Self-diagnosis and self-healing polyurethane modified asphalt as well as preparation method and application thereof

Abstract

The invention discloses self-diagnosis and self-healing polyurethane modified asphalt as well as a preparation method and application thereof, and the self-diagnosis and self-healing polyurethane modified asphalt comprises the following raw material components in parts by weight: 100 parts of asphalt, 2-40 parts of a polyurethane prepolymer, 0.5-5 parts of a self-healing agent, 2-5 parts of a self-diagnosis agent and 0.2-2 parts of an auxiliary agent. The self-diagnosis and self-healing polyurethane modified asphalt can remarkably improve the obdurability of an asphalt material, has the effects of self-diagnosis of cracks and self-healing of microcracks, effectively avoids early cracking, can be used for environments or high-grade highways with strict requirements on asphalt, and can obviously prolong the service life of asphalt pavements.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials and road engineering materials, and specifically relates to a self-diagnosing and self-healing polyurethane modified asphalt and a preparation method and application thereof. Background Art

[0002] Traditional asphalt materials are prone to cracks and damage during use, which shortens their service life and increases maintenance costs. In recent years, research on self-healing materials has gradually gained attention, using the material's own repair ability to extend service life and reduce maintenance costs. However, most existing self-healing materials lack the self-diagnosis function of diseases and cannot identify and repair early damage in a timely manner.

[0003] During the in-situ polymerization of polyurethane (PU), the molecular structure design is extremely flexible, and intrinsic self-healing can be achieved by introducing reversible structural changes. This makes PU play an important role in the research of self-healing modified asphalt. As a weak, dynamically reversible non-covalent bond, hydrogen bond has a bond energy of only one-tenth of carbon-carbon covalent bond (about 400 kJ / mol), and is easy to break and reform at room temperature. Therefore, polymers containing hydrogen bonds have room temperature self-healing properties. In polyurethane, hydrogen bonds are mainly self-assembled by proton donors (NH) and proton acceptors (C=O) in carbamate groups or urea groups. Multiple hydrogen bonds provide a strong force, bringing abundant cross-linking points to the polymer network, which can be quickly reorganized at the material fracture interface, thereby realizing the reconstruction of the polymer network. For the chain breaks caused by thermal oxidation and light aging of the polymer, dynamic covalent bonds form self-healing units to achieve the self-healing effect of polymer materials. Although a large number of studies have been conducted on the reversible structure of self-healing polyurethane, the research on self-healing polyurethane modified asphalt mainly focuses on the introduction of dynamic covalent bonds, and related research is still insufficient.

[0004] Patent (CN113292701A) uses dynamic ionic bonds between molecules to quickly repair mechanical damage. However, the strength of the ionic bond may be affected by changes in humidity and temperature, resulting in unstable self-healing performance. In addition, ionic polyurethane may exhibit low chemical resistance in certain chemical environments. Patent (CN116426138A) uses dynamic covalent bonds for self-repair, but the cross-linking temperature of covalent bonds is low. During construction, the mixing temperature of asphalt mixture is about 180°C, which may cause the covalent bonds to be inactivated during the mixing stage. Patent (CN117924955A) introduces hydrogels, and self-healing is achieved through hydrogel water absorption and polyurethane polymerization, but the active end -NCO group of polyurethane will react with water in the air, and the polymerization effect provided by the hydrogel water absorption in the later stage is small, and the self-healing ability is limited. Summary of the invention

[0005] Technical problem to be solved: In response to the above technical problem, the present invention provides a self-diagnosing and self-healing polyurethane modified asphalt and its preparation method and application, which has the functions of self-diagnosis of diseases and self-healing, can automatically identify and repair cracks after being damaged by external forces, thereby extending service life and reducing maintenance costs.

[0006] Technical solution: In the first aspect, the present invention provides a self-diagnostic and self-healing polyurethane modified asphalt. Its raw material components include 100 parts of asphalt, 2-40 parts of polyurethane, 0.5-5 parts of self-healing agent, 2-5 parts of self-diagnostic agent and 0-2 parts of auxiliary agent by weight ratio.

