; the time of the anaerobic pyrolysis treatment is 35-45 minutes, preferably 36-43 minutes, more preferably 38-41 minutes, and more preferably 40 minutes; the environment of the anaerobic pyrolysis treatment is preferably an inert atmosphere, more preferably a nitrogen atmosphere.

[0052] In the present invention, the porous carbon fiber in step 2) is preferably a honeycomb structure, which can enhance light absorption; the specific surface area of the porous carbon fiber is preferably ≥600m 2 / g, more preferably 605 to 650m 2 / g, more preferably 610 to 625 m 2 / g; the porosity of the porous carbon fiber is preferably ≥80%, more preferably 81 to 90%, and more preferably 83 to 85%.

[0053] In the present invention, the phase change material in step 3) is a mixture of paraffin wax and lauric acid; the mass ratio of the paraffin wax to lauric acid is 6:4 to 7:3, preferably one of 6:4, 6.2:3.8, 6.5:3.5, 6.8:3.2, and 7:3.

[0054] In the present invention, the enthalpy value of the phase change material is preferably ≥180 J / g, more preferably 181 to 190 J / g, and even more preferably 182 to 185 J / g.

[0055] In the present invention, the phase change material is preferably heated to melt before the vacuum adsorption in step 3).

[0056] In the present invention, the melting temperature of the phase change material is preferably 50-80°C, more preferably 55-75°C, and even more preferably 60-65°C; the melting temperature of the phase change material matches the day-night temperature difference of -20-40°C.

[0057] In the present invention, the pressure of the vacuum adsorption in step 3) is -0.08 to -0.12 MPa, preferably -0.09 to -0.11 MPa, and more preferably -0.1 MPa; the temperature of the vacuum adsorption is 50 to 80°C, preferably 52 to 76°C, more preferably 55 to 75°C, and more preferably 60 to 65°C; the time of the vacuum adsorption is 25 to 35 min, preferably 26 to 34 min, more preferably 28 to 32 min, and more preferably 30 min.

[0058] In the present invention, the loading rate of the phase change material in the photothermal responsive fiber material in step 3) is ≥65%, preferably 66-75%, further preferably 68-72%, and more preferably 69-70%; the remaining pores can absorb salt in the soil. At the same time, the salt corrosion resistance of the photothermal responsive fiber material is improved to 2.3 times that of traditional polyester fiber, and the strength retention rate after 500 hours of salt spray test is ≥80%, which has excellent self-cleaning and salt resistance effects.

[0059] In the present invention, the length of the photothermal responsive fiber material in step 3) is 8 to 12 cm, preferably 9 to 11 cm, and more preferably 10 cm.

[0060] The present invention also provides a photothermal responsive fiber material prepared by the above-mentioned method for preparing the photothermal responsive fiber material.

[0061] The present invention also provides a photothermal responsive seal layer, comprising an asphalt bonding layer, a photothermal responsive fiber material layer and a chip seal layer; the photothermal responsive fiber material layer is obtained by laying the above-mentioned photothermal responsive fiber material.

[0062] In the present invention, the chip seal layer includes a first chip seal layer and a second chip seal layer; the first chip seal layer is basalt crushed stone coated with a microcapsule repair agent, and has a porosity of 28-32%, preferably 29-31%, and more preferably 30%; the particle size of the basalt crushed stone is 9-12 mm, preferably 9.5-11.5 mm, more preferably 9.8-11.2 mm, and more preferably 10-11 mm; the second chip seal layer is diabase crushed stone coated with a microcapsule repair agent, and has a porosity of ≤5%, preferably 2-4.9%, more preferably 2.5-4.0%, and more preferably 3.0-3.5%; the particle size of the diabase crushed stone is 5-8 mm, preferably 5.2-7.5 mm, more preferably 5.5-7.0 mm, and more preferably 6.0-6.5 mm.

[0063] In the present invention, the first chip seal layer coated with microcapsule repair agent and the second chip seal layer coated with microcapsule repair agent preferably use vibrating fluidized bed technology to wrap the microcapsule repair agent on the gravel surface; the encapsulation rate of the microcapsule repair agent is preferably ≥95%, more preferably 96-100%, and more preferably 97-98%.

