Self-repairing modified asphalt waterproof coiled material

Abstract

The invention relates to the technical field of building materials, and discloses a self-repairing modified asphalt waterproof coiled material, which comprises the following components by weight: 60-70 parts of an asphalt matrix; the invention also provides a preparation method of the self-repairing modified asphalt waterproof coiled material, and the preparation method comprises the following steps: S1, material pretreatment and mixing: mixing the modified asphalt matrix with the nano reinforcing material, the shape memory polymer, the thermal reversible high polymer material and the microcapsule repairing material; and S2, performing high-energy mechanical mixing treatment: performing mixing treatment by using high-energy mechanical mixing equipment to ensure that all components are uniformly dispersed. By adopting ultrasonic treatment, low-temperature freeze drying, vacuum hot-pressing curing and microcapsule repairing technologies, the excellent flexibility, self-repairing efficiency and stability of the modified asphalt waterproof coiled material at low temperature are realized, and the long-acting waterproof performance and durability of the material are remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of building materials, in particular to a self-repairing modified asphalt waterproofing coiled material. Background Art

[0002] In the construction of modern buildings and infrastructure, the application of waterproof layers is crucial. As the core material in the waterproof system, waterproof membranes are widely used in structures such as roofs, basements, and bridges to prevent water intrusion and damage to building structures. Especially in extreme climatic conditions, the performance of waterproof membranes is particularly critical. Although conventional asphalt waterproof membranes can provide certain waterproof protection, the waterproof effect often decreases when facing long-term use and harsh environments. In order to solve this problem, modified asphalt waterproof membranes with self-healing functions came into being.

[0003] The self-repairing modified asphalt waterproofing membrane in the prior art mainly improves the mechanical properties and anti-aging ability of asphalt by adding a certain proportion of nano-reinforced materials, polymers and microcapsule repair materials. These materials enhance the durability, toughness and waterproof performance of asphalt to a certain extent. During use, the microcapsule repair technology can release repair agents when cracks occur, fill the cracks and restore the waterproof effect. Through the high shear mixing process, reinforcing materials such as carbon nanotubes and graphene can improve the material's crack resistance and enhance the material's strength. In addition, the conventional hot pressing curing process can also improve the material's compactness, thereby enhancing the waterproof effect.

[0004] However, the existing technology still has some shortcomings, especially in terms of material uniformity, low-temperature performance and repair efficiency; first, the nanomaterials have poor dispersibility in the asphalt matrix and are easy to agglomerate, resulting in unstable material performance, which limits its overall mechanical properties and stability for long-term use; second, traditional waterproof membranes are prone to brittleness in low-temperature environments, resulting in failure of the waterproof layer. In cold climates, the repair ability of waterproof membranes is weak and cracks cannot be effectively restored, which in turn affects the waterproof effect; in addition, the repair reaction speed in the existing technology is slow, and the repair effect often lags behind the occurrence of damage, and the function cannot be restored immediately when cracks appear. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a self-repairing modified asphalt waterproofing membrane, which solves the problems of poor dispersibility of nanomaterials, insufficient low-temperature performance and low self-repairing efficiency in the prior art.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: a self-repairing modified asphalt waterproofing membrane, the waterproofing membrane comprising the following components in parts by weight:

[0007] Asphalt matrix: 60-70 parts. Asphalt is used as the base material. In this solution, appropriate modification (such as adding polymers, rubber powder, etc.) is used to improve its flexibility and anti-aging properties, so as to avoid cracks caused by temperature changes, ultraviolet radiation or mechanical loads during long-term use of asphalt. The polymer in the modified asphalt matrix significantly enhances the waterproofness and durability of the material by toughening and improving adhesion;

[0008] Nano-reinforced materials: 0.2-2.5 parts. Nano-materials have a huge specific surface area due to their extremely small particle size, which enables them to form a strong physical cross-linking structure in the asphalt matrix, improving the overall strength and toughness of the material. Nano-carbon tubes and graphene can not only enhance the mechanical properties of the material, but also improve the thermal conductivity of asphalt and prevent asphalt from over-softening under high temperature conditions;

[0009] Polymer repair materials: 4 to 12 parts;

[0010] Microcapsule repair material: 2 to 5 portions.

[0011] Preferably, the nano-enhanced material comprises:

[0012] Carbon nanotubes: 0.2-1.5 parts. The mechanism of action of carbon nanotubes is mainly reflected in their role as a reinforcing material, which enhances the mechanical properties of asphalt at the microscopic level. Due to the extremely small size of carbon nanotubes and their large specific surface area, they can have a strong physical effect with the molecules in the asphalt matrix, so that the carbon nanotubes form a strong network structure when dispersed in the asphalt matrix. These carbon nanotubes play a supporting and bridging role, which can effectively disperse external loads and prevent the formation of cracks;

[0013] Graphene: 0.1-0.5 parts. Due to its two-dimensional structure, graphene can form strong chemical and physical interactions with the molecules in the asphalt after being evenly dispersed in the asphalt matrix. These interactions enhance the structural stability of the asphalt. The addition of graphene enhances the bonding force between molecules when the asphalt material is subjected to external forces, thereby improving its crack resistance. Graphene also has excellent thermal conductivity, which improves the thermal stability of asphalt.