[0007] Preferably, the asphalt is base asphalt or modified asphalt; The polyurethane comprises a soft segment, a hard segment and a chain extender, wherein the soft segment is a polyol or a polyamine, the hard segment is an isocyanate, and the chain extender is a dynamic disulfide bond material, a multiple hydrogen bond material or a combination thereof; The self-healing agent comprises a self-healing material and a self-healing material carrier, wherein the self-healing material is one or a combination of paraffin-based phase change material, bio-oil, and asphalt regeneration agent, and the self-healing agent carrier is a porous material; The self-diagnostic agent is a pressure-sensitive curing material or carbon fiber. The carbon fiber is deformed, causing the self-healing agent adhered to its surface to desorb and break, and fill in the microcracks, thereby performing self-repair. In addition, carbon fiber is an intelligent material for early warning of diseases. When the structure of the carbon fiber matrix material is about to change, the material responsible for the sensing task can transmit this change (such as stress, strain, pressure, displacement, temperature) to the collection system for analysis and processing. When the structural layer where the pressure-sensitive curing material is located is subjected to excessive external force, it promotes self-curing and reinforces the material in time. The auxiliary agent is a stabilizer or a plasticizer.

[0008] Further, the polyol is a polyether polyol or a polyester polyol, the polyamine is one or a combination of polyethylenediamine, polydiethylenetriamine, polytriethylenetetramine, polyolamine, polyisophoronediamine, poly-4,4'-diaminodiphenylmethane, poly-1,6-hexanediamine, polydimethylsilanediamine; the material containing dynamic disulfide bonds is one or a combination of disulfide, polydisulfide, galactose disulfide, hydroxylated disulfide; the multiple hydrogen bond material is one or a combination of urea derivatives, urea-based compounds, imidazole compounds, isocyanurates, dopamine derivatives, urea-based ureas, mercaptourea compounds, polyethylene glycol; The pressure-sensitive curing material is one or a combination of epoxy resin, polyurethane, silicone, acrylate, phenolic resin, and photosensitive polymer; The stabilizer is a phenolic antioxidant, a hindered amine light stabilizer or a benzotriazole complex; and the plasticizer is a phthalate or an alkyl polyoxyethylene ether.

[0009] Furthermore, the polyol is one or a combination of polyoxypropylene glycol, polyoxyethylene glycol, copolyether polyol, polyoxypropylene triol, polytetramethylene glycol, polycaprolactone polyol, adipic acid-1,4-butylene glycol polyester, terephthalic acid-ethylene glycol polyester, polycaprolactone polyol, polycarbonate polyol, castor oil-based polyester polyol, phthalate polyester polyol; The isocyanate is one or a combination of diphenylmethane diisocyanate, toluene diisocyanate, 1,5-naphthalene diisocyanate, dimethylbiphenyl diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, trimethylhexamethylene diisocyanate, meta-xylyl diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, carbodiisocyanate, thiourea-modified isocyanate, melamine-modified isocyanate, polyether-modified isocyanate, polyester-modified isocyanate, prepolymer isocyanate, polyetheramine-modified isocyanate, silica-modified isocyanate, fluorinated isocyanate, amide isocyanate, thiol isocyanate, cyano isocyanate, hydroxy isocyanate, and ether isocyanate; The disulfide is glycerol disulfide, dihydroxypropane disulfide, acetyl disulfide, acrylic acid disulfide or propylene disulfide, the polydisulfide is polyglycerol disulfide, polystyrene-disulfide ester or polyacrylic acid disulfide, the galactose disulfide is galactitol disulfide or galactose disulfide ester, and the hydroxylated disulfide is polyvinyl alcohol disulfide or polylactic acid disulfide.

[0010] Preferably, the self-healing material is dispersed in the asphalt in the form of microcapsules, wherein the microcapsules have the self-healing material as a core material and are coated with a layer of polyurea or polyurethane film.