[0064] In the present invention, the first chip seal layer and the second chip seal layer form a gradient embedded structure and a top-dense and bottom-sparse structure, which have both drainage and crack resistance functions.

[0065] In the present invention, the microcapsule repair agent includes one or more of chitosan-encapsulated SBS modifier, polyurethane-encapsulated epoxy resin, and gelatin-encapsulated asphalt regeneration agent.

[0066] In the present invention, the preparation method of the chitosan-coated SBS modifier is preferably to dissolve chitosan in an acetic acid solution, then add an SBS emulsion, stir and mix, and then inject into a vibrating fluidized bed to obtain the chitosan-coated SBS modifier.

[0067] In the present invention, the degree of deacetylation of the chitosan is preferably ≥85%, more preferably 86-95%, and more preferably 90%; the molecular weight of the chitosan is preferably in the range of 50-200 kDa, more preferably 60-160 kDa, and more preferably 100-120 kDa; the SBS in the SBS emulsion is preferably a styrene-butadiene block copolymer, wherein the styrene content is preferably 25-35%, more preferably 27-32%, and more preferably 30%; the solvent in the SBS emulsion is preferably toluene; and the mass concentration of the acetic acid solution is preferably 1-3%, more preferably 1.5-2.5%, and more preferably 2%.

[0068] In the present invention, the mass ratio of the chitosan to the SBS in the SBS emulsion is preferably 1:3-5, more preferably 1:3.5-4.5, and more preferably 1:4; the mass volume ratio of the chitosan to the acetic acid solution is preferably 1 g:30-60 mL, more preferably 1 g:35-50 mL, and more preferably 1 g:40-45 mL; the mass volume ratio of the SBS to the solvent in the SBS emulsion is preferably 1 g:3-6 mL, more preferably 1 g:3.5-5.5 mL, and more preferably 1 g:4-5 mL.

[0069] In the present invention, the shell thickness of the chitosan-coated SBS modifier is preferably 10-15 μm, more preferably 11-14 μm, and more preferably 12-13 μm; the particle size of the chitosan-coated SBS modifier is preferably 50-100 μm, more preferably 55-95 μm, and more preferably 60-80 μm.

[0070] In the present invention, the preparation method of the polyurethane-wrapped epoxy resin is preferably to mix polyurethane with epoxy resin and prepare the polyurethane-wrapped epoxy resin by interfacial polymerization (the pH of the aqueous phase is preferably 9.0, and the oil phase is preferably xylene).

[0071] In the present invention, the mass ratio of the polyurethane to the epoxy resin is preferably 1:1-2, more preferably 1:1.2-1.8, and even more preferably 1:1.5.

[0072] In the present invention, the polyurethane preferably includes an aliphatic polyurethane prepolymer (BASF Elastollan 1185A); the isocyanate index (NCO / OH) of the aliphatic polyurethane prepolymer is preferably 1.1 to 1.3, more preferably 1.2; the epoxy resin preferably includes a bisphenol A epoxy resin (Dow DER 331); the epoxy value of the bisphenol A epoxy resin is preferably 0.45 to 0.55 eq / 100 g, more preferably 0.46 to 0.52 eq / 100 g, and more preferably 0.5 eq / 100 g.

[0073] In the present invention, the shell thickness of the polyurethane-wrapped epoxy resin is preferably 15 to 20 μm, more preferably 16 to 19 μm, and more preferably 18 μm; the crushing strength of the polyurethane-wrapped epoxy resin is preferably ≥8 MPa, more preferably 8.1 to 10 MPa, and more preferably 8.5 to 9 MPa; the particle size of the polyurethane-wrapped epoxy resin is preferably 80 to 120 μm, more preferably 90 to 100 μm, and more preferably 95 μm.

[0074] In the present invention, the preparation method of the gelatin-coated asphalt regeneration agent is preferably to dissolve gelatin in water, then add the asphalt regeneration agent, and sequentially perform emulsification and spray drying to obtain the gelatin-coated asphalt regeneration agent.

[0075] In the present invention, the mass ratio of gelatin to asphalt regeneration agent is preferably 1:2-4, more preferably 1:2.5-3.5, and even more preferably 1:3.