[0014] Nano silicon: 0.5-2 parts. Since nano silicon particles are small in size and have a large specific surface area, they can fill the tiny gaps and cracks in the asphalt matrix after being evenly dispersed in the asphalt matrix. This filling effect improves the compactness and anti-permeability of asphalt, thereby effectively improving the waterproofness of the waterproof membrane. Nano silicon can also improve the anti-aging property of asphalt and slow down its aging process caused by environmental factors such as ultraviolet rays, oxygen and high temperature. By enhancing the water resistance of asphalt, nano silicon can also effectively reduce the degradation of material performance caused by water penetration during the use of asphalt, and extend the service life of waterproof membrane.

[0015] Preferably, the polymer repair material comprises:

[0016] Polyurethane-based shape memory polymer: 3-7 parts; ( 5000), polyurethane-based shape memory polymer (SMP) is a class of polymer materials with unique shape memory properties. When cracks appear in asphalt materials due to external pressure or temperature fluctuations during use, the molecular structure of polyurethane-based shape memory polymers will undergo physical changes at a specific temperature. Specifically, shape memory polymers become soft or fluid at higher temperatures (usually when the temperature exceeds its transition temperature), which enables it to fill and repair cracks. As the temperature drops, the polyurethane-based shape memory polymer will return to its original shape, completing the self-healing process;

[0017] Polyester type thermoreversible polymer: 1 to 5 parts Polyester thermoreversible polymer is a polymer material with thermoreversibility. When cracks appear in asphalt waterproofing membrane under external load or temperature change, polyester thermoreversible polymer material will undergo cross-linking reaction at high temperature to form a strong three-dimensional network structure, thereby improving the mechanical properties of the material. At the same time, when the temperature drops, the cross-linking structure will de-crosslink and recombine, releasing the repair function and filling the crack area.

[0018] Preferably, the microcapsule repair material is a polyurethane-based repair adhesive, and the polyurethane-based repair adhesive comprises the following components:

[0019] Polyurethane polymer: 10-15 parts. When cracks occur, polyurethane polymer can flow quickly and combine with the asphalt matrix in a short time due to the adaptability of its molecular structure. This adhesion enables the repair glue to adhere firmly to the crack surface and improve the repair effect of the material through the cross-linking reaction of the polyurethane polymer molecular chain;

[0020] Repair liquid containing supercritical carbon dioxide: 2 to 3 parts. Supercritical carbon dioxide, as a solvent, can change its physical properties in a supercritical state, making it have lower viscosity and stronger solubility. This property enables supercritical carbon dioxide to quickly penetrate into tiny cracks and quickly bring the repair glue into the cracks for repair. Once the microcapsules are broken, supercritical carbon dioxide is released, driving the repair liquid to quickly fill the cracks, and through its solubility, it helps the repair glue react with the asphalt matrix to form a repair layer;

[0021] Stabilizer: 1-2 parts ( 56-88, Carbomer940 or PTFE), the mechanism of action of the stabilizer is mainly to ensure the uniform distribution and stability of the repair liquid by adjusting the physical and chemical properties inside the microcapsule. The stabilizer can prevent the supercritical carbon dioxide from stratifying or chemically reacting with the repair glue components through the intermolecular force, thereby maintaining the fluidity of the liquid.

[0022] The present invention also provides a method for preparing a self-repairing modified asphalt waterproofing membrane, comprising the following steps:

[0023] S1. Material pretreatment and mixing: mixing the modified asphalt matrix with nano-reinforcement materials, shape memory polymers, thermoreversible polymer materials and microcapsule repair materials;

[0024] S2, high energy mechanical mixing process: use high energy mechanical mixing equipment for mixing to ensure that all components are evenly dispersed;

[0025] S3, Vacuum hot pressing curing: High temperature hot pressing is performed in a vacuum environment to cure the mixed material while removing bubbles and impurities;

[0026] S4. Low-temperature freeze drying: The solidified material is placed in a low-temperature environment for freeze drying to ensure that the material has self-healing properties at low temperatures.

[0027] Preferably, the material pretreatment and mixing includes:

[0028] Heat the modified asphalt matrix to 160℃-180℃. By controlling the temperature in the range of 160℃-180℃, the asphalt matrix can be prevented from excessive degradation, while improving its processing convenience and efficiency. This temperature range also helps to promote better dispersion of polymers, nano-reinforced materials, etc., and ensure the stability of the final material performance;

[0029] Adding carbon nanotubes, graphene and nano-silicon to the modified asphalt matrix, through the combination of these three nano-reinforced materials, the mechanical, thermal stability and aging resistance of asphalt can be significantly improved, which enables the modified asphalt waterproof membrane to maintain better waterproofness and crack resistance in long-term use;

[0030] Add shape memory polymer and thermoreversible polymer materials and mix them thoroughly. The combination of these two materials can ensure that the asphalt waterproofing membrane has good self-repairing ability when the temperature changes, and can automatically adjust its physical state according to the ambient temperature changes to maintain the best performance;

[0031] Add microcapsule repair materials containing supercritical carbon dioxide. When cracks occur in asphalt waterproofing membranes, the microcapsules distributed in them will rupture and release supercritical carbon dioxide repair liquid. Supercritical carbon dioxide has low viscosity and high diffusivity, and can quickly penetrate into the cracks, fill the cracks and restore the integrity of the material. Since the microcapsules only rupture when cracks occur, such a repair process can maintain long-term stability and prevent external factors (such as temperature changes, loads, etc.) from affecting the repair effect;

[0032] After mixing, continue to heat to 180℃-200℃ and stir with a mechanical stirrer. The stirring speed is set to 500rpm-1500rpm to fully dissolve and disperse the components. This temperature range can ensure that the asphalt matrix and all added reinforcement materials and repair materials can fully dissolve and blend with each other. In this temperature range, the fluidity of the asphalt matrix reaches the best, which can effectively promote the dispersion of each component. At the same time, the use of a mechanical stirrer ensures the uniform distribution of the materials during the stirring process, avoids any unevenness of the components, and ensures the quality of the final product. The stirring speed in this range can fully mix the various materials without causing excessive decomposition of the asphalt, and ensure the uniformity of the materials and efficient repair function.