[0011] Preferably, the self-healing material or the microcapsule containing the self-healing material is filled in a self-healing material carrier, the self-healing material carrier is a porous material, and the porous material is a carbon-based material, an alumina porous material, a titanium dioxide porous material, a silicone porous material, a glass porous material, a ceramic porous material, a polymer porous material or a metal organic framework porous material.

[0012] In a second aspect, the present invention provides a method for preparing the self-diagnostic and self-healing polyurethane modified asphalt according to the first aspect, comprising the following steps: S1. Synthetic polyurethane prepolymer: S1-1, put the soft segment into a dry container, heat it in an oil bath at 80 ℃ ~ 110 ℃, and evacuate to remove moisture. During this process, adjust the stirrer speed to 100 r / min ~ 400 r / min, and continue dehydration for 60 min ~ 120 min; S1-2, lower the system temperature to 40 ℃ ~ 70 ℃, add isocyanate, stir evenly, raise the temperature to 75 ℃ ~ 90 ℃, and introduce dry nitrogen for protection, and react at a constant temperature and speed for 1 h ~ 4 h; S1-3, lowering the system temperature to 40 ℃~60 ℃, adding a chain extender, reacting for 10 min~30 min, vacuuming and degassing, and finally obtaining polyurethane; S2. Preparation of modified asphalt: S2-1. Heat and soften the asphalt in an oven at 120℃~160℃, transfer the softened asphalt to an oil bath at 130℃~180℃ and stir to make the temperature uniform; S2-2, slowly add the pre-dehydrated chain extender into the asphalt, keep the temperature constant and high-speed shear at 3500 r / min~4500 r / min for 10 min; S2-3, adding the polyurethane obtained in step S1 to the asphalt in small amounts and multiple times, and continuing high-speed shearing at 130°C to 180°C and 3500 r / min to 4500 r / min for 10 min to 2 h, thereby obtaining polyurethane modified asphalt; S2-4, add self-healing agent and self-diagnostic agent to polyurethane modified asphalt, and stir the mixture for 10 min~30 min; S2-5. Place the mixture obtained in step S2-4 in a 90 ℃ ~ 120 ℃ oven for development for 30 min ~ 4 h to promote the interaction between polyurethane and asphalt and the homogenization of the system. After the development is completed, a polyurethane modified asphalt with self-diagnosis and self-healing functions is obtained.

[0013] In a third aspect, the present invention provides the use of the self-diagnostic self-healing polyurethane modified asphalt described in the first aspect or the self-diagnostic self-healing polyurethane modified asphalt prepared by the preparation method described in the second aspect in asphalt pavement or engineering protection.

[0014] Beneficial effects: 1) The introduction of polyurethane improves the elasticity and durability of asphalt and enhances the comprehensive mechanical properties of the material; 2) Self-healing agents can release repair substances when cracks occur, effectively filling and repairing cracks and extending the service life of the material; 3) Introducing self-diagnostic agents that can automatically detect and release repair materials when microcracks form, and facilitate external equipment to detect and identify early damage; 4) Self-diagnosis and self-healing functions reduce the frequent maintenance required due to cracks and damage, significantly reducing maintenance costs; 5) Has broad application prospects: It is suitable for various road projects and building materials and has important application value. DETAILED DESCRIPTION