[0076] In the present invention, the gelatin is preferably type A gelatin; the isoelectric point pH of the type A gelatin is preferably 7 to 9, further preferably 7.5 to 8.5, and more preferably 8; the gel strength of the type A gelatin is preferably ≥200 Bloom, further preferably 210 to 300 Bloom, and more preferably 250 Bloom; the asphalt regeneration agent is preferably a mixture of cyclohexane oil and aromatic hydrocarbons; the mass ratio of the cyclohexane oil to aromatic hydrocarbons is preferably 7:3.

[0077] In the present invention, the emulsification temperature is preferably 50°C; the emulsification rotation speed is preferably 12000 rpm; the emulsification time is preferably 10 min; the inlet air temperature of the spray drying is preferably 180°C, and the outlet air temperature is preferably 80°C.

[0078] In the present invention, the loading rate of the asphalt regeneration agent in the gelatin-coated asphalt regeneration agent is preferably ≥75%, more preferably 76-90%, and more preferably 80-85%; the shell porosity of the gelatin-coated asphalt regeneration agent is preferably ≤5%, more preferably 2-4.8%, and more preferably 2.5-4%; the particle size of the gelatin-coated asphalt regeneration agent is preferably 100-150 μm, more preferably 120-145 μm, and more preferably 130-140 μm.

[0079] In the present invention, the asphalt bonding layer is a hot mix asphalt bonding layer or an emulsified asphalt bonding layer.

[0080] The present invention also provides a method for preparing the above-mentioned photothermal responsive sealing layer, comprising the following steps:

[0081] An asphalt bonding layer, a photothermal responsive fiber material layer, a first chip seal layer and a second chip seal layer are laid on the road surface in sequence. After paving, the layers are rolled and cured to obtain a photothermal responsive seal layer.

[0082] In the present invention, the spreading amount of the photothermal response fiber material layer is 100-120 g / m 2 , preferably 102 to 118 g / m 2 , more preferably 105 to 115 g / m 2 , more preferably 110 to 112 g / m 2The spreading amount of the first chip seal is 3.5~4.5kg / m 2 , preferably 3.6~4.3kg / m 2 , more preferably 3.8 to 4.1 kg / m 2 , more preferably 4kg / m 2 Coverage rate ≥ 90%, preferably 91-99%, more preferably 92-97%, more preferably 93-95%; the spreading amount of the second chip seal is 2.5-3.5 kg / m 2 , preferably 2.6~3.4kg / m 2 , more preferably 2.8 to 3.2 kg / m 2 , more preferably 3kg / m 2 ; Coverage ≥ 85%, preferably 86-99%, more preferably 88-95%, more preferably 90-92%; When the asphalt bonding layer is a hot mix asphalt bonding layer, the spreading amount of the asphalt bonding layer is ≥ 2.0 kg / m 2 , preferably 2.2 to 3.0 kg / m 2 , more preferably 2.3 to 2.8 kg / m 2 , more preferably 2.5 to 2.7 kg / m 2 When the asphalt bonding layer is an emulsified asphalt bonding layer, the spreading amount of the asphalt bonding layer is ≥2.4kg / m 2 , preferably 2.5~3.4kg / m 2 , more preferably 2.6 to 3.2 kg / m 2 , more preferably 2.7 to 3.0 kg / m 2 .

[0083] In the present invention, the asphalt bonding layer, the photothermal responsive fiber material layer, the first chip seal layer and the second chip seal layer are preferably laid sequentially on the road surface using an intelligent temperature-controlled spreader, which completes the spraying of the asphalt bonding layer, the photothermal responsive fiber material layer, the first chip seal layer and the second chip seal layer at one time, thereby achieving high construction efficiency.

[0084] In the present invention, the intelligent temperature-controlled spreader preferably includes base treatment and equipment debugging operations before spreading; the base treatment is preferably to clean up road debris, repair local potholes, and ensure that the base is dry and clean; the equipment debugging is preferably to control the spreading temperature of the intelligent temperature-controlled spreader and the weight of the rubber-wheel roller.