[0033] Preferably, the mechanical agitator comprises:

[0034] The periodic pause technology is adopted, that is, pausing for 1-2 minutes every 10 minutes of stirring, so that the materials can be fully and evenly mixed during the stirring process. The main purpose of the periodic pause is to avoid overheating or excessive shearing of the materials due to excessive stirring. Pausing for 1-2 minutes after each 10 minutes of stirring helps to allow the materials to have a short static time in the mixer, which can reduce the impact of high shear force on the materials and avoid degradation of the modified asphalt matrix at excessively high temperatures;

[0035] Ensure that the mixing time is 15 minutes to 30 minutes to ensure that all components are evenly dispersed. A mixing time of 15 to 30 minutes helps to achieve the best dispersion effect while avoiding excessive heat and shear forces due to too long mixing, which may cause degradation of the asphalt matrix or damage to the reinforcement material.

[0036] During the mixing process, monitor the temperature and ensure that it is maintained at 160℃-180℃ to prevent the degradation of the modified asphalt matrix due to excessively high temperatures. Excessive temperatures can cause thermal degradation of polymers and other modifiers in the asphalt matrix, thereby reducing its mechanical properties and durability. According to the principles of thermodynamics, macromolecular polymers in the asphalt matrix are prone to thermal cracking at excessively high temperatures, resulting in the destruction of the molecular structure, affecting its waterproofness and adhesion. Therefore, maintaining a temperature range of 160℃-180℃ during the mixing process can not only ensure the ideal processability of the modified asphalt, but also avoid the negative impact of high temperature on the material, thereby achieving material stability and efficient mixing.

[0037] Preferably, the high energy mechanical mixing process comprises:

[0038] Use a high shear mixer for mixing, and the mixing time is 30 minutes to 60 minutes. Reinforcement materials such as carbon nanotubes and graphene are prone to agglomeration or accumulation due to their high specific surface area and strong interaction. The high shear force makes them evenly distributed in the asphalt matrix to form a stable composite structure. This range of mixing time can ensure that each material can fully contact and fuse, avoiding material stratification or aggregation;

[0039] The mixing speed is controlled between 2000rpm-4000rpm to ensure uniform dispersion of the nanomaterials. Too low a speed will lead to uneven mixing, while too high a speed will easily lead to local overheating of the material and even degradation of the asphalt matrix. Therefore, controlling the speed within the range of 2000rpm-4000rpm can ensure the best mixing effect without causing overheating or degradation.

[0040] Ultrasonic treatment technology is used, and the ultrasonic frequency is set in the range of 20kHz-40kHz to further break up and evenly disperse carbon nanotubes and graphene. Due to the high surface area and agglomeration of carbon nanotubes and graphene, they tend to form large agglomerates when not treated with ultrasound, affecting the uniformity and performance of the final product. Ultrasonic treatment can break up these agglomerates through cavitation, ensuring that the reinforcing materials can be evenly distributed in the asphalt matrix, thereby improving the performance of the final waterproof membrane, such as mechanical strength, crack resistance and thermal conductivity;

[0041] Maintaining the temperature range of 160℃-180℃ ensures the thermal fluidity of the material. In this temperature range, the viscosity of asphalt is low, and reinforcing materials such as carbon nanotubes and graphene can be more easily mixed with the asphalt matrix without thermal degradation or decomposition. Too high a temperature can easily cause the degradation of polymers in asphalt or the decomposition of other sensitive components, thus affecting the final performance of the asphalt waterproofing membrane. By maintaining the temperature at 160℃-180℃, not only can the stability of the material be ensured, but also the mixing efficiency can be optimized to ensure the best distribution of reinforcing materials and repair materials.

[0042] Preferably, the vacuum hot pressing curing comprises:

[0043] Hot pressing is performed under vacuum conditions, with the vacuum degree set between 50Pa-100Pa. Under vacuum conditions, bubbles and dissolved gases can be effectively removed, reducing the porosity inside the material, which makes the final waterproof membrane have better permeability resistance and stability. At the same time, vacuum helps to ensure uniform heating of the material during the heating process, reducing the problem of inconsistent material performance caused by uneven temperature. By performing hot pressing under this range of vacuum, it is ensured that the asphalt matrix and the reinforcing material can be evenly fused to form a composite material with a compact structure and high density;

[0044] The heating temperature is set to 180℃-220℃. The heating temperature in this range can make the asphalt matrix achieve the best fluidity. This temperature range can enhance the activity of the molecular chains in the asphalt matrix, thereby reducing its viscosity and ensuring that the material can flow quickly during the hot pressing process, fill the mold and fully cover the reinforcing materials (such as carbon nanotubes, graphene and microcapsules);

[0045] The hot pressing time is 30 minutes to 45 minutes. If the hot pressing time is too short, the material cannot be fully cured, resulting in insufficient strength and stability of the composite material. If the hot pressing time is too long, the excessively high temperature will cause degradation of the material, especially for thermosensitive materials (such as shape memory polymers and polymer repair materials). Long-term heat treatment can easily lead to performance degradation. By controlling the hot pressing time between 30 minutes and 45 minutes, it can ensure that the material is fully cured and stable, and there is no risk of overheating or excessive degradation.