[0015] The present invention is described in detail below in conjunction with specific embodiments: Embodiment 1: A self-diagnostic and self-healing polyurethane modified asphalt, comprising: SBS asphalt, 100 parts; Polyurethane, 2 parts; wherein the soft segment is polytetramethylene glycol (molecular weight 2000), the hard segment is diphenylmethane diisocyanate (MDI), and the chain extender is glycerol disulfide; the molar ratio of soft segment: hard segment: chain extender is 1:1.2:1; The self-healing material is a bio-oil capsule, and the self-healing material carrier is a porous carbon-based material, 0.5 parts; The self-diagnostic agent is carbon fiber, 2 parts; The auxiliary agent is a phenolic antioxidant, 2 parts; The preparation method comprises the following steps: S1. Synthetic polyurethane: S1-1, put the soft segment into a dry container, heat it in an oil bath at 110 ℃, and evacuate to remove moisture. During this process, adjust the stirrer speed to 200 r / min, and continue dehydration for 90 min; S1-2, lower the system temperature to 50 °C, add the hard segment, stir evenly, raise the temperature to 80 °C, introduce dry nitrogen for protection, and react at a constant temperature and speed for 1 h; S1-3, lowering the system temperature to 60 °C, adding a chain extender, reacting for 10 min, and vacuum degassing to finally obtain a polyurethane prepolymer; S2. Preparation of modified asphalt: S2-1, heat the asphalt in a 140 ℃ oven to soften it, transfer the softened asphalt to a 160 ℃ oil bath and stir it to make the temperature uniform; S2-2, slowly add the pre-dehydrated chain extender into the asphalt, keep the temperature constant and high-speed shear at 4500 r / min for 10 min; S2-3, adding the polyurethane prepolymer obtained in step S1 to the asphalt in small amounts and multiple times, and continuing high-speed shearing at 160°C and 4500 r / min for 30 min to obtain polyurethane modified asphalt; S2-4, add self-healing agent and self-diagnostic agent to polyurethane modified asphalt, and stir the mixture for 10 minutes; S2-5. Place the mixture obtained in step S2-4 in a 90°C oven for 30 minutes to promote the interaction between polyurethane and asphalt and homogenization of the system. After the development is completed, a polyurethane modified asphalt with self-diagnosis and self-healing functions is obtained.

[0016] Embodiment 2: A self-diagnostic and self-healing polyurethane modified asphalt, comprising: 100 parts of base asphalt; Polyurethane, 40 parts; wherein the soft segment is polyethylenediamine (molecular weight is 1000), the hard segment is toluene diisocyanate (TDI), and the chain extender is isocyanurate; the molar ratio of soft segment: hard segment: chain extender is 1:1.1:0.5; The self-healing agent is polyurea microcapsule-encapsulated asphalt regeneration agent, 3 parts; The self-diagnostic agent is a pressure-sensitive curing material, 5 parts; The auxiliary agent is 1 part of hindered amine light stabilizer and 1 part of alkyl polyoxyethylene ether plasticizer; The preparation method comprises the following steps: S1. Synthetic polyurethane: S1-1, put the soft segment into a dry container, heat it in an oil bath at 80 ℃, and evacuate to remove moisture. During this process, adjust the stirrer speed to 100 r / min, and continue dehydration for 120 min; S1-2, lower the system temperature to 40 °C, add the hard segment, stir evenly, raise the temperature to 75 °C, introduce dry nitrogen for protection, and react at a constant temperature and speed for 4 h; S1-3, lowering the system temperature to 40 °C, adding a chain extender, reacting for 30 min, and vacuum degassing to finally obtain a polyurethane prepolymer; S2. Preparation of modified asphalt: S2-1, heat and soften the asphalt in a 120°C oven, transfer the softened asphalt to a 180°C oil bath and stir to make the temperature uniform; S2-2, slowly add the pre-dehydrated chain extender into the asphalt, keep the temperature constant and high-speed shear at 3500 r / min for 10 min; S2-3, adding the polyurethane prepolymer obtained in step S1 to the asphalt in small amounts and multiple times, and continuing high-speed shearing at 180°C and 3500 r / min for 1 h, thereby obtaining polyurethane modified asphalt; S2-4, add self-healing agent and self-diagnostic agent to polyurethane modified asphalt, and stir the mixture for 30 minutes; S2-5. Place the mixture obtained in step S2-4 in a 120°C oven for 4 hours to promote the interaction between polyurethane and asphalt and the homogenization of the system. After the development is completed, a polyurethane modified asphalt with self-diagnosis and self-healing functions is obtained.

[0017] Comparative Example 1: Commercially available 70 # Base asphalt.

[0018] Comparative Example 2: Commercially available SBS modified asphalt.

[0019] Comparative Example 3: The difference from Example 1 is that no self-healing agent is added, and the rest is the same as Example 1.