[0085] In the present invention, the spreading temperature of the intelligent temperature-controlled spreader is preferably 158-162°C, more preferably 159-161°C, and even more preferably 160°C; the weight of the rubber-wheel roller is preferably 10 tons.

[0086] In the present invention, the rolling is preferably performed by a rubber-wheel roller; the rolling speed of the rubber-wheel roller is preferably 5 km / h, and the number of times is preferably 3 times, with each time overlapping 1 / 3 of the wheel width.

[0087] In the present invention, the health preservation time is preferably 2.3 to 2.7 hours, more preferably 2.4 to 2.6 hours, and more preferably 2.5 hours, during which traffic is closed.

[0088] In the present invention, the curing step preferably further includes sweeping to remove loose gravel and ensure that the surface of the sealing layer is smooth.

[0089] In the present invention, the porous carbon fibers are combined with the double-layer gravel reflection suppression to ensure that the comprehensive photothermal efficiency of the photothermal responsive seal is ≥75% and the nighttime temperature release rate is ≤0.5°C / min.

[0090] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0091] Example 1

[0092] Preparation of photothermal responsive fiber materials:

[0093] 1) cutting wheat straw into a length of 10 cm, washing with water, and then immersing in a 1% NaOH solution, performing an alkali activation treatment at a temperature of 60° C. for 1 hour to remove impurities; then performing microwave pretreatment at a power of 800 W for 3 minutes to destroy the dense fiber structure; then immersing in a 0.5% cellulase solution for bioenzymatic hydrolysis for 2 hours, while controlling the system pH to 5.0 and the temperature to 50° C. to further open the pores; then immersing in a KH550 silane coupling agent solution with a mass concentration of 5% and a pH of 4.5, performing a silane coupling agent modification treatment at a temperature of 50° C. for 30 minutes, and then drying and curing at a temperature of 80° C. for 60 minutes to obtain modified wheat straw fibers;

[0094] 2) Under nitrogen protection, the modified wheat straw fiber was subjected to anoxic pyrolysis at 350 °C for 40 min to obtain a specific surface area of 620 m 2 / g, porous carbon fibers with a porosity of 82%;

[0095] 3) Paraffin wax and lauric acid were melted to a liquid state at a mass ratio of 7:3 at a temperature of 65°C to obtain a paraffin wax / lauric acid eutectic system phase change material with an enthalpy value of 185 J / g. The porous carbon fiber was then impregnated with the above paraffin wax / lauric acid eutectic system phase change material and vacuum adsorbed at a pressure of -0.1 MPa and a temperature of 65°C for 30 minutes to obtain a photothermal responsive fiber material with a loading rate of 68% and a length of 10 cm.

[0096] Preparation of photothermal responsive sealing layer:

[0097] First, clean up the debris on the road, repair the local potholes, ensure that the base is dry and clean, and adjust the spreading temperature of the intelligent temperature-controlled spreader to 160℃ and the weight of the rubber-wheel roller to 10 tons. At the same time, dissolve chitosan (Qingdao Haipu Chitosan HP-90D) with a deacetylation degree of 90% and a molecular weight of 100kDa in acetic acid solution with a mass concentration of 2%, and add SBS (Kateng FG1901, styrene content of 30%) emulsion, wherein the mass ratio of chitosan to SBS in SBS emulsion is 1:4, the mass volume ratio of chitosan to acetic acid solution is 1g:45mL, and the mass volume ratio of SBS to toluene in SBS emulsion is 1g:4.5mL. After stirring and mixing, inject into the vibrating fluidized bed (GLATT GPCG 3.1), the inlet air temperature was controlled at 50° C. and the vibration frequency was 30 Hz. After drying, chitosan-coated SBS modifier microcapsules with a particle size of 65 μm and a shell thickness of 12 μm were obtained, with a loading rate of 80%. The chitosan-coated SBS modifier was then coated on the surface of basalt gravel with a particle size of 10 mm and diabase gravel with a particle size of 6 mm using a vibrating fluidized bed technique, with a coating rate of 95%, and set aside.