[0046] During the hot pressing process, the pressing pressure is maintained at 0.5MPa-1.0MPa to ensure the uniformity and density of the asphalt material. Too low a pressure will lead to insufficient contact between the materials, resulting in voids or uneven distribution in the materials, thus affecting the overall performance; while too high a pressure will cause deformation, damage or over-compression of the materials, affecting their elasticity and repair performance. Therefore, by maintaining a pressing pressure of 0.5MPa to 1.0MPa, it is possible to ensure sufficient contact between the asphalt and the reinforcing material and the repair material, while avoiding excessive compression of the materials or structural damage.

[0047] Preferably, the low-temperature freeze-drying comprises:

[0048] The hot-pressed material is placed in a low-temperature freeze dryer with the temperature set at -20°C to -50°C. At low temperatures, the molecular activity of the asphalt material is restricted, the liquid water is frozen into ice, and because the gas pressure is low under low temperature conditions, the water or solvent in the material can be effectively evaporated. This evaporation optimizes the microstructure of the surface and interior of the material, thereby improving its flexibility and stability at low temperatures. In addition, the effect of low temperatures can also ensure that temperature-sensitive components such as microcapsule repair materials and polymer materials remain stable after curing, avoiding possible degradation or performance degradation at high temperatures;

[0049] The low-temperature freeze drying time is 8 to 12 hours. If the freeze drying time is too short, the moisture or solvent will not be completely removed, leaving moisture or unstable components, affecting the final performance and repair effect of the material. Too long a freeze drying time will cause the material to be over-dried or cause thermal stress, affecting its physical properties. By controlling the time between 8 and 12 hours, freeze drying can ensure that the internal structure of the material is effectively stabilized without affecting the flexibility and elasticity of the material.

[0050] During the freeze-drying process, the vacuum degree is maintained at 20Pa-50Pa. By maintaining a vacuum degree of 20Pa to 50Pa, the freeze-drying process can effectively remove moisture or solvents, and due to the low pressure conditions in the vacuum environment, the internal structure of the material will not be damaged, ensuring the stability of its molecular structure. Low vacuum helps to improve the density of the material, prevent the influence of bubbles or residual solvents, and thus ensure the long-term performance of the material;

[0051] Ensure that the material has good flexibility and self-repair ability at low temperatures after freeze-drying. During the freeze-drying process, the repair material maintains its self-repair function, ensuring that the asphalt material can be quickly repaired when cracks occur, thereby improving the crack resistance and long-term use performance of the waterproof membrane.

[0052] The present invention provides a self-repairing modified asphalt waterproofing membrane. It has the following beneficial effects:

[0053] 1. The present invention uses ultrasonic treatment and high-energy mechanical mixing to ensure uniform distribution of reinforcing materials such as carbon nanotubes and graphene in the asphalt matrix. This treatment method avoids the disadvantage of easy agglomeration of nanomaterials in traditional methods, improves the stability and mechanical properties of composite materials, and solves the problems of uneven dispersion and performance fluctuations in the prior art.

[0054] 2. By introducing the low-temperature freeze-drying process, the present invention greatly improves the low-temperature flexibility of the material. Freeze-drying not only effectively avoids the embrittlement of the material at low temperatures, but also retains its strong self-repairing ability, allowing the asphalt waterproofing membrane to still perform excellent waterproofing effects in cold environments, which is an advantage that traditional technologies cannot provide.

[0055] 3. The vacuum hot pressing curing process makes the material of the present invention have higher density and uniformity. This innovative process eliminates the bubble problem existing in the traditional hot pressing method, improves the water resistance and durability of the material, and solves the problems of uneven structure and poor water resistance of composite materials in conventional technologies.

[0056] 4. Through microcapsule repair technology, the present invention can quickly and efficiently repair cracks, greatly shortening the repair time. Compared with traditional repair methods, this technology allows waterproof membranes to quickly restore their functions after being damaged. This efficiency and effect cannot be achieved by existing technologies, especially in high-load use environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 The present invention is a flow chart of the preparation method. DETAILED DESCRIPTION

[0058] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0059] Please refer to the attached Figure 1 :

[0060] Example 1: Preparation of self-repairing modified asphalt waterproof membrane

[0061] Step 1: Pretreatment and heating: The modified asphalt matrix is ​​heated to 175°C to ensure that the asphalt matrix has good fluidity at this temperature. Then, carbon nanotubes (0.8 parts), graphene (0.3 parts), and nano silicon (1.5 parts) are added to the asphalt for preliminary mixing.

[0062] Step 2: Material addition and stirring: Next, add the shape memory polymer (5 parts) and the polyester type thermoreversible polymer (3 parts). Continue stirring, keep the temperature at 170°C, and use a mechanical stirrer at 1200 rpm for 15 minutes to ensure that all materials are evenly distributed.