[0020] Comparative Example 4: The difference from Example 1 is that no self-diagnostic agent is added, and the rest is the same as Example 1.

[0021] Comparative Example 5: The difference from Example 2 is that no self-healing agent is added, and the rest is the same as Example 2.

[0022] Comparative Example 6: The difference from Example 2 is that no self-diagnostic agent is added, and the rest is the same as Example 2.

[0023] In the examples and comparative examples, asphalt is used to prepare molded asphalt concrete to evaluate its performance. The mineral aggregate gradation adopts the dense graded asphalt concrete AC-13 gradation specified in the specification JTG F40-2004 (as shown in Table 1 below) close to the median area, the mineral aggregate is basalt, the mineral powder is limestone, and the oil-stone ratio is 5.0%. The wheel rolling method is used to form a 50 mm×300 mm×300 mm rutting plate, which is cut into 30 mm×35 mm×250 mm small beam specimens. The small beam bending test is used as the initial value. The cracked specimens are assembled and placed horizontally, and the two ends are compacted with a force of 0.5 kN for 30 minutes, and then released. After being placed for a predetermined time, the small beam bending test is performed.

[0024] Table 1 Dense graded asphalt concrete AC-13 gradation , Table 2 Maximum bending strain of asphalt of Examples 1-2 and Comparative Examples 1-6 at -10°C , As shown in Table 2, polyurethane can significantly improve the elasticity and toughness of asphalt, the self-diagnostic agent plays a role in accelerating the healing process in the initial stage, and the self-healing agent has a long-term repair function.

[0025] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A self-diagnostic and self-healing polyurethane modified asphalt, characterized in that: According to the weight ratio, the raw material components include 100 parts of asphalt, 2-40 parts of polyurethane, 0.5-5 parts of self-healing agent, 2-5 parts of self-diagnostic agent and 0-2 parts of auxiliary agent, and the asphalt is base asphalt or modified asphalt; The polyurethane comprises a soft segment, a hard segment and a chain extender, wherein the soft segment is a polyol or a polyamine, the hard segment is an isocyanate, and the chain extender is a dynamic disulfide bond material, a multiple hydrogen bond material or a combination thereof; The self-healing agent comprises a self-healing material and a self-healing material carrier, wherein the self-healing material is one or a combination of paraffin-based phase change material, bio-oil, and asphalt regeneration agent, and the self-healing agent carrier is a porous material; The self-diagnostic agent is a pressure-sensitive curing material or a carbon fiber; The auxiliary agent is a stabilizer or a plasticizer.

2. The self-diagnostic and self-healing polyurethane modified asphalt according to claim 1, characterized in that: The polyol is a polyether polyol or a polyester polyol; the polyamine is one or a combination of polyethylenediamine, polydiethylenetriamine, polytriethylenetetramine, polyolamine, polyisophoronediamine, poly-4,4'-diaminodiphenylmethane, poly-1,6-hexanediamine, polydimethylsilanediamine; the material containing dynamic disulfide bonds is one or a combination of disulfide, polydisulfide, galactose disulfide, hydroxylated disulfide; the multiple hydrogen bond material is one or a combination of urea derivatives, urea-based compounds, imidazole compounds, isocyanurates, dopamine derivatives, urea-based urea, mercapto-urea compounds, polyethylene glycol; The pressure-sensitive curing material is one or a combination of epoxy resin, polyurethane, silicone, acrylate, phenolic resin, and photosensitive polymer; The stabilizer is a phenolic antioxidant, a hindered amine light stabilizer or a benzotriazole complex; and the plasticizer is a phthalate or an alkyl polyoxyethylene ether.