[0098] Then, an intelligent temperature-controlled spreader was used to sequentially lay an asphalt bonding layer, a photothermal responsive fiber material layer, a basalt gravel layer coated with a chitosan-coated SBS modifier, and a diabase gravel layer coated with a polysaccharide-coated SBS modifier on a road surface with a PCI (pavement condition index) of 72 (moderate damage), a crack rate of 18% (mainly thermal shrinkage cracks and reflective cracks), a day-night temperature difference of -20°C to 38°C, and an annual average sunshine duration of 3100 hours. Among them, the spreading amount of the SBS modified emulsified asphalt layer (purchased from Hunan Petrochemical, model HNSIN-SBS-E1500, viscosity of 1500 cP) was 2.4 kg / m 2 The spreading amount of the photothermal response fiber layer is 110g / m 2 The spreading amount of basalt crushed stone layer coated with chitosan-coated SBS modifier is 4kg / m 2 The porosity is 30%, the coverage is 92%, and the spreading amount of the diabase crushed stone layer coated with polysaccharide-coated SBS modifier is 3kg / m 2 The void ratio is 23% and the coverage rate is 88%. After paving is completed, a rubber-wheel roller is used to roll it three times at a speed of 5km / h, overlapping 1 / 3 of the wheel width each time; then it is cured for 2.5 hours, during which time traffic is closed, and finally loose gravel is removed to ensure that the surface of the seal layer is flat, thereby obtaining a light and heat responsive seal layer.

[0099] The performance of the photothermal responsive seal prepared in this embodiment and the traditional seal (the traditional seal is an ordinary chip seal, a polyester fiber reinforced seal, or an emulsified asphalt chip seal) was tested. The crack self-repair efficiency was tested according to the ASTM D7312 test standard; the strength retention rate after the salt spray test was tested according to the ASTM B117 standard; the crack reflectivity was tested according to the AASHTO T321 standard; the specific detection method for road surface temperature fluctuations was actual measurement using an infrared thermal imager; the environmental performance was tested according to the ISO 17556 test standard; and the specific detection method for the full life cycle cost was an engineering economic analysis model. The performance test results are shown in Table 1:

[0100] Table 1 Performance of photothermal responsive sealant

[0101]

[0102] As can be seen from Table 1, in Example 1 of the present invention, by subjecting wheat straw to alkaline activation treatment in a NaOH solution with a mass concentration of 1%, microwave pretreatment at a power of 800 W, and anoxic pyrolysis treatment at a temperature of 350° C., the photothermal responsive seal prepared has a crack self-repair efficiency of 85%, a 42% reduction in pavement temperature fluctuation, the best overall performance, and a 20% reduction in cost.

[0103] Example 2

[0104] Preparation of photothermal responsive fiber materials:

[0105] 1) cutting wheat straw into a length of 9 cm, washing with water, and then soaking in a 0.8% NaOH solution, performing an alkali activation treatment at a temperature of 55° C. for 0.8 h to remove impurities; then performing a microwave pretreatment at a power of 700 W for 2.5 min to destroy the dense fiber structure; then soaking in a 0.4% cellulase solution for bioenzymatic hydrolysis for 1.8 h, while controlling the system pH to 4.3 and the temperature to 48° C. to further open the pores; then soaking in a KH550 silane coupling agent solution with a mass concentration of 4% and a pH of 4.2, performing a silane coupling agent modification treatment at a temperature of 45° C. for 25 min, and then drying and curing at a temperature of 70° C. for 90 min to obtain modified wheat straw fiber;

[0106] 2) Under nitrogen protection, the modified wheat straw fiber was subjected to anoxic pyrolysis at 340 °C for 35 min to obtain a specific surface area of 590 m 2 / g, porous carbon fibers with a porosity of 78%;

[0107] 3) Paraffin wax and lauric acid were melted to a liquid state at a mass ratio of 6:4 at a temperature of 50°C to obtain a paraffin wax / lauric acid eutectic system phase change material with an enthalpy value of 185 J / g. The porous carbon fiber was then impregnated with the above paraffin wax / lauric acid eutectic system phase change material and vacuum adsorbed at a pressure of -0.09 MPa and a temperature of 50°C for 25 minutes to obtain a photothermal responsive fiber material with a loading rate of 63% and a length of 9 cm.