[0063] Step 3: Adding microcapsules and further mixing: Add microcapsule repair material containing supercritical carbon dioxide (4 parts) to the above mixture and stir again. Continue to maintain the temperature at 180°C, the stirring speed at 1000 rpm, and the stirring time for 20 minutes to ensure that the microcapsules are completely dispersed.

[0064] Step 4: High-energy mixing and ultrasonic treatment: The materials were mixed for another 30 minutes using a high-shear mixer to ensure that the nanomaterials and repair materials were fully dispersed. Ultrasonic treatment was then performed with the ultrasonic frequency set at 25kHz for 10 minutes to further improve the dispersion of carbon nanotubes and graphene.

[0065] Step 5: Vacuum hot pressing curing: Place the mixed material in a vacuum hot pressing device, set the vacuum degree to 80Pa, heat to 200°C, maintain the temperature for 10 minutes, set the pressing pressure to 0.8MPa, and the hot pressing time to 30 minutes.

[0066] Step 6: Low-temperature freeze drying: Transfer the solidified material to a low-temperature freeze dryer, set the temperature to -30°C, maintain the vacuum degree at 40Pa, and freeze-dry for 10 hours to ensure that the material maintains good flexibility and self-healing ability at low temperatures.

[0067] Example 2: Preparation of fast self-repairing modified asphalt waterproof membrane

[0068] Step 1: Heating and premixing: First, heat the modified asphalt base to 165°C, then add carbon nanotubes (0.5 parts) and nano silicon (1.2 parts) for preliminary mixing. Maintain the temperature at 175°C and stir with a mechanical stirrer for 10 minutes.

[0069] Step 2: Add shape memory polymer and thermoreversible material: Then add shape memory polymer (4 parts) and thermoreversible polymer (2 parts), continue to maintain the temperature at 175°C, and stir at 1500 rpm for 10 minutes to ensure uniform distribution.

[0070] Step 3: Adding microcapsules and secondary mixing: Add microcapsule repair material containing supercritical carbon dioxide (3 parts) to the mixture, continue heating to 180°C, and stir for 15 minutes to ensure that the microcapsules are evenly distributed.

[0071] Step 4: High energy mixing and ultrasonic treatment: A high shear mixer was used with the mixing time set to 40 minutes and the stirring speed set to 2500 rpm. Ultrasonic treatment was then performed with the frequency set to 30 kHz and the treatment time set to 8 minutes to ensure further dispersion of graphene and carbon nanotubes.

[0072] Step 5: Vacuum hot pressing curing: The mixed material is placed in a vacuum hot pressing device, the vacuum degree is set to 60Pa, the hot pressing temperature is set to 190°C, the hot pressing time is set to 35 minutes, and the pressing pressure is set to 0.6MPa.

[0073] Step 6: Low-temperature freeze drying: Place the hot-pressed solidified material in a freeze dryer, set the temperature to -40°C, the vacuum degree to 30Pa, and the freeze drying time to 12 hours to ensure that the final material maintains high flexibility and self-healing ability at low temperatures.

[0074] Example 3: Preparation of modified asphalt waterproofing membrane with enhanced self-repairing function

[0075] Step 1: Heating the modified asphalt base: Heat the modified asphalt base to 175°C to ensure its fluidity. Then add carbon nanotubes (0.7 parts), graphene (0.4 parts), and nano silicon (1.8 parts) and start stirring.

[0076] Step 2: Add repair material: Add shape memory polymer (6 parts) and polyester type thermoreversible polymer material (4 parts), continue heating to 180°C, and stir at 1000 rpm for 15 minutes to ensure complete dissolution and uniform distribution.

[0077] Step 3: Add microcapsules: Add microcapsule repair material containing supercritical carbon dioxide (5 parts), continue heating to 185°C, and stir at a stirring speed of 1200 rpm for 20 minutes to ensure that the microcapsules are completely dispersed in the asphalt matrix.

[0078] Step 4: High-energy mixing and ultrasonic treatment: Use a high-shear mixer for mixing for 45 minutes at a stirring speed of 3000 rpm to ensure that all components are completely dispersed. On this basis, ultrasonic treatment is performed at a frequency of 28 kHz for 12 minutes to ensure that the nanomaterials are further dispersed and agglomeration is eliminated.

[0079] Step 5: Vacuum hot pressing curing: Place the mixed material in a vacuum hot pressing device, set the vacuum degree to 50Pa, the hot pressing temperature to 210°C, the hot pressing time to 40 minutes, and the pressing pressure to 0.7MPa.

[0080] Step 6: Low-temperature freeze drying: The hot-pressed material is placed in a low-temperature freeze dryer, the temperature is set to -30°C, the vacuum degree is maintained at 20Pa, and the freeze drying time is 10 hours to ensure that the final product has good self-healing ability and flexibility under low temperature conditions.

[0081] Example 4: Rapid preparation of highly efficient self-repairing asphalt waterproofing membrane

[0082] Step 1: Heating and mixing modified asphalt: The modified asphalt base was heated to 170°C, and then carbon nanotubes (0.4 parts) and graphene (0.2 parts) were added and mixed. The heating temperature was maintained at 175°C and the stirring time was 12 minutes.