3. The self-diagnostic and self-healing polyurethane modified asphalt according to claim 2, characterized in that: The polyol is one or a combination of polyoxypropylene glycol, polyoxyethylene glycol, copolyether polyol, polyoxypropylene triol, polytetramethylene glycol, polycaprolactone polyol, adipic acid-1,4-butylene glycol polyester, terephthalic acid-ethylene glycol polyester, polycaprolactone polyol, polycarbonate polyol, castor oil-based polyester polyol, phthalate polyester polyol; The isocyanate is one or a combination of diphenylmethane diisocyanate, toluene diisocyanate, 1,5-naphthalene diisocyanate, dimethylbiphenyl diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, trimethylhexamethylene diisocyanate, meta-xylyl diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, carbodiisocyanate, thiourea-modified isocyanate, melamine-modified isocyanate, polyether-modified isocyanate, polyester-modified isocyanate, prepolymer isocyanate, polyetheramine-modified isocyanate, silica-modified isocyanate, fluorinated isocyanate, amide isocyanate, thiol isocyanate, cyano isocyanate, hydroxy isocyanate, and ether isocyanate; The disulfide is glycerol disulfide, dihydroxypropane disulfide, acetyl disulfide, acrylic acid disulfide or propylene disulfide, the polydisulfide is polyglycerol disulfide, polystyrene-disulfide ester or polyacrylic acid disulfide, the galactose disulfide is galactitol disulfide or galactose disulfide ester, and the hydroxylated disulfide is polyvinyl alcohol disulfide or polylactic acid disulfide.

4. The self-diagnosing and self-healing polyurethane modified asphalt according to claim 1, characterized in that: The self-healing material is dispersed in the asphalt in the form of microcapsules. The microcapsules use the self-healing material as a core material and are coated with a layer of polyurea or polyurethane film.

5. The self-diagnosing and self-healing polyurethane modified asphalt according to claim 1, characterized in that: The self-healing material or the microcapsule containing the self-healing material is filled in a self-healing material carrier, and the self-healing material carrier is a porous material, and the porous material is a carbon-based material, an alumina porous material, a titanium dioxide porous material, an organosilicon porous material, a glass porous material, a ceramic porous material, a polymer porous material or a metal organic framework porous material.

6. A method for preparing the self-diagnostic and self-healing polyurethane modified asphalt according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Synthetic polyurethane prepolymer: S1-1, put the soft segment into a dry container, heat it in an oil bath at 80 ℃ ~ 110 ℃, and evacuate to remove moisture. During this process, adjust the stirrer speed to 100 r / min ~ 400 r / min, and continue dehydration for 60 min ~ 120 min; S1-2, lower the system temperature to 40 ℃ ~ 70 ℃, add isocyanate, stir evenly, raise the temperature to 75 ℃ ~ 90 ℃, and introduce dry nitrogen for protection, and react at a constant temperature and speed for 1 h ~ 4 h; S1-3, lowering the system temperature to 40 ℃~60 ℃, adding a chain extender, reacting for 10 min~30 min, vacuuming and degassing, and finally obtaining polyurethane; S2. Preparation of modified asphalt: S2-1. Heat and soften the asphalt in an oven at 120℃~160℃, transfer the softened asphalt to an oil bath at 130℃~180℃ and stir to make the temperature uniform; S2-2, slowly add the pre-dehydrated chain extender into the asphalt, keep the temperature constant and high-speed shear at 3500 r / min~4500 r / min for 10 min; S2-3, adding the polyurethane obtained in step S1 to the asphalt in small amounts and multiple times, and continuing high-speed shearing at 130°C to 180°C and 3500r / min to 4500r / min for 10 min to 2 h, thereby obtaining polyurethane modified asphalt; S2-4, add self-healing agent and self-diagnostic agent to polyurethane modified asphalt, and stir the mixture for 10 min to 30 min; S2-5. Place the mixture obtained in S2-4 in a 90 ℃ ~ 120 ℃ oven for development for 30 min ~ 4 h to promote the interaction between polyurethane and asphalt and the homogenization of the system. After the development is completed, a polyurethane modified asphalt with self-diagnosis and self-healing functions is obtained.

7. Use of the self-diagnosing and self-healing polyurethane modified asphalt described in any one of claims 1 to 5 or the self-diagnosing and self-healing polyurethane modified asphalt prepared by the preparation method described in claim 6 in asphalt pavement or engineering protection.