[0108] Preparation of photothermal responsive sealing layer:

[0109] First, the road surface was cleaned of debris, local potholes were repaired, and the base layer was ensured to be dry and clean. The spreading temperature of the intelligent temperature-controlled spreader was adjusted to 160° C. and the weight of the rubber-wheel roller was adjusted to 10 tons. At the same time, chitosan with a particle size of 65 μm was used to encapsulate the SBS modifier (same as in Example 1) and the chitosan-encapsulated SBS modifier was encapsulated on the surface of basalt gravel with a particle size of 9.5 mm and diabase gravel with a particle size of 5.5 mm using a vibrating fluidized bed technology. The encapsulation rate was 95% and the mixture was set aside. Then, an intelligent temperature-controlled spreader was used to sequentially lay an asphalt bonding layer, a photothermal responsive fiber material layer, a basalt gravel layer coated with a chitosan-coated SBS modifier, and a diabase gravel layer coated with a polysaccharide-coated SBS modifier on a road surface with a PCI (pavement condition index) of 72 (moderate damage), a crack rate of 18% (mainly thermal shrinkage cracks and reflective cracks), a day-night temperature difference of -20°C to 38°C, and an annual average sunshine duration of 3100 hours. Among them, the spreading amount of the SBS modified emulsified asphalt layer (purchased from Hunan Petrochemical, model HNSIN-SBS-E1500, viscosity of 1500 cP) was 2.5 kg / m 2 The spreading amount of the photothermal response fiber layer is 100g / m 2 The spreading amount of basalt crushed stone layer coated with chitosan-coated SBS modifier is 3.8 kg / m 2 The porosity is 31%, the coverage is 88%, and the spreading amount of the diabase crushed stone layer coated with polysaccharide-coated SBS modifier is 2.8 kg / m 2 The void ratio is 25% and the coverage rate is 83%. After paving is completed, a rubber-wheel roller is used to roll it three times at a speed of 5km / h, overlapping 1 / 3 of the wheel width each time; then it is cured for 2.5 hours, during which time traffic is closed, and finally loose gravel is removed to ensure that the surface of the seal layer is flat to obtain a light and heat responsive seal layer.

[0110] The performance of the photothermal responsive seal prepared in this embodiment and the traditional seal (same as in Example 1) were tested, and the performance testing method was the same as in Example 1. The performance test results are shown in Table 2.

[0111] Table 2 Performance of photothermal responsive seal

[0112] Performance indicators Photothermal responsive seal Traditional sealing layer Crack self-repair efficiency 78％ ≤40％ Strength retention rate after salt spray test 75％ ≤50％ Crack reflectivity 5.6％ ≥15％ Pavement temperature fluctuations 35% reduction No adjustment capability Environmental degradation rate 85％ Non-degradable Life cycle cost 18% reduction High regular maintenance costs

[0113] As can be seen from Table 2, in Example 2 of the present invention, wheat straw is subjected to alkaline activation treatment in a NaOH solution with a mass concentration of 0.8%, microwave pretreatment at a power of 700 W, and anoxic pyrolysis treatment at a temperature of 340° C. The photothermal responsive seal prepared has a crack self-repair efficiency of 78%, a 35% reduction in pavement temperature fluctuation, is suitable for mild environments, and has a cost reduction of 18%.

[0114] Example 3

[0115] Preparation of photothermal responsive fiber materials:

[0116] 1) cutting wheat straw into a length of 11 cm, washing with water, and then immersing in a 1.2% NaOH solution, performing an alkali activation treatment at a temperature of 65° C. for 1.5 hours to remove impurities; then performing microwave pretreatment at a power of 900 W for 4 minutes to destroy the dense fiber structure; then immersing in a 0.6% cellulase solution for bioenzymatic hydrolysis for 2.5 hours, while controlling the system pH to 5.0 and the temperature to 55° C. to further open the pores; then immersing in a KH550 silane coupling agent solution with a mass concentration of 6% and a pH of 4.9, performing a silane coupling agent modification treatment at a temperature of 55° C. for 35 minutes, and then drying and curing at a temperature of 85° C. for 50 minutes to obtain modified wheat straw fiber;