[0083] Step 2: Add polymer and repair material: Add shape memory polymer (3 parts) and thermoreversible polymer material (2 parts), continue heating to 180°C, and stir at 1200 rpm for 20 minutes to ensure that the materials are evenly dispersed.

[0084] Step 3: Adding and stirring microcapsules: Add microcapsule repair material containing supercritical carbon dioxide (2 parts), continue heating to 185°C, and stir for 20 minutes to fully disperse the microcapsules in the matrix.

[0085] Step 4: High energy mixing and ultrasonic treatment: Use a high shear mixer to mix at 3000 rpm for 35 minutes, followed by ultrasonic treatment with a frequency of 35 kHz for 10 minutes.

[0086] Step 5: Vacuum hot pressing curing: Place the mixed material in a vacuum hot pressing machine, set the vacuum degree to 60Pa, the hot pressing temperature to 200°C, the pressing pressure to 0.6MPa, and the hot pressing time to 30 minutes.

[0087] Step 6: Low-temperature freeze drying: Place the solidified material in a low-temperature freeze dryer, set the temperature to -25°C, the vacuum degree to 30Pa, and the freeze drying time to 8 hours to ensure that the material maintains good flexibility and self-healing ability at low temperatures.

[0088] Comparative Example 1: Preparation without using ultrasonic treatment technology

[0089] Material pretreatment and heating: The modified asphalt matrix was heated to 165°C, and carbon nanotubes (0.5 parts), graphene (0.4 parts), and nano-silicon (1.6 parts) were added for preliminary mixing.

[0090] Adding and mixing repair materials:

[0091] Shape memory polymer (4 parts) and thermoreversible polymer material (2.5 parts) were added, and the mixture was stirred for 20 minutes while maintaining the temperature at 180°C.

[0092] Addition and mixing of microcapsules: Add microcapsule repair material (4 parts) containing supercritical carbon dioxide to the mixture and continue stirring for 20 minutes to ensure that the microcapsules are evenly dispersed.

[0093] High shear mixing: Use a high shear mixer to stir for 30 minutes with the stirring speed set at 2000 rpm.

[0094] Vacuum hot pressing curing: put the mixed material into vacuum hot pressing equipment, set the vacuum degree to 70Pa, the heating temperature to 200℃, the pressing pressure to 0.7MPa, and the hot pressing time to 35 minutes.

[0095] Low-temperature freeze drying: Finally, the solidified material was transferred to a freeze dryer, the temperature was set to -30 °C, the vacuum degree was set to 30 Pa, and the freeze drying time was 10 hours.

[0096] Comparative Example 2: Lack of low temperature freeze drying step

[0097] Material pretreatment and heating: Heat the modified asphalt matrix to 175°C, add carbon nanotubes (0.6 parts), graphene (0.3 parts), and nano silicon (1.2 parts), and start mixing.

[0098] Addition and stirring of repair materials: Add shape memory polymer (5 parts) and thermoreversible polymer material (3 parts), continue heating to 180°C, and stir for 20 minutes.

[0099] Addition of microcapsules and stirring: Add microcapsule repair material containing supercritical carbon dioxide (3 parts) and stir for 10 minutes.

[0100] High shear mixing and ultrasonic treatment: A high shear mixer was used for mixing for 30 minutes, with the stirring speed set at 2500 rpm. Ultrasonic treatment was then performed with the frequency set at 28 kHz for 10 minutes to ensure uniform dispersion of carbon nanotubes and graphene.

[0101] Vacuum hot pressing curing: put the mixture into a vacuum hot pressing device, set the vacuum degree to 80Pa, the heating temperature to 200°C, the pressing pressure to 0.8MPa, and the hot pressing time to 40 minutes.

[0102] Missing freeze-drying step: No low-temperature freeze-drying process is performed.

[0103] Comparative Example 3: High Shear Mixing without Vacuum Environment

[0104] Material pretreatment and heating: Heat the modified asphalt matrix to 160°C, add carbon nanotubes (0.4 parts), graphene (0.5 parts), and nano silicon (1.4 parts), and start stirring.

[0105] Addition and stirring of repair materials: Add shape memory polymer (3 parts) and thermoreversible polymer material (2.5 parts), continue heating to 175° C., and stir for 15 minutes.

[0106] Microcapsule addition and mixing: Add microcapsule repair material containing supercritical carbon dioxide (4 parts) and stir for 15 minutes to ensure it is evenly distributed.

[0107] High shear mixing: stirring for 30 minutes in a conventional stirring device with a stirring speed set at 2000 rpm, but without a vacuum environment.

[0108] Vacuum hot pressing curing: Place the mixture in a hot pressing device, set the vacuum degree to 100 Pa, the heating temperature to 190°C, the pressing pressure to 0.6 MPa, and the hot pressing time to 30 minutes.

[0109] Low-temperature freeze drying: The hot-pressed material was transferred to a low-temperature freeze dryer, the temperature was set to -40°C, the vacuum degree was 25Pa, and the freeze drying time was 8 hours.

[0110] Comparative Example 4: Too high temperature affects the polymer repair effect

[0111] Material pretreatment and heating: Heat the modified asphalt matrix to 185°C, add carbon nanotubes (0.7 parts), graphene (0.4 parts), and nano silicon (1.7 parts), and stir for 15 minutes.

[0112] Repair material addition and stirring: Add shape memory polymer (6 parts) and thermoreversible polymer material (3 parts), increase the temperature to 200°C, and continue stirring for 15 minutes.

[0113] Microcapsule addition and mixing: Add microcapsule repair material containing supercritical carbon dioxide (5 parts) and continue stirring for 15 minutes.

[0114] High shear mixing: Use a high shear mixer to mix for 30 minutes with the stirring speed set at 3000 rpm to ensure that the materials are fully dispersed.

[0115] Hot pressing curing: put the mixture into a hot press, set the temperature to 210°C, the pressing pressure to 0.7 MPa, and the hot pressing time to 45 minutes.

[0116] Low-temperature freeze drying: Finally, the material was placed in a low-temperature freeze dryer, the temperature was set to -30°C, the vacuum degree was 20Pa, and the freeze drying time was 10 hours.

[0117] Test experiment: The experimental steps are:

[0118] Sample preparation: According to different experimental designs, 4 groups of example samples and 4 groups of comparative samples were prepared. The materials and proportions of each group of example samples and comparative samples were configured according to the following requirements:

[0119] Example 1 (using ultrasonic treatment technology and high shear mixing): using carbon nanotubes (0.8 parts), graphene (0.3 parts), nano silicon (1.5 parts), shape memory polymer (5 parts), thermoreversible polymer material (3 parts), and microcapsule repair material (4 parts).

[0120] Example 2 (no ultrasonic treatment, only high shear mixing): Same as above, but without ultrasonic treatment.

[0121] Example 3 (addition of low-temperature freeze-drying): Same as Example 1, but with the addition of a low-temperature freeze-drying step.

[0122] Example 4 (using vacuum hot pressing curing): Same as Example 1, but using vacuum hot pressing curing technology.

[0123] Comparative group:

[0124] Comparative Example 1: No ultrasonic treatment was used and no freeze drying was performed.

[0125] Comparative Example 2: Conventional high shear mixing was used, but no vacuum hot press curing was performed.

[0126] Comparative Example 3: No microcapsule repair material was used.

[0127] Comparative Example 4: No shape memory polymer or thermoreversible polymer material was used.

[0128] Mixing and processing:

[0129] The materials of the above groups were heated to 180°C and stirred in proportion. The Example group used high shear mixing and ultrasonic treatment to ensure that the nanomaterials were fully dispersed. The Control group only used conventional mixing without ultrasonic treatment.

[0130] Then some samples were placed in a low-temperature freeze dryer for low-temperature drying to ensure that the samples maintained flexibility and low-temperature self-healing ability.

[0131] For Example 4, all mixed materials were hot-pressed under a vacuum environment to ensure the uniformity and density of the materials.

[0132] test:

[0133] Mechanical properties test: tensile strength and compressive strength tests are carried out, using electronic tensile testing machines and pressure testing machines to record the mechanical properties of different samples.

[0134] Low temperature performance test: Use a low temperature impact tester to test the flexibility and crack resistance of the sample at -40°C. Then conduct a low temperature self-repair test to simulate the crack repair process and record the repair efficiency and repair time.

[0135] Durability test: An accelerated aging test was conducted, where the samples were exposed to an aging chamber at 60°C for 72 hours to test their anti-aging properties.

[0136] Data recording and analysis:

[0137] The mechanical properties, low temperature performance, repair efficiency and durability of different samples were recorded.

[0138] The experimental data were converted into a table to show the differences between the embodiment and the comparison group.

[0139] Comparative data of performance of each group of self-repairing modified asphalt waterproof membrane

[0140]

[0141] The experimental results show that:

[0142] In terms of material uniformity and nanomaterial dispersion, the comparison between Example 1 (using ultrasonic treatment technology) and Comparative Example 1 (not using ultrasonic treatment) shows that the dispersion of carbon nanotubes and graphene is significantly improved after ultrasonic treatment. The material of Example 1 shows a more uniform distribution of reinforcement materials, while the sample of Comparative Example 1 shows agglomeration of reinforcement materials. This shows that ultrasonic treatment effectively avoids the aggregation of carbon nanotubes and graphene, ensures the uniformity of the material, and helps to improve the mechanical properties of the final composite material.

[0143] For low temperature performance and flexibility, the comparison between Example 2 (using low temperature freeze drying) and Comparative Example 2 (without freeze drying) shows the important role of low temperature freeze drying process on material flexibility and low temperature self-healing ability. The deformation and low temperature self-healing effect of Example 2 in low temperature impact test are better than those of Comparative Example 2. Comparative Example 2 without freeze drying loses flexibility significantly at low temperature, and the repair process is slow, which proves that low temperature freeze drying is essential to maintain the good performance of the material in a low temperature environment.

[0144] In terms of tensile strength and compressive strength, the comparison between Example 3 (using vacuum hot pressing curing technology) and Comparative Example 3 (not using vacuum environment for high shear mixing) shows that vacuum hot pressing curing greatly improves the density and strength of the material. Example 3 showed higher results in both tensile strength and compressive strength tests, while Comparative Example 3 did not use a vacuum environment, resulting in the failure to effectively remove bubbles in the material, reducing the overall mechanical properties. This shows that vacuum hot pressing curing technology effectively improves the stability and mechanical strength of the composite material.