[0117] 2) Under nitrogen protection, the modified wheat straw fiber was subjected to anoxic pyrolysis at 360 °C for 45 min to obtain a specific surface area of 640 m 2 / g, porous carbon fiber with a porosity of 85%;

[0118] 3) Paraffin wax and lauric acid were melted to a liquid state at a mass ratio of 8:2 at a temperature of 70°C to obtain a paraffin wax / lauric acid eutectic system phase change material with an enthalpy value of 185 J / g. The porous carbon fiber was then impregnated with the above paraffin wax / lauric acid eutectic system phase change material and vacuum adsorbed for 35 minutes at a pressure of -0.11 MPa and a temperature of 70°C to obtain a photothermal responsive fiber material with a loading rate of 70% and a length of 11 cm.

[0119] Preparation of photothermal responsive sealing layer:

[0120] First, the road surface was cleaned of debris, local potholes were repaired, and the base layer was ensured to be dry and clean. The spreading temperature of the intelligent temperature-controlled spreader was adjusted to 160° C. and the weight of the rubber-wheel roller was adjusted to 10 tons. At the same time, chitosan with a particle size of 65 μm was used to encapsulate the SBS modifier (same as in Example 1) and the chitosan-encapsulated SBS modifier was encapsulated on the surface of basalt gravel with a particle size of 12.5 mm and diabase gravel with a particle size of 7.5 mm using a vibrating fluidized bed technology. The encapsulation rate was 95% and the mixture was set aside. Then, an intelligent temperature-controlled spreader was used to sequentially lay an asphalt bonding layer, a photothermal responsive fiber material layer, a basalt gravel layer coated with a chitosan-coated SBS modifier, and a diabase gravel layer coated with a polysaccharide-coated SBS modifier on a road surface with a PCI (pavement condition index) of 72 (moderate damage), a crack rate of 18% (mainly thermal shrinkage cracks and reflective cracks), a day-night temperature difference of -20°C to 38°C, and an annual average sunshine duration of 3100 hours. Among them, the spreading amount of the SBS modified emulsified asphalt layer (purchased from Hunan Petrochemical, model HNSIN-SBS-E1500, viscosity of 1500 cP) was 2.6 kg / m 2 The spreading amount of the photothermal response fiber layer is 120g / m 2 The spreading amount of basalt crushed stone layer coated with chitosan-coated SBS modifier is 4.3 kg / m 2 The porosity is 28%, the coverage is 92%, and the spreading amount of the diabase crushed stone layer coated with polysaccharide-coated SBS modifier is 3.3 kg / m 2 The void ratio is 20% and the coverage rate is 87%. After paving is completed, a rubber-wheel roller is used to roll it three times at a speed of 5km / h, overlapping 1 / 3 of the wheel width each time; then it is cured for 2.5 hours, during which time traffic is closed, and finally loose gravel is removed to ensure that the surface of the seal layer is flat, thereby obtaining a light and heat responsive seal layer.

[0121] The performance of the photothermal responsive seal prepared in this example and the traditional seal (same as in Example 1) were tested, and the performance testing method was the same as in Example 1. The performance test results are shown in Table 3.

[0122] Table 3 Performance of photothermal responsive seal

[0123]

[0124]

[0125] As can be seen from Table 3, Example 3 of the present invention, by subjecting wheat straw to alkaline activation treatment in a NaOH solution with a mass concentration of 1.2%, microwave pretreatment at a power of 700 W, and anoxic pyrolysis treatment at a temperature of 340°C, the photothermal responsive seal prepared has a crack self-repair efficiency of 88%, a 45% reduction in pavement temperature fluctuations, is suitable for extreme conditions, and reduces costs by 25%.

[0126] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a photothermal responsive fiber material, characterized in that: The steps include: 1) sequentially subjecting wheat straw to alkali activation treatment, microwave pretreatment, bioenzymatic hydrolysis treatment, and silane coupling agent modification treatment to obtain modified wheat straw fiber; 2) subjecting the modified wheat straw fibers to anoxic pyrolysis to obtain porous carbon fibers; 3) The porous carbon fiber is mixed with the phase change material and vacuum adsorbed to obtain a photothermal responsive fiber material.