[0145] In terms of self-repair efficiency and repair time, the comparison between Example 4 (using supercritical carbon dioxide microcapsule repair technology) and Comparative Example 4 (not using microcapsule repair material) shows that Example 4 is significantly better than Comparative Example 4 in terms of crack repair time and repair effect. The microcapsule repair technology in Example 4 can quickly release the repair liquid and fill the cracks, significantly improving the self-repair efficiency, while Comparative Example 4 has a long repair time and unsatisfactory repair effect due to the lack of microcapsule materials.

[0146] Through various experiments, not only the superiority of the technical solution of the present invention in practical applications is verified, but also the important role of ultrasonic treatment, low-temperature freeze-drying, vacuum hot pressing curing and microcapsule repair materials in improving material performance is highlighted, providing a more reliable and durable self-healing modified asphalt waterproof membrane.

[0147] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A self-repairing modified asphalt waterproofing membrane, characterized in that: The waterproof coiled material comprises the following components in parts by weight: Asphalt matrix: 60-70 parts; Nano-enhanced material: 0.2-2.5 parts; Polymer repair materials: 4 to 12 parts; Microcapsule repair material: 2 to 5 portions.

2. The self-repairing modified asphalt waterproofing membrane according to claim 1, characterized in that: The nano-enhanced material comprises: Carbon nanotubes: 0.2-1.5 parts; Graphene: 0.1-0.5 parts; Nano silicon: 0.5 to 2 parts.

3. The self-repairing modified asphalt waterproofing membrane according to claim 1, characterized in that: The polymer repair material comprises: Polyurethane-based shape memory polymer: 3-7 parts; Polyester type thermoreversible polymer: 1 to 5 parts.

4. The self-repairing modified asphalt waterproofing membrane according to claim 1, characterized in that: The microcapsule repair material is a polyurethane-based repair adhesive, and the polyurethane-based repair adhesive comprises the following components: Polyurethane polymer: 10-15 parts; Repair liquid containing supercritical carbon dioxide: 2-3 parts; Stabilizer: 1 to 2 parts.

5. A method for preparing a self-repairing modified asphalt waterproofing membrane, characterized in that: Using the self-repairing modified asphalt waterproofing membrane according to any one of claims 1 to 4 comprises the following steps: S1. Material pretreatment and mixing: mixing the modified asphalt matrix with nano-reinforcement materials, shape memory polymers, thermoreversible polymer materials and microcapsule repair materials; S2, high energy mechanical mixing process: use high energy mechanical mixing equipment for mixing to ensure that all components are evenly dispersed; S3, Vacuum hot pressing curing: High temperature hot pressing is performed in a vacuum environment to cure the mixed material while removing bubbles and impurities; S4. Low-temperature freeze drying: The solidified material is placed in a low-temperature environment for freeze drying to ensure that the material has self-healing properties at low temperatures.

6. The method for preparing a self-repairing modified asphalt waterproofing membrane according to claim 5, characterized in that: The material pretreatment and mixing include: Heat the modified asphalt matrix to 160°C-180°C; adding carbon nanotubes, graphene and nanosilicon to a modified asphalt matrix; Adding shape memory polymer and thermoreversible polymer material and mixing them thoroughly; Adding microcapsule repair materials containing supercritical carbon dioxide; After mixing, continue to heat to 180°C-200°C and stir with a mechanical stirrer at a stirring speed of 500rpm-1500rpm to fully dissolve and disperse the components.

7. The method for preparing a self-repairing modified asphalt waterproofing membrane according to claim 6, characterized in that: The mechanical agitator comprises: Use regular pause technology, that is, pause for 1-2 minutes every 10 minutes of stirring, so that the materials can be fully and evenly mixed during the stirring process; Ensure that the stirring time is 15 minutes to 30 minutes to ensure that all components are evenly dispersed; During the mixing process, monitor the temperature and ensure that it is maintained at 160°C-180°C to prevent excessive temperature from causing degradation of the modified asphalt matrix.

8. The method for preparing a self-repairing modified asphalt waterproofing membrane according to claim 5, characterized in that: The high energy mechanical mixing process comprises: Use a high shear mixer to mix for 30 to 60 minutes; Control the mixing speed between 2000rpm-4000rpm to ensure uniform dispersion of nanomaterials; Ultrasonic treatment technology is used, and the ultrasonic frequency is set in the range of 20kHz-40kHz to further break up and evenly disperse the carbon nanotubes and graphene; Maintain the temperature range between 160℃-180℃ to ensure the thermal fluidity of the material.

9. The method for preparing a self-repairing modified asphalt waterproofing membrane according to claim 5, characterized in that: The vacuum hot pressing curing comprises: Hot pressing is performed in a vacuum environment, with the vacuum degree set between 50Pa-100Pa; The heating temperature is set to 180℃-220℃; The hot pressing time is 30 minutes to 45 minutes; During the hot pressing process, the pressing pressure is maintained at 0.5MPa-1.0MPa to ensure the uniformity and density of the asphalt material.

10. The method for preparing a self-repairing modified asphalt waterproofing membrane according to claim 5, characterized in that: The low-temperature freeze-drying comprises: The hot-pressed material is placed in a low-temperature freeze dryer, and the temperature is set at -20°C to -50°C; Low temperature freeze drying time is 8 hours to 12 hours; During the freeze-drying process, the vacuum degree is maintained at 20Pa-50Pa; Ensure that the material has good flexibility and self-healing ability at low temperatures after freeze-drying.

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