2. The method for preparing a photothermal responsive fiber material according to claim 1, characterized in that: The alkali activation treatment in step 1) is carried out in an alkali solution; The temperature of the alkali activation treatment is 50-70°C and the time is 0.5-2h; The mass concentration of the alkali solution is 0.5-3%; The alkali solution includes sodium hydroxide and / or potassium hydroxide; The power of the microwave pretreatment in step 1) is 700-900W, and the time is 2.5-4 minutes.

3. The method for preparing a photothermal responsive fiber material according to claim 2, characterized in that: The bio-enzymatic hydrolysis treatment in step 1) is carried out in a bio-enzyme solution; The temperature of the bio-enzymatic hydrolysis treatment is 45-55°C, the system pH is 4.5-5.0, and the time is 1.5-3 hours; The biological enzyme solution includes one or more of cellulase, xylanase and β-glucanase; The mass concentration of the biological enzyme solution is 0.3-1.5%.

4. The method for preparing a photothermal responsive fiber material according to any one of claims 1 to 3, characterized in that: The silane coupling agent modification treatment in step 1) is carried out in a silane coupling agent; The silane coupling agent modification treatment is performed at a temperature of 40 to 60° C. and for a time of 20 to 40 minutes; The mass concentration of the silane coupling agent is 3-7%, and the pH is 4-5; The silane coupling agent includes one or more of KH550 silane coupling agent, KH560 silane coupling agent, KH570 silane coupling agent, and KH590 silane coupling agent.

5. The method for preparing a photothermal responsive fiber material according to claim 4, characterized in that: The temperature of the anoxic pyrolysis treatment in step 2) is 320-380° C. and the time is 35-45 minutes.

6. The method for preparing a photothermal responsive fiber material according to claim 5, characterized in that: The phase change material in step 3) is a mixture of paraffin and lauric acid; The mass ratio of the paraffin wax to lauric acid is 6:4 to 7:

3.

7. The method for preparing a photothermal responsive fiber material according to claim 6, characterized in that: The vacuum adsorption pressure in step 3) is -0.08 to -0.12 MPa, the temperature is 50 to 80°C, and the time is 25 to 35 minutes; The loading rate of the phase change material in the photothermal responsive fiber material is ≥65%, and the length of the photothermal responsive fiber material is 8-12 cm.

8. The photothermal responsive fiber material obtained by the method for preparing a photothermal responsive fiber material according to any one of claims 1 to 7.

9. A photothermal responsive sealing layer, characterized in that: It includes an asphalt bonding layer, a light and heat responsive fiber material layer, and a chip seal layer; The photothermal responsive fiber material layer is obtained by laying the photothermal responsive fiber material according to claim 8; The chip seal includes a first chip seal and a second chip seal; The first chip seal layer is basalt chip coated with a microcapsule repair agent, with a porosity of 28-32% and a particle size of 9-12 mm; The second gravel seal layer is diabase gravel coated with a microcapsule repair agent, with a porosity of ≤25%, and a particle size of 5 to 8 mm; The microcapsule repair agent includes one or more of chitosan-encapsulated SBS modifier, polyurethane-encapsulated epoxy resin, and gelatin-encapsulated asphalt regeneration agent; The asphalt bonding layer is a hot mix asphalt bonding layer or an emulsified asphalt bonding layer.

10. The method for preparing the photothermal responsive sealing layer according to claim 9, characterized in that: The steps include: An asphalt bonding layer, a photothermal responsive fiber material layer, a first chip seal layer, and a second chip seal layer are sequentially laid on the road surface, and after paving, the layers are rolled and cured to obtain a photothermal responsive seal layer. The spreading amount of the photothermal response fiber material layer is 100-120 g / m 2 ; The spreading amount of the first chip seal is 3.5-4.5 kg / m 2 , coverage ≥ 90%; The spreading amount of the second chip seal is 2.5-3.5 kg / m 2 , coverage ≥85%; When the asphalt bonding layer is a hot mix asphalt bonding layer, the spreading amount of the asphalt bonding layer is ≥ 2.0 kg / m 2 ; When the asphalt bonding layer is an emulsified asphalt bonding layer, the spreading amount of the asphalt bonding layer is ≥ 2.4 kg / m 2 .